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1 | Kernel Parameters | |
2 | ~~~~~~~~~~~~~~~~~ | |
3 | ||
4 | The following is a consolidated list of the kernel parameters as implemented | |
5 | (mostly) by the __setup() macro and sorted into English Dictionary order | |
6 | (defined as ignoring all punctuation and sorting digits before letters in a | |
7 | case insensitive manner), and with descriptions where known. | |
8 | ||
9 | Module parameters for loadable modules are specified only as the | |
10 | parameter name with optional '=' and value as appropriate, such as: | |
11 | ||
12 | modprobe usbcore blinkenlights=1 | |
13 | ||
14 | Module parameters for modules that are built into the kernel image | |
15 | are specified on the kernel command line with the module name plus | |
16 | '.' plus parameter name, with '=' and value if appropriate, such as: | |
17 | ||
18 | usbcore.blinkenlights=1 | |
19 | ||
20 | Hyphens (dashes) and underscores are equivalent in parameter names, so | |
21 | log_buf_len=1M print-fatal-signals=1 | |
22 | can also be entered as | |
23 | log-buf-len=1M print_fatal_signals=1 | |
24 | ||
25 | ||
26 | This document may not be entirely up to date and comprehensive. The command | |
27 | "modinfo -p ${modulename}" shows a current list of all parameters of a loadable | |
28 | module. Loadable modules, after being loaded into the running kernel, also | |
29 | reveal their parameters in /sys/module/${modulename}/parameters/. Some of these | |
30 | parameters may be changed at runtime by the command | |
31 | "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}". | |
32 | ||
33 | The parameters listed below are only valid if certain kernel build options were | |
34 | enabled and if respective hardware is present. The text in square brackets at | |
35 | the beginning of each description states the restrictions within which a | |
36 | parameter is applicable: | |
37 | ||
38 | ACPI ACPI support is enabled. | |
39 | AGP AGP (Accelerated Graphics Port) is enabled. | |
40 | ALSA ALSA sound support is enabled. | |
41 | APIC APIC support is enabled. | |
42 | APM Advanced Power Management support is enabled. | |
43 | ARM ARM architecture is enabled. | |
44 | AVR32 AVR32 architecture is enabled. | |
45 | AX25 Appropriate AX.25 support is enabled. | |
46 | BLACKFIN Blackfin architecture is enabled. | |
47 | DRM Direct Rendering Management support is enabled. | |
48 | DYNAMIC_DEBUG Build in debug messages and enable them at runtime | |
49 | EDD BIOS Enhanced Disk Drive Services (EDD) is enabled | |
50 | EFI EFI Partitioning (GPT) is enabled | |
51 | EIDE EIDE/ATAPI support is enabled. | |
52 | EVM Extended Verification Module | |
53 | FB The frame buffer device is enabled. | |
54 | FTRACE Function tracing enabled. | |
55 | GCOV GCOV profiling is enabled. | |
56 | HW Appropriate hardware is enabled. | |
57 | IA-64 IA-64 architecture is enabled. | |
58 | IMA Integrity measurement architecture is enabled. | |
59 | IOSCHED More than one I/O scheduler is enabled. | |
60 | IP_PNP IP DHCP, BOOTP, or RARP is enabled. | |
61 | IPV6 IPv6 support is enabled. | |
62 | ISAPNP ISA PnP code is enabled. | |
63 | ISDN Appropriate ISDN support is enabled. | |
64 | JOY Appropriate joystick support is enabled. | |
65 | KGDB Kernel debugger support is enabled. | |
66 | KVM Kernel Virtual Machine support is enabled. | |
67 | LIBATA Libata driver is enabled | |
68 | LP Printer support is enabled. | |
69 | LOOP Loopback device support is enabled. | |
70 | M68k M68k architecture is enabled. | |
71 | These options have more detailed description inside of | |
72 | Documentation/m68k/kernel-options.txt. | |
73 | MCA MCA bus support is enabled. | |
74 | MDA MDA console support is enabled. | |
75 | MIPS MIPS architecture is enabled. | |
76 | MOUSE Appropriate mouse support is enabled. | |
77 | MSI Message Signaled Interrupts (PCI). | |
78 | MTD MTD (Memory Technology Device) support is enabled. | |
79 | NET Appropriate network support is enabled. | |
80 | NUMA NUMA support is enabled. | |
81 | NFS Appropriate NFS support is enabled. | |
82 | OSS OSS sound support is enabled. | |
83 | PV_OPS A paravirtualized kernel is enabled. | |
84 | PARIDE The ParIDE (parallel port IDE) subsystem is enabled. | |
85 | PARISC The PA-RISC architecture is enabled. | |
86 | PCI PCI bus support is enabled. | |
87 | PCIE PCI Express support is enabled. | |
88 | PCMCIA The PCMCIA subsystem is enabled. | |
89 | PNP Plug & Play support is enabled. | |
90 | PPC PowerPC architecture is enabled. | |
91 | PPT Parallel port support is enabled. | |
92 | PS2 Appropriate PS/2 support is enabled. | |
93 | RAM RAM disk support is enabled. | |
94 | S390 S390 architecture is enabled. | |
95 | SCSI Appropriate SCSI support is enabled. | |
96 | A lot of drivers have their options described inside | |
97 | the Documentation/scsi/ sub-directory. | |
98 | SECURITY Different security models are enabled. | |
99 | SELINUX SELinux support is enabled. | |
100 | APPARMOR AppArmor support is enabled. | |
101 | SERIAL Serial support is enabled. | |
102 | SH SuperH architecture is enabled. | |
103 | SMP The kernel is an SMP kernel. | |
104 | SPARC Sparc architecture is enabled. | |
105 | SWSUSP Software suspend (hibernation) is enabled. | |
106 | SUSPEND System suspend states are enabled. | |
107 | TPM TPM drivers are enabled. | |
108 | TS Appropriate touchscreen support is enabled. | |
109 | UMS USB Mass Storage support is enabled. | |
110 | USB USB support is enabled. | |
111 | USBHID USB Human Interface Device support is enabled. | |
112 | V4L Video For Linux support is enabled. | |
113 | VGA The VGA console has been enabled. | |
114 | VT Virtual terminal support is enabled. | |
115 | WDT Watchdog support is enabled. | |
116 | XT IBM PC/XT MFM hard disk support is enabled. | |
117 | X86-32 X86-32, aka i386 architecture is enabled. | |
118 | X86-64 X86-64 architecture is enabled. | |
119 | More X86-64 boot options can be found in | |
120 | Documentation/x86/x86_64/boot-options.txt . | |
121 | X86 Either 32-bit or 64-bit x86 (same as X86-32+X86-64) | |
122 | XEN Xen support is enabled | |
123 | ||
124 | In addition, the following text indicates that the option: | |
125 | ||
126 | BUGS= Relates to possible processor bugs on the said processor. | |
127 | KNL Is a kernel start-up parameter. | |
128 | BOOT Is a boot loader parameter. | |
129 | ||
130 | Parameters denoted with BOOT are actually interpreted by the boot | |
131 | loader, and have no meaning to the kernel directly. | |
132 | Do not modify the syntax of boot loader parameters without extreme | |
133 | need or coordination with <Documentation/x86/boot.txt>. | |
134 | ||
135 | There are also arch-specific kernel-parameters not documented here. | |
136 | See for example <Documentation/x86/x86_64/boot-options.txt>. | |
137 | ||
138 | Note that ALL kernel parameters listed below are CASE SENSITIVE, and that | |
139 | a trailing = on the name of any parameter states that that parameter will | |
140 | be entered as an environment variable, whereas its absence indicates that | |
141 | it will appear as a kernel argument readable via /proc/cmdline by programs | |
142 | running once the system is up. | |
143 | ||
144 | The number of kernel parameters is not limited, but the length of the | |
145 | complete command line (parameters including spaces etc.) is limited to | |
146 | a fixed number of characters. This limit depends on the architecture | |
147 | and is between 256 and 4096 characters. It is defined in the file | |
148 | ./include/asm/setup.h as COMMAND_LINE_SIZE. | |
149 | ||
150 | Finally, the [KMG] suffix is commonly described after a number of kernel | |
151 | parameter values. These 'K', 'M', and 'G' letters represent the _binary_ | |
152 | multipliers 'Kilo', 'Mega', and 'Giga', equalling 2^10, 2^20, and 2^30 | |
153 | bytes respectively. Such letter suffixes can also be entirely omitted. | |
154 | ||
155 | ||
156 | acpi= [HW,ACPI,X86] | |
157 | Advanced Configuration and Power Interface | |
158 | Format: { force | off | strict | noirq | rsdt } | |
159 | force -- enable ACPI if default was off | |
160 | off -- disable ACPI if default was on | |
161 | noirq -- do not use ACPI for IRQ routing | |
162 | strict -- Be less tolerant of platforms that are not | |
163 | strictly ACPI specification compliant. | |
164 | rsdt -- prefer RSDT over (default) XSDT | |
165 | copy_dsdt -- copy DSDT to memory | |
166 | ||
167 | See also Documentation/power/runtime_pm.txt, pci=noacpi | |
168 | ||
169 | acpi_rsdp= [ACPI,EFI,KEXEC] | |
170 | Pass the RSDP address to the kernel, mostly used | |
171 | on machines running EFI runtime service to boot the | |
172 | second kernel for kdump. | |
173 | ||
174 | acpi_apic_instance= [ACPI, IOAPIC] | |
175 | Format: <int> | |
176 | 2: use 2nd APIC table, if available | |
177 | 1,0: use 1st APIC table | |
178 | default: 0 | |
179 | ||
180 | acpi_backlight= [HW,ACPI] | |
181 | acpi_backlight=vendor | |
182 | acpi_backlight=video | |
183 | If set to vendor, prefer vendor specific driver | |
184 | (e.g. thinkpad_acpi, sony_acpi, etc.) instead | |
185 | of the ACPI video.ko driver. | |
186 | ||
187 | acpi.debug_layer= [HW,ACPI,ACPI_DEBUG] | |
188 | acpi.debug_level= [HW,ACPI,ACPI_DEBUG] | |
189 | Format: <int> | |
190 | CONFIG_ACPI_DEBUG must be enabled to produce any ACPI | |
191 | debug output. Bits in debug_layer correspond to a | |
192 | _COMPONENT in an ACPI source file, e.g., | |
193 | #define _COMPONENT ACPI_PCI_COMPONENT | |
194 | Bits in debug_level correspond to a level in | |
195 | ACPI_DEBUG_PRINT statements, e.g., | |
196 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, ... | |
197 | The debug_level mask defaults to "info". See | |
198 | Documentation/acpi/debug.txt for more information about | |
199 | debug layers and levels. | |
200 | ||
201 | Enable processor driver info messages: | |
202 | acpi.debug_layer=0x20000000 | |
203 | Enable PCI/PCI interrupt routing info messages: | |
204 | acpi.debug_layer=0x400000 | |
205 | Enable AML "Debug" output, i.e., stores to the Debug | |
206 | object while interpreting AML: | |
207 | acpi.debug_layer=0xffffffff acpi.debug_level=0x2 | |
208 | Enable all messages related to ACPI hardware: | |
209 | acpi.debug_layer=0x2 acpi.debug_level=0xffffffff | |
210 | ||
211 | Some values produce so much output that the system is | |
212 | unusable. The "log_buf_len" parameter may be useful | |
213 | if you need to capture more output. | |
214 | ||
215 | acpi_irq_balance [HW,ACPI] | |
216 | ACPI will balance active IRQs | |
217 | default in APIC mode | |
218 | ||
219 | acpi_irq_nobalance [HW,ACPI] | |
220 | ACPI will not move active IRQs (default) | |
221 | default in PIC mode | |
222 | ||
223 | acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA | |
224 | Format: <irq>,<irq>... | |
225 | ||
226 | acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for | |
227 | use by PCI | |
228 | Format: <irq>,<irq>... | |
229 | ||
230 | acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT | |
231 | ||
232 | acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS | |
233 | Format: To spoof as Windows 98: ="Microsoft Windows" | |
234 | ||
235 | acpi_osi= [HW,ACPI] Modify list of supported OS interface strings | |
236 | acpi_osi="string1" # add string1 -- only one string | |
237 | acpi_osi="!string2" # remove built-in string2 | |
238 | acpi_osi= # disable all strings | |
239 | ||
240 | acpi_pm_good [X86] | |
241 | Override the pmtimer bug detection: force the kernel | |
242 | to assume that this machine's pmtimer latches its value | |
243 | and always returns good values. | |
244 | ||
245 | acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode | |
246 | Format: { level | edge | high | low } | |
247 | ||
248 | acpi_serialize [HW,ACPI] force serialization of AML methods | |
249 | ||
250 | acpi_skip_timer_override [HW,ACPI] | |
251 | Recognize and ignore IRQ0/pin2 Interrupt Override. | |
252 | For broken nForce2 BIOS resulting in XT-PIC timer. | |
253 | ||
254 | acpi_sleep= [HW,ACPI] Sleep options | |
255 | Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, | |
256 | old_ordering, nonvs, sci_force_enable } | |
257 | See Documentation/power/video.txt for information on | |
258 | s3_bios and s3_mode. | |
259 | s3_beep is for debugging; it makes the PC's speaker beep | |
260 | as soon as the kernel's real-mode entry point is called. | |
261 | s4_nohwsig prevents ACPI hardware signature from being | |
262 | used during resume from hibernation. | |
263 | old_ordering causes the ACPI 1.0 ordering of the _PTS | |
264 | control method, with respect to putting devices into | |
265 | low power states, to be enforced (the ACPI 2.0 ordering | |
266 | of _PTS is used by default). | |
267 | nonvs prevents the kernel from saving/restoring the | |
268 | ACPI NVS memory during suspend/hibernation and resume. | |
269 | sci_force_enable causes the kernel to set SCI_EN directly | |
270 | on resume from S1/S3 (which is against the ACPI spec, | |
271 | but some broken systems don't work without it). | |
272 | ||
273 | acpi_use_timer_override [HW,ACPI] | |
274 | Use timer override. For some broken Nvidia NF5 boards | |
275 | that require a timer override, but don't have HPET | |
276 | ||
277 | acpi_enforce_resources= [ACPI] | |
278 | { strict | lax | no } | |
279 | Check for resource conflicts between native drivers | |
280 | and ACPI OperationRegions (SystemIO and SystemMemory | |
281 | only). IO ports and memory declared in ACPI might be | |
282 | used by the ACPI subsystem in arbitrary AML code and | |
283 | can interfere with legacy drivers. | |
284 | strict (default): access to resources claimed by ACPI | |
285 | is denied; legacy drivers trying to access reserved | |
286 | resources will fail to bind to device using them. | |
287 | lax: access to resources claimed by ACPI is allowed; | |
288 | legacy drivers trying to access reserved resources | |
289 | will bind successfully but a warning message is logged. | |
290 | no: ACPI OperationRegions are not marked as reserved, | |
291 | no further checks are performed. | |
292 | ||
293 | add_efi_memmap [EFI; X86] Include EFI memory map in | |
294 | kernel's map of available physical RAM. | |
295 | ||
296 | agp= [AGP] | |
297 | { off | try_unsupported } | |
298 | off: disable AGP support | |
299 | try_unsupported: try to drive unsupported chipsets | |
300 | (may crash computer or cause data corruption) | |
301 | ||
302 | ALSA [HW,ALSA] | |
303 | See Documentation/sound/alsa/alsa-parameters.txt | |
304 | ||
305 | alignment= [KNL,ARM] | |
306 | Allow the default userspace alignment fault handler | |
307 | behaviour to be specified. Bit 0 enables warnings, | |
308 | bit 1 enables fixups, and bit 2 sends a segfault. | |
309 | ||
310 | align_va_addr= [X86-64] | |
311 | Align virtual addresses by clearing slice [14:12] when | |
312 | allocating a VMA at process creation time. This option | |
313 | gives you up to 3% performance improvement on AMD F15h | |
314 | machines (where it is enabled by default) for a | |
315 | CPU-intensive style benchmark, and it can vary highly in | |
316 | a microbenchmark depending on workload and compiler. | |
317 | ||
318 | 1: only for 32-bit processes | |
319 | 2: only for 64-bit processes | |
320 | on: enable for both 32- and 64-bit processes | |
321 | off: disable for both 32- and 64-bit processes | |
322 | ||
323 | amd_iommu= [HW,X86-84] | |
324 | Pass parameters to the AMD IOMMU driver in the system. | |
325 | Possible values are: | |
326 | fullflush - enable flushing of IO/TLB entries when | |
327 | they are unmapped. Otherwise they are | |
328 | flushed before they will be reused, which | |
329 | is a lot of faster | |
330 | off - do not initialize any AMD IOMMU found in | |
331 | the system | |
332 | ||
333 | amijoy.map= [HW,JOY] Amiga joystick support | |
334 | Map of devices attached to JOY0DAT and JOY1DAT | |
335 | Format: <a>,<b> | |
336 | See also Documentation/input/joystick.txt | |
337 | ||
338 | analog.map= [HW,JOY] Analog joystick and gamepad support | |
339 | Specifies type or capabilities of an analog joystick | |
340 | connected to one of 16 gameports | |
341 | Format: <type1>,<type2>,..<type16> | |
342 | ||
343 | apc= [HW,SPARC] | |
344 | Power management functions (SPARCstation-4/5 + deriv.) | |
345 | Format: noidle | |
346 | Disable APC CPU standby support. SPARCstation-Fox does | |
347 | not play well with APC CPU idle - disable it if you have | |
348 | APC and your system crashes randomly. | |
349 | ||
350 | apic= [APIC,X86-32] Advanced Programmable Interrupt Controller | |
351 | Change the output verbosity whilst booting | |
352 | Format: { quiet (default) | verbose | debug } | |
353 | Change the amount of debugging information output | |
354 | when initialising the APIC and IO-APIC components. | |
355 | ||
356 | autoconf= [IPV6] | |
357 | See Documentation/networking/ipv6.txt. | |
358 | ||
359 | show_lapic= [APIC,X86] Advanced Programmable Interrupt Controller | |
360 | Limit apic dumping. The parameter defines the maximal | |
361 | number of local apics being dumped. Also it is possible | |
362 | to set it to "all" by meaning -- no limit here. | |
363 | Format: { 1 (default) | 2 | ... | all }. | |
364 | The parameter valid if only apic=debug or | |
365 | apic=verbose is specified. | |
366 | Example: apic=debug show_lapic=all | |
367 | ||
368 | apm= [APM] Advanced Power Management | |
369 | See header of arch/x86/kernel/apm_32.c. | |
370 | ||
371 | arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards | |
372 | Format: <io>,<irq>,<nodeID> | |
373 | ||
374 | ataflop= [HW,M68k] | |
375 | ||
376 | atarimouse= [HW,MOUSE] Atari Mouse | |
377 | ||
378 | atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess, | |
379 | EzKey and similar keyboards | |
380 | ||
381 | atkbd.reset= [HW] Reset keyboard during initialization | |
382 | ||
383 | atkbd.set= [HW] Select keyboard code set | |
384 | Format: <int> (2 = AT (default), 3 = PS/2) | |
385 | ||
386 | atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar | |
387 | keyboards | |
388 | ||
389 | atkbd.softraw= [HW] Choose between synthetic and real raw mode | |
390 | Format: <bool> (0 = real, 1 = synthetic (default)) | |
391 | ||
392 | atkbd.softrepeat= [HW] | |
393 | Use software keyboard repeat | |
394 | ||
395 | autotest [IA-64] | |
396 | ||
397 | baycom_epp= [HW,AX25] | |
398 | Format: <io>,<mode> | |
399 | ||
400 | baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem | |
401 | Format: <io>,<mode> | |
402 | See header of drivers/net/hamradio/baycom_par.c. | |
403 | ||
404 | baycom_ser_fdx= [HW,AX25] | |
405 | BayCom Serial Port AX.25 Modem (Full Duplex Mode) | |
406 | Format: <io>,<irq>,<mode>[,<baud>] | |
407 | See header of drivers/net/hamradio/baycom_ser_fdx.c. | |
408 | ||
409 | baycom_ser_hdx= [HW,AX25] | |
410 | BayCom Serial Port AX.25 Modem (Half Duplex Mode) | |
411 | Format: <io>,<irq>,<mode> | |
412 | See header of drivers/net/hamradio/baycom_ser_hdx.c. | |
413 | ||
414 | boot_delay= Milliseconds to delay each printk during boot. | |
415 | Values larger than 10 seconds (10000) are changed to | |
416 | no delay (0). | |
417 | Format: integer | |
418 | ||
419 | bootmem_debug [KNL] Enable bootmem allocator debug messages. | |
420 | ||
421 | bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) | |
422 | bttv.radio= Most important insmod options are available as | |
423 | kernel args too. | |
424 | bttv.pll= See Documentation/video4linux/bttv/Insmod-options | |
425 | bttv.tuner= | |
426 | ||
427 | bulk_remove=off [PPC] This parameter disables the use of the pSeries | |
428 | firmware feature for flushing multiple hpte entries | |
429 | at a time. | |
430 | ||
431 | c101= [NET] Moxa C101 synchronous serial card | |
432 | ||
433 | cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection. | |
434 | Sometimes CPU hardware bugs make them report the cache | |
435 | size incorrectly. The kernel will attempt work arounds | |
436 | to fix known problems, but for some CPUs it is not | |
437 | possible to determine what the correct size should be. | |
438 | This option provides an override for these situations. | |
439 | ||
440 | capability.disable= | |
441 | [SECURITY] Disable capabilities. This would normally | |
442 | be used only if an alternative security model is to be | |
443 | configured. Potentially dangerous and should only be | |
444 | used if you are entirely sure of the consequences. | |
445 | ||
446 | ccw_timeout_log [S390] | |
447 | See Documentation/s390/CommonIO for details. | |
448 | ||
449 | cgroup_disable= [KNL] Disable a particular controller | |
450 | Format: {name of the controller(s) to disable} | |
451 | {Currently supported controllers - "memory"} | |
452 | ||
453 | checkreqprot [SELINUX] Set initial checkreqprot flag value. | |
454 | Format: { "0" | "1" } | |
455 | See security/selinux/Kconfig help text. | |
456 | 0 -- check protection applied by kernel (includes | |
457 | any implied execute protection). | |
458 | 1 -- check protection requested by application. | |
459 | Default value is set via a kernel config option. | |
460 | Value can be changed at runtime via | |
461 | /selinux/checkreqprot. | |
462 | ||
463 | cio_ignore= [S390] | |
464 | See Documentation/s390/CommonIO for details. | |
465 | ||
466 | clock= [BUGS=X86-32, HW] gettimeofday clocksource override. | |
467 | [Deprecated] | |
468 | Forces specified clocksource (if available) to be used | |
469 | when calculating gettimeofday(). If specified | |
470 | clocksource is not available, it defaults to PIT. | |
471 | Format: { pit | tsc | cyclone | pmtmr } | |
472 | ||
473 | clocksource= Override the default clocksource | |
474 | Format: <string> | |
475 | Override the default clocksource and use the clocksource | |
476 | with the name specified. | |
477 | Some clocksource names to choose from, depending on | |
478 | the platform: | |
479 | [all] jiffies (this is the base, fallback clocksource) | |
480 | [ACPI] acpi_pm | |
481 | [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2, | |
482 | pxa_timer,timer3,32k_counter,timer0_1 | |
483 | [AVR32] avr32 | |
484 | [X86-32] pit,hpet,tsc; | |
485 | scx200_hrt on Geode; cyclone on IBM x440 | |
486 | [MIPS] MIPS | |
487 | [PARISC] cr16 | |
488 | [S390] tod | |
489 | [SH] SuperH | |
490 | [SPARC64] tick | |
491 | [X86-64] hpet,tsc | |
492 | ||
493 | clearcpuid=BITNUM [X86] | |
494 | Disable CPUID feature X for the kernel. See | |
495 | arch/x86/include/asm/cpufeature.h for the valid bit | |
496 | numbers. Note the Linux specific bits are not necessarily | |
497 | stable over kernel options, but the vendor specific | |
498 | ones should be. | |
499 | Also note that user programs calling CPUID directly | |
500 | or using the feature without checking anything | |
501 | will still see it. This just prevents it from | |
502 | being used by the kernel or shown in /proc/cpuinfo. | |
503 | Also note the kernel might malfunction if you disable | |
504 | some critical bits. | |
505 | ||
506 | cmo_free_hint= [PPC] Format: { yes | no } | |
507 | Specify whether pages are marked as being inactive | |
508 | when they are freed. This is used in CMO environments | |
509 | to determine OS memory pressure for page stealing by | |
510 | a hypervisor. | |
511 | Default: yes | |
512 | ||
513 | code_bytes [X86] How many bytes of object code to print | |
514 | in an oops report. | |
515 | Range: 0 - 8192 | |
516 | Default: 64 | |
517 | ||
518 | com20020= [HW,NET] ARCnet - COM20020 chipset | |
519 | Format: | |
520 | <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]] | |
521 | ||
522 | com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers) | |
523 | Format: <io>[,<irq>] | |
524 | ||
525 | com90xx= [HW,NET] | |
526 | ARCnet - COM90xx chipset (memory-mapped buffers) | |
527 | Format: <io>[,<irq>[,<memstart>]] | |
528 | ||
529 | condev= [HW,S390] console device | |
530 | conmode= | |
531 | ||
532 | console= [KNL] Output console device and options. | |
533 | ||
534 | tty<n> Use the virtual console device <n>. | |
535 | ||
536 | ttyS<n>[,options] | |
537 | ttyUSB0[,options] | |
538 | Use the specified serial port. The options are of | |
539 | the form "bbbbpnf", where "bbbb" is the baud rate, | |
540 | "p" is parity ("n", "o", or "e"), "n" is number of | |
541 | bits, and "f" is flow control ("r" for RTS or | |
542 | omit it). Default is "9600n8". | |
543 | ||
544 | See Documentation/serial-console.txt for more | |
545 | information. See | |
546 | Documentation/networking/netconsole.txt for an | |
547 | alternative. | |
548 | ||
549 | uart[8250],io,<addr>[,options] | |
550 | uart[8250],mmio,<addr>[,options] | |
551 | Start an early, polled-mode console on the 8250/16550 | |
552 | UART at the specified I/O port or MMIO address, | |
553 | switching to the matching ttyS device later. The | |
554 | options are the same as for ttyS, above. | |
555 | ||
556 | If the device connected to the port is not a TTY but a braille | |
557 | device, prepend "brl," before the device type, for instance | |
558 | console=brl,ttyS0 | |
559 | For now, only VisioBraille is supported. | |
560 | ||
561 | consoleblank= [KNL] The console blank (screen saver) timeout in | |
562 | seconds. Defaults to 10*60 = 10mins. A value of 0 | |
563 | disables the blank timer. | |
564 | ||
565 | coredump_filter= | |
566 | [KNL] Change the default value for | |
567 | /proc/<pid>/coredump_filter. | |
568 | See also Documentation/filesystems/proc.txt. | |
569 | ||
570 | cpuidle.off=1 [CPU_IDLE] | |
571 | disable the cpuidle sub-system | |
572 | ||
573 | cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver | |
574 | Format: | |
575 | <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] | |
576 | ||
577 | crashkernel=size[KMG][@offset[KMG]] | |
578 | [KNL] Using kexec, Linux can switch to a 'crash kernel' | |
579 | upon panic. This parameter reserves the physical | |
580 | memory region [offset, offset + size] for that kernel | |
581 | image. If '@offset' is omitted, then a suitable offset | |
582 | is selected automatically. Check | |
583 | Documentation/kdump/kdump.txt for further details. | |
584 | ||
585 | crashkernel=range1:size1[,range2:size2,...][@offset] | |
586 | [KNL] Same as above, but depends on the memory | |
587 | in the running system. The syntax of range is | |
588 | start-[end] where start and end are both | |
589 | a memory unit (amount[KMG]). See also | |
590 | Documentation/kdump/kdump.txt for an example. | |
591 | ||
592 | cs89x0_dma= [HW,NET] | |
593 | Format: <dma> | |
594 | ||
595 | cs89x0_media= [HW,NET] | |
596 | Format: { rj45 | aui | bnc } | |
597 | ||
598 | dasd= [HW,NET] | |
599 | See header of drivers/s390/block/dasd_devmap.c. | |
600 | ||
601 | db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port | |
602 | (one device per port) | |
603 | Format: <port#>,<type> | |
604 | See also Documentation/input/joystick-parport.txt | |
605 | ||
606 | ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot | |
607 | time. See Documentation/dynamic-debug-howto.txt for | |
608 | details. | |
609 | ||
610 | debug [KNL] Enable kernel debugging (events log level). | |
611 | ||
612 | debug_locks_verbose= | |
613 | [KNL] verbose self-tests | |
614 | Format=<0|1> | |
615 | Print debugging info while doing the locking API | |
616 | self-tests. | |
617 | We default to 0 (no extra messages), setting it to | |
618 | 1 will print _a lot_ more information - normally | |
619 | only useful to kernel developers. | |
620 | ||
621 | debug_objects [KNL] Enable object debugging | |
622 | ||
623 | no_debug_objects | |
624 | [KNL] Disable object debugging | |
625 | ||
626 | debugpat [X86] Enable PAT debugging | |
627 | ||
628 | decnet.addr= [HW,NET] | |
629 | Format: <area>[,<node>] | |
630 | See also Documentation/networking/decnet.txt. | |
631 | ||
632 | default_hugepagesz= | |
633 | [same as hugepagesz=] The size of the default | |
634 | HugeTLB page size. This is the size represented by | |
635 | the legacy /proc/ hugepages APIs, used for SHM, and | |
636 | default size when mounting hugetlbfs filesystems. | |
637 | Defaults to the default architecture's huge page size | |
638 | if not specified. | |
639 | ||
640 | dhash_entries= [KNL] | |
641 | Set number of hash buckets for dentry cache. | |
642 | ||
643 | digi= [HW,SERIAL] | |
644 | IO parameters + enable/disable command. | |
645 | ||
646 | digiepca= [HW,SERIAL] | |
647 | See drivers/char/README.epca and | |
648 | Documentation/serial/digiepca.txt. | |
649 | ||
650 | disable= [IPV6] | |
651 | See Documentation/networking/ipv6.txt. | |
652 | ||
653 | disable_ddw [PPC/PSERIES] | |
654 | Disable Dynamic DMA Window support. Use this if | |
655 | to workaround buggy firmware. | |
656 | ||
657 | disable_ipv6= [IPV6] | |
658 | See Documentation/networking/ipv6.txt. | |
659 | ||
660 | disable_mtrr_cleanup [X86] | |
661 | The kernel tries to adjust MTRR layout from continuous | |
662 | to discrete, to make X server driver able to add WB | |
663 | entry later. This parameter disables that. | |
664 | ||
665 | disable_mtrr_trim [X86, Intel and AMD only] | |
666 | By default the kernel will trim any uncacheable | |
667 | memory out of your available memory pool based on | |
668 | MTRR settings. This parameter disables that behavior, | |
669 | possibly causing your machine to run very slowly. | |
670 | ||
671 | disable_timer_pin_1 [X86] | |
672 | Disable PIN 1 of APIC timer | |
673 | Can be useful to work around chipset bugs. | |
674 | ||
675 | dma_debug=off If the kernel is compiled with DMA_API_DEBUG support, | |
676 | this option disables the debugging code at boot. | |
677 | ||
678 | dma_debug_entries=<number> | |
679 | This option allows to tune the number of preallocated | |
680 | entries for DMA-API debugging code. One entry is | |
681 | required per DMA-API allocation. Use this if the | |
682 | DMA-API debugging code disables itself because the | |
683 | architectural default is too low. | |
684 | ||
685 | dma_debug_driver=<driver_name> | |
686 | With this option the DMA-API debugging driver | |
687 | filter feature can be enabled at boot time. Just | |
688 | pass the driver to filter for as the parameter. | |
689 | The filter can be disabled or changed to another | |
690 | driver later using sysfs. | |
691 | ||
692 | dscc4.setup= [NET] | |
693 | ||
694 | earlycon= [KNL] Output early console device and options. | |
695 | uart[8250],io,<addr>[,options] | |
696 | uart[8250],mmio,<addr>[,options] | |
697 | uart[8250],mmio32,<addr>[,options] | |
698 | Start an early, polled-mode console on the 8250/16550 | |
699 | UART at the specified I/O port or MMIO address. | |
700 | MMIO inter-register address stride is either 8-bit | |
701 | (mmio) or 32-bit (mmio32). | |
702 | The options are the same as for ttyS, above. | |
703 | ||
704 | earlyprintk= [X86,SH,BLACKFIN] | |
705 | earlyprintk=vga | |
706 | earlyprintk=serial[,ttySn[,baudrate]] | |
707 | earlyprintk=ttySn[,baudrate] | |
708 | earlyprintk=dbgp[debugController#] | |
709 | ||
710 | Append ",keep" to not disable it when the real console | |
711 | takes over. | |
712 | ||
713 | Only vga or serial or usb debug port at a time. | |
714 | ||
715 | Currently only ttyS0 and ttyS1 are supported. | |
716 | ||
717 | Interaction with the standard serial driver is not | |
718 | very good. | |
719 | ||
720 | The VGA output is eventually overwritten by the real | |
721 | console. | |
722 | ||
723 | ekgdboc= [X86,KGDB] Allow early kernel console debugging | |
724 | ekgdboc=kbd | |
725 | ||
726 | This is designed to be used in conjunction with | |
727 | the boot argument: earlyprintk=vga | |
728 | ||
729 | edd= [EDD] | |
730 | Format: {"off" | "on" | "skip[mbr]"} | |
731 | ||
732 | eisa_irq_edge= [PARISC,HW] | |
733 | See header of drivers/parisc/eisa.c. | |
734 | ||
735 | elanfreq= [X86-32] | |
736 | See comment before function elanfreq_setup() in | |
737 | arch/x86/kernel/cpu/cpufreq/elanfreq.c. | |
738 | ||
739 | elevator= [IOSCHED] | |
740 | Format: {"cfq" | "deadline" | "noop"} | |
741 | See Documentation/block/cfq-iosched.txt and | |
742 | Documentation/block/deadline-iosched.txt for details. | |
743 | ||
744 | elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390] | |
745 | Specifies physical address of start of kernel core | |
746 | image elf header and optionally the size. Generally | |
747 | kexec loader will pass this option to capture kernel. | |
748 | See Documentation/kdump/kdump.txt for details. | |
749 | ||
750 | enable_mtrr_cleanup [X86] | |
751 | The kernel tries to adjust MTRR layout from continuous | |
752 | to discrete, to make X server driver able to add WB | |
753 | entry later. This parameter enables that. | |
754 | ||
755 | enable_timer_pin_1 [X86] | |
756 | Enable PIN 1 of APIC timer | |
757 | Can be useful to work around chipset bugs | |
758 | (in particular on some ATI chipsets). | |
759 | The kernel tries to set a reasonable default. | |
760 | ||
761 | enforcing [SELINUX] Set initial enforcing status. | |
762 | Format: {"0" | "1"} | |
763 | See security/selinux/Kconfig help text. | |
764 | 0 -- permissive (log only, no denials). | |
765 | 1 -- enforcing (deny and log). | |
766 | Default value is 0. | |
767 | Value can be changed at runtime via /selinux/enforce. | |
768 | ||
769 | erst_disable [ACPI] | |
770 | Disable Error Record Serialization Table (ERST) | |
771 | support. | |
772 | ||
773 | ether= [HW,NET] Ethernet cards parameters | |
774 | This option is obsoleted by the "netdev=" option, which | |
775 | has equivalent usage. See its documentation for details. | |
776 | ||
777 | evm= [EVM] | |
778 | Format: { "fix" } | |
779 | Permit 'security.evm' to be updated regardless of | |
780 | current integrity status. | |
781 | ||
782 | failslab= | |
783 | fail_page_alloc= | |
784 | fail_make_request=[KNL] | |
785 | General fault injection mechanism. | |
786 | Format: <interval>,<probability>,<space>,<times> | |
787 | See also Documentation/fault-injection/. | |
788 | ||
789 | floppy= [HW] | |
790 | See Documentation/blockdev/floppy.txt. | |
791 | ||
792 | force_pal_cache_flush | |
793 | [IA-64] Avoid check_sal_cache_flush which may hang on | |
794 | buggy SAL_CACHE_FLUSH implementations. Using this | |
795 | parameter will force ia64_sal_cache_flush to call | |
796 | ia64_pal_cache_flush instead of SAL_CACHE_FLUSH. | |
797 | ||
798 | ftrace=[tracer] | |
799 | [FTRACE] will set and start the specified tracer | |
800 | as early as possible in order to facilitate early | |
801 | boot debugging. | |
802 | ||
803 | ftrace_dump_on_oops[=orig_cpu] | |
804 | [FTRACE] will dump the trace buffers on oops. | |
805 | If no parameter is passed, ftrace will dump | |
806 | buffers of all CPUs, but if you pass orig_cpu, it will | |
807 | dump only the buffer of the CPU that triggered the | |
808 | oops. | |
809 | ||
810 | ftrace_filter=[function-list] | |
811 | [FTRACE] Limit the functions traced by the function | |
812 | tracer at boot up. function-list is a comma separated | |
813 | list of functions. This list can be changed at run | |
814 | time by the set_ftrace_filter file in the debugfs | |
815 | tracing directory. | |
816 | ||
817 | ftrace_notrace=[function-list] | |
818 | [FTRACE] Do not trace the functions specified in | |
819 | function-list. This list can be changed at run time | |
820 | by the set_ftrace_notrace file in the debugfs | |
821 | tracing directory. | |
822 | ||
823 | ftrace_graph_filter=[function-list] | |
824 | [FTRACE] Limit the top level callers functions traced | |
825 | by the function graph tracer at boot up. | |
826 | function-list is a comma separated list of functions | |
827 | that can be changed at run time by the | |
828 | set_graph_function file in the debugfs tracing directory. | |
829 | ||
830 | gamecon.map[2|3]= | |
831 | [HW,JOY] Multisystem joystick and NES/SNES/PSX pad | |
832 | support via parallel port (up to 5 devices per port) | |
833 | Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5> | |
834 | See also Documentation/input/joystick-parport.txt | |
835 | ||
836 | gamma= [HW,DRM] | |
837 | ||
838 | gart_fix_e820= [X86_64] disable the fix e820 for K8 GART | |
839 | Format: off | on | |
840 | default: on | |
841 | ||
842 | gcov_persist= [GCOV] When non-zero (default), profiling data for | |
843 | kernel modules is saved and remains accessible via | |
844 | debugfs, even when the module is unloaded/reloaded. | |
845 | When zero, profiling data is discarded and associated | |
846 | debugfs files are removed at module unload time. | |
847 | ||
848 | gpt [EFI] Forces disk with valid GPT signature but | |
849 | invalid Protective MBR to be treated as GPT. | |
850 | ||
851 | hashdist= [KNL,NUMA] Large hashes allocated during boot | |
852 | are distributed across NUMA nodes. Defaults on | |
853 | for 64-bit NUMA, off otherwise. | |
854 | Format: 0 | 1 (for off | on) | |
855 | ||
856 | hcl= [IA-64] SGI's Hardware Graph compatibility layer | |
857 | ||
858 | hd= [EIDE] (E)IDE hard drive subsystem geometry | |
859 | Format: <cyl>,<head>,<sect> | |
860 | ||
861 | hest_disable [ACPI] | |
862 | Disable Hardware Error Source Table (HEST) support; | |
863 | corresponding firmware-first mode error processing | |
864 | logic will be disabled. | |
865 | ||
866 | highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact | |
867 | size of <nn>. This works even on boxes that have no | |
868 | highmem otherwise. This also works to reduce highmem | |
869 | size on bigger boxes. | |
870 | ||
871 | highres= [KNL] Enable/disable high resolution timer mode. | |
872 | Valid parameters: "on", "off" | |
873 | Default: "on" | |
874 | ||
875 | hisax= [HW,ISDN] | |
876 | See Documentation/isdn/README.HiSax. | |
877 | ||
878 | hlt [BUGS=ARM,SH] | |
879 | ||
880 | hpet= [X86-32,HPET] option to control HPET usage | |
881 | Format: { enable (default) | disable | force | | |
882 | verbose } | |
883 | disable: disable HPET and use PIT instead | |
884 | force: allow force enabled of undocumented chips (ICH4, | |
885 | VIA, nVidia) | |
886 | verbose: show contents of HPET registers during setup | |
887 | ||
888 | hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot. | |
889 | hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages. | |
890 | On x86-64 and powerpc, this option can be specified | |
891 | multiple times interleaved with hugepages= to reserve | |
892 | huge pages of different sizes. Valid pages sizes on | |
893 | x86-64 are 2M (when the CPU supports "pse") and 1G | |
894 | (when the CPU supports the "pdpe1gb" cpuinfo flag) | |
895 | Note that 1GB pages can only be allocated at boot time | |
896 | using hugepages= and not freed afterwards. | |
897 | ||
898 | hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC) | |
899 | terminal devices. Valid values: 0..8 | |
900 | hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs. | |
901 | If specified, z/VM IUCV HVC accepts connections | |
902 | from listed z/VM user IDs only. | |
903 | ||
904 | keep_bootcon [KNL] | |
905 | Do not unregister boot console at start. This is only | |
906 | useful for debugging when something happens in the window | |
907 | between unregistering the boot console and initializing | |
908 | the real console. | |
909 | ||
910 | i2c_bus= [HW] Override the default board specific I2C bus speed | |
911 | or register an additional I2C bus that is not | |
912 | registered from board initialization code. | |
913 | Format: | |
914 | <bus_id>,<clkrate> | |
915 | ||
916 | i8042.debug [HW] Toggle i8042 debug mode | |
917 | i8042.direct [HW] Put keyboard port into non-translated mode | |
918 | i8042.dumbkbd [HW] Pretend that controller can only read data from | |
919 | keyboard and cannot control its state | |
920 | (Don't attempt to blink the leds) | |
921 | i8042.noaux [HW] Don't check for auxiliary (== mouse) port | |
922 | i8042.nokbd [HW] Don't check/create keyboard port | |
923 | i8042.noloop [HW] Disable the AUX Loopback command while probing | |
924 | for the AUX port | |
925 | i8042.nomux [HW] Don't check presence of an active multiplexing | |
926 | controller | |
927 | i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX | |
928 | controllers | |
929 | i8042.notimeout [HW] Ignore timeout condition signalled by conroller | |
930 | i8042.reset [HW] Reset the controller during init and cleanup | |
931 | i8042.unlock [HW] Unlock (ignore) the keylock | |
932 | ||
933 | i810= [HW,DRM] | |
934 | ||
935 | i8k.ignore_dmi [HW] Continue probing hardware even if DMI data | |
936 | indicates that the driver is running on unsupported | |
937 | hardware. | |
938 | i8k.force [HW] Activate i8k driver even if SMM BIOS signature | |
939 | does not match list of supported models. | |
940 | i8k.power_status | |
941 | [HW] Report power status in /proc/i8k | |
942 | (disabled by default) | |
943 | i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN | |
944 | capability is set. | |
945 | ||
946 | icn= [HW,ISDN] | |
947 | Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] | |
948 | ||
949 | ide-core.nodma= [HW] (E)IDE subsystem | |
950 | Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc | |
951 | .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr | |
952 | .cdrom .chs .ignore_cable are additional options | |
953 | See Documentation/ide/ide.txt. | |
954 | ||
955 | ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem | |
956 | Claim all unknown PCI IDE storage controllers. | |
957 | ||
958 | idle= [X86] | |
959 | Format: idle=poll, idle=mwait, idle=halt, idle=nomwait | |
960 | Poll forces a polling idle loop that can slightly | |
961 | improve the performance of waking up a idle CPU, but | |
962 | will use a lot of power and make the system run hot. | |
963 | Not recommended. | |
964 | idle=mwait: On systems which support MONITOR/MWAIT but | |
965 | the kernel chose to not use it because it doesn't save | |
966 | as much power as a normal idle loop, use the | |
967 | MONITOR/MWAIT idle loop anyways. Performance should be | |
968 | the same as idle=poll. | |
969 | idle=halt: Halt is forced to be used for CPU idle. | |
970 | In such case C2/C3 won't be used again. | |
971 | idle=nomwait: Disable mwait for CPU C-states | |
972 | ||
973 | ignore_loglevel [KNL] | |
974 | Ignore loglevel setting - this will print /all/ | |
975 | kernel messages to the console. Useful for debugging. | |
976 | We also add it as printk module parameter, so users | |
977 | could change it dynamically, usually by | |
978 | /sys/module/printk/parameters/ignore_loglevel. | |
979 | ||
980 | ihash_entries= [KNL] | |
981 | Set number of hash buckets for inode cache. | |
982 | ||
983 | ima_audit= [IMA] | |
984 | Format: { "0" | "1" } | |
985 | 0 -- integrity auditing messages. (Default) | |
986 | 1 -- enable informational integrity auditing messages. | |
987 | ||
988 | ima_hash= [IMA] | |
989 | Format: { "sha1" | "md5" } | |
990 | default: "sha1" | |
991 | ||
992 | ima_tcb [IMA] | |
993 | Load a policy which meets the needs of the Trusted | |
994 | Computing Base. This means IMA will measure all | |
995 | programs exec'd, files mmap'd for exec, and all files | |
996 | opened for read by uid=0. | |
997 | ||
998 | init= [KNL] | |
999 | Format: <full_path> | |
1000 | Run specified binary instead of /sbin/init as init | |
1001 | process. | |
1002 | ||
1003 | initcall_debug [KNL] Trace initcalls as they are executed. Useful | |
1004 | for working out where the kernel is dying during | |
1005 | startup. | |
1006 | ||
1007 | initrd= [BOOT] Specify the location of the initial ramdisk | |
1008 | ||
1009 | inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver | |
1010 | Format: <irq> | |
1011 | ||
1012 | intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option | |
1013 | on | |
1014 | Enable intel iommu driver. | |
1015 | off | |
1016 | Disable intel iommu driver. | |
1017 | igfx_off [Default Off] | |
1018 | By default, gfx is mapped as normal device. If a gfx | |
1019 | device has a dedicated DMAR unit, the DMAR unit is | |
1020 | bypassed by not enabling DMAR with this option. In | |
1021 | this case, gfx device will use physical address for | |
1022 | DMA. | |
1023 | forcedac [x86_64] | |
1024 | With this option iommu will not optimize to look | |
1025 | for io virtual address below 32-bit forcing dual | |
1026 | address cycle on pci bus for cards supporting greater | |
1027 | than 32-bit addressing. The default is to look | |
1028 | for translation below 32-bit and if not available | |
1029 | then look in the higher range. | |
1030 | strict [Default Off] | |
1031 | With this option on every unmap_single operation will | |
1032 | result in a hardware IOTLB flush operation as opposed | |
1033 | to batching them for performance. | |
1034 | sp_off [Default Off] | |
1035 | By default, super page will be supported if Intel IOMMU | |
1036 | has the capability. With this option, super page will | |
1037 | not be supported. | |
1038 | intremap= [X86-64, Intel-IOMMU] | |
1039 | on enable Interrupt Remapping (default) | |
1040 | off disable Interrupt Remapping | |
1041 | nosid disable Source ID checking | |
1042 | no_x2apic_optout | |
1043 | BIOS x2APIC opt-out request will be ignored | |
1044 | ||
1045 | inttest= [IA-64] | |
1046 | ||
1047 | iomem= Disable strict checking of access to MMIO memory | |
1048 | strict regions from userspace. | |
1049 | relaxed | |
1050 | ||
1051 | iommu= [x86] | |
1052 | off | |
1053 | force | |
1054 | noforce | |
1055 | biomerge | |
1056 | panic | |
1057 | nopanic | |
1058 | merge | |
1059 | nomerge | |
1060 | forcesac | |
1061 | soft | |
1062 | pt [x86, IA-64] | |
1063 | ||
1064 | io7= [HW] IO7 for Marvel based alpha systems | |
1065 | See comment before marvel_specify_io7 in | |
1066 | arch/alpha/kernel/core_marvel.c. | |
1067 | ||
1068 | io_delay= [X86] I/O delay method | |
1069 | 0x80 | |
1070 | Standard port 0x80 based delay | |
1071 | 0xed | |
1072 | Alternate port 0xed based delay (needed on some systems) | |
1073 | udelay | |
1074 | Simple two microseconds delay | |
1075 | none | |
1076 | No delay | |
1077 | ||
1078 | ip= [IP_PNP] | |
1079 | See Documentation/filesystems/nfs/nfsroot.txt. | |
1080 | ||
1081 | ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards | |
1082 | See comment before ip2_setup() in | |
1083 | drivers/char/ip2/ip2base.c. | |
1084 | ||
1085 | irqfixup [HW] | |
1086 | When an interrupt is not handled search all handlers | |
1087 | for it. Intended to get systems with badly broken | |
1088 | firmware running. | |
1089 | ||
1090 | irqpoll [HW] | |
1091 | When an interrupt is not handled search all handlers | |
1092 | for it. Also check all handlers each timer | |
1093 | interrupt. Intended to get systems with badly broken | |
1094 | firmware running. | |
1095 | ||
1096 | isapnp= [ISAPNP] | |
1097 | Format: <RDP>,<reset>,<pci_scan>,<verbosity> | |
1098 | ||
1099 | isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler. | |
1100 | Format: | |
1101 | <cpu number>,...,<cpu number> | |
1102 | or | |
1103 | <cpu number>-<cpu number> | |
1104 | (must be a positive range in ascending order) | |
1105 | or a mixture | |
1106 | <cpu number>,...,<cpu number>-<cpu number> | |
1107 | ||
1108 | This option can be used to specify one or more CPUs | |
1109 | to isolate from the general SMP balancing and scheduling | |
1110 | algorithms. You can move a process onto or off an | |
1111 | "isolated" CPU via the CPU affinity syscalls or cpuset. | |
1112 | <cpu number> begins at 0 and the maximum value is | |
1113 | "number of CPUs in system - 1". | |
1114 | ||
1115 | This option is the preferred way to isolate CPUs. The | |
1116 | alternative -- manually setting the CPU mask of all | |
1117 | tasks in the system -- can cause problems and | |
1118 | suboptimal load balancer performance. | |
1119 | ||
1120 | iucv= [HW,NET] | |
1121 | ||
1122 | js= [HW,JOY] Analog joystick | |
1123 | See Documentation/input/joystick.txt. | |
1124 | ||
1125 | keepinitrd [HW,ARM] | |
1126 | ||
1127 | kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter | |
1128 | specifies the amount of memory usable by the kernel | |
1129 | for non-movable allocations. The requested amount is | |
1130 | spread evenly throughout all nodes in the system. The | |
1131 | remaining memory in each node is used for Movable | |
1132 | pages. In the event, a node is too small to have both | |
1133 | kernelcore and Movable pages, kernelcore pages will | |
1134 | take priority and other nodes will have a larger number | |
1135 | of kernelcore pages. The Movable zone is used for the | |
1136 | allocation of pages that may be reclaimed or moved | |
1137 | by the page migration subsystem. This means that | |
1138 | HugeTLB pages may not be allocated from this zone. | |
1139 | Note that allocations like PTEs-from-HighMem still | |
1140 | use the HighMem zone if it exists, and the Normal | |
1141 | zone if it does not. | |
1142 | ||
1143 | kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port. | |
1144 | Format: <Controller#>[,poll interval] | |
1145 | The controller # is the number of the ehci usb debug | |
1146 | port as it is probed via PCI. The poll interval is | |
1147 | optional and is the number seconds in between | |
1148 | each poll cycle to the debug port in case you need | |
1149 | the functionality for interrupting the kernel with | |
1150 | gdb or control-c on the dbgp connection. When | |
1151 | not using this parameter you use sysrq-g to break into | |
1152 | the kernel debugger. | |
1153 | ||
1154 | kgdboc= [KGDB,HW] kgdb over consoles. | |
1155 | Requires a tty driver that supports console polling, | |
1156 | or a supported polling keyboard driver (non-usb). | |
1157 | Serial only format: <serial_device>[,baud] | |
1158 | keyboard only format: kbd | |
1159 | keyboard and serial format: kbd,<serial_device>[,baud] | |
1160 | Optional Kernel mode setting: | |
1161 | kms, kbd format: kms,kbd | |
1162 | kms, kbd and serial format: kms,kbd,<ser_dev>[,baud] | |
1163 | ||
1164 | kgdbwait [KGDB] Stop kernel execution and enter the | |
1165 | kernel debugger at the earliest opportunity. | |
1166 | ||
1167 | kmac= [MIPS] korina ethernet MAC address. | |
1168 | Configure the RouterBoard 532 series on-chip | |
1169 | Ethernet adapter MAC address. | |
1170 | ||
1171 | kmemleak= [KNL] Boot-time kmemleak enable/disable | |
1172 | Valid arguments: on, off | |
1173 | Default: on | |
1174 | ||
1175 | kstack=N [X86] Print N words from the kernel stack | |
1176 | in oops dumps. | |
1177 | ||
1178 | kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs. | |
1179 | Default is 0 (don't ignore, but inject #GP) | |
1180 | ||
1181 | kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging. | |
1182 | Default is 1 (enabled) | |
1183 | ||
1184 | kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit | |
1185 | KVM MMU at runtime. | |
1186 | Default is 0 (off) | |
1187 | ||
1188 | kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM. | |
1189 | Default is 1 (enabled) | |
1190 | ||
1191 | kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU) | |
1192 | for all guests. | |
1193 | Default is 1 (enabled) if in 64-bit or 32-bit PAE mode. | |
1194 | ||
1195 | kvm-intel.ept= [KVM,Intel] Disable extended page tables | |
1196 | (virtualized MMU) support on capable Intel chips. | |
1197 | Default is 1 (enabled) | |
1198 | ||
1199 | kvm-intel.emulate_invalid_guest_state= | |
1200 | [KVM,Intel] Enable emulation of invalid guest states | |
1201 | Default is 0 (disabled) | |
1202 | ||
1203 | kvm-intel.flexpriority= | |
1204 | [KVM,Intel] Disable FlexPriority feature (TPR shadow). | |
1205 | Default is 1 (enabled) | |
1206 | ||
1207 | kvm-intel.nested= | |
1208 | [KVM,Intel] Enable VMX nesting (nVMX). | |
1209 | Default is 0 (disabled) | |
1210 | ||
1211 | kvm-intel.unrestricted_guest= | |
1212 | [KVM,Intel] Disable unrestricted guest feature | |
1213 | (virtualized real and unpaged mode) on capable | |
1214 | Intel chips. Default is 1 (enabled) | |
1215 | ||
1216 | kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification | |
1217 | feature (tagged TLBs) on capable Intel chips. | |
1218 | Default is 1 (enabled) | |
1219 | ||
1220 | l2cr= [PPC] | |
1221 | ||
1222 | l3cr= [PPC] | |
1223 | ||
1224 | lapic [X86-32,APIC] Enable the local APIC even if BIOS | |
1225 | disabled it. | |
1226 | ||
1227 | lapic_timer_c2_ok [X86,APIC] trust the local apic timer | |
1228 | in C2 power state. | |
1229 | ||
1230 | libata.dma= [LIBATA] DMA control | |
1231 | libata.dma=0 Disable all PATA and SATA DMA | |
1232 | libata.dma=1 PATA and SATA Disk DMA only | |
1233 | libata.dma=2 ATAPI (CDROM) DMA only | |
1234 | libata.dma=4 Compact Flash DMA only | |
1235 | Combinations also work, so libata.dma=3 enables DMA | |
1236 | for disks and CDROMs, but not CFs. | |
1237 | ||
1238 | libata.ignore_hpa= [LIBATA] Ignore HPA limit | |
1239 | libata.ignore_hpa=0 keep BIOS limits (default) | |
1240 | libata.ignore_hpa=1 ignore limits, using full disk | |
1241 | ||
1242 | libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume | |
1243 | when set. | |
1244 | Format: <int> | |
1245 | ||
1246 | libata.force= [LIBATA] Force configurations. The format is comma | |
1247 | separated list of "[ID:]VAL" where ID is | |
1248 | PORT[.DEVICE]. PORT and DEVICE are decimal numbers | |
1249 | matching port, link or device. Basically, it matches | |
1250 | the ATA ID string printed on console by libata. If | |
1251 | the whole ID part is omitted, the last PORT and DEVICE | |
1252 | values are used. If ID hasn't been specified yet, the | |
1253 | configuration applies to all ports, links and devices. | |
1254 | ||
1255 | If only DEVICE is omitted, the parameter applies to | |
1256 | the port and all links and devices behind it. DEVICE | |
1257 | number of 0 either selects the first device or the | |
1258 | first fan-out link behind PMP device. It does not | |
1259 | select the host link. DEVICE number of 15 selects the | |
1260 | host link and device attached to it. | |
1261 | ||
1262 | The VAL specifies the configuration to force. As long | |
1263 | as there's no ambiguity shortcut notation is allowed. | |
1264 | For example, both 1.5 and 1.5G would work for 1.5Gbps. | |
1265 | The following configurations can be forced. | |
1266 | ||
1267 | * Cable type: 40c, 80c, short40c, unk, ign or sata. | |
1268 | Any ID with matching PORT is used. | |
1269 | ||
1270 | * SATA link speed limit: 1.5Gbps or 3.0Gbps. | |
1271 | ||
1272 | * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7]. | |
1273 | udma[/][16,25,33,44,66,100,133] notation is also | |
1274 | allowed. | |
1275 | ||
1276 | * [no]ncq: Turn on or off NCQ. | |
1277 | ||
1278 | * nohrst, nosrst, norst: suppress hard, soft | |
1279 | and both resets. | |
1280 | ||
1281 | * dump_id: dump IDENTIFY data. | |
1282 | ||
1283 | If there are multiple matching configurations changing | |
1284 | the same attribute, the last one is used. | |
1285 | ||
1286 | memblock=debug [KNL] Enable memblock debug messages. | |
1287 | ||
1288 | load_ramdisk= [RAM] List of ramdisks to load from floppy | |
1289 | See Documentation/blockdev/ramdisk.txt. | |
1290 | ||
1291 | lockd.nlm_grace_period=P [NFS] Assign grace period. | |
1292 | Format: <integer> | |
1293 | ||
1294 | lockd.nlm_tcpport=N [NFS] Assign TCP port. | |
1295 | Format: <integer> | |
1296 | ||
1297 | lockd.nlm_timeout=T [NFS] Assign timeout value. | |
1298 | Format: <integer> | |
1299 | ||
1300 | lockd.nlm_udpport=M [NFS] Assign UDP port. | |
1301 | Format: <integer> | |
1302 | ||
1303 | logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver | |
1304 | Format: <irq> | |
1305 | ||
1306 | loglevel= All Kernel Messages with a loglevel smaller than the | |
1307 | console loglevel will be printed to the console. It can | |
1308 | also be changed with klogd or other programs. The | |
1309 | loglevels are defined as follows: | |
1310 | ||
1311 | 0 (KERN_EMERG) system is unusable | |
1312 | 1 (KERN_ALERT) action must be taken immediately | |
1313 | 2 (KERN_CRIT) critical conditions | |
1314 | 3 (KERN_ERR) error conditions | |
1315 | 4 (KERN_WARNING) warning conditions | |
1316 | 5 (KERN_NOTICE) normal but significant condition | |
1317 | 6 (KERN_INFO) informational | |
1318 | 7 (KERN_DEBUG) debug-level messages | |
1319 | ||
1320 | log_buf_len=n[KMG] Sets the size of the printk ring buffer, | |
1321 | in bytes. n must be a power of two. The default | |
1322 | size is set in the kernel config file. | |
1323 | ||
1324 | logo.nologo [FB] Disables display of the built-in Linux logo. | |
1325 | This may be used to provide more screen space for | |
1326 | kernel log messages and is useful when debugging | |
1327 | kernel boot problems. | |
1328 | ||
1329 | lp=0 [LP] Specify parallel ports to use, e.g, | |
1330 | lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses | |
1331 | lp=reset first parallel port). 'lp=0' disables the | |
1332 | lp=auto printer driver. 'lp=reset' (which can be | |
1333 | specified in addition to the ports) causes | |
1334 | attached printers to be reset. Using | |
1335 | lp=port1,port2,... specifies the parallel ports | |
1336 | to associate lp devices with, starting with | |
1337 | lp0. A port specification may be 'none' to skip | |
1338 | that lp device, or a parport name such as | |
1339 | 'parport0'. Specifying 'lp=auto' instead of a | |
1340 | port specification list means that device IDs | |
1341 | from each port should be examined, to see if | |
1342 | an IEEE 1284-compliant printer is attached; if | |
1343 | so, the driver will manage that printer. | |
1344 | See also header of drivers/char/lp.c. | |
1345 | ||
1346 | lpj=n [KNL] | |
1347 | Sets loops_per_jiffy to given constant, thus avoiding | |
1348 | time-consuming boot-time autodetection (up to 250 ms per | |
1349 | CPU). 0 enables autodetection (default). To determine | |
1350 | the correct value for your kernel, boot with normal | |
1351 | autodetection and see what value is printed. Note that | |
1352 | on SMP systems the preset will be applied to all CPUs, | |
1353 | which is likely to cause problems if your CPUs need | |
1354 | significantly divergent settings. An incorrect value | |
1355 | will cause delays in the kernel to be wrong, leading to | |
1356 | unpredictable I/O errors and other breakage. Although | |
1357 | unlikely, in the extreme case this might damage your | |
1358 | hardware. | |
1359 | ||
1360 | ltpc= [NET] | |
1361 | Format: <io>,<irq>,<dma> | |
1362 | ||
1363 | machvec= [IA-64] Force the use of a particular machine-vector | |
1364 | (machvec) in a generic kernel. | |
1365 | Example: machvec=hpzx1_swiotlb | |
1366 | ||
1367 | machtype= [Loongson] Share the same kernel image file between different | |
1368 | yeeloong laptop. | |
1369 | Example: machtype=lemote-yeeloong-2f-7inch | |
1370 | ||
1371 | max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater | |
1372 | than or equal to this physical address is ignored. | |
1373 | ||
1374 | maxcpus= [SMP] Maximum number of processors that an SMP kernel | |
1375 | should make use of. maxcpus=n : n >= 0 limits the | |
1376 | kernel to using 'n' processors. n=0 is a special case, | |
1377 | it is equivalent to "nosmp", which also disables | |
1378 | the IO APIC. | |
1379 | ||
1380 | max_loop= [LOOP] The number of loop block devices that get | |
1381 | (loop.max_loop) unconditionally pre-created at init time. The default | |
1382 | number is configured by BLK_DEV_LOOP_MIN_COUNT. Instead | |
1383 | of statically allocating a predefined number, loop | |
1384 | devices can be requested on-demand with the | |
1385 | /dev/loop-control interface. | |
1386 | ||
1387 | mcatest= [IA-64] | |
1388 | ||
1389 | mce [X86-32] Machine Check Exception | |
1390 | ||
1391 | mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt | |
1392 | ||
1393 | md= [HW] RAID subsystems devices and level | |
1394 | See Documentation/md.txt. | |
1395 | ||
1396 | mdacon= [MDA] | |
1397 | Format: <first>,<last> | |
1398 | Specifies range of consoles to be captured by the MDA. | |
1399 | ||
1400 | mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory | |
1401 | Amount of memory to be used when the kernel is not able | |
1402 | to see the whole system memory or for test. | |
1403 | [X86-32] Use together with memmap= to avoid physical | |
1404 | address space collisions. Without memmap= PCI devices | |
1405 | could be placed at addresses belonging to unused RAM. | |
1406 | ||
1407 | mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel | |
1408 | memory. | |
1409 | ||
1410 | memchunk=nn[KMG] | |
1411 | [KNL,SH] Allow user to override the default size for | |
1412 | per-device physically contiguous DMA buffers. | |
1413 | ||
1414 | memmap=exactmap [KNL,X86] Enable setting of an exact | |
1415 | E820 memory map, as specified by the user. | |
1416 | Such memmap=exactmap lines can be constructed based on | |
1417 | BIOS output or other requirements. See the memmap=nn@ss | |
1418 | option description. | |
1419 | ||
1420 | memmap=nn[KMG]@ss[KMG] | |
1421 | [KNL] Force usage of a specific region of memory | |
1422 | Region of memory to be used, from ss to ss+nn. | |
1423 | ||
1424 | memmap=nn[KMG]#ss[KMG] | |
1425 | [KNL,ACPI] Mark specific memory as ACPI data. | |
1426 | Region of memory to be used, from ss to ss+nn. | |
1427 | ||
1428 | memmap=nn[KMG]$ss[KMG] | |
1429 | [KNL,ACPI] Mark specific memory as reserved. | |
1430 | Region of memory to be used, from ss to ss+nn. | |
1431 | Example: Exclude memory from 0x18690000-0x1869ffff | |
1432 | memmap=64K$0x18690000 | |
1433 | or | |
1434 | memmap=0x10000$0x18690000 | |
1435 | ||
1436 | memory_corruption_check=0/1 [X86] | |
1437 | Some BIOSes seem to corrupt the first 64k of | |
1438 | memory when doing things like suspend/resume. | |
1439 | Setting this option will scan the memory | |
1440 | looking for corruption. Enabling this will | |
1441 | both detect corruption and prevent the kernel | |
1442 | from using the memory being corrupted. | |
1443 | However, its intended as a diagnostic tool; if | |
1444 | repeatable BIOS-originated corruption always | |
1445 | affects the same memory, you can use memmap= | |
1446 | to prevent the kernel from using that memory. | |
1447 | ||
1448 | memory_corruption_check_size=size [X86] | |
1449 | By default it checks for corruption in the low | |
1450 | 64k, making this memory unavailable for normal | |
1451 | use. Use this parameter to scan for | |
1452 | corruption in more or less memory. | |
1453 | ||
1454 | memory_corruption_check_period=seconds [X86] | |
1455 | By default it checks for corruption every 60 | |
1456 | seconds. Use this parameter to check at some | |
1457 | other rate. 0 disables periodic checking. | |
1458 | ||
1459 | memtest= [KNL,X86] Enable memtest | |
1460 | Format: <integer> | |
1461 | default : 0 <disable> | |
1462 | Specifies the number of memtest passes to be | |
1463 | performed. Each pass selects another test | |
1464 | pattern from a given set of patterns. Memtest | |
1465 | fills the memory with this pattern, validates | |
1466 | memory contents and reserves bad memory | |
1467 | regions that are detected. | |
1468 | ||
1469 | meye.*= [HW] Set MotionEye Camera parameters | |
1470 | See Documentation/video4linux/meye.txt. | |
1471 | ||
1472 | mfgpt_irq= [IA-32] Specify the IRQ to use for the | |
1473 | Multi-Function General Purpose Timers on AMD Geode | |
1474 | platforms. | |
1475 | ||
1476 | mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when | |
1477 | the BIOS has incorrectly applied a workaround. TinyBIOS | |
1478 | version 0.98 is known to be affected, 0.99 fixes the | |
1479 | problem by letting the user disable the workaround. | |
1480 | ||
1481 | mga= [HW,DRM] | |
1482 | ||
1483 | min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this | |
1484 | physical address is ignored. | |
1485 | ||
1486 | mini2440= [ARM,HW,KNL] | |
1487 | Format:[0..2][b][c][t] | |
1488 | Default: "0tb" | |
1489 | MINI2440 configuration specification: | |
1490 | 0 - The attached screen is the 3.5" TFT | |
1491 | 1 - The attached screen is the 7" TFT | |
1492 | 2 - The VGA Shield is attached (1024x768) | |
1493 | Leaving out the screen size parameter will not load | |
1494 | the TFT driver, and the framebuffer will be left | |
1495 | unconfigured. | |
1496 | b - Enable backlight. The TFT backlight pin will be | |
1497 | linked to the kernel VESA blanking code and a GPIO | |
1498 | LED. This parameter is not necessary when using the | |
1499 | VGA shield. | |
1500 | c - Enable the s3c camera interface. | |
1501 | t - Reserved for enabling touchscreen support. The | |
1502 | touchscreen support is not enabled in the mainstream | |
1503 | kernel as of 2.6.30, a preliminary port can be found | |
1504 | in the "bleeding edge" mini2440 support kernel at | |
1505 | http://repo.or.cz/w/linux-2.6/mini2440.git | |
1506 | ||
1507 | mminit_loglevel= | |
1508 | [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this | |
1509 | parameter allows control of the logging verbosity for | |
1510 | the additional memory initialisation checks. A value | |
1511 | of 0 disables mminit logging and a level of 4 will | |
1512 | log everything. Information is printed at KERN_DEBUG | |
1513 | so loglevel=8 may also need to be specified. | |
1514 | ||
1515 | mousedev.tap_time= | |
1516 | [MOUSE] Maximum time between finger touching and | |
1517 | leaving touchpad surface for touch to be considered | |
1518 | a tap and be reported as a left button click (for | |
1519 | touchpads working in absolute mode only). | |
1520 | Format: <msecs> | |
1521 | mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices | |
1522 | reporting absolute coordinates, such as tablets | |
1523 | mousedev.yres= [MOUSE] Vertical screen resolution, used for devices | |
1524 | reporting absolute coordinates, such as tablets | |
1525 | ||
1526 | movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter | |
1527 | is similar to kernelcore except it specifies the | |
1528 | amount of memory used for migratable allocations. | |
1529 | If both kernelcore and movablecore is specified, | |
1530 | then kernelcore will be at *least* the specified | |
1531 | value but may be more. If movablecore on its own | |
1532 | is specified, the administrator must be careful | |
1533 | that the amount of memory usable for all allocations | |
1534 | is not too small. | |
1535 | ||
1536 | MTD_Partition= [MTD] | |
1537 | Format: <name>,<region-number>,<size>,<offset> | |
1538 | ||
1539 | MTD_Region= [MTD] Format: | |
1540 | <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>] | |
1541 | ||
1542 | mtdparts= [MTD] | |
1543 | See drivers/mtd/cmdlinepart.c. | |
1544 | ||
1545 | multitce=off [PPC] This parameter disables the use of the pSeries | |
1546 | firmware feature for updating multiple TCE entries | |
1547 | at a time. | |
1548 | ||
1549 | onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration | |
1550 | ||
1551 | Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock] | |
1552 | ||
1553 | boundary - index of last SLC block on Flex-OneNAND. | |
1554 | The remaining blocks are configured as MLC blocks. | |
1555 | lock - Configure if Flex-OneNAND boundary should be locked. | |
1556 | Once locked, the boundary cannot be changed. | |
1557 | 1 indicates lock status, 0 indicates unlock status. | |
1558 | ||
1559 | mtdset= [ARM] | |
1560 | ARM/S3C2412 JIVE boot control | |
1561 | ||
1562 | See arch/arm/mach-s3c2412/mach-jive.c | |
1563 | ||
1564 | mtouchusb.raw_coordinates= | |
1565 | [HW] Make the MicroTouch USB driver use raw coordinates | |
1566 | ('y', default) or cooked coordinates ('n') | |
1567 | ||
1568 | mtrr_chunk_size=nn[KMG] [X86] | |
1569 | used for mtrr cleanup. It is largest continuous chunk | |
1570 | that could hold holes aka. UC entries. | |
1571 | ||
1572 | mtrr_gran_size=nn[KMG] [X86] | |
1573 | Used for mtrr cleanup. It is granularity of mtrr block. | |
1574 | Default is 1. | |
1575 | Large value could prevent small alignment from | |
1576 | using up MTRRs. | |
1577 | ||
1578 | mtrr_spare_reg_nr=n [X86] | |
1579 | Format: <integer> | |
1580 | Range: 0,7 : spare reg number | |
1581 | Default : 1 | |
1582 | Used for mtrr cleanup. It is spare mtrr entries number. | |
1583 | Set to 2 or more if your graphical card needs more. | |
1584 | ||
1585 | n2= [NET] SDL Inc. RISCom/N2 synchronous serial card | |
1586 | ||
1587 | netdev= [NET] Network devices parameters | |
1588 | Format: <irq>,<io>,<mem_start>,<mem_end>,<name> | |
1589 | Note that mem_start is often overloaded to mean | |
1590 | something different and driver-specific. | |
1591 | This usage is only documented in each driver source | |
1592 | file if at all. | |
1593 | ||
1594 | nf_conntrack.acct= | |
1595 | [NETFILTER] Enable connection tracking flow accounting | |
1596 | 0 to disable accounting | |
1597 | 1 to enable accounting | |
1598 | Default value is 0. | |
1599 | ||
1600 | nfsaddrs= [NFS] Deprecated. Use ip= instead. | |
1601 | See Documentation/filesystems/nfs/nfsroot.txt. | |
1602 | ||
1603 | nfsroot= [NFS] nfs root filesystem for disk-less boxes. | |
1604 | See Documentation/filesystems/nfs/nfsroot.txt. | |
1605 | ||
1606 | nfsrootdebug [NFS] enable nfsroot debugging messages. | |
1607 | See Documentation/filesystems/nfs/nfsroot.txt. | |
1608 | ||
1609 | nfs.callback_tcpport= | |
1610 | [NFS] set the TCP port on which the NFSv4 callback | |
1611 | channel should listen. | |
1612 | ||
1613 | nfs.cache_getent= | |
1614 | [NFS] sets the pathname to the program which is used | |
1615 | to update the NFS client cache entries. | |
1616 | ||
1617 | nfs.cache_getent_timeout= | |
1618 | [NFS] sets the timeout after which an attempt to | |
1619 | update a cache entry is deemed to have failed. | |
1620 | ||
1621 | nfs.idmap_cache_timeout= | |
1622 | [NFS] set the maximum lifetime for idmapper cache | |
1623 | entries. | |
1624 | ||
1625 | nfs.enable_ino64= | |
1626 | [NFS] enable 64-bit inode numbers. | |
1627 | If zero, the NFS client will fake up a 32-bit inode | |
1628 | number for the readdir() and stat() syscalls instead | |
1629 | of returning the full 64-bit number. | |
1630 | The default is to return 64-bit inode numbers. | |
1631 | ||
1632 | nfs.nfs4_disable_idmapping= | |
1633 | [NFSv4] When set, this option disables the NFSv4 | |
1634 | idmapper on the client, but only if the mount | |
1635 | is using the 'sec=sys' security flavour. This may | |
1636 | make migration from legacy NFSv2/v3 systems easier | |
1637 | provided that the server has the appropriate support. | |
1638 | The default is to always enable NFSv4 idmapping. | |
1639 | ||
1640 | nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take | |
1641 | when a NMI is triggered. | |
1642 | Format: [state][,regs][,debounce][,die] | |
1643 | ||
1644 | nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels | |
1645 | Format: [panic,][nopanic,][num] | |
1646 | Valid num: 0 | |
1647 | 0 - turn nmi_watchdog off | |
1648 | When panic is specified, panic when an NMI watchdog | |
1649 | timeout occurs (or 'nopanic' to override the opposite | |
1650 | default). | |
1651 | This is useful when you use a panic=... timeout and | |
1652 | need the box quickly up again. | |
1653 | ||
1654 | netpoll.carrier_timeout= | |
1655 | [NET] Specifies amount of time (in seconds) that | |
1656 | netpoll should wait for a carrier. By default netpoll | |
1657 | waits 4 seconds. | |
1658 | ||
1659 | no387 [BUGS=X86-32] Tells the kernel to use the 387 maths | |
1660 | emulation library even if a 387 maths coprocessor | |
1661 | is present. | |
1662 | ||
1663 | no_console_suspend | |
1664 | [HW] Never suspend the console | |
1665 | Disable suspending of consoles during suspend and | |
1666 | hibernate operations. Once disabled, debugging | |
1667 | messages can reach various consoles while the rest | |
1668 | of the system is being put to sleep (ie, while | |
1669 | debugging driver suspend/resume hooks). This may | |
1670 | not work reliably with all consoles, but is known | |
1671 | to work with serial and VGA consoles. | |
1672 | To facilitate more flexible debugging, we also add | |
1673 | console_suspend, a printk module parameter to control | |
1674 | it. Users could use console_suspend (usually | |
1675 | /sys/module/printk/parameters/console_suspend) to | |
1676 | turn on/off it dynamically. | |
1677 | ||
1678 | noaliencache [MM, NUMA, SLAB] Disables the allocation of alien | |
1679 | caches in the slab allocator. Saves per-node memory, | |
1680 | but will impact performance. | |
1681 | ||
1682 | noalign [KNL,ARM] | |
1683 | ||
1684 | noapic [SMP,APIC] Tells the kernel to not make use of any | |
1685 | IOAPICs that may be present in the system. | |
1686 | ||
1687 | noautogroup Disable scheduler automatic task group creation. | |
1688 | ||
1689 | nobats [PPC] Do not use BATs for mapping kernel lowmem | |
1690 | on "Classic" PPC cores. | |
1691 | ||
1692 | nocache [ARM] | |
1693 | ||
1694 | noclflush [BUGS=X86] Don't use the CLFLUSH instruction | |
1695 | ||
1696 | nodelayacct [KNL] Disable per-task delay accounting | |
1697 | ||
1698 | nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects. | |
1699 | ||
1700 | nodsp [SH] Disable hardware DSP at boot time. | |
1701 | ||
1702 | noefi [X86] Disable EFI runtime services support. | |
1703 | ||
1704 | noexec [IA-64] | |
1705 | ||
1706 | noexec [X86] | |
1707 | On X86-32 available only on PAE configured kernels. | |
1708 | noexec=on: enable non-executable mappings (default) | |
1709 | noexec=off: disable non-executable mappings | |
1710 | ||
1711 | nosmep [X86] | |
1712 | Disable SMEP (Supervisor Mode Execution Protection) | |
1713 | even if it is supported by processor. | |
1714 | ||
1715 | noexec32 [X86-64] | |
1716 | This affects only 32-bit executables. | |
1717 | noexec32=on: enable non-executable mappings (default) | |
1718 | read doesn't imply executable mappings | |
1719 | noexec32=off: disable non-executable mappings | |
1720 | read implies executable mappings | |
1721 | ||
1722 | nofpu [SH] Disable hardware FPU at boot time. | |
1723 | ||
1724 | nofxsr [BUGS=X86-32] Disables x86 floating point extended | |
1725 | register save and restore. The kernel will only save | |
1726 | legacy floating-point registers on task switch. | |
1727 | ||
1728 | noxsave [BUGS=X86] Disables x86 extended register state save | |
1729 | and restore using xsave. The kernel will fallback to | |
1730 | enabling legacy floating-point and sse state. | |
1731 | ||
1732 | nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or | |
1733 | wfi(ARM) instruction doesn't work correctly and not to | |
1734 | use it. This is also useful when using JTAG debugger. | |
1735 | ||
1736 | no-hlt [BUGS=X86-32] Tells the kernel that the hlt | |
1737 | instruction doesn't work correctly and not to | |
1738 | use it. | |
1739 | ||
1740 | no_file_caps Tells the kernel not to honor file capabilities. The | |
1741 | only way then for a file to be executed with privilege | |
1742 | is to be setuid root or executed by root. | |
1743 | ||
1744 | nohalt [IA-64] Tells the kernel not to use the power saving | |
1745 | function PAL_HALT_LIGHT when idle. This increases | |
1746 | power-consumption. On the positive side, it reduces | |
1747 | interrupt wake-up latency, which may improve performance | |
1748 | in certain environments such as networked servers or | |
1749 | real-time systems. | |
1750 | ||
1751 | nohz= [KNL] Boottime enable/disable dynamic ticks | |
1752 | Valid arguments: on, off | |
1753 | Default: on | |
1754 | ||
1755 | noiotrap [SH] Disables trapped I/O port accesses. | |
1756 | ||
1757 | noirqdebug [X86-32] Disables the code which attempts to detect and | |
1758 | disable unhandled interrupt sources. | |
1759 | ||
1760 | no_timer_check [X86,APIC] Disables the code which tests for | |
1761 | broken timer IRQ sources. | |
1762 | ||
1763 | noisapnp [ISAPNP] Disables ISA PnP code. | |
1764 | ||
1765 | noinitrd [RAM] Tells the kernel not to load any configured | |
1766 | initial RAM disk. | |
1767 | ||
1768 | nointremap [X86-64, Intel-IOMMU] Do not enable interrupt | |
1769 | remapping. | |
1770 | [Deprecated - use intremap=off] | |
1771 | ||
1772 | nointroute [IA-64] | |
1773 | ||
1774 | nojitter [IA-64] Disables jitter checking for ITC timers. | |
1775 | ||
1776 | no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver | |
1777 | ||
1778 | no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page | |
1779 | fault handling. | |
1780 | ||
1781 | no-steal-acc [X86,KVM] Disable paravirtualized steal time accounting. | |
1782 | steal time is computed, but won't influence scheduler | |
1783 | behaviour | |
1784 | ||
1785 | nolapic [X86-32,APIC] Do not enable or use the local APIC. | |
1786 | ||
1787 | nolapic_timer [X86-32,APIC] Do not use the local APIC timer. | |
1788 | ||
1789 | noltlbs [PPC] Do not use large page/tlb entries for kernel | |
1790 | lowmem mapping on PPC40x. | |
1791 | ||
1792 | nomca [IA-64] Disable machine check abort handling | |
1793 | ||
1794 | nomce [X86-32] Machine Check Exception | |
1795 | ||
1796 | nomfgpt [X86-32] Disable Multi-Function General Purpose | |
1797 | Timer usage (for AMD Geode machines). | |
1798 | ||
1799 | nopat [X86] Disable PAT (page attribute table extension of | |
1800 | pagetables) support. | |
1801 | ||
1802 | norandmaps Don't use address space randomization. Equivalent to | |
1803 | echo 0 > /proc/sys/kernel/randomize_va_space | |
1804 | ||
1805 | noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops | |
1806 | ||
1807 | noreplace-smp [X86-32,SMP] Don't replace SMP instructions | |
1808 | with UP alternatives | |
1809 | ||
1810 | noresidual [PPC] Don't use residual data on PReP machines. | |
1811 | ||
1812 | nordrand [X86] Disable the direct use of the RDRAND | |
1813 | instruction even if it is supported by the | |
1814 | processor. RDRAND is still available to user | |
1815 | space applications. | |
1816 | ||
1817 | noresume [SWSUSP] Disables resume and restores original swap | |
1818 | space. | |
1819 | ||
1820 | no-scroll [VGA] Disables scrollback. | |
1821 | This is required for the Braillex ib80-piezo Braille | |
1822 | reader made by F.H. Papenmeier (Germany). | |
1823 | ||
1824 | nosbagart [IA-64] | |
1825 | ||
1826 | nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support. | |
1827 | ||
1828 | nosmp [SMP] Tells an SMP kernel to act as a UP kernel, | |
1829 | and disable the IO APIC. legacy for "maxcpus=0". | |
1830 | ||
1831 | nosoftlockup [KNL] Disable the soft-lockup detector. | |
1832 | ||
1833 | nosync [HW,M68K] Disables sync negotiation for all devices. | |
1834 | ||
1835 | notsc [BUGS=X86-32] Disable Time Stamp Counter | |
1836 | ||
1837 | nousb [USB] Disable the USB subsystem | |
1838 | ||
1839 | nowatchdog [KNL] Disable the lockup detector (NMI watchdog). | |
1840 | ||
1841 | nowb [ARM] | |
1842 | ||
1843 | nox2apic [X86-64,APIC] Do not enable x2APIC mode. | |
1844 | ||
1845 | nptcg= [IA-64] Override max number of concurrent global TLB | |
1846 | purges which is reported from either PAL_VM_SUMMARY or | |
1847 | SAL PALO. | |
1848 | ||
1849 | nr_cpus= [SMP] Maximum number of processors that an SMP kernel | |
1850 | could support. nr_cpus=n : n >= 1 limits the kernel to | |
1851 | supporting 'n' processors. Later in runtime you can not | |
1852 | use hotplug cpu feature to put more cpu back to online. | |
1853 | just like you compile the kernel NR_CPUS=n | |
1854 | ||
1855 | nr_uarts= [SERIAL] maximum number of UARTs to be registered. | |
1856 | ||
1857 | numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA. | |
1858 | one of ['zone', 'node', 'default'] can be specified | |
1859 | This can be set from sysctl after boot. | |
1860 | See Documentation/sysctl/vm.txt for details. | |
1861 | ||
1862 | ohci1394_dma=early [HW] enable debugging via the ohci1394 driver. | |
1863 | See Documentation/debugging-via-ohci1394.txt for more | |
1864 | info. | |
1865 | ||
1866 | olpc_ec_timeout= [OLPC] ms delay when issuing EC commands | |
1867 | Rather than timing out after 20 ms if an EC | |
1868 | command is not properly ACKed, override the length | |
1869 | of the timeout. We have interrupts disabled while | |
1870 | waiting for the ACK, so if this is set too high | |
1871 | interrupts *may* be lost! | |
1872 | ||
1873 | omap_mux= [OMAP] Override bootloader pin multiplexing. | |
1874 | Format: <mux_mode0.mode_name=value>... | |
1875 | For example, to override I2C bus2: | |
1876 | omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100 | |
1877 | ||
1878 | oprofile.timer= [HW] | |
1879 | Use timer interrupt instead of performance counters | |
1880 | ||
1881 | oprofile.cpu_type= Force an oprofile cpu type | |
1882 | This might be useful if you have an older oprofile | |
1883 | userland or if you want common events. | |
1884 | Format: { arch_perfmon } | |
1885 | arch_perfmon: [X86] Force use of architectural | |
1886 | perfmon on Intel CPUs instead of the | |
1887 | CPU specific event set. | |
1888 | ||
1889 | oops=panic Always panic on oopses. Default is to just kill the | |
1890 | process, but there is a small probability of | |
1891 | deadlocking the machine. | |
1892 | This will also cause panics on machine check exceptions. | |
1893 | Useful together with panic=30 to trigger a reboot. | |
1894 | ||
1895 | OSS [HW,OSS] | |
1896 | See Documentation/sound/oss/oss-parameters.txt | |
1897 | ||
1898 | panic= [KNL] Kernel behaviour on panic: delay <timeout> | |
1899 | timeout > 0: seconds before rebooting | |
1900 | timeout = 0: wait forever | |
1901 | timeout < 0: reboot immediately | |
1902 | Format: <timeout> | |
1903 | ||
1904 | parkbd.port= [HW] Parallel port number the keyboard adapter is | |
1905 | connected to, default is 0. | |
1906 | Format: <parport#> | |
1907 | parkbd.mode= [HW] Parallel port keyboard adapter mode of operation, | |
1908 | 0 for XT, 1 for AT (default is AT). | |
1909 | Format: <mode> | |
1910 | ||
1911 | parport= [HW,PPT] Specify parallel ports. 0 disables. | |
1912 | Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] } | |
1913 | Use 'auto' to force the driver to use any | |
1914 | IRQ/DMA settings detected (the default is to | |
1915 | ignore detected IRQ/DMA settings because of | |
1916 | possible conflicts). You can specify the base | |
1917 | address, IRQ, and DMA settings; IRQ and DMA | |
1918 | should be numbers, or 'auto' (for using detected | |
1919 | settings on that particular port), or 'nofifo' | |
1920 | (to avoid using a FIFO even if it is detected). | |
1921 | Parallel ports are assigned in the order they | |
1922 | are specified on the command line, starting | |
1923 | with parport0. | |
1924 | ||
1925 | parport_init_mode= [HW,PPT] | |
1926 | Configure VIA parallel port to operate in | |
1927 | a specific mode. This is necessary on Pegasos | |
1928 | computer where firmware has no options for setting | |
1929 | up parallel port mode and sets it to spp. | |
1930 | Currently this function knows 686a and 8231 chips. | |
1931 | Format: [spp|ps2|epp|ecp|ecpepp] | |
1932 | ||
1933 | pause_on_oops= | |
1934 | Halt all CPUs after the first oops has been printed for | |
1935 | the specified number of seconds. This is to be used if | |
1936 | your oopses keep scrolling off the screen. | |
1937 | ||
1938 | pcbit= [HW,ISDN] | |
1939 | ||
1940 | pcd. [PARIDE] | |
1941 | See header of drivers/block/paride/pcd.c. | |
1942 | See also Documentation/blockdev/paride.txt. | |
1943 | ||
1944 | pci=option[,option...] [PCI] various PCI subsystem options: | |
1945 | earlydump [X86] dump PCI config space before the kernel | |
1946 | changes anything | |
1947 | off [X86] don't probe for the PCI bus | |
1948 | bios [X86-32] force use of PCI BIOS, don't access | |
1949 | the hardware directly. Use this if your machine | |
1950 | has a non-standard PCI host bridge. | |
1951 | nobios [X86-32] disallow use of PCI BIOS, only direct | |
1952 | hardware access methods are allowed. Use this | |
1953 | if you experience crashes upon bootup and you | |
1954 | suspect they are caused by the BIOS. | |
1955 | conf1 [X86] Force use of PCI Configuration | |
1956 | Mechanism 1. | |
1957 | conf2 [X86] Force use of PCI Configuration | |
1958 | Mechanism 2. | |
1959 | noaer [PCIE] If the PCIEAER kernel config parameter is | |
1960 | enabled, this kernel boot option can be used to | |
1961 | disable the use of PCIE advanced error reporting. | |
1962 | nodomains [PCI] Disable support for multiple PCI | |
1963 | root domains (aka PCI segments, in ACPI-speak). | |
1964 | nommconf [X86] Disable use of MMCONFIG for PCI | |
1965 | Configuration | |
1966 | check_enable_amd_mmconf [X86] check for and enable | |
1967 | properly configured MMIO access to PCI | |
1968 | config space on AMD family 10h CPU | |
1969 | nomsi [MSI] If the PCI_MSI kernel config parameter is | |
1970 | enabled, this kernel boot option can be used to | |
1971 | disable the use of MSI interrupts system-wide. | |
1972 | noioapicquirk [APIC] Disable all boot interrupt quirks. | |
1973 | Safety option to keep boot IRQs enabled. This | |
1974 | should never be necessary. | |
1975 | ioapicreroute [APIC] Enable rerouting of boot IRQs to the | |
1976 | primary IO-APIC for bridges that cannot disable | |
1977 | boot IRQs. This fixes a source of spurious IRQs | |
1978 | when the system masks IRQs. | |
1979 | noioapicreroute [APIC] Disable workaround that uses the | |
1980 | boot IRQ equivalent of an IRQ that connects to | |
1981 | a chipset where boot IRQs cannot be disabled. | |
1982 | The opposite of ioapicreroute. | |
1983 | biosirq [X86-32] Use PCI BIOS calls to get the interrupt | |
1984 | routing table. These calls are known to be buggy | |
1985 | on several machines and they hang the machine | |
1986 | when used, but on other computers it's the only | |
1987 | way to get the interrupt routing table. Try | |
1988 | this option if the kernel is unable to allocate | |
1989 | IRQs or discover secondary PCI buses on your | |
1990 | motherboard. | |
1991 | rom [X86] Assign address space to expansion ROMs. | |
1992 | Use with caution as certain devices share | |
1993 | address decoders between ROMs and other | |
1994 | resources. | |
1995 | norom [X86] Do not assign address space to | |
1996 | expansion ROMs that do not already have | |
1997 | BIOS assigned address ranges. | |
1998 | nobar [X86] Do not assign address space to the | |
1999 | BARs that weren't assigned by the BIOS. | |
2000 | irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be | |
2001 | assigned automatically to PCI devices. You can | |
2002 | make the kernel exclude IRQs of your ISA cards | |
2003 | this way. | |
2004 | pirqaddr=0xAAAAA [X86] Specify the physical address | |
2005 | of the PIRQ table (normally generated | |
2006 | by the BIOS) if it is outside the | |
2007 | F0000h-100000h range. | |
2008 | lastbus=N [X86] Scan all buses thru bus #N. Can be | |
2009 | useful if the kernel is unable to find your | |
2010 | secondary buses and you want to tell it | |
2011 | explicitly which ones they are. | |
2012 | assign-busses [X86] Always assign all PCI bus | |
2013 | numbers ourselves, overriding | |
2014 | whatever the firmware may have done. | |
2015 | usepirqmask [X86] Honor the possible IRQ mask stored | |
2016 | in the BIOS $PIR table. This is needed on | |
2017 | some systems with broken BIOSes, notably | |
2018 | some HP Pavilion N5400 and Omnibook XE3 | |
2019 | notebooks. This will have no effect if ACPI | |
2020 | IRQ routing is enabled. | |
2021 | noacpi [X86] Do not use ACPI for IRQ routing | |
2022 | or for PCI scanning. | |
2023 | use_crs [X86] Use PCI host bridge window information | |
2024 | from ACPI. On BIOSes from 2008 or later, this | |
2025 | is enabled by default. If you need to use this, | |
2026 | please report a bug. | |
2027 | nocrs [X86] Ignore PCI host bridge windows from ACPI. | |
2028 | If you need to use this, please report a bug. | |
2029 | routeirq Do IRQ routing for all PCI devices. | |
2030 | This is normally done in pci_enable_device(), | |
2031 | so this option is a temporary workaround | |
2032 | for broken drivers that don't call it. | |
2033 | skip_isa_align [X86] do not align io start addr, so can | |
2034 | handle more pci cards | |
2035 | firmware [ARM] Do not re-enumerate the bus but instead | |
2036 | just use the configuration from the | |
2037 | bootloader. This is currently used on | |
2038 | IXP2000 systems where the bus has to be | |
2039 | configured a certain way for adjunct CPUs. | |
2040 | noearly [X86] Don't do any early type 1 scanning. | |
2041 | This might help on some broken boards which | |
2042 | machine check when some devices' config space | |
2043 | is read. But various workarounds are disabled | |
2044 | and some IOMMU drivers will not work. | |
2045 | bfsort Sort PCI devices into breadth-first order. | |
2046 | This sorting is done to get a device | |
2047 | order compatible with older (<= 2.4) kernels. | |
2048 | nobfsort Don't sort PCI devices into breadth-first order. | |
2049 | cbiosize=nn[KMG] The fixed amount of bus space which is | |
2050 | reserved for the CardBus bridge's IO window. | |
2051 | The default value is 256 bytes. | |
2052 | cbmemsize=nn[KMG] The fixed amount of bus space which is | |
2053 | reserved for the CardBus bridge's memory | |
2054 | window. The default value is 64 megabytes. | |
2055 | resource_alignment= | |
2056 | Format: | |
2057 | [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...] | |
2058 | Specifies alignment and device to reassign | |
2059 | aligned memory resources. | |
2060 | If <order of align> is not specified, | |
2061 | PAGE_SIZE is used as alignment. | |
2062 | PCI-PCI bridge can be specified, if resource | |
2063 | windows need to be expanded. | |
2064 | ecrc= Enable/disable PCIe ECRC (transaction layer | |
2065 | end-to-end CRC checking). | |
2066 | bios: Use BIOS/firmware settings. This is the | |
2067 | the default. | |
2068 | off: Turn ECRC off | |
2069 | on: Turn ECRC on. | |
2070 | realloc reallocate PCI resources if allocations done by BIOS | |
2071 | are erroneous. | |
2072 | ||
2073 | pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power | |
2074 | Management. | |
2075 | off Disable ASPM. | |
2076 | force Enable ASPM even on devices that claim not to support it. | |
2077 | WARNING: Forcing ASPM on may cause system lockups. | |
2078 | ||
2079 | pcie_ports= [PCIE] PCIe ports handling: | |
2080 | auto Ask the BIOS whether or not to use native PCIe services | |
2081 | associated with PCIe ports (PME, hot-plug, AER). Use | |
2082 | them only if that is allowed by the BIOS. | |
2083 | native Use native PCIe services associated with PCIe ports | |
2084 | unconditionally. | |
2085 | compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe | |
2086 | ports driver. | |
2087 | ||
2088 | pcie_pme= [PCIE,PM] Native PCIe PME signaling options: | |
2089 | nomsi Do not use MSI for native PCIe PME signaling (this makes | |
2090 | all PCIe root ports use INTx for all services). | |
2091 | ||
2092 | pcmv= [HW,PCMCIA] BadgePAD 4 | |
2093 | ||
2094 | pd. [PARIDE] | |
2095 | See Documentation/blockdev/paride.txt. | |
2096 | ||
2097 | pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at | |
2098 | boot time. | |
2099 | Format: { 0 | 1 } | |
2100 | See arch/parisc/kernel/pdc_chassis.c | |
2101 | ||
2102 | percpu_alloc= Select which percpu first chunk allocator to use. | |
2103 | Currently supported values are "embed" and "page". | |
2104 | Archs may support subset or none of the selections. | |
2105 | See comments in mm/percpu.c for details on each | |
2106 | allocator. This parameter is primarily for debugging | |
2107 | and performance comparison. | |
2108 | ||
2109 | pf. [PARIDE] | |
2110 | See Documentation/blockdev/paride.txt. | |
2111 | ||
2112 | pg. [PARIDE] | |
2113 | See Documentation/blockdev/paride.txt. | |
2114 | ||
2115 | pirq= [SMP,APIC] Manual mp-table setup | |
2116 | See Documentation/x86/i386/IO-APIC.txt. | |
2117 | ||
2118 | plip= [PPT,NET] Parallel port network link | |
2119 | Format: { parport<nr> | timid | 0 } | |
2120 | See also Documentation/parport.txt. | |
2121 | ||
2122 | pmtmr= [X86] Manual setup of pmtmr I/O Port. | |
2123 | Override pmtimer IOPort with a hex value. | |
2124 | e.g. pmtmr=0x508 | |
2125 | ||
2126 | pnp.debug=1 [PNP] | |
2127 | Enable PNP debug messages (depends on the | |
2128 | CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time | |
2129 | via /sys/module/pnp/parameters/debug. We always show | |
2130 | current resource usage; turning this on also shows | |
2131 | possible settings and some assignment information. | |
2132 | ||
2133 | pnpacpi= [ACPI] | |
2134 | { off } | |
2135 | ||
2136 | pnpbios= [ISAPNP] | |
2137 | { on | off | curr | res | no-curr | no-res } | |
2138 | ||
2139 | pnp_reserve_irq= | |
2140 | [ISAPNP] Exclude IRQs for the autoconfiguration | |
2141 | ||
2142 | pnp_reserve_dma= | |
2143 | [ISAPNP] Exclude DMAs for the autoconfiguration | |
2144 | ||
2145 | pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration | |
2146 | Ranges are in pairs (I/O port base and size). | |
2147 | ||
2148 | pnp_reserve_mem= | |
2149 | [ISAPNP] Exclude memory regions for the | |
2150 | autoconfiguration. | |
2151 | Ranges are in pairs (memory base and size). | |
2152 | ||
2153 | ports= [IP_VS_FTP] IPVS ftp helper module | |
2154 | Default is 21. | |
2155 | Up to 8 (IP_VS_APP_MAX_PORTS) ports | |
2156 | may be specified. | |
2157 | Format: <port>,<port>.... | |
2158 | ||
2159 | print-fatal-signals= | |
2160 | [KNL] debug: print fatal signals | |
2161 | ||
2162 | If enabled, warn about various signal handling | |
2163 | related application anomalies: too many signals, | |
2164 | too many POSIX.1 timers, fatal signals causing a | |
2165 | coredump - etc. | |
2166 | ||
2167 | If you hit the warning due to signal overflow, | |
2168 | you might want to try "ulimit -i unlimited". | |
2169 | ||
2170 | default: off. | |
2171 | ||
2172 | printk.time= Show timing data prefixed to each printk message line | |
2173 | Format: <bool> (1/Y/y=enable, 0/N/n=disable) | |
2174 | ||
2175 | processor.max_cstate= [HW,ACPI] | |
2176 | Limit processor to maximum C-state | |
2177 | max_cstate=9 overrides any DMI blacklist limit. | |
2178 | ||
2179 | processor.nocst [HW,ACPI] | |
2180 | Ignore the _CST method to determine C-states, | |
2181 | instead using the legacy FADT method | |
2182 | ||
2183 | profile= [KNL] Enable kernel profiling via /proc/profile | |
2184 | Format: [schedule,]<number> | |
2185 | Param: "schedule" - profile schedule points. | |
2186 | Param: <number> - step/bucket size as a power of 2 for | |
2187 | statistical time based profiling. | |
2188 | Param: "sleep" - profile D-state sleeping (millisecs). | |
2189 | Requires CONFIG_SCHEDSTATS | |
2190 | Param: "kvm" - profile VM exits. | |
2191 | ||
2192 | prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk | |
2193 | before loading. | |
2194 | See Documentation/blockdev/ramdisk.txt. | |
2195 | ||
2196 | psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to | |
2197 | probe for; one of (bare|imps|exps|lifebook|any). | |
2198 | psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports | |
2199 | per second. | |
2200 | psmouse.resetafter= [HW,MOUSE] | |
2201 | Try to reset the device after so many bad packets | |
2202 | (0 = never). | |
2203 | psmouse.resolution= | |
2204 | [HW,MOUSE] Set desired mouse resolution, in dpi. | |
2205 | psmouse.smartscroll= | |
2206 | [HW,MOUSE] Controls Logitech smartscroll autorepeat. | |
2207 | 0 = disabled, 1 = enabled (default). | |
2208 | ||
2209 | pstore.backend= Specify the name of the pstore backend to use | |
2210 | ||
2211 | pt. [PARIDE] | |
2212 | See Documentation/blockdev/paride.txt. | |
2213 | ||
2214 | pty.legacy_count= | |
2215 | [KNL] Number of legacy pty's. Overwrites compiled-in | |
2216 | default number. | |
2217 | ||
2218 | quiet [KNL] Disable most log messages | |
2219 | ||
2220 | r128= [HW,DRM] | |
2221 | ||
2222 | raid= [HW,RAID] | |
2223 | See Documentation/md.txt. | |
2224 | ||
2225 | ramdisk_blocksize= [RAM] | |
2226 | See Documentation/blockdev/ramdisk.txt. | |
2227 | ||
2228 | ramdisk_size= [RAM] Sizes of RAM disks in kilobytes | |
2229 | See Documentation/blockdev/ramdisk.txt. | |
2230 | ||
2231 | rcupdate.blimit= [KNL,BOOT] | |
2232 | Set maximum number of finished RCU callbacks to process | |
2233 | in one batch. | |
2234 | ||
2235 | rcupdate.qhimark= [KNL,BOOT] | |
2236 | Set threshold of queued | |
2237 | RCU callbacks over which batch limiting is disabled. | |
2238 | ||
2239 | rcupdate.qlowmark= [KNL,BOOT] | |
2240 | Set threshold of queued RCU callbacks below which | |
2241 | batch limiting is re-enabled. | |
2242 | ||
2243 | rdinit= [KNL] | |
2244 | Format: <full_path> | |
2245 | Run specified binary instead of /init from the ramdisk, | |
2246 | used for early userspace startup. See initrd. | |
2247 | ||
2248 | reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode | |
2249 | Format: <reboot_mode>[,<reboot_mode2>[,...]] | |
2250 | See arch/*/kernel/reboot.c or arch/*/kernel/process.c | |
2251 | ||
2252 | relax_domain_level= | |
2253 | [KNL, SMP] Set scheduler's default relax_domain_level. | |
2254 | See Documentation/cgroups/cpusets.txt. | |
2255 | ||
2256 | reserve= [KNL,BUGS] Force the kernel to ignore some iomem area | |
2257 | ||
2258 | reservetop= [X86-32] | |
2259 | Format: nn[KMG] | |
2260 | Reserves a hole at the top of the kernel virtual | |
2261 | address space. | |
2262 | ||
2263 | reservelow= [X86] | |
2264 | Format: nn[K] | |
2265 | Set the amount of memory to reserve for BIOS at | |
2266 | the bottom of the address space. | |
2267 | ||
2268 | reset_devices [KNL] Force drivers to reset the underlying device | |
2269 | during initialization. | |
2270 | ||
2271 | resume= [SWSUSP] | |
2272 | Specify the partition device for software suspend | |
2273 | ||
2274 | resume_offset= [SWSUSP] | |
2275 | Specify the offset from the beginning of the partition | |
2276 | given by "resume=" at which the swap header is located, | |
2277 | in <PAGE_SIZE> units (needed only for swap files). | |
2278 | See Documentation/power/swsusp-and-swap-files.txt | |
2279 | ||
2280 | resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to | |
2281 | read the resume files | |
2282 | ||
2283 | resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up. | |
2284 | Useful for devices that are detected asynchronously | |
2285 | (e.g. USB and MMC devices). | |
2286 | ||
2287 | hibernate= [HIBERNATION] | |
2288 | noresume Don't check if there's a hibernation image | |
2289 | present during boot. | |
2290 | nocompress Don't compress/decompress hibernation images. | |
2291 | ||
2292 | retain_initrd [RAM] Keep initrd memory after extraction | |
2293 | ||
2294 | rhash_entries= [KNL,NET] | |
2295 | Set number of hash buckets for route cache | |
2296 | ||
2297 | riscom8= [HW,SERIAL] | |
2298 | Format: <io_board1>[,<io_board2>[,...<io_boardN>]] | |
2299 | ||
2300 | ro [KNL] Mount root device read-only on boot | |
2301 | ||
2302 | root= [KNL] Root filesystem | |
2303 | See name_to_dev_t comment in init/do_mounts.c. | |
2304 | ||
2305 | rootdelay= [KNL] Delay (in seconds) to pause before attempting to | |
2306 | mount the root filesystem | |
2307 | ||
2308 | rootflags= [KNL] Set root filesystem mount option string | |
2309 | ||
2310 | rootfstype= [KNL] Set root filesystem type | |
2311 | ||
2312 | rootwait [KNL] Wait (indefinitely) for root device to show up. | |
2313 | Useful for devices that are detected asynchronously | |
2314 | (e.g. USB and MMC devices). | |
2315 | ||
2316 | rw [KNL] Mount root device read-write on boot | |
2317 | ||
2318 | S [KNL] Run init in single mode | |
2319 | ||
2320 | sa1100ir [NET] | |
2321 | See drivers/net/irda/sa1100_ir.c. | |
2322 | ||
2323 | sbni= [NET] Granch SBNI12 leased line adapter | |
2324 | ||
2325 | sched_debug [KNL] Enables verbose scheduler debug messages. | |
2326 | ||
2327 | security= [SECURITY] Choose a security module to enable at boot. | |
2328 | If this boot parameter is not specified, only the first | |
2329 | security module asking for security registration will be | |
2330 | loaded. An invalid security module name will be treated | |
2331 | as if no module has been chosen. | |
2332 | ||
2333 | selinux= [SELINUX] Disable or enable SELinux at boot time. | |
2334 | Format: { "0" | "1" } | |
2335 | See security/selinux/Kconfig help text. | |
2336 | 0 -- disable. | |
2337 | 1 -- enable. | |
2338 | Default value is set via kernel config option. | |
2339 | If enabled at boot time, /selinux/disable can be used | |
2340 | later to disable prior to initial policy load. | |
2341 | ||
2342 | apparmor= [APPARMOR] Disable or enable AppArmor at boot time | |
2343 | Format: { "0" | "1" } | |
2344 | See security/apparmor/Kconfig help text | |
2345 | 0 -- disable. | |
2346 | 1 -- enable. | |
2347 | Default value is set via kernel config option. | |
2348 | ||
2349 | serialnumber [BUGS=X86-32] | |
2350 | ||
2351 | shapers= [NET] | |
2352 | Maximal number of shapers. | |
2353 | ||
2354 | show_msr= [x86] show boot-time MSR settings | |
2355 | Format: { <integer> } | |
2356 | Show boot-time (BIOS-initialized) MSR settings. | |
2357 | The parameter means the number of CPUs to show, | |
2358 | for example 1 means boot CPU only. | |
2359 | ||
2360 | simeth= [IA-64] | |
2361 | simscsi= | |
2362 | ||
2363 | slram= [HW,MTD] | |
2364 | ||
2365 | slub_debug[=options[,slabs]] [MM, SLUB] | |
2366 | Enabling slub_debug allows one to determine the | |
2367 | culprit if slab objects become corrupted. Enabling | |
2368 | slub_debug can create guard zones around objects and | |
2369 | may poison objects when not in use. Also tracks the | |
2370 | last alloc / free. For more information see | |
2371 | Documentation/vm/slub.txt. | |
2372 | ||
2373 | slub_max_order= [MM, SLUB] | |
2374 | Determines the maximum allowed order for slabs. | |
2375 | A high setting may cause OOMs due to memory | |
2376 | fragmentation. For more information see | |
2377 | Documentation/vm/slub.txt. | |
2378 | ||
2379 | slub_min_objects= [MM, SLUB] | |
2380 | The minimum number of objects per slab. SLUB will | |
2381 | increase the slab order up to slub_max_order to | |
2382 | generate a sufficiently large slab able to contain | |
2383 | the number of objects indicated. The higher the number | |
2384 | of objects the smaller the overhead of tracking slabs | |
2385 | and the less frequently locks need to be acquired. | |
2386 | For more information see Documentation/vm/slub.txt. | |
2387 | ||
2388 | slub_min_order= [MM, SLUB] | |
2389 | Determines the mininum page order for slabs. Must be | |
2390 | lower than slub_max_order. | |
2391 | For more information see Documentation/vm/slub.txt. | |
2392 | ||
2393 | slub_nomerge [MM, SLUB] | |
2394 | Disable merging of slabs with similar size. May be | |
2395 | necessary if there is some reason to distinguish | |
2396 | allocs to different slabs. Debug options disable | |
2397 | merging on their own. | |
2398 | For more information see Documentation/vm/slub.txt. | |
2399 | ||
2400 | smart2= [HW] | |
2401 | Format: <io1>[,<io2>[,...,<io8>]] | |
2402 | ||
2403 | smp-alt-once [X86-32,SMP] On a hotplug CPU system, only | |
2404 | attempt to substitute SMP alternatives once at boot. | |
2405 | ||
2406 | smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices | |
2407 | smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port | |
2408 | smsc-ircc2.ircc_sir= [HW] SIR base I/O port | |
2409 | smsc-ircc2.ircc_fir= [HW] FIR base I/O port | |
2410 | smsc-ircc2.ircc_irq= [HW] IRQ line | |
2411 | smsc-ircc2.ircc_dma= [HW] DMA channel | |
2412 | smsc-ircc2.ircc_transceiver= [HW] Transceiver type: | |
2413 | 0: Toshiba Satellite 1800 (GP data pin select) | |
2414 | 1: Fast pin select (default) | |
2415 | 2: ATC IRMode | |
2416 | ||
2417 | softlockup_panic= | |
2418 | [KNL] Should the soft-lockup detector generate panics. | |
2419 | Format: <integer> | |
2420 | ||
2421 | sonypi.*= [HW] Sony Programmable I/O Control Device driver | |
2422 | See Documentation/laptops/sonypi.txt | |
2423 | ||
2424 | specialix= [HW,SERIAL] Specialix multi-serial port adapter | |
2425 | See Documentation/serial/specialix.txt. | |
2426 | ||
2427 | spia_io_base= [HW,MTD] | |
2428 | spia_fio_base= | |
2429 | spia_pedr= | |
2430 | spia_peddr= | |
2431 | ||
2432 | stacktrace [FTRACE] | |
2433 | Enabled the stack tracer on boot up. | |
2434 | ||
2435 | sti= [PARISC,HW] | |
2436 | Format: <num> | |
2437 | Set the STI (builtin display/keyboard on the HP-PARISC | |
2438 | machines) console (graphic card) which should be used | |
2439 | as the initial boot-console. | |
2440 | See also comment in drivers/video/console/sticore.c. | |
2441 | ||
2442 | sti_font= [HW] | |
2443 | See comment in drivers/video/console/sticore.c. | |
2444 | ||
2445 | stifb= [HW] | |
2446 | Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]] | |
2447 | ||
2448 | sunrpc.min_resvport= | |
2449 | sunrpc.max_resvport= | |
2450 | [NFS,SUNRPC] | |
2451 | SunRPC servers often require that client requests | |
2452 | originate from a privileged port (i.e. a port in the | |
2453 | range 0 < portnr < 1024). | |
2454 | An administrator who wishes to reserve some of these | |
2455 | ports for other uses may adjust the range that the | |
2456 | kernel's sunrpc client considers to be privileged | |
2457 | using these two parameters to set the minimum and | |
2458 | maximum port values. | |
2459 | ||
2460 | sunrpc.pool_mode= | |
2461 | [NFS] | |
2462 | Control how the NFS server code allocates CPUs to | |
2463 | service thread pools. Depending on how many NICs | |
2464 | you have and where their interrupts are bound, this | |
2465 | option will affect which CPUs will do NFS serving. | |
2466 | Note: this parameter cannot be changed while the | |
2467 | NFS server is running. | |
2468 | ||
2469 | auto the server chooses an appropriate mode | |
2470 | automatically using heuristics | |
2471 | global a single global pool contains all CPUs | |
2472 | percpu one pool for each CPU | |
2473 | pernode one pool for each NUMA node (equivalent | |
2474 | to global on non-NUMA machines) | |
2475 | ||
2476 | sunrpc.tcp_slot_table_entries= | |
2477 | sunrpc.udp_slot_table_entries= | |
2478 | [NFS,SUNRPC] | |
2479 | Sets the upper limit on the number of simultaneous | |
2480 | RPC calls that can be sent from the client to a | |
2481 | server. Increasing these values may allow you to | |
2482 | improve throughput, but will also increase the | |
2483 | amount of memory reserved for use by the client. | |
2484 | ||
2485 | swapaccount[=0|1] | |
2486 | [KNL] Enable accounting of swap in memory resource | |
2487 | controller if no parameter or 1 is given or disable | |
2488 | it if 0 is given (See Documentation/cgroups/memory.txt) | |
2489 | ||
2490 | swiotlb= [IA-64] Number of I/O TLB slabs | |
2491 | ||
2492 | switches= [HW,M68k] | |
2493 | ||
2494 | sysfs.deprecated=0|1 [KNL] | |
2495 | Enable/disable old style sysfs layout for old udev | |
2496 | on older distributions. When this option is enabled | |
2497 | very new udev will not work anymore. When this option | |
2498 | is disabled (or CONFIG_SYSFS_DEPRECATED not compiled) | |
2499 | in older udev will not work anymore. | |
2500 | Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in | |
2501 | the kernel configuration. | |
2502 | ||
2503 | sysrq_always_enabled | |
2504 | [KNL] | |
2505 | Ignore sysrq setting - this boot parameter will | |
2506 | neutralize any effect of /proc/sys/kernel/sysrq. | |
2507 | Useful for debugging. | |
2508 | ||
2509 | tdfx= [HW,DRM] | |
2510 | ||
2511 | test_suspend= [SUSPEND] | |
2512 | Specify "mem" (for Suspend-to-RAM) or "standby" (for | |
2513 | standby suspend) as the system sleep state to briefly | |
2514 | enter during system startup. The system is woken from | |
2515 | this state using a wakeup-capable RTC alarm. | |
2516 | ||
2517 | thash_entries= [KNL,NET] | |
2518 | Set number of hash buckets for TCP connection | |
2519 | ||
2520 | thermal.act= [HW,ACPI] | |
2521 | -1: disable all active trip points in all thermal zones | |
2522 | <degrees C>: override all lowest active trip points | |
2523 | ||
2524 | thermal.crt= [HW,ACPI] | |
2525 | -1: disable all critical trip points in all thermal zones | |
2526 | <degrees C>: override all critical trip points | |
2527 | ||
2528 | thermal.nocrt= [HW,ACPI] | |
2529 | Set to disable actions on ACPI thermal zone | |
2530 | critical and hot trip points. | |
2531 | ||
2532 | thermal.off= [HW,ACPI] | |
2533 | 1: disable ACPI thermal control | |
2534 | ||
2535 | thermal.psv= [HW,ACPI] | |
2536 | -1: disable all passive trip points | |
2537 | <degrees C>: override all passive trip points to this | |
2538 | value | |
2539 | ||
2540 | thermal.tzp= [HW,ACPI] | |
2541 | Specify global default ACPI thermal zone polling rate | |
2542 | <deci-seconds>: poll all this frequency | |
2543 | 0: no polling (default) | |
2544 | ||
2545 | threadirqs [KNL] | |
2546 | Force threading of all interrupt handlers except those | |
2547 | marked explicitely IRQF_NO_THREAD. | |
2548 | ||
2549 | topology= [S390] | |
2550 | Format: {off | on} | |
2551 | Specify if the kernel should make use of the cpu | |
2552 | topology information if the hardware supports this. | |
2553 | The scheduler will make use of this information and | |
2554 | e.g. base its process migration decisions on it. | |
2555 | Default is on. | |
2556 | ||
2557 | tp720= [HW,PS2] | |
2558 | ||
2559 | tpm_suspend_pcr=[HW,TPM] | |
2560 | Format: integer pcr id | |
2561 | Specify that at suspend time, the tpm driver | |
2562 | should extend the specified pcr with zeros, | |
2563 | as a workaround for some chips which fail to | |
2564 | flush the last written pcr on TPM_SaveState. | |
2565 | This will guarantee that all the other pcrs | |
2566 | are saved. | |
2567 | ||
2568 | trace_buf_size=nn[KMG] | |
2569 | [FTRACE] will set tracing buffer size. | |
2570 | ||
2571 | trace_event=[event-list] | |
2572 | [FTRACE] Set and start specified trace events in order | |
2573 | to facilitate early boot debugging. | |
2574 | See also Documentation/trace/events.txt | |
2575 | ||
2576 | tsc= Disable clocksource stability checks for TSC. | |
2577 | Format: <string> | |
2578 | [x86] reliable: mark tsc clocksource as reliable, this | |
2579 | disables clocksource verification at runtime, as well | |
2580 | as the stability checks done at bootup. Used to enable | |
2581 | high-resolution timer mode on older hardware, and in | |
2582 | virtualized environment. | |
2583 | [x86] noirqtime: Do not use TSC to do irq accounting. | |
2584 | Used to run time disable IRQ_TIME_ACCOUNTING on any | |
2585 | platforms where RDTSC is slow and this accounting | |
2586 | can add overhead. | |
2587 | ||
2588 | turbografx.map[2|3]= [HW,JOY] | |
2589 | TurboGraFX parallel port interface | |
2590 | Format: | |
2591 | <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7> | |
2592 | See also Documentation/input/joystick-parport.txt | |
2593 | ||
2594 | udbg-immortal [PPC] When debugging early kernel crashes that | |
2595 | happen after console_init() and before a proper | |
2596 | console driver takes over, this boot options might | |
2597 | help "seeing" what's going on. | |
2598 | ||
2599 | uhash_entries= [KNL,NET] | |
2600 | Set number of hash buckets for UDP/UDP-Lite connections | |
2601 | ||
2602 | uhci-hcd.ignore_oc= | |
2603 | [USB] Ignore overcurrent events (default N). | |
2604 | Some badly-designed motherboards generate lots of | |
2605 | bogus events, for ports that aren't wired to | |
2606 | anything. Set this parameter to avoid log spamming. | |
2607 | Note that genuine overcurrent events won't be | |
2608 | reported either. | |
2609 | ||
2610 | unknown_nmi_panic | |
2611 | [X86] Cause panic on unknown NMI. | |
2612 | ||
2613 | usbcore.authorized_default= | |
2614 | [USB] Default USB device authorization: | |
2615 | (default -1 = authorized except for wireless USB, | |
2616 | 0 = not authorized, 1 = authorized) | |
2617 | ||
2618 | usbcore.autosuspend= | |
2619 | [USB] The autosuspend time delay (in seconds) used | |
2620 | for newly-detected USB devices (default 2). This | |
2621 | is the time required before an idle device will be | |
2622 | autosuspended. Devices for which the delay is set | |
2623 | to a negative value won't be autosuspended at all. | |
2624 | ||
2625 | usbcore.usbfs_snoop= | |
2626 | [USB] Set to log all usbfs traffic (default 0 = off). | |
2627 | ||
2628 | usbcore.blinkenlights= | |
2629 | [USB] Set to cycle leds on hubs (default 0 = off). | |
2630 | ||
2631 | usbcore.old_scheme_first= | |
2632 | [USB] Start with the old device initialization | |
2633 | scheme (default 0 = off). | |
2634 | ||
2635 | usbcore.use_both_schemes= | |
2636 | [USB] Try the other device initialization scheme | |
2637 | if the first one fails (default 1 = enabled). | |
2638 | ||
2639 | usbcore.initial_descriptor_timeout= | |
2640 | [USB] Specifies timeout for the initial 64-byte | |
2641 | USB_REQ_GET_DESCRIPTOR request in milliseconds | |
2642 | (default 5000 = 5.0 seconds). | |
2643 | ||
2644 | usbhid.mousepoll= | |
2645 | [USBHID] The interval which mice are to be polled at. | |
2646 | ||
2647 | usb-storage.delay_use= | |
2648 | [UMS] The delay in seconds before a new device is | |
2649 | scanned for Logical Units (default 5). | |
2650 | ||
2651 | usb-storage.quirks= | |
2652 | [UMS] A list of quirks entries to supplement or | |
2653 | override the built-in unusual_devs list. List | |
2654 | entries are separated by commas. Each entry has | |
2655 | the form VID:PID:Flags where VID and PID are Vendor | |
2656 | and Product ID values (4-digit hex numbers) and | |
2657 | Flags is a set of characters, each corresponding | |
2658 | to a common usb-storage quirk flag as follows: | |
2659 | a = SANE_SENSE (collect more than 18 bytes | |
2660 | of sense data); | |
2661 | b = BAD_SENSE (don't collect more than 18 | |
2662 | bytes of sense data); | |
2663 | c = FIX_CAPACITY (decrease the reported | |
2664 | device capacity by one sector); | |
2665 | d = NO_READ_DISC_INFO (don't use | |
2666 | READ_DISC_INFO command); | |
2667 | e = NO_READ_CAPACITY_16 (don't use | |
2668 | READ_CAPACITY_16 command); | |
2669 | h = CAPACITY_HEURISTICS (decrease the | |
2670 | reported device capacity by one | |
2671 | sector if the number is odd); | |
2672 | i = IGNORE_DEVICE (don't bind to this | |
2673 | device); | |
2674 | l = NOT_LOCKABLE (don't try to lock and | |
2675 | unlock ejectable media); | |
2676 | m = MAX_SECTORS_64 (don't transfer more | |
2677 | than 64 sectors = 32 KB at a time); | |
2678 | n = INITIAL_READ10 (force a retry of the | |
2679 | initial READ(10) command); | |
2680 | o = CAPACITY_OK (accept the capacity | |
2681 | reported by the device); | |
2682 | r = IGNORE_RESIDUE (the device reports | |
2683 | bogus residue values); | |
2684 | s = SINGLE_LUN (the device has only one | |
2685 | Logical Unit); | |
2686 | w = NO_WP_DETECT (don't test whether the | |
2687 | medium is write-protected). | |
2688 | Example: quirks=0419:aaf5:rl,0421:0433:rc | |
2689 | ||
2690 | user_debug= [KNL,ARM] | |
2691 | Format: <int> | |
2692 | See arch/arm/Kconfig.debug help text. | |
2693 | 1 - undefined instruction events | |
2694 | 2 - system calls | |
2695 | 4 - invalid data aborts | |
2696 | 8 - SIGSEGV faults | |
2697 | 16 - SIGBUS faults | |
2698 | Example: user_debug=31 | |
2699 | ||
2700 | userpte= | |
2701 | [X86] Flags controlling user PTE allocations. | |
2702 | ||
2703 | nohigh = do not allocate PTE pages in | |
2704 | HIGHMEM regardless of setting | |
2705 | of CONFIG_HIGHPTE. | |
2706 | ||
2707 | vdso= [X86,SH] | |
2708 | vdso=2: enable compat VDSO (default with COMPAT_VDSO) | |
2709 | vdso=1: enable VDSO (default) | |
2710 | vdso=0: disable VDSO mapping | |
2711 | ||
2712 | vdso32= [X86] | |
2713 | vdso32=2: enable compat VDSO (default with COMPAT_VDSO) | |
2714 | vdso32=1: enable 32-bit VDSO (default) | |
2715 | vdso32=0: disable 32-bit VDSO mapping | |
2716 | ||
2717 | vector= [IA-64,SMP] | |
2718 | vector=percpu: enable percpu vector domain | |
2719 | ||
2720 | video= [FB] Frame buffer configuration | |
2721 | See Documentation/fb/modedb.txt. | |
2722 | ||
2723 | vga= [BOOT,X86-32] Select a particular video mode | |
2724 | See Documentation/x86/boot.txt and | |
2725 | Documentation/svga.txt. | |
2726 | Use vga=ask for menu. | |
2727 | This is actually a boot loader parameter; the value is | |
2728 | passed to the kernel using a special protocol. | |
2729 | ||
2730 | vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact | |
2731 | size of <nn>. This can be used to increase the | |
2732 | minimum size (128MB on x86). It can also be used to | |
2733 | decrease the size and leave more room for directly | |
2734 | mapped kernel RAM. | |
2735 | ||
2736 | vmhalt= [KNL,S390] Perform z/VM CP command after system halt. | |
2737 | Format: <command> | |
2738 | ||
2739 | vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic. | |
2740 | Format: <command> | |
2741 | ||
2742 | vmpoff= [KNL,S390] Perform z/VM CP command after power off. | |
2743 | Format: <command> | |
2744 | ||
2745 | vsyscall= [X86-64] | |
2746 | Controls the behavior of vsyscalls (i.e. calls to | |
2747 | fixed addresses of 0xffffffffff600x00 from legacy | |
2748 | code). Most statically-linked binaries and older | |
2749 | versions of glibc use these calls. Because these | |
2750 | functions are at fixed addresses, they make nice | |
2751 | targets for exploits that can control RIP. | |
2752 | ||
2753 | emulate Vsyscalls turn into traps and are emulated | |
2754 | reasonably safely. | |
2755 | ||
2756 | native [default] Vsyscalls are native syscall | |
2757 | instructions. | |
2758 | This is a little bit faster than trapping | |
2759 | and makes a few dynamic recompilers work | |
2760 | better than they would in emulation mode. | |
2761 | It also makes exploits much easier to write. | |
2762 | ||
2763 | none Vsyscalls don't work at all. This makes | |
2764 | them quite hard to use for exploits but | |
2765 | might break your system. | |
2766 | ||
2767 | vt.cur_default= [VT] Default cursor shape. | |
2768 | Format: 0xCCBBAA, where AA, BB, and CC are the same as | |
2769 | the parameters of the <Esc>[?A;B;Cc escape sequence; | |
2770 | see VGA-softcursor.txt. Default: 2 = underline. | |
2771 | ||
2772 | vt.default_blu= [VT] | |
2773 | Format: <blue0>,<blue1>,<blue2>,...,<blue15> | |
2774 | Change the default blue palette of the console. | |
2775 | This is a 16-member array composed of values | |
2776 | ranging from 0-255. | |
2777 | ||
2778 | vt.default_grn= [VT] | |
2779 | Format: <green0>,<green1>,<green2>,...,<green15> | |
2780 | Change the default green palette of the console. | |
2781 | This is a 16-member array composed of values | |
2782 | ranging from 0-255. | |
2783 | ||
2784 | vt.default_red= [VT] | |
2785 | Format: <red0>,<red1>,<red2>,...,<red15> | |
2786 | Change the default red palette of the console. | |
2787 | This is a 16-member array composed of values | |
2788 | ranging from 0-255. | |
2789 | ||
2790 | vt.default_utf8= | |
2791 | [VT] | |
2792 | Format=<0|1> | |
2793 | Set system-wide default UTF-8 mode for all tty's. | |
2794 | Default is 1, i.e. UTF-8 mode is enabled for all | |
2795 | newly opened terminals. | |
2796 | ||
2797 | vt.global_cursor_default= | |
2798 | [VT] | |
2799 | Format=<-1|0|1> | |
2800 | Set system-wide default for whether a cursor | |
2801 | is shown on new VTs. Default is -1, | |
2802 | i.e. cursors will be created by default unless | |
2803 | overridden by individual drivers. 0 will hide | |
2804 | cursors, 1 will display them. | |
2805 | ||
2806 | watchdog timers [HW,WDT] For information on watchdog timers, | |
2807 | see Documentation/watchdog/watchdog-parameters.txt | |
2808 | or other driver-specific files in the | |
2809 | Documentation/watchdog/ directory. | |
2810 | ||
2811 | x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of | |
2812 | default x2apic cluster mode on platforms | |
2813 | supporting x2apic. | |
2814 | ||
2815 | x86_mrst_timer= [X86-32,APBT] | |
2816 | Choose timer option for x86 Moorestown MID platform. | |
2817 | Two valid options are apbt timer only and lapic timer | |
2818 | plus one apbt timer for broadcast timer. | |
2819 | x86_mrst_timer=apbt_only | lapic_and_apbt | |
2820 | ||
2821 | xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks. | |
2822 | xd_geo= See header of drivers/block/xd.c. | |
2823 | ||
2824 | xen_emul_unplug= [HW,X86,XEN] | |
2825 | Unplug Xen emulated devices | |
2826 | Format: [unplug0,][unplug1] | |
2827 | ide-disks -- unplug primary master IDE devices | |
2828 | aux-ide-disks -- unplug non-primary-master IDE devices | |
2829 | nics -- unplug network devices | |
2830 | all -- unplug all emulated devices (NICs and IDE disks) | |
2831 | unnecessary -- unplugging emulated devices is | |
2832 | unnecessary even if the host did not respond to | |
2833 | the unplug protocol | |
2834 | never -- do not unplug even if version check succeeds | |
2835 | ||
2836 | xirc2ps_cs= [NET,PCMCIA] | |
2837 | Format: | |
2838 | <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]] | |
2839 | ||
2840 | ______________________________________________________________________ | |
2841 | ||
2842 | TODO: | |
2843 | ||
2844 | Add more DRM drivers. |