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1 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
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3
4The 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
7case insensitive manner), and with descriptions where known.
8
9Module parameters for loadable modules are specified only as the
10parameter name with optional '=' and value as appropriate, such as:
11
12 modprobe usbcore blinkenlights=1
13
14Module parameters for modules that are built into the kernel image
15are 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
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20This document may not be entirely up to date and comprehensive. The command
21"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22module. Loadable modules, after being loaded into the running kernel, also
23reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24parameters may be changed at runtime by the command
25"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
26
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27The parameters listed below are only valid if certain kernel build options were
28enabled and if respective hardware is present. The text in square brackets at
29the beginning of each description states the restrictions within which a
30parameter is applicable:
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31
32 ACPI ACPI support is enabled.
c99c108a 33 AGP AGP (Accelerated Graphics Port) is enabled.
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34 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
e7ba176b 37 AVR32 AVR32 architecture is enabled.
1da177e4 38 AX25 Appropriate AX.25 support is enabled.
0ae53640 39 BLACKFIN Blackfin architecture is enabled.
a9913044 40 DRM Direct Rendering Management support is enabled.
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41 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
42 EFI EFI Partitioning (GPT) is enabled
43 EIDE EIDE/ATAPI support is enabled.
44 FB The frame buffer device is enabled.
45 HW Appropriate hardware is enabled.
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46 IA-64 IA-64 architecture is enabled.
47 IOSCHED More than one I/O scheduler is enabled.
41e2e8be 48 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
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49 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
11ef697b 52 LIBATA Libata driver is enabled
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53 LP Printer support is enabled.
54 LOOP Loopback device support is enabled.
55 M68k M68k architecture is enabled.
56 These options have more detailed description inside of
57 Documentation/m68k/kernel-options.txt.
58 MCA MCA bus support is enabled.
59 MDA MDA console support is enabled.
60 MOUSE Appropriate mouse support is enabled.
309e57df 61 MSI Message Signaled Interrupts (PCI).
c8facbb6 62 MTD MTD (Memory Technology Device) support is enabled.
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63 NET Appropriate network support is enabled.
64 NUMA NUMA support is enabled.
734efb46 65 GENERIC_TIME The generic timeofday code is enabled.
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66 NFS Appropriate NFS support is enabled.
67 OSS OSS sound support is enabled.
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68 PV_OPS A paravirtualized kernel is enabled.
69 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
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70 PARISC The PA-RISC architecture is enabled.
71 PCI PCI bus support is enabled.
7f785763 72 PCIE PCI Express support is enabled.
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73 PCMCIA The PCMCIA subsystem is enabled.
74 PNP Plug & Play support is enabled.
75 PPC PowerPC architecture is enabled.
76 PPT Parallel port support is enabled.
77 PS2 Appropriate PS/2 support is enabled.
78 RAM RAM disk support is enabled.
20510f2f 79 ROOTPLUG The example Root Plug LSM is enabled.
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80 S390 S390 architecture is enabled.
81 SCSI Appropriate SCSI support is enabled.
82 A lot of drivers has their options described inside of
83 Documentation/scsi/.
20510f2f 84 SECURITY Different security models are enabled.
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85 SELINUX SELinux support is enabled.
86 SERIAL Serial support is enabled.
e523d93c 87 SH SuperH architecture is enabled.
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88 SMP The kernel is an SMP kernel.
89 SPARC Sparc architecture is enabled.
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90 SWSUSP Software suspend (hibernation) is enabled.
91 SUSPEND System suspend states are enabled.
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92 TS Appropriate touchscreen support is enabled.
93 USB USB support is enabled.
94 USBHID USB Human Interface Device support is enabled.
95 V4L Video For Linux support is enabled.
96 VGA The VGA console has been enabled.
97 VT Virtual terminal support is enabled.
98 WDT Watchdog support is enabled.
99 XT IBM PC/XT MFM hard disk support is enabled.
cd4f0ef7 100 X86-32 X86-32, aka i386 architecture is enabled.
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101 X86-64 X86-64 architecture is enabled.
102 More X86-64 boot options can be found in
103 Documentation/x86_64/boot-options.txt .
104
105In addition, the following text indicates that the option:
106
107 BUGS= Relates to possible processor bugs on the said processor.
108 KNL Is a kernel start-up parameter.
109 BOOT Is a boot loader parameter.
110
111Parameters denoted with BOOT are actually interpreted by the boot
112loader, and have no meaning to the kernel directly.
113Do not modify the syntax of boot loader parameters without extreme
114need or coordination with <Documentation/i386/boot.txt>.
115
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116There are also arch-specific kernel-parameters not documented here.
117See for example <Documentation/x86_64/boot-options.txt>.
118
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119Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
120a trailing = on the name of any parameter states that that parameter will
121be entered as an environment variable, whereas its absence indicates that
122it will appear as a kernel argument readable via /proc/cmdline by programs
123running once the system is up.
124
9c4751fd 125The number of kernel parameters is not limited, but the length of the
126complete command line (parameters including spaces etc.) is limited to
127a fixed number of characters. This limit depends on the architecture
128and is between 256 and 4096 characters. It is defined in the file
129./include/asm/setup.h as COMMAND_LINE_SIZE.
130
131
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132 acpi= [HW,ACPI,X86-64,i386]
133 Advanced Configuration and Power Interface
a9913044 134 Format: { force | off | ht | strict | noirq }
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135 force -- enable ACPI if default was off
136 off -- disable ACPI if default was on
137 noirq -- do not use ACPI for IRQ routing
138 ht -- run only enough ACPI to enable Hyper Threading
a9913044 139 strict -- Be less tolerant of platforms that are not
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140 strictly ACPI specification compliant.
141
53471121 142 See also Documentation/power/pm.txt, pci=noacpi
1da177e4 143
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144 acpi_apic_instance= [ACPI, IOAPIC]
145 Format: <int>
146 2: use 2nd APIC table, if available
147 1,0: use 1st APIC table
4e381a4f 148 default: 0
a1fdcc0d 149
1da177e4 150 acpi_sleep= [HW,ACPI] Sleep options
bdfe6b7c 151 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
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152 See Documentation/power/video.txt for s3_bios and s3_mode.
153 s3_beep is for debugging; it makes the PC's speaker beep
154 as soon as the kernel's real-mode entry point is called.
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155 s4_nohwsig prevents ACPI hardware signature from being
156 used during resume from hibernation.
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157 old_ordering causes the ACPI 1.0 ordering of the _PTS
158 control method, wrt putting devices into low power
159 states, to be enforced (the ACPI 2.0 ordering of _PTS is
160 used by default).
a9913044 161
1da177e4 162 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
a9913044 163 Format: { level | edge | high | low }
1da177e4 164
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165 acpi_irq_balance [HW,ACPI]
166 ACPI will balance active IRQs
167 default in APIC mode
1da177e4 168
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169 acpi_irq_nobalance [HW,ACPI]
170 ACPI will not move active IRQs (default)
171 default in PIC mode
1da177e4 172
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173 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
174 use by PCI
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175 Format: <irq>,<irq>...
176
a9913044 177 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
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178 Format: <irq>,<irq>...
179
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180 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
181
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182 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
183 Format: To spoof as Windows 98: ="Microsoft Windows"
184
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185 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
186 acpi_osi="string1" # add string1 -- only one string
187 acpi_osi="!string2" # remove built-in string2
188 acpi_osi= # disable all strings
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189
190 acpi_serialize [HW,ACPI] force serialization of AML methods
191
192 acpi_skip_timer_override [HW,ACPI]
193 Recognize and ignore IRQ0/pin2 Interrupt Override.
194 For broken nForce2 BIOS resulting in XT-PIC timer.
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195 acpi_use_timer_override [HW,ACPI}
196 Use timer override. For some broken Nvidia NF5 boards
197 that require a timer override, but don't have
198 HPET
1da177e4 199
f989106c 200 acpi.debug_layer= [HW,ACPI]
1da177e4 201 Format: <int>
a9913044 202 Each bit of the <int> indicates an ACPI debug layer,
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203 1: enable, 0: disable. It is useful for boot time
204 debugging. After system has booted up, it can be set
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205 via /sys/module/acpi/parameters/debug_layer.
206 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
207 Available bits (add the numbers together) to enable debug output
208 for specific parts of the ACPI subsystem:
209 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
210 0x10 namespace 0x20 parser 0x40 dispatcher
211 0x80 executer 0x100 resources 0x200 acpica debugger
212 0x400 os services 0x800 acpica disassembler.
213 The number can be in decimal or prefixed with 0x in hex.
214 Warning: Many of these options can produce a lot of
215 output and make your system unusable. Be very careful.
216
217 acpi.debug_level= [HW,ACPI]
1da177e4 218 Format: <int>
a9913044 219 Each bit of the <int> indicates an ACPI debug level,
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220 1: enable, 0: disable. It is useful for boot time
221 debugging. After system has booted up, it can be set
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222 via /sys/module/acpi/parameters/debug_level.
223 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
224 Available bits (add the numbers together) to enable different
225 debug output levels of the ACPI subsystem:
226 0x01 error 0x02 warn 0x04 init 0x08 debug object
227 0x10 info 0x20 init names 0x40 parse 0x80 load
228 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
229 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
230 0x10000 resources 0x20000 user requests 0x40000 package.
231 The number can be in decimal or prefixed with 0x in hex.
232 Warning: Many of these options can produce a lot of
233 output and make your system unusable. Be very careful.
234
cd4f0ef7 235 acpi_pm_good [X86-32,X86-64]
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236 Override the pmtimer bug detection: force the kernel
237 to assume that this machine's pmtimer latches its value
238 and always returns good values.
239
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240 agp= [AGP]
241 { off | try_unsupported }
242 off: disable AGP support
243 try_unsupported: try to drive unsupported chipsets
244 (may crash computer or cause data corruption)
245
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246 enable_timer_pin_1 [i386,x86-64]
247 Enable PIN 1 of APIC timer
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248 Can be useful to work around chipset bugs
249 (in particular on some ATI chipsets).
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250 The kernel tries to set a reasonable default.
251
252 disable_timer_pin_1 [i386,x86-64]
253 Disable PIN 1 of APIC timer
254 Can be useful to work around chipset bugs.
255
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256 ad1848= [HW,OSS]
257 Format: <io>,<irq>,<dma>,<dma2>,<type>
258
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259 advansys= [HW,SCSI]
260 See header of drivers/scsi/advansys.c.
261
262 advwdt= [HW,WDT] Advantech WDT
263 Format: <iostart>,<iostop>
264
265 aedsp16= [HW,OSS] Audio Excel DSP 16
266 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
267 See also header of sound/oss/aedsp16.c.
a9913044 268
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269 aha152x= [HW,SCSI]
270 See Documentation/scsi/aha152x.txt.
271
272 aha1542= [HW,SCSI]
273 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
274
275 aic7xxx= [HW,SCSI]
276 See Documentation/scsi/aic7xxx.txt.
277
278 aic79xx= [HW,SCSI]
279 See Documentation/scsi/aic79xx.txt.
280
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281 amd_iommu= [HW,X86-84]
282 Pass parameters to the AMD IOMMU driver in the system.
283 Possible values are:
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284 isolate - enable device isolation (each device, as far
285 as possible, will get its own protection
286 domain)
287 amd_iommu_size= [HW,X86-64]
288 Define the size of the aperture for the AMD IOMMU
289 driver. Possible values are:
290 '32M', '64M' (default), '128M', '256M', '512M', '1G'
291
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292 amijoy.map= [HW,JOY] Amiga joystick support
293 Map of devices attached to JOY0DAT and JOY1DAT
294 Format: <a>,<b>
295 See also Documentation/kernel/input/joystick.txt
296
297 analog.map= [HW,JOY] Analog joystick and gamepad support
298 Specifies type or capabilities of an analog joystick
299 connected to one of 16 gameports
300 Format: <type1>,<type2>,..<type16>
301
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302 apc= [HW,SPARC]
303 Power management functions (SPARCstation-4/5 + deriv.)
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304 Format: noidle
305 Disable APC CPU standby support. SPARCstation-Fox does
306 not play well with APC CPU idle - disable it if you have
307 APC and your system crashes randomly.
308
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309 apic= [APIC,i386] Advanced Programmable Interrupt Controller
310 Change the output verbosity whilst booting
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311 Format: { quiet (default) | verbose | debug }
312 Change the amount of debugging information output
313 when initialising the APIC and IO-APIC components.
a9913044 314
1da177e4 315 apm= [APM] Advanced Power Management
71f77055 316 See header of arch/x86/kernel/apm_32.c.
1da177e4 317
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318 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
319 Format: <io>,<irq>,<nodeID>
320
321 ataflop= [HW,M68k]
322
323 atarimouse= [HW,MOUSE] Atari Mouse
324
325 atascsi= [HW,SCSI] Atari SCSI
326
327 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
328 EzKey and similar keyboards
329
330 atkbd.reset= [HW] Reset keyboard during initialization
331
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332 atkbd.set= [HW] Select keyboard code set
333 Format: <int> (2 = AT (default), 3 = PS/2)
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334
335 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
336 keyboards
337
338 atkbd.softraw= [HW] Choose between synthetic and real raw mode
339 Format: <bool> (0 = real, 1 = synthetic (default))
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340
341 atkbd.softrepeat= [HW]
342 Use software keyboard repeat
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343
344 autotest [IA64]
345
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346 baycom_epp= [HW,AX25]
347 Format: <io>,<mode>
a9913044 348
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349 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
350 Format: <io>,<mode>
351 See header of drivers/net/hamradio/baycom_par.c.
352
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353 baycom_ser_fdx= [HW,AX25]
354 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
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355 Format: <io>,<irq>,<mode>[,<baud>]
356 See header of drivers/net/hamradio/baycom_ser_fdx.c.
357
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358 baycom_ser_hdx= [HW,AX25]
359 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
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360 Format: <io>,<irq>,<mode>
361 See header of drivers/net/hamradio/baycom_ser_hdx.c.
362
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363 bios_corruption_check=0/1 [X86]
364 Some BIOSes seem to corrupt the first 64k of memory
365 when doing things like suspend/resume. Setting this
366 option will scan the memory looking for corruption.
367
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368 boot_delay= Milliseconds to delay each printk during boot.
369 Values larger than 10 seconds (10000) are changed to
370 no delay (0).
371 Format: integer
372
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373 bootmem_debug [KNL] Enable bootmem allocator debug messages.
374
1da177e4 375 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
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376 bttv.radio= Most important insmod options are available as
377 kernel args too.
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378 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
379 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
380
381 BusLogic= [HW,SCSI]
382 See drivers/scsi/BusLogic.c, comment before function
383 BusLogic_ParseDriverOptions().
384
385 c101= [NET] Moxa C101 synchronous serial card
386
cd4f0ef7 387 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
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388 Sometimes CPU hardware bugs make them report the cache
389 size incorrectly. The kernel will attempt work arounds
390 to fix known problems, but for some CPUs it is not
391 possible to determine what the correct size should be.
392 This option provides an override for these situations.
393
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394 security= [SECURITY] Choose a security module to enable at boot.
395 If this boot parameter is not specified, only the first
396 security module asking for security registration will be
397 loaded. An invalid security module name will be treated
398 as if no module has been chosen.
399
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400 capability.disable=
401 [SECURITY] Disable capabilities. This would normally
402 be used only if an alternative security model is to be
403 configured. Potentially dangerous and should only be
404 used if you are entirely sure of the consequences.
405
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406 ccw_timeout_log [S390]
407 See Documentation/s390/CommonIO for details.
1da177e4 408
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409 cgroup_disable= [KNL] Disable a particular controller
410 Format: {name of the controller(s) to disable}
411 {Currently supported controllers - "memory"}
412
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413 checkreqprot [SELINUX] Set initial checkreqprot flag value.
414 Format: { "0" | "1" }
415 See security/selinux/Kconfig help text.
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416 0 -- check protection applied by kernel (includes
417 any implied execute protection).
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418 1 -- check protection requested by application.
419 Default value is set via a kernel config option.
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420 Value can be changed at runtime via
421 /selinux/checkreqprot.
422
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423 cio_ignore= [S390]
424 See Documentation/s390/CommonIO for details.
425
cd4f0ef7 426 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
734efb46 427 [Deprecated]
3f6dee9b 428 Forces specified clocksource (if available) to be used
734efb46 429 when calculating gettimeofday(). If specified
3f6dee9b 430 clocksource is not available, it defaults to PIT.
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431 Format: { pit | tsc | cyclone | pmtmr }
432
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433 clocksource= [GENERIC_TIME] Override the default clocksource
434 Format: <string>
435 Override the default clocksource and use the clocksource
436 with the name specified.
437 Some clocksource names to choose from, depending on
438 the platform:
439 [all] jiffies (this is the base, fallback clocksource)
440 [ACPI] acpi_pm
441 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
442 pxa_timer,timer3,32k_counter,timer0_1
443 [AVR32] avr32
cd4f0ef7 444 [X86-32] pit,hpet,tsc,vmi-timer;
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445 scx200_hrt on Geode; cyclone on IBM x440
446 [MIPS] MIPS
447 [PARISC] cr16
448 [S390] tod
449 [SH] SuperH
450 [SPARC64] tick
451 [X86-64] hpet,tsc
452
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453 clearcpuid=BITNUM [X86]
454 Disable CPUID feature X for the kernel. See
455 include/asm-x86/cpufeature.h for the valid bit numbers.
456 Note the Linux specific bits are not necessarily
457 stable over kernel options, but the vendor specific
458 ones should be.
459 Also note that user programs calling CPUID directly
460 or using the feature without checking anything
461 will still see it. This just prevents it from
462 being used by the kernel or shown in /proc/cpuinfo.
463 Also note the kernel might malfunction if you disable
464 some critical bits.
465
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466 code_bytes [IA32/X86_64] How many bytes of object code to print
467 in an oops report.
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468 Range: 0 - 8192
469 Default: 64
470
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471 disable_8254_timer
472 enable_8254_timer
473 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
474 over the 8254 in addition to over the IO-APIC. The
475 kernel tries to set a sensible default.
476
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477 hpet= [X86-32,HPET] option to control HPET usage
478 Format: { enable (default) | disable | force }
479 disable: disable HPET and use PIT instead
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480 force: allow force enabled of undocumented chips (ICH4,
481 VIA, nVidia)
1da177e4 482
1da177e4 483 com20020= [HW,NET] ARCnet - COM20020 chipset
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484 Format:
485 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
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486
487 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
488 Format: <io>[,<irq>]
489
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490 com90xx= [HW,NET]
491 ARCnet - COM90xx chipset (memory-mapped buffers)
1da177e4
LT
492 Format: <io>[,<irq>[,<memstart>]]
493
494 condev= [HW,S390] console device
495 conmode=
a9913044 496
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497 console= [KNL] Output console device and options.
498
499 tty<n> Use the virtual console device <n>.
500
501 ttyS<n>[,options]
f1a1c2dc 502 ttyUSB0[,options]
1da177e4 503 Use the specified serial port. The options are of
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RD
504 the form "bbbbpnf", where "bbbb" is the baud rate,
505 "p" is parity ("n", "o", or "e"), "n" is number of
506 bits, and "f" is flow control ("r" for RTS or
507 omit it). Default is "9600n8".
508
509 See Documentation/serial-console.txt for more
510 information. See
511 Documentation/networking/netconsole.txt for an
512 alternative.
1da177e4 513
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514 uart[8250],io,<addr>[,options]
515 uart[8250],mmio,<addr>[,options]
1da177e4
LT
516 Start an early, polled-mode console on the 8250/16550
517 UART at the specified I/O port or MMIO address,
518 switching to the matching ttyS device later. The
519 options are the same as for ttyS, above.
520
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521 If the device connected to the port is not a TTY but a braille
522 device, prepend "brl," before the device type, for instance
523 console=brl,ttyS0
524 For now, only VisioBraille is supported.
525
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526 earlycon= [KNL] Output early console device and options.
527 uart[8250],io,<addr>[,options]
528 uart[8250],mmio,<addr>[,options]
529 Start an early, polled-mode console on the 8250/16550
530 UART at the specified I/O port or MMIO address.
531 The options are the same as for ttyS, above.
532
8f4ce8c3
AS
533 no_console_suspend
534 [HW] Never suspend the console
535 Disable suspending of consoles during suspend and
536 hibernate operations. Once disabled, debugging
537 messages can reach various consoles while the rest
538 of the system is being put to sleep (ie, while
539 debugging driver suspend/resume hooks). This may
540 not work reliably with all consoles, but is known
541 to work with serial and VGA consoles.
542
1da177e4 543 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
a9913044
RD
544 Format:
545 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
1da177e4 546
dc009d92
EB
547 crashkernel=nn[KMG]@ss[KMG]
548 [KNL] Reserve a chunk of physical memory to
549 hold a kernel to switch to with kexec on panic.
550
fb391599
BW
551 crashkernel=range1:size1[,range2:size2,...][@offset]
552 [KNL] Same as above, but depends on the memory
553 in the running system. The syntax of range is
554 start-[end] where start and end are both
555 a memory unit (amount[KMG]). See also
556 Documentation/kdump/kdump.txt for a example.
557
1da177e4
LT
558 cs4232= [HW,OSS]
559 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
560
561 cs89x0_dma= [HW,NET]
562 Format: <dma>
563
564 cs89x0_media= [HW,NET]
565 Format: { rj45 | aui | bnc }
a9913044 566
a9913044 567 dasd= [HW,NET]
1da177e4
LT
568 See header of drivers/s390/block/dasd_devmap.c.
569
570 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
571 (one device per port)
572 Format: <port#>,<type>
573 See also Documentation/input/joystick-parport.txt
574
575 debug [KNL] Enable kernel debugging (events log level).
576
cae2ed9a
IM
577 debug_locks_verbose=
578 [KNL] verbose self-tests
579 Format=<0|1>
580 Print debugging info while doing the locking API
581 self-tests.
582 We default to 0 (no extra messages), setting it to
583 1 will print _a lot_ more information - normally
584 only useful to kernel developers.
585
3ac7fe5a
TG
586 debug_objects [KNL] Enable object debugging
587
d3af01f1
TG
588 debugpat [X86] Enable PAT debugging
589
2d27a966 590 decnet.addr= [HW,NET]
1da177e4
LT
591 Format: <area>[,<node>]
592 See also Documentation/networking/decnet.txt.
593
ecb77fa9 594 vt.default_blu= [VT]
55ff9780
AD
595 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
596 Change the default blue palette of the console.
597 This is a 16-member array composed of values
598 ranging from 0-255.
599
ecb77fa9 600 vt.default_grn= [VT]
55ff9780
AD
601 Format: <green0>,<green1>,<green2>,...,<green15>
602 Change the default green palette of the console.
603 This is a 16-member array composed of values
604 ranging from 0-255.
605
ecb77fa9 606 vt.default_red= [VT]
55ff9780
AD
607 Format: <red0>,<red1>,<red2>,...,<red15>
608 Change the default red palette of the console.
609 This is a 16-member array composed of values
610 ranging from 0-255.
611
ecb77fa9
ST
612 vt.default_utf8=
613 [VT]
55ff9780
AD
614 Format=<0|1>
615 Set system-wide default UTF-8 mode for all tty's.
ecb77fa9
ST
616 Default is 1, i.e. UTF-8 mode is enabled for all
617 newly opened terminals.
55ff9780 618
1da177e4
LT
619 dhash_entries= [KNL]
620 Set number of hash buckets for dentry cache.
a9913044 621
1da177e4
LT
622 digi= [HW,SERIAL]
623 IO parameters + enable/disable command.
624
625 digiepca= [HW,SERIAL]
626 See drivers/char/README.epca and
627 Documentation/digiepca.txt.
628
95ffa243
YL
629 disable_mtrr_cleanup [X86]
630 enable_mtrr_cleanup [X86]
631 The kernel tries to adjust MTRR layout from continuous
632 to discrete, to make X server driver able to add WB
633 entry later. This parameter enables/disables that.
634
635 mtrr_chunk_size=nn[KMG] [X86]
636 used for mtrr cleanup. It is largest continous chunk
637 that could hold holes aka. UC entries.
638
639 mtrr_gran_size=nn[KMG] [X86]
12031a62
YL
640 Used for mtrr cleanup. It is granularity of mtrr block.
641 Default is 1.
642 Large value could prevent small alignment from
643 using up MTRRs.
644
645 mtrr_spare_reg_nr=n [X86]
646 Format: <integer>
647 Range: 0,7 : spare reg number
648 Default : 1
649 Used for mtrr cleanup. It is spare mtrr entries number.
650 Set to 2 or more if your graphical card needs more.
95ffa243 651
093af8d7 652 disable_mtrr_trim [X86, Intel and AMD only]
99fc8d42
JB
653 By default the kernel will trim any uncacheable
654 memory out of your available memory pool based on
655 MTRR settings. This parameter disables that behavior,
656 possibly causing your machine to run very slowly.
657
1da177e4
LT
658 dmasound= [HW,OSS] Sound subsystem buffers
659
660 dscc4.setup= [NET]
661
662 dtc3181e= [HW,SCSI]
663
0ae53640 664 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
1da177e4
LT
665 earlyprintk=vga
666 earlyprintk=serial[,ttySn[,baudrate]]
667
a9913044 668 Append ",keep" to not disable it when the real console
1da177e4
LT
669 takes over.
670
671 Only vga or serial at a time, not both.
672
673 Currently only ttyS0 and ttyS1 are supported.
674
675 Interaction with the standard serial driver is not
676 very good.
677
678 The VGA output is eventually overwritten by the real
679 console.
680
681 eata= [HW,SCSI]
682
1da177e4 683 edd= [EDD]
8c4dd606 684 Format: {"off" | "on" | "skip[mbr]"}
1da177e4 685
1da177e4
LT
686 eisa_irq_edge= [PARISC,HW]
687 See header of drivers/parisc/eisa.c.
688
cd4f0ef7 689 elanfreq= [X86-32]
1da177e4 690 See comment before function elanfreq_setup() in
71f77055 691 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
1da177e4
LT
692
693 elevator= [IOSCHED]
16ab3adf 694 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
a9913044
RD
695 See Documentation/block/as-iosched.txt and
696 Documentation/block/deadline-iosched.txt for details.
697
cd4f0ef7 698 elfcorehdr= [X86-32, X86_64]
a9913044 699 Specifies physical address of start of kernel core
aac04b32
VG
700 image elf header. Generally kexec loader will
701 pass this option to capture kernel.
702 See Documentation/kdump/kdump.txt for details.
1da177e4
LT
703
704 enforcing [SELINUX] Set initial enforcing status.
705 Format: {"0" | "1"}
706 See security/selinux/Kconfig help text.
707 0 -- permissive (log only, no denials).
708 1 -- enforcing (deny and log).
709 Default value is 0.
710 Value can be changed at runtime via /selinux/enforce.
711
1da177e4
LT
712 es1371= [HW,OSS]
713 Format: <spdif>,[<nomix>,[<amplifier>]]
714 See also header of sound/oss/es1371.c.
a9913044 715
1da177e4
LT
716 ether= [HW,NET] Ethernet cards parameters
717 This option is obsoleted by the "netdev=" option, which
718 has equivalent usage. See its documentation for details.
719
720 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
721 Format: <io>[,<irq>]
722
de1ba09b
AM
723 failslab=
724 fail_page_alloc=
725 fail_make_request=[KNL]
726 General fault injection mechanism.
727 Format: <interval>,<probability>,<space>,<times>
728 See also /Documentation/fault-injection/.
729
1da177e4
LT
730 fd_mcs= [HW,SCSI]
731 See header of drivers/scsi/fd_mcs.c.
732
733 fdomain= [HW,SCSI]
734 See header of drivers/scsi/fdomain.c.
735
736 floppy= [HW]
737 See Documentation/floppy.txt.
738
f13ae30e
AC
739 force_pal_cache_flush
740 [IA-64] Avoid check_sal_cache_flush which may hang on
741 buggy SAL_CACHE_FLUSH implementations. Using this
742 parameter will force ia64_sal_cache_flush to call
743 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
744
1da177e4
LT
745 gamecon.map[2|3]=
746 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
747 support via parallel port (up to 5 devices per port)
748 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
749 See also Documentation/input/joystick-parport.txt
750
751 gamma= [HW,DRM]
752
aaf23042
YL
753 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
754 Format: off | on
755 default: on
756
1da177e4
LT
757 gdth= [HW,SCSI]
758 See header of drivers/scsi/gdth.c.
759
760 gpt [EFI] Forces disk with valid GPT signature but
761 invalid Protective MBR to be treated as GPT.
762
1da177e4
LT
763 gvp11= [HW,SCSI]
764
765 hashdist= [KNL,NUMA] Large hashes allocated during boot
766 are distributed across NUMA nodes. Defaults on
767 for IA-64, off otherwise.
a9913044 768 Format: 0 | 1 (for off | on)
1da177e4
LT
769
770 hcl= [IA-64] SGI's Hardware Graph compatibility layer
771
772 hd= [EIDE] (E)IDE hard drive subsystem geometry
773 Format: <cyl>,<head>,<sect>
774
1da177e4
LT
775 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
776 size of <nn>. This works even on boxes that have no
777 highmem otherwise. This also works to reduce highmem
778 size on bigger boxes.
779
54cdfdb4
TG
780 highres= [KNL] Enable/disable high resolution timer mode.
781 Valid parameters: "on", "off"
782 Default: "on"
783
1da177e4
LT
784 hisax= [HW,ISDN]
785 See Documentation/isdn/README.HiSax.
786
b4718e62
AK
787 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
788 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
0d9ea754
JT
789 On x86-64 and powerpc, this option can be specified
790 multiple times interleaved with hugepages= to reserve
791 huge pages of different sizes. Valid pages sizes on
792 x86-64 are 2M (when the CPU supports "pse") and 1G
793 (when the CPU supports the "pdpe1gb" cpuinfo flag)
b4718e62
AK
794 Note that 1GB pages can only be allocated at boot time
795 using hugepages= and not freed afterwards.
e11bfbfc
NP
796 default_hugepagesz=
797 [same as hugepagesz=] The size of the default
798 HugeTLB page size. This is the size represented by
799 the legacy /proc/ hugepages APIs, used for SHM, and
800 default size when mounting hugetlbfs filesystems.
801 Defaults to the default architecture's huge page size
802 if not specified.
1da177e4 803
1da177e4 804 i8042.direct [HW] Put keyboard port into non-translated mode
84eb8d06
ML
805 i8042.dumbkbd [HW] Pretend that controller can only read data from
806 keyboard and cannot control its state
1da177e4
LT
807 (Don't attempt to blink the leds)
808 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
945ef0d4 809 i8042.nokbd [HW] Don't check/create keyboard port
75d08c78
JK
810 i8042.noloop [HW] Disable the AUX Loopback command while probing
811 for the AUX port
1da177e4
LT
812 i8042.nomux [HW] Don't check presence of an active multiplexing
813 controller
814 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
815 controllers
816 i8042.panicblink=
817 [HW] Frequency with which keyboard LEDs should blink
818 when kernel panics (default is 0.5 sec)
819 i8042.reset [HW] Reset the controller during init and cleanup
820 i8042.unlock [HW] Unlock (ignore) the keylock
821
822 i810= [HW,DRM]
823
e70c9d5e
DT
824 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
825 indicates that the driver is running on unsupported
826 hardware.
1da177e4
LT
827 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
828 does not match list of supported models.
829 i8k.power_status
830 [HW] Report power status in /proc/i8k
831 (disabled by default)
832 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
833 capability is set.
834
835 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
836 See Documentation/mca.txt.
837
838 icn= [HW,ISDN]
839 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
840
841 ide= [HW] (E)IDE subsystem
a594eeb1 842 Format: ide=nodma or ide=doubler
1c10e938 843 See Documentation/ide/ide.txt.
1da177e4 844
1da177e4 845 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
1c10e938 846 See Documentation/ide/ide.txt.
1da177e4 847
f039b754 848 idle= [X86]
da5e09a1 849 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
f039b754
AK
850 Poll forces a polling idle loop that can slightly improves the performance
851 of waking up a idle CPU, but will use a lot of power and make the system
852 run hot. Not recommended.
853 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
854 to not use it because it doesn't save as much power as a normal idle
855 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
856 as idle=poll.
c1e3b377
ZY
857 idle=halt. Halt is forced to be used for CPU idle.
858 In such case C2/C3 won't be used again.
da5e09a1 859 idle=nomwait. Disable mwait for CPU C-states
a9913044 860
594765a7
DC
861 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
862 Claim all unknown PCI IDE storage controllers.
863
79290822
IM
864 ignore_loglevel [KNL]
865 Ignore loglevel setting - this will print /all/
866 kernel messages to the console. Useful for debugging.
867
1da177e4
LT
868 ihash_entries= [KNL]
869 Set number of hash buckets for inode cache.
870
871 in2000= [HW,SCSI]
872 See header of drivers/scsi/in2000.c.
873
874 init= [KNL]
875 Format: <full_path>
876 Run specified binary instead of /sbin/init as init
877 process.
878
879 initcall_debug [KNL] Trace initcalls as they are executed. Useful
880 for working out where the kernel is dying during
881 startup.
882
883 initrd= [BOOT] Specify the location of the initial ramdisk
884
885 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
886 Format: <irq>
887
888 inttest= [IA64]
889
b552da87
PM
890 iommu= [x86]
891 off
892 force
893 noforce
894 biomerge
895 panic
896 nopanic
897 merge
898 nomerge
899 forcesac
900 soft
901
902
ba395927
KA
903 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
904 off
905 Disable intel iommu driver.
906 igfx_off [Default Off]
907 By default, gfx is mapped as normal device. If a gfx
908 device has a dedicated DMAR unit, the DMAR unit is
909 bypassed by not enabling DMAR with this option. In
910 this case, gfx device will use physical address for
911 DMA.
7d3b03ce
KA
912 forcedac [x86_64]
913 With this option iommu will not optimize to look
914 for io virtual address below 32 bit forcing dual
915 address cycle on pci bus for cards supporting greater
916 than 32 bit addressing. The default is to look
917 for translation below 32 bit and if not available
918 then look in the higher range.
5e0d2a6f 919 strict [Default Off]
920 With this option on every unmap_single operation will
921 result in a hardware IOTLB flush operation as opposed
922 to batching them for performance.
ba395927 923
b02aae9c 924 io_delay= [X86-32,X86-64] I/O delay method
6e7c4025
IM
925 0x80
926 Standard port 0x80 based delay
927 0xed
928 Alternate port 0xed based delay (needed on some systems)
b02aae9c 929 udelay
6e7c4025
IM
930 Simple two microseconds delay
931 none
932 No delay
b02aae9c 933
1da177e4
LT
934 io7= [HW] IO7 for Marvel based alpha systems
935 See comment before marvel_specify_io7 in
936 arch/alpha/kernel/core_marvel.c.
937
938 ip= [IP_PNP]
6ded55da 939 See Documentation/filesystems/nfsroot.txt.
1da177e4
LT
940
941 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
c8facbb6
RD
942 See comment before ip2_setup() in
943 drivers/char/ip2/ip2base.c.
1da177e4
LT
944
945 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
946 See header of drivers/scsi/ips.c.
947
72c4a13a
SH
948 ports= [IP_VS_FTP] IPVS ftp helper module
949 Default is 21.
950 Up to 8 (IP_VS_APP_MAX_PORTS) ports
951 may be specified.
952 Format: <port>,<port>....
953
200803df
AC
954 irqfixup [HW]
955 When an interrupt is not handled search all handlers
956 for it. Intended to get systems with badly broken
957 firmware running.
958
959 irqpoll [HW]
960 When an interrupt is not handled search all handlers
961 for it. Also check all handlers each timer
962 interrupt. Intended to get systems with badly broken
963 firmware running.
964
1da177e4 965 isapnp= [ISAPNP]
a9913044 966 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1da177e4
LT
967
968 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
22f2e280
DF
969 Format:
970 <cpu number>,...,<cpu number>
971 or
972 <cpu number>-<cpu number> (must be a positive range in ascending order)
973 or a mixture
974 <cpu number>,...,<cpu number>-<cpu number>
1da177e4
LT
975 This option can be used to specify one or more CPUs
976 to isolate from the general SMP balancing and scheduling
977 algorithms. The only way to move a process onto or off
978 an "isolated" CPU is via the CPU affinity syscalls.
979 <cpu number> begins at 0 and the maximum value is
980 "number of CPUs in system - 1".
981
982 This option is the preferred way to isolate CPUs. The
a9913044
RD
983 alternative -- manually setting the CPU mask of all
984 tasks in the system -- can cause problems and
985 suboptimal load balancer performance.
1da177e4 986
a9913044 987 iucv= [HW,NET]
1da177e4
LT
988
989 js= [HW,JOY] Analog joystick
990 See Documentation/input/joystick.txt.
991
cd4f0ef7 992 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
ed7ed365
MG
993 specifies the amount of memory usable by the kernel
994 for non-movable allocations. The requested amount is
995 spread evenly throughout all nodes in the system. The
996 remaining memory in each node is used for Movable
997 pages. In the event, a node is too small to have both
998 kernelcore and Movable pages, kernelcore pages will
999 take priority and other nodes will have a larger number
1000 of kernelcore pages. The Movable zone is used for the
1001 allocation of pages that may be reclaimed or moved
1002 by the page migration subsystem. This means that
1003 HugeTLB pages may not be allocated from this zone.
1004 Note that allocations like PTEs-from-HighMem still
1005 use the HighMem zone if it exists, and the Normal
1006 zone if it does not.
1007
cd4f0ef7 1008 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
7e63efef
MG
1009 is similar to kernelcore except it specifies the
1010 amount of memory used for migratable allocations.
1011 If both kernelcore and movablecore is specified,
1012 then kernelcore will be at *least* the specified
1013 value but may be more. If movablecore on its own
1014 is specified, the administrator must be careful
1015 that the amount of memory usable for all allocations
1016 is not too small.
1017
1da177e4
LT
1018 keepinitrd [HW,ARM]
1019
cd4f0ef7 1020 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1da177e4
LT
1021 in oops dumps.
1022
6cdf6e06
JW
1023 kgdboc= [HW] kgdb over consoles.
1024 Requires a tty driver that supports console polling.
1025 (only serial suported for now)
1026 Format: <serial_device>[,baud]
1027
1da177e4
LT
1028 l2cr= [PPC]
1029
a78bfbfc
RB
1030 l3cr= [PPC]
1031
cd4f0ef7 1032 lapic [X86-32,APIC] Enable the local APIC even if BIOS
a9913044 1033 disabled it.
1da177e4 1034
cd4f0ef7 1035 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
e585bef8
TG
1036 C2 power state.
1037
fcb71f6f
FC
1038 libata.dma= [LIBATA] DMA control
1039 libata.dma=0 Disable all PATA and SATA DMA
1040 libata.dma=1 PATA and SATA Disk DMA only
1041 libata.dma=2 ATAPI (CDROM) DMA only
1042 libata.dma=4 Compact Flash DMA only
1043 Combinations also work, so libata.dma=3 enables DMA
1044 for disks and CDROMs, but not CFs.
1045
78e70c23
DJ
1046 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1047 when set.
1048 Format: <int>
1049
33267325
TH
1050 libata.force= [LIBATA] Force configurations. The format is comma
1051 separated list of "[ID:]VAL" where ID is
1052 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1053 matching port, link or device. Basically, it matches
1054 the ATA ID string printed on console by libata. If
1055 the whole ID part is omitted, the last PORT and DEVICE
1056 values are used. If ID hasn't been specified yet, the
1057 configuration applies to all ports, links and devices.
1058
1059 If only DEVICE is omitted, the parameter applies to
1060 the port and all links and devices behind it. DEVICE
1061 number of 0 either selects the first device or the
1062 first fan-out link behind PMP device. It does not
1063 select the host link. DEVICE number of 15 selects the
1064 host link and device attached to it.
1065
1066 The VAL specifies the configuration to force. As long
1067 as there's no ambiguity shortcut notation is allowed.
1068 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1069 The following configurations can be forced.
1070
1071 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1072 Any ID with matching PORT is used.
1073
1074 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1075
1076 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1077 udma[/][16,25,33,44,66,100,133] notation is also
1078 allowed.
1079
1080 * [no]ncq: Turn on or off NCQ.
1081
05944bdf
TH
1082 * nohrst, nosrst, norst: suppress hard, soft
1083 and both resets.
1084
33267325
TH
1085 If there are multiple matching configurations changing
1086 the same attribute, the last one is used.
1087
1da177e4
LT
1088 load_ramdisk= [RAM] List of ramdisks to load from floppy
1089 See Documentation/ramdisk.txt.
1090
a6b25b67
RD
1091 lockd.nlm_grace_period=P [NFS] Assign grace period.
1092 Format: <integer>
1da177e4 1093
a6b25b67
RD
1094 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1095 Format: <integer>
1096
1097 lockd.nlm_timeout=T [NFS] Assign timeout value.
1098 Format: <integer>
1099
1100 lockd.nlm_udpport=M [NFS] Assign UDP port.
1101 Format: <integer>
1da177e4
LT
1102
1103 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1104 Format: <irq>
1105
1106 loglevel= All Kernel Messages with a loglevel smaller than the
1107 console loglevel will be printed to the console. It can
1108 also be changed with klogd or other programs. The
1109 loglevels are defined as follows:
1110
1111 0 (KERN_EMERG) system is unusable
1112 1 (KERN_ALERT) action must be taken immediately
1113 2 (KERN_CRIT) critical conditions
1114 3 (KERN_ERR) error conditions
1115 4 (KERN_WARNING) warning conditions
1116 5 (KERN_NOTICE) normal but significant condition
1117 6 (KERN_INFO) informational
1118 7 (KERN_DEBUG) debug-level messages
1119
1120 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
a9913044
RD
1121 Format: { n | nk | nM }
1122 n must be a power of two. The default size
1123 is set in the kernel config file.
1da177e4 1124
accaa24c
RD
1125 logo.nologo [FB] Disables display of the built-in Linux logo.
1126 This may be used to provide more screen space for
1127 kernel log messages and is useful when debugging
1128 kernel boot problems.
1129
1da177e4
LT
1130 lp=0 [LP] Specify parallel ports to use, e.g,
1131 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1132 lp=reset first parallel port). 'lp=0' disables the
1133 lp=auto printer driver. 'lp=reset' (which can be
1134 specified in addition to the ports) causes
1135 attached printers to be reset. Using
1136 lp=port1,port2,... specifies the parallel ports
1137 to associate lp devices with, starting with
1138 lp0. A port specification may be 'none' to skip
1139 that lp device, or a parport name such as
1140 'parport0'. Specifying 'lp=auto' instead of a
1141 port specification list means that device IDs
1142 from each port should be examined, to see if
1143 an IEEE 1284-compliant printer is attached; if
1144 so, the driver will manage that printer.
1145 See also header of drivers/char/lp.c.
1146
1147 lpj=n [KNL]
1148 Sets loops_per_jiffy to given constant, thus avoiding
1149 time-consuming boot-time autodetection (up to 250 ms per
1150 CPU). 0 enables autodetection (default). To determine
1151 the correct value for your kernel, boot with normal
1152 autodetection and see what value is printed. Note that
1153 on SMP systems the preset will be applied to all CPUs,
1154 which is likely to cause problems if your CPUs need
1155 significantly divergent settings. An incorrect value
1156 will cause delays in the kernel to be wrong, leading to
1157 unpredictable I/O errors and other breakage. Although
1158 unlikely, in the extreme case this might damage your
1159 hardware.
1160
1161 ltpc= [NET]
1162 Format: <io>,<irq>,<dma>
1163
a9913044
RD
1164 mac5380= [HW,SCSI] Format:
1165 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 1166
a9913044
RD
1167 machvec= [IA64] Force the use of a particular machine-vector
1168 (machvec) in a generic kernel.
1169 Example: machvec=hpzx1_swiotlb
1da177e4 1170
a9913044 1171 max_loop= [LOOP] Maximum number of loopback devices that can
1da177e4
LT
1172 be mounted
1173 Format: <1-256>
1174
1175 maxcpus= [SMP] Maximum number of processors that an SMP kernel
61ec7567
LB
1176 should make use of. maxcpus=n : n >= 0 limits the
1177 kernel to using 'n' processors. n=0 is a special case,
1178 it is equivalent to "nosmp", which also disables
1179 the IO APIC.
1da177e4 1180
2b2c3750
BP
1181 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1182 equal to this physical address is ignored.
1183
a9913044 1184 max_luns= [SCSI] Maximum number of LUNs to probe.
1da177e4
LT
1185 Should be between 1 and 2^32-1.
1186
1187 max_report_luns=
a9913044 1188 [SCSI] Maximum number of LUNs received.
1da177e4
LT
1189 Should be between 1 and 16384.
1190
1da177e4
LT
1191 mcatest= [IA-64]
1192
cd4f0ef7 1193 mce [X86-32] Machine Check Exception
1da177e4 1194
909dd324
AK
1195 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1196
1da177e4
LT
1197 md= [HW] RAID subsystems devices and level
1198 See Documentation/md.txt.
a9913044 1199
1da177e4
LT
1200 mdacon= [MDA]
1201 Format: <first>,<last>
1202 Specifies range of consoles to be captured by the MDA.
a9913044 1203
1da177e4
LT
1204 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1205 Amount of memory to be used when the kernel is not able
1206 to see the whole system memory or for test.
cd4f0ef7 1207 [X86-32] Use together with memmap= to avoid physical
1da177e4
LT
1208 address space collisions. Without memmap= PCI devices
1209 could be placed at addresses belonging to unused RAM.
1210
cd4f0ef7 1211 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1da177e4
LT
1212 memory.
1213
cd4f0ef7 1214 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1da177e4
LT
1215 E820 memory map, as specified by the user.
1216 Such memmap=exactmap lines can be constructed based on
1217 BIOS output or other requirements. See the memmap=nn@ss
1218 option description.
1219
1220 memmap=nn[KMG]@ss[KMG]
1221 [KNL] Force usage of a specific region of memory
1222 Region of memory to be used, from ss to ss+nn.
1223
1224 memmap=nn[KMG]#ss[KMG]
1225 [KNL,ACPI] Mark specific memory as ACPI data.
1226 Region of memory to be used, from ss to ss+nn.
1227
1228 memmap=nn[KMG]$ss[KMG]
1229 [KNL,ACPI] Mark specific memory as reserved.
1230 Region of memory to be used, from ss to ss+nn.
1312848e
PM
1231 Example: Exclude memory from 0x18690000-0x1869ffff
1232 memmap=64K$0x18690000
1233 or
1234 memmap=0x10000$0x18690000
1da177e4 1235
caadbdce 1236 memtest= [KNL,X86] Enable memtest
c64df707
YL
1237 Format: <integer>
1238 range: 0,4 : pattern number
1239 default : 0 <disable>
1240
1da177e4
LT
1241 meye.*= [HW] Set MotionEye Camera parameters
1242 See Documentation/video4linux/meye.txt.
1243
8f36881b
AS
1244 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1245 Multi-Function General Purpose Timers on AMD Geode
1246 platforms.
1247
e6c4dc6c
WT
1248 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1249 the BIOS has incorrectly applied a workaround. TinyBIOS
1250 version 0.98 is known to be affected, 0.99 fixes the
1251 problem by letting the user disable the workaround.
1252
1da177e4
LT
1253 mga= [HW,DRM]
1254
6b74ab97
MG
1255 mminit_loglevel=
1256 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1257 parameter allows control of the logging verbosity for
1258 the additional memory initialisation checks. A value
1259 of 0 disables mminit logging and a level of 4 will
1260 log everything. Information is printed at KERN_DEBUG
1261 so loglevel=8 may also need to be specified.
1262
1da177e4
LT
1263 mousedev.tap_time=
1264 [MOUSE] Maximum time between finger touching and
1265 leaving touchpad surface for touch to be considered
1266 a tap and be reported as a left button click (for
1267 touchpads working in absolute mode only).
1268 Format: <msecs>
1269 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1270 reporting absolute coordinates, such as tablets
1271 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1272 reporting absolute coordinates, such as tablets
1273
1274 mpu401= [HW,OSS]
1275 Format: <io>,<irq>
1276
1277 MTD_Partition= [MTD]
1278 Format: <name>,<region-number>,<size>,<offset>
1279
a9913044
RD
1280 MTD_Region= [MTD] Format:
1281 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1da177e4
LT
1282
1283 mtdparts= [MTD]
c8facbb6 1284 See drivers/mtd/cmdlinepart.c.
1da177e4 1285
9db829f4
BD
1286 mtdset= [ARM]
1287 ARM/S3C2412 JIVE boot control
1288
1289 See arch/arm/mach-s3c2412/mach-jive.c
1290
1da177e4 1291 mtouchusb.raw_coordinates=
a9913044
RD
1292 [HW] Make the MicroTouch USB driver use raw coordinates
1293 ('y', default) or cooked coordinates ('n')
1da177e4
LT
1294
1295 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1296
1297 NCR_D700= [HW,SCSI]
1298 See header of drivers/scsi/NCR_D700.c.
1299
1300 ncr5380= [HW,SCSI]
1301
1302 ncr53c400= [HW,SCSI]
1303
1304 ncr53c400a= [HW,SCSI]
1305
1306 ncr53c406a= [HW,SCSI]
1307
1308 ncr53c8xx= [HW,SCSI]
1309
1310 netdev= [NET] Network devices parameters
1311 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1312 Note that mem_start is often overloaded to mean
1313 something different and driver-specific.
a9913044
RD
1314 This usage is only documented in each driver source
1315 file if at all.
1316
58401572
KPO
1317 nf_conntrack.acct=
1318 [NETFILTER] Enable connection tracking flow accounting
1319 0 to disable accounting
1320 1 to enable accounting
1321 Default value depends on CONFIG_NF_CT_ACCT that is
1322 going to be removed in 2.6.29.
1323
1da177e4 1324 nfsaddrs= [NFS]
6ded55da 1325 See Documentation/filesystems/nfsroot.txt.
1da177e4
LT
1326
1327 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
6ded55da 1328 See Documentation/filesystems/nfsroot.txt.
1da177e4 1329
a72b4422
TM
1330 nfs.callback_tcpport=
1331 [NFS] set the TCP port on which the NFSv4 callback
1332 channel should listen.
1333
58df095b
TM
1334 nfs.idmap_cache_timeout=
1335 [NFS] set the maximum lifetime for idmapper cache
1336 entries.
1337
f43bf0be
TM
1338 nfs.enable_ino64=
1339 [NFS] enable 64-bit inode numbers.
1340 If zero, the NFS client will fake up a 32-bit inode
1341 number for the readdir() and stat() syscalls instead
1342 of returning the full 64-bit number.
1343 The default is to return 64-bit inode numbers.
1344
e7ba176b
HS
1345 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1346 when a NMI is triggered.
1347 Format: [state][,regs][,debounce][,die]
1348
cd4f0ef7 1349 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1da177e4 1350
cd4f0ef7 1351 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1da177e4
LT
1352 emulation library even if a 387 maths coprocessor
1353 is present.
1354
c1aee215
CL
1355 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1356 caches in the slab allocator. Saves per-node memory,
1357 but will impact performance.
3395ee05 1358
a9913044
RD
1359 noalign [KNL,ARM]
1360
1da177e4
LT
1361 noapic [SMP,APIC] Tells the kernel to not make use of any
1362 IOAPICs that may be present in the system.
1363
1da177e4
LT
1364 nobats [PPC] Do not use BATs for mapping kernel lowmem
1365 on "Classic" PPC cores.
1366
1367 nocache [ARM]
a9913044 1368
163ecdff
SN
1369 nodelayacct [KNL] Disable per-task delay accounting
1370
1da177e4
LT
1371 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1372
8b2cb7a8
HY
1373 noefi [X86-32,X86-64] Disable EFI runtime services support.
1374
1da177e4
LT
1375 noexec [IA-64]
1376
cd4f0ef7 1377 noexec [X86-32,X86-64]
f5a1b191 1378 On X86-32 available only on PAE configured kernels.
1da177e4 1379 noexec=on: enable non-executable mappings (default)
f5a1b191
JS
1380 noexec=off: disable non-executable mappings
1381
1382 noexec32 [X86-64]
1383 This affects only 32-bit executables.
1384 noexec32=on: enable non-executable mappings (default)
1385 read doesn't imply executable mappings
1386 noexec32=off: disable non-executable mappings
1387 read implies executable mappings
1da177e4 1388
cd4f0ef7 1389 nofxsr [BUGS=X86-32] Disables x86 floating point extended
4f886511
CE
1390 register save and restore. The kernel will only save
1391 legacy floating-point registers on task switch.
1da177e4 1392
191679fd
AK
1393 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1394
1da177e4 1395 nohlt [BUGS=ARM]
a9913044 1396
cd4f0ef7 1397 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1da177e4
LT
1398 instruction doesn't work correctly and not to
1399 use it.
1400
1401 nohalt [IA-64] Tells the kernel not to use the power saving
1402 function PAL_HALT_LIGHT when idle. This increases
1403 power-consumption. On the positive side, it reduces
1404 interrupt wake-up latency, which may improve performance
1405 in certain environments such as networked servers or
1406 real-time systems.
1407
79bf2bb3
TG
1408 nohz= [KNL] Boottime enable/disable dynamic ticks
1409 Valid arguments: on, off
1410 Default: on
1411
cd4f0ef7 1412 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
8542b200 1413
cd4f0ef7 1414 noirqdebug [X86-32] Disables the code which attempts to detect and
1da177e4
LT
1415 disable unhandled interrupt sources.
1416
cd4f0ef7 1417 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
8542b200
ZA
1418 broken timer IRQ sources.
1419
1da177e4
LT
1420 noisapnp [ISAPNP] Disables ISA PnP code.
1421
1422 noinitrd [RAM] Tells the kernel not to load any configured
1423 initial RAM disk.
1424
1425 nointroute [IA-64]
1426
0aa366f3
TL
1427 nojitter [IA64] Disables jitter checking for ITC timers.
1428
cd4f0ef7 1429 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1da177e4 1430
cd4f0ef7 1431 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
ad62ca2b 1432
1da177e4
LT
1433 noltlbs [PPC] Do not use large page/tlb entries for kernel
1434 lowmem mapping on PPC40x.
1435
312f1f01
H
1436 nomca [IA-64] Disable machine check abort handling
1437
cd4f0ef7 1438 nomce [X86-32] Machine Check Exception
abe37e5a 1439
83d7384f
AS
1440 nomfgpt [X86-32] Disable Multi-Function General Purpose
1441 Timer usage (for AMD Geode machines).
1442
cd4f0ef7 1443 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
959b4fdf 1444
cd4f0ef7 1445 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
b7fb4af0
JF
1446 with UP alternatives
1447
1da177e4
LT
1448 noresidual [PPC] Don't use residual data on PReP machines.
1449
a9913044
RD
1450 noresume [SWSUSP] Disables resume and restores original swap
1451 space.
1452
1da177e4
LT
1453 no-scroll [VGA] Disables scrollback.
1454 This is required for the Braillex ib80-piezo Braille
1455 reader made by F.H. Papenmeier (Germany).
1456
1457 nosbagart [IA-64]
1458
cd4f0ef7 1459 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
4f886511 1460
61ec7567
LB
1461 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1462 and disable the IO APIC. legacy for "maxcpus=0".
1da177e4 1463
97842216
DJ
1464 nosoftlockup [KNL] Disable the soft-lockup detector.
1465
1da177e4
LT
1466 nosync [HW,M68K] Disables sync negotiation for all devices.
1467
cd4f0ef7 1468 notsc [BUGS=X86-32] Disable Time Stamp Counter
1da177e4
LT
1469
1470 nousb [USB] Disable the USB subsystem
1471
1472 nowb [ARM]
a9913044 1473
a6c75b86
FY
1474 nptcg= [IA64] Override max number of concurrent global TLB
1475 purges which is reported from either PAL_VM_SUMMARY or
1476 SAL PALO.
1477
f0c0b2b8
KH
1478 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1479 one of ['zone', 'node', 'default'] can be specified
1480 This can be set from sysctl after boot.
1481 See Documentation/sysctl/vm.txt for details.
1482
a61c2d78
DJ
1483 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1484
3ef0e1f8
AS
1485 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1486 Rather than timing out after 20 ms if an EC
1487 command is not properly ACKed, override the length
1488 of the timeout. We have interrupts disabled while
1489 waiting for the ACK, so if this is set too high
1490 interrupts *may* be lost!
1491
1da177e4
LT
1492 opl3= [HW,OSS]
1493 Format: <io>
1494
1da177e4
LT
1495 oprofile.timer= [HW]
1496 Use timer interrupt instead of performance counters
1497
1da177e4
LT
1498 osst= [HW,SCSI] SCSI Tape Driver
1499 Format: <buffer_size>,<write_threshold>
1500 See also Documentation/scsi/st.txt.
1501
1502 panic= [KNL] Kernel behaviour on panic
1503 Format: <timeout>
1504
1505 parkbd.port= [HW] Parallel port number the keyboard adapter is
1506 connected to, default is 0.
1507 Format: <parport#>
1508 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1509 0 for XT, 1 for AT (default is AT).
a9913044
RD
1510 Format: <mode>
1511
1512 parport= [HW,PPT] Specify parallel ports. 0 disables.
1513 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1514 Use 'auto' to force the driver to use any
1515 IRQ/DMA settings detected (the default is to
1516 ignore detected IRQ/DMA settings because of
1517 possible conflicts). You can specify the base
1518 address, IRQ, and DMA settings; IRQ and DMA
1519 should be numbers, or 'auto' (for using detected
1520 settings on that particular port), or 'nofifo'
1521 (to avoid using a FIFO even if it is detected).
1522 Parallel ports are assigned in the order they
1523 are specified on the command line, starting
1524 with parport0.
1525
1526 parport_init_mode= [HW,PPT]
1527 Configure VIA parallel port to operate in
1528 a specific mode. This is necessary on Pegasos
1529 computer where firmware has no options for setting
1530 up parallel port mode and sets it to spp.
1531 Currently this function knows 686a and 8231 chips.
1da177e4
LT
1532 Format: [spp|ps2|epp|ecp|ecpepp]
1533
a9913044
RD
1534 pas2= [HW,OSS] Format:
1535 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1536
1da177e4
LT
1537 pas16= [HW,SCSI]
1538 See header of drivers/scsi/pas16.c.
1539
dd287796
AM
1540 pause_on_oops=
1541 Halt all CPUs after the first oops has been printed for
1542 the specified number of seconds. This is to be used if
1543 your oopses keep scrolling off the screen.
1544
1da177e4
LT
1545 pcbit= [HW,ISDN]
1546
1547 pcd. [PARIDE]
1548 See header of drivers/block/paride/pcd.c.
1549 See also Documentation/paride.txt.
1550
a9913044 1551 pci=option[,option...] [PCI] various PCI subsystem options:
cd4f0ef7
AC
1552 off [X86-32] don't probe for the PCI bus
1553 bios [X86-32] force use of PCI BIOS, don't access
a9913044
RD
1554 the hardware directly. Use this if your machine
1555 has a non-standard PCI host bridge.
cd4f0ef7 1556 nobios [X86-32] disallow use of PCI BIOS, only direct
a9913044
RD
1557 hardware access methods are allowed. Use this
1558 if you experience crashes upon bootup and you
1559 suspect they are caused by the BIOS.
cd4f0ef7 1560 conf1 [X86-32] Force use of PCI Configuration
a9913044 1561 Mechanism 1.
cd4f0ef7 1562 conf2 [X86-32] Force use of PCI Configuration
a9913044 1563 Mechanism 2.
7f785763
RD
1564 noaer [PCIE] If the PCIEAER kernel config parameter is
1565 enabled, this kernel boot option can be used to
1566 disable the use of PCIE advanced error reporting.
32a2eea7
JG
1567 nodomains [PCI] Disable support for multiple PCI
1568 root domains (aka PCI segments, in ACPI-speak).
cd4f0ef7 1569 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
61be6d66 1570 Configuration
309e57df
MW
1571 nomsi [MSI] If the PCI_MSI kernel config parameter is
1572 enabled, this kernel boot option can be used to
1573 disable the use of MSI interrupts system-wide.
cd4f0ef7 1574 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
a9913044
RD
1575 routing table. These calls are known to be buggy
1576 on several machines and they hang the machine
1577 when used, but on other computers it's the only
1578 way to get the interrupt routing table. Try
1579 this option if the kernel is unable to allocate
1580 IRQs or discover secondary PCI buses on your
1581 motherboard.
cd4f0ef7 1582 rom [X86-32] Assign address space to expansion ROMs.
a9913044
RD
1583 Use with caution as certain devices share
1584 address decoders between ROMs and other
1585 resources.
bb71ad88
GH
1586 norom [X86-32,X86_64] Do not assign address space to
1587 expansion ROMs that do not already have
1588 BIOS assigned address ranges.
cd4f0ef7 1589 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
a9913044
RD
1590 assigned automatically to PCI devices. You can
1591 make the kernel exclude IRQs of your ISA cards
1592 this way.
cd4f0ef7 1593 pirqaddr=0xAAAAA [X86-32] Specify the physical address
a9913044
RD
1594 of the PIRQ table (normally generated
1595 by the BIOS) if it is outside the
1596 F0000h-100000h range.
cd4f0ef7 1597 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
a9913044
RD
1598 useful if the kernel is unable to find your
1599 secondary buses and you want to tell it
1600 explicitly which ones they are.
cd4f0ef7 1601 assign-busses [X86-32] Always assign all PCI bus
a9913044
RD
1602 numbers ourselves, overriding
1603 whatever the firmware may have done.
cd4f0ef7 1604 usepirqmask [X86-32] Honor the possible IRQ mask stored
a9913044
RD
1605 in the BIOS $PIR table. This is needed on
1606 some systems with broken BIOSes, notably
1607 some HP Pavilion N5400 and Omnibook XE3
1608 notebooks. This will have no effect if ACPI
1609 IRQ routing is enabled.
cd4f0ef7 1610 noacpi [X86-32] Do not use ACPI for IRQ routing
a9913044 1611 or for PCI scanning.
62f420f8
GH
1612 use_crs [X86-32] Use _CRS for PCI resource
1613 allocation.
a9913044
RD
1614 routeirq Do IRQ routing for all PCI devices.
1615 This is normally done in pci_enable_device(),
1616 so this option is a temporary workaround
1617 for broken drivers that don't call it.
13a6ddb0
YL
1618 skip_isa_align [X86] do not align io start addr, so can
1619 handle more pci cards
a9913044
RD
1620 firmware [ARM] Do not re-enumerate the bus but instead
1621 just use the configuration from the
1622 bootloader. This is currently used on
1623 IXP2000 systems where the bus has to be
1624 configured a certain way for adjunct CPUs.
0637a70a
AK
1625 noearly [X86] Don't do any early type 1 scanning.
1626 This might help on some broken boards which
1627 machine check when some devices' config space
1628 is read. But various workarounds are disabled
1629 and some IOMMU drivers will not work.
6b4b78fe
MD
1630 bfsort Sort PCI devices into breadth-first order.
1631 This sorting is done to get a device
1632 order compatible with older (<= 2.4) kernels.
1633 nobfsort Don't sort PCI devices into breadth-first order.
4516a618
AN
1634 cbiosize=nn[KMG] The fixed amount of bus space which is
1635 reserved for the CardBus bridge's IO window.
1636 The default value is 256 bytes.
1637 cbmemsize=nn[KMG] The fixed amount of bus space which is
1638 reserved for the CardBus bridge's memory
1639 window. The default value is 64 megabytes.
6b4b78fe 1640
1da177e4
LT
1641 pcmv= [HW,PCMCIA] BadgePAD 4
1642
1643 pd. [PARIDE]
1644 See Documentation/paride.txt.
1645
1646 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1647 boot time.
1648 Format: { 0 | 1 }
1649 See arch/parisc/kernel/pdc_chassis.c
1650
1651 pf. [PARIDE]
1652 See Documentation/paride.txt.
1653
1654 pg. [PARIDE]
1655 See Documentation/paride.txt.
1656
1657 pirq= [SMP,APIC] Manual mp-table setup
1658 See Documentation/i386/IO-APIC.txt.
1659
1660 plip= [PPT,NET] Parallel port network link
1661 Format: { parport<nr> | timid | 0 }
1662 See also Documentation/parport.txt.
1663
de32a243
TG
1664 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1665 Override pmtimer IOPort with a hex value.
1666 e.g. pmtmr=0x508
1667
1da177e4
LT
1668 pnpacpi= [ACPI]
1669 { off }
1670
1671 pnpbios= [ISAPNP]
1672 { on | off | curr | res | no-curr | no-res }
1673
1674 pnp_reserve_irq=
1675 [ISAPNP] Exclude IRQs for the autoconfiguration
1676
1677 pnp_reserve_dma=
1678 [ISAPNP] Exclude DMAs for the autoconfiguration
1679
1680 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
a9913044 1681 Ranges are in pairs (I/O port base and size).
1da177e4
LT
1682
1683 pnp_reserve_mem=
a9913044
RD
1684 [ISAPNP] Exclude memory regions for the
1685 autoconfiguration.
1da177e4
LT
1686 Ranges are in pairs (memory base and size).
1687
45807a1d
IM
1688 print-fatal-signals=
1689 [KNL] debug: print fatal signals
1690 print-fatal-signals=1: print segfault info to
1691 the kernel console.
1692 default: off.
1693
e84845c4
RD
1694 printk.time= Show timing data prefixed to each printk message line
1695 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1696
1da177e4 1697 profile= [KNL] Enable kernel profiling via /proc/profile
a9913044
RD
1698 Format: [schedule,]<number>
1699 Param: "schedule" - profile schedule points.
1700 Param: <number> - step/bucket size as a power of 2 for
1701 statistical time based profiling.
b3da2a73
MG
1702 Param: "sleep" - profile D-state sleeping (millisecs).
1703 Requires CONFIG_SCHEDSTATS
c0fe2e69 1704 Param: "kvm" - profile VM exits.
1da177e4 1705
a9913044 1706 processor.max_cstate= [HW,ACPI]
1da177e4
LT
1707 Limit processor to maximum C-state
1708 max_cstate=9 overrides any DMI blacklist limit.
1709
41c0d868
LB
1710 processor.nocst [HW,ACPI]
1711 Ignore the _CST method to determine C-states,
1712 instead using the legacy FADT method
1713
1da177e4
LT
1714 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1715 before loading.
1716 See Documentation/ramdisk.txt.
1717
a9913044
RD
1718 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1719 probe for; one of (bare|imps|exps|lifebook|any).
1da177e4
LT
1720 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1721 per second.
a9913044
RD
1722 psmouse.resetafter= [HW,MOUSE]
1723 Try to reset the device after so many bad packets
1da177e4
LT
1724 (0 = never).
1725 psmouse.resolution=
1726 [HW,MOUSE] Set desired mouse resolution, in dpi.
1727 psmouse.smartscroll=
a9913044 1728 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1da177e4
LT
1729 0 = disabled, 1 = enabled (default).
1730
1731 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
a9913044
RD
1732 Format:
1733 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1da177e4
LT
1734
1735 pt. [PARIDE]
1736 See Documentation/paride.txt.
1737
dc8c8587
KS
1738 pty.legacy_count=
1739 [KNL] Number of legacy pty's. Overwrites compiled-in
1740 default number.
1741
7d2c502f 1742 quiet [KNL] Disable most log messages
a9913044 1743
1da177e4
LT
1744 r128= [HW,DRM]
1745
1746 raid= [HW,RAID]
1747 See Documentation/md.txt.
1748
a9913044 1749 ramdisk_blocksize= [RAM]
1da177e4 1750 See Documentation/ramdisk.txt.
a9913044 1751
1da177e4 1752 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1da177e4
LT
1753 See Documentation/ramdisk.txt.
1754
24aaef8d
RD
1755 rcupdate.blimit= [KNL,BOOT]
1756 Set maximum number of finished RCU callbacks to process
1757 in one batch.
21a1ea9e 1758
24aaef8d
RD
1759 rcupdate.qhimark= [KNL,BOOT]
1760 Set threshold of queued
21a1ea9e
DS
1761 RCU callbacks over which batch limiting is disabled.
1762
24aaef8d
RD
1763 rcupdate.qlowmark= [KNL,BOOT]
1764 Set threshold of queued RCU callbacks below which
1765 batch limiting is re-enabled.
21a1ea9e 1766
ffdfc409
OJ
1767 rdinit= [KNL]
1768 Format: <full_path>
1769 Run specified binary instead of /init from the ramdisk,
1770 used for early userspace startup. See initrd.
1771
cd4f0ef7 1772 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1da177e4 1773 Format: <reboot_mode>[,<reboot_mode2>[,...]]
e53dd083 1774 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1da177e4 1775
46b6d94e
PJ
1776 relax_domain_level=
1777 [KNL, SMP] Set scheduler's default relax_domain_level.
1778 See Documentation/cpusets.txt.
1779
1da177e4
LT
1780 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1781
cd4f0ef7 1782 reservetop= [X86-32]
461a9aff
ZA
1783 Format: nn[KMG]
1784 Reserves a hole at the top of the kernel virtual
1785 address space.
1786
7e96287d
VG
1787 reset_devices [KNL] Force drivers to reset the underlying device
1788 during initialization.
1789
a9913044
RD
1790 resume= [SWSUSP]
1791 Specify the partition device for software suspend
1da177e4 1792
ecbd0da1
RW
1793 resume_offset= [SWSUSP]
1794 Specify the offset from the beginning of the partition
1795 given by "resume=" at which the swap header is located,
1796 in <PAGE_SIZE> units (needed only for swap files).
1797 See Documentation/power/swsusp-and-swap-files.txt
1798
0a7b35cb
MN
1799 retain_initrd [RAM] Keep initrd memory after extraction
1800
1da177e4
LT
1801 rhash_entries= [KNL,NET]
1802 Set number of hash buckets for route cache
1803
1804 riscom8= [HW,SERIAL]
1805 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1806
1807 ro [KNL] Mount root device read-only on boot
1808
1809 root= [KNL] Root filesystem
1810
1811 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1812 mount the root filesystem
1813
1814 rootflags= [KNL] Set root filesystem mount option string
1815
1816 rootfstype= [KNL] Set root filesystem type
1817
cc1ed754
PO
1818 rootwait [KNL] Wait (indefinitely) for root device to show up.
1819 Useful for devices that are detected asynchronously
1820 (e.g. USB and MMC devices).
1821
20510f2f
JM
1822 root_plug.vendor_id=
1823 [ROOTPLUG] Override the default vendor ID
1824
1825 root_plug.product_id=
1826 [ROOTPLUG] Override the default product ID
1827
1828 root_plug.debug=
1829 [ROOTPLUG] Enable debugging output
1830
1da177e4
LT
1831 rw [KNL] Mount root device read-write on boot
1832
1833 S [KNL] Run init in single mode
1834
1835 sa1100ir [NET]
1836 See drivers/net/irda/sa1100_ir.c.
1837
1da177e4 1838 sbni= [NET] Granch SBNI12 leased line adapter
a9913044 1839
1da177e4
LT
1840 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1841 Format: <io>[,<timeout>[,<isapnp>]]
1842
1843 scsi_debug_*= [SCSI]
1844 See drivers/scsi/scsi_debug.c.
1845
1846 scsi_default_dev_flags=
1847 [SCSI] SCSI default device flags
1848 Format: <integer>
1849
1850 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1851 Format: <vendor>:<model>:<flags>
1852 (flags are integer value)
1853
6af6632a
RD
1854 scsi_logging_level= [SCSI] a bit mask of logging levels
1855 See drivers/scsi/scsi_logging.h for bits. Also
1856 settable via sysctl at dev.scsi.logging_level
1857 (/proc/sys/dev/scsi/logging_level).
1858 There is also a nice 'scsi_logging_level' script in the
1859 S390-tools package, available for download at
1860 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1da177e4 1861
3e082a91
MW
1862 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1863 discovered. async scans them in kernel threads,
1864 allowing boot to proceed. none ignores them, expecting
1865 user space to do the scan.
1866
1da177e4
LT
1867 selinux [SELINUX] Disable or enable SELinux at boot time.
1868 Format: { "0" | "1" }
1869 See security/selinux/Kconfig help text.
1870 0 -- disable.
1871 1 -- enable.
1872 Default value is set via kernel config option.
1873 If enabled at boot time, /selinux/disable can be used
1874 later to disable prior to initial policy load.
1875
4e5ab4cb
JM
1876 selinux_compat_net =
1877 [SELINUX] Set initial selinux_compat_net flag value.
e53dd083
MCC
1878 Format: { "0" | "1" }
1879 0 -- use new secmark-based packet controls
1880 1 -- use legacy packet controls
1881 Default value is 0 (preferred).
1882 Value can be changed at runtime via
1883 /selinux/compat_net.
4e5ab4cb 1884
cd4f0ef7 1885 serialnumber [BUGS=X86-32]
1da177e4 1886
1da177e4
LT
1887 shapers= [NET]
1888 Maximal number of shapers.
a9913044 1889
1da177e4
LT
1890 sim710= [SCSI,HW]
1891 See header of drivers/scsi/sim710.c.
1892
1893 simeth= [IA-64]
1894 simscsi=
a9913044 1895
1da177e4
LT
1896 slram= [HW,MTD]
1897
f0630fff
CL
1898 slub_debug[=options[,slabs]] [MM, SLUB]
1899 Enabling slub_debug allows one to determine the
1900 culprit if slab objects become corrupted. Enabling
1901 slub_debug can create guard zones around objects and
1902 may poison objects when not in use. Also tracks the
1903 last alloc / free. For more information see
1904 Documentation/vm/slub.txt.
c1aee215
CL
1905
1906 slub_max_order= [MM, SLUB]
f0630fff
CL
1907 Determines the maximum allowed order for slabs.
1908 A high setting may cause OOMs due to memory
1909 fragmentation. For more information see
1910 Documentation/vm/slub.txt.
c1aee215
CL
1911
1912 slub_min_objects= [MM, SLUB]
f0630fff
CL
1913 The minimum number of objects per slab. SLUB will
1914 increase the slab order up to slub_max_order to
1915 generate a sufficiently large slab able to contain
1916 the number of objects indicated. The higher the number
1917 of objects the smaller the overhead of tracking slabs
1918 and the less frequently locks need to be acquired.
c1aee215
CL
1919 For more information see Documentation/vm/slub.txt.
1920
1921 slub_min_order= [MM, SLUB]
1922 Determines the mininum page order for slabs. Must be
f0630fff 1923 lower than slub_max_order.
c1aee215
CL
1924 For more information see Documentation/vm/slub.txt.
1925
1926 slub_nomerge [MM, SLUB]
f0630fff 1927 Disable merging of slabs with similar size. May be
c1aee215 1928 necessary if there is some reason to distinguish
f0630fff
CL
1929 allocs to different slabs. Debug options disable
1930 merging on their own.
c1aee215
CL
1931 For more information see Documentation/vm/slub.txt.
1932
1da177e4
LT
1933 smart2= [HW]
1934 Format: <io1>[,<io2>[,...,<io8>]]
1935
cd4f0ef7 1936 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
b7fb4af0
JF
1937 attempt to substitute SMP alternatives once at boot.
1938
d0d4f69b
BH
1939 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1940 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1941 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1942 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1943 smsc-ircc2.ircc_irq= [HW] IRQ line
1944 smsc-ircc2.ircc_dma= [HW] DMA channel
1945 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1946 0: Toshiba Satellite 1800 (GP data pin select)
1947 1: Fast pin select (default)
1948 2: ATC IRMode
1949
1da177e4
LT
1950 snd-ad1816a= [HW,ALSA]
1951
1952 snd-ad1848= [HW,ALSA]
1953
1954 snd-ali5451= [HW,ALSA]
1955
1956 snd-als100= [HW,ALSA]
1957
1958 snd-als4000= [HW,ALSA]
1959
1960 snd-azt2320= [HW,ALSA]
1961
1962 snd-cmi8330= [HW,ALSA]
1963
1964 snd-cmipci= [HW,ALSA]
1965
1966 snd-cs4231= [HW,ALSA]
1967
1968 snd-cs4232= [HW,ALSA]
1969
1970 snd-cs4236= [HW,ALSA]
1971
1972 snd-cs4281= [HW,ALSA]
1973
1974 snd-cs46xx= [HW,ALSA]
1975
1976 snd-dt019x= [HW,ALSA]
1977
1978 snd-dummy= [HW,ALSA]
1979
1980 snd-emu10k1= [HW,ALSA]
1981
1982 snd-ens1370= [HW,ALSA]
1983
1984 snd-ens1371= [HW,ALSA]
1985
1986 snd-es968= [HW,ALSA]
1987
1988 snd-es1688= [HW,ALSA]
1989
1990 snd-es18xx= [HW,ALSA]
1991
1992 snd-es1938= [HW,ALSA]
1993
1994 snd-es1968= [HW,ALSA]
1995
1996 snd-fm801= [HW,ALSA]
1997
1998 snd-gusclassic= [HW,ALSA]
1999
2000 snd-gusextreme= [HW,ALSA]
2001
2002 snd-gusmax= [HW,ALSA]
2003
2004 snd-hdsp= [HW,ALSA]
2005
2006 snd-ice1712= [HW,ALSA]
2007
2008 snd-intel8x0= [HW,ALSA]
2009
2010 snd-interwave= [HW,ALSA]
2011
2012 snd-interwave-stb=
2013 [HW,ALSA]
2014
2015 snd-korg1212= [HW,ALSA]
2016
2017 snd-maestro3= [HW,ALSA]
2018
2019 snd-mpu401= [HW,ALSA]
2020
2021 snd-mtpav= [HW,ALSA]
2022
2023 snd-nm256= [HW,ALSA]
2024
2025 snd-opl3sa2= [HW,ALSA]
2026
2027 snd-opti92x-ad1848=
2028 [HW,ALSA]
2029
2030 snd-opti92x-cs4231=
2031 [HW,ALSA]
2032
2033 snd-opti93x= [HW,ALSA]
2034
2035 snd-pmac= [HW,ALSA]
2036
2037 snd-rme32= [HW,ALSA]
2038
2039 snd-rme96= [HW,ALSA]
2040
2041 snd-rme9652= [HW,ALSA]
2042
2043 snd-sb8= [HW,ALSA]
2044
2045 snd-sb16= [HW,ALSA]
2046
2047 snd-sbawe= [HW,ALSA]
2048
2049 snd-serial= [HW,ALSA]
2050
2051 snd-sgalaxy= [HW,ALSA]
2052
2053 snd-sonicvibes= [HW,ALSA]
2054
2055 snd-sun-amd7930=
2056 [HW,ALSA]
2057
2058 snd-sun-cs4231= [HW,ALSA]
2059
2060 snd-trident= [HW,ALSA]
2061
2062 snd-usb-audio= [HW,ALSA,USB]
2063
2064 snd-via82xx= [HW,ALSA]
2065
2066 snd-virmidi= [HW,ALSA]
2067
2068 snd-wavefront= [HW,ALSA]
2069
2070 snd-ymfpci= [HW,ALSA]
a9913044 2071
9c44bc03
IM
2072 softlockup_panic=
2073 [KNL] Should the soft-lockup detector generate panics.
2074
1da177e4
LT
2075 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2076 See Documentation/sonypi.txt
2077
2078 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2079 See Documentation/specialix.txt.
2080
2081 spia_io_base= [HW,MTD]
2082 spia_fio_base=
2083 spia_pedr=
2084 spia_peddr=
2085
2086 sscape= [HW,OSS]
2087 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
a9913044 2088
1da177e4
LT
2089 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2090 See Documentation/scsi/st.txt.
2091
1da177e4
LT
2092 sti= [PARISC,HW]
2093 Format: <num>
2094 Set the STI (builtin display/keyboard on the HP-PARISC
2095 machines) console (graphic card) which should be used
2096 as the initial boot-console.
2097 See also comment in drivers/video/console/sticore.c.
2098
2099 sti_font= [HW]
2100 See comment in drivers/video/console/sticore.c.
2101
2102 stifb= [HW]
2103 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2104
42a7fc4a
GB
2105 sunrpc.pool_mode=
2106 [NFS]
2107 Control how the NFS server code allocates CPUs to
2108 service thread pools. Depending on how many NICs
2109 you have and where their interrupts are bound, this
2110 option will affect which CPUs will do NFS serving.
2111 Note: this parameter cannot be changed while the
2112 NFS server is running.
2113
2114 auto the server chooses an appropriate mode
2115 automatically using heuristics
2116 global a single global pool contains all CPUs
2117 percpu one pool for each CPU
2118 pernode one pool for each NUMA node (equivalent
2119 to global on non-NUMA machines)
2120
1da177e4 2121 swiotlb= [IA-64] Number of I/O TLB slabs
a9913044 2122
1da177e4
LT
2123 switches= [HW,M68k]
2124
2125 sym53c416= [HW,SCSI]
2126 See header of drivers/scsi/sym53c416.c.
2127
5d6f647f
IM
2128 sysrq_always_enabled
2129 [KNL]
2130 Ignore sysrq setting - this boot parameter will
2131 neutralize any effect of /proc/sys/kernel/sysrq.
2132 Useful for debugging.
2133
1da177e4
LT
2134 t128= [HW,SCSI]
2135 See header of drivers/scsi/t128.c.
2136
2137 tdfx= [HW,DRM]
2138
77437fd4
DB
2139 test_suspend= [SUSPEND]
2140 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2141 standby suspend) as the system sleep state to briefly
2142 enter during system startup. The system is woken from
2143 this state using a wakeup-capable RTC alarm.
2144
1da177e4
LT
2145 thash_entries= [KNL,NET]
2146 Set number of hash buckets for TCP connection
2147
f8707ec9
LB
2148 thermal.act= [HW,ACPI]
2149 -1: disable all active trip points in all thermal zones
2150 <degrees C>: override all lowest active trip points
2151
c52a7419
LB
2152 thermal.crt= [HW,ACPI]
2153 -1: disable all critical trip points in all thermal zones
2154 <degrees C>: lower all critical trip points
2155
f5487145
LB
2156 thermal.nocrt= [HW,ACPI]
2157 Set to disable actions on ACPI thermal zone
2158 critical and hot trip points.
2159
72b33ef8
LB
2160 thermal.off= [HW,ACPI]
2161 1: disable ACPI thermal control
2162
a70cdc52
LB
2163 thermal.psv= [HW,ACPI]
2164 -1: disable all passive trip points
2165 <degrees C>: override all passive trip points to this value
2166
730ff34d
LB
2167 thermal.tzp= [HW,ACPI]
2168 Specify global default ACPI thermal zone polling rate
2169 <deci-seconds>: poll all this frequency
2170 0: no polling (default)
2171
1da177e4
LT
2172 tmscsim= [HW,SCSI]
2173 See comment before function dc390_setup() in
2174 drivers/scsi/tmscsim.c.
2175
2176 tp720= [HW,PS2]
2177
2178 trix= [HW,OSS] MediaTrix AudioTrix Pro
a9913044
RD
2179 Format:
2180 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2181
a9913044
RD
2182 turbografx.map[2|3]= [HW,JOY]
2183 TurboGraFX parallel port interface
2184 Format:
2185 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1da177e4
LT
2186 See also Documentation/input/joystick-parport.txt
2187
2188 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2189 See header of drivers/scsi/u14-34f.c.
2190
2191 uart401= [HW,OSS]
2192 Format: <io>,<irq>
2193
2194 uart6850= [HW,OSS]
2195 Format: <io>,<irq>
2196
5f8364b7
AS
2197 uhci-hcd.ignore_oc=
2198 [USB] Ignore overcurrent events (default N).
2199 Some badly-designed motherboards generate lots of
2200 bogus events, for ports that aren't wired to
2201 anything. Set this parameter to avoid log spamming.
2202 Note that genuine overcurrent events won't be
2203 reported either.
2204
e3a61b0a
SA
2205 unknown_nmi_panic
2206 [X86-32,X86-64]
2207 Set unknown_nmi_panic=1 early on boot.
2208
b5e795f8
AS
2209 usbcore.autosuspend=
2210 [USB] The autosuspend time delay (in seconds) used
2211 for newly-detected USB devices (default 2). This
2212 is the time required before an idle device will be
2213 autosuspended. Devices for which the delay is set
eaafbc3a 2214 to a negative value won't be autosuspended at all.
b5e795f8 2215
1da177e4
LT
2216 usbhid.mousepoll=
2217 [USBHID] The interval which mice are to be polled at.
a9913044 2218
200001eb
PJ
2219 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2220 kernel's map of available physical RAM.
2221
cd4f0ef7 2222 vdso= [X86-32,SH,x86-64]
1dbf527c 2223 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
e6e5494c
IM
2224 vdso=1: enable VDSO (default)
2225 vdso=0: disable VDSO mapping
2226
af65d648
RM
2227 vdso32= [X86-32,X86-64]
2228 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2229 vdso32=1: enable 32-bit VDSO (default)
2230 vdso32=0: disable 32-bit VDSO mapping
2231
d080d397
YI
2232 vector= [IA-64,SMP]
2233 vector=percpu: enable percpu vector domain
2234
1da177e4
LT
2235 video= [FB] Frame buffer configuration
2236 See Documentation/fb/modedb.txt.
2237
cd4f0ef7 2238 vga= [BOOT,X86-32] Select a particular video mode
a9913044
RD
2239 See Documentation/i386/boot.txt and
2240 Documentation/svga.txt.
1da177e4
LT
2241 Use vga=ask for menu.
2242 This is actually a boot loader parameter; the value is
2243 passed to the kernel using a special protocol.
2244
a9913044 2245 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1da177e4
LT
2246 size of <nn>. This can be used to increase the
2247 minimum size (128MB on x86). It can also be used to
2248 decrease the size and leave more room for directly
2249 mapped kernel RAM.
2250
585c3047
PO
2251 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2252 Format: <command>
1da177e4 2253
585c3047
PO
2254 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2255 Format: <command>
2256
2257 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2258 Format: <command>
a9913044 2259
1da177e4
LT
2260 waveartist= [HW,OSS]
2261 Format: <io>,<irq>,<dma>,<dma2>
a9913044 2262
1da177e4
LT
2263 wd33c93= [HW,SCSI]
2264 See header of drivers/scsi/wd33c93.c.
2265
2266 wd7000= [HW,SCSI]
2267 See header of drivers/scsi/wd7000.c.
2268
2269 wdt= [WDT] Watchdog
8dfe9c21 2270 See Documentation/watchdog/wdt.txt.
1da177e4
LT
2271
2272 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2273 xd_geo= See header of drivers/block/xd.c.
2274
2275 xirc2ps_cs= [NET,PCMCIA]
a9913044
RD
2276 Format:
2277 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1da177e4 2278
a62eaf15
AK
2279 norandmaps Don't use address space randomization
2280 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2281
a9913044 2282______________________________________________________________________
1da177e4
LT
2283
2284TODO:
2285
2286 Add documentation for ALSA options.
2287 Add more DRM drivers.