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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 boot_delay= Milliseconds to delay each printk during boot.
364 Values larger than 10 seconds (10000) are changed to
365 no delay (0).
366 Format: integer
367
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368 bootmem_debug [KNL] Enable bootmem allocator debug messages.
369
1da177e4 370 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
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371 bttv.radio= Most important insmod options are available as
372 kernel args too.
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373 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
374 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
375
376 BusLogic= [HW,SCSI]
377 See drivers/scsi/BusLogic.c, comment before function
378 BusLogic_ParseDriverOptions().
379
380 c101= [NET] Moxa C101 synchronous serial card
381
cd4f0ef7 382 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
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383 Sometimes CPU hardware bugs make them report the cache
384 size incorrectly. The kernel will attempt work arounds
385 to fix known problems, but for some CPUs it is not
386 possible to determine what the correct size should be.
387 This option provides an override for these situations.
388
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389 security= [SECURITY] Choose a security module to enable at boot.
390 If this boot parameter is not specified, only the first
391 security module asking for security registration will be
392 loaded. An invalid security module name will be treated
393 as if no module has been chosen.
394
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395 capability.disable=
396 [SECURITY] Disable capabilities. This would normally
397 be used only if an alternative security model is to be
398 configured. Potentially dangerous and should only be
399 used if you are entirely sure of the consequences.
400
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401 ccw_timeout_log [S390]
402 See Documentation/s390/CommonIO for details.
1da177e4 403
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404 cgroup_disable= [KNL] Disable a particular controller
405 Format: {name of the controller(s) to disable}
406 {Currently supported controllers - "memory"}
407
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408 checkreqprot [SELINUX] Set initial checkreqprot flag value.
409 Format: { "0" | "1" }
410 See security/selinux/Kconfig help text.
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411 0 -- check protection applied by kernel (includes
412 any implied execute protection).
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413 1 -- check protection requested by application.
414 Default value is set via a kernel config option.
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415 Value can be changed at runtime via
416 /selinux/checkreqprot.
417
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418 cio_ignore= [S390]
419 See Documentation/s390/CommonIO for details.
420
cd4f0ef7 421 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
734efb46 422 [Deprecated]
3f6dee9b 423 Forces specified clocksource (if available) to be used
734efb46 424 when calculating gettimeofday(). If specified
3f6dee9b 425 clocksource is not available, it defaults to PIT.
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426 Format: { pit | tsc | cyclone | pmtmr }
427
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428 clocksource= [GENERIC_TIME] Override the default clocksource
429 Format: <string>
430 Override the default clocksource and use the clocksource
431 with the name specified.
432 Some clocksource names to choose from, depending on
433 the platform:
434 [all] jiffies (this is the base, fallback clocksource)
435 [ACPI] acpi_pm
436 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
437 pxa_timer,timer3,32k_counter,timer0_1
438 [AVR32] avr32
cd4f0ef7 439 [X86-32] pit,hpet,tsc,vmi-timer;
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440 scx200_hrt on Geode; cyclone on IBM x440
441 [MIPS] MIPS
442 [PARISC] cr16
443 [S390] tod
444 [SH] SuperH
445 [SPARC64] tick
446 [X86-64] hpet,tsc
447
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448 clearcpuid=BITNUM [X86]
449 Disable CPUID feature X for the kernel. See
450 include/asm-x86/cpufeature.h for the valid bit numbers.
451 Note the Linux specific bits are not necessarily
452 stable over kernel options, but the vendor specific
453 ones should be.
454 Also note that user programs calling CPUID directly
455 or using the feature without checking anything
456 will still see it. This just prevents it from
457 being used by the kernel or shown in /proc/cpuinfo.
458 Also note the kernel might malfunction if you disable
459 some critical bits.
460
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461 code_bytes [IA32/X86_64] How many bytes of object code to print
462 in an oops report.
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463 Range: 0 - 8192
464 Default: 64
465
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466 disable_8254_timer
467 enable_8254_timer
468 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
469 over the 8254 in addition to over the IO-APIC. The
470 kernel tries to set a sensible default.
471
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472 hpet= [X86-32,HPET] option to control HPET usage
473 Format: { enable (default) | disable | force }
474 disable: disable HPET and use PIT instead
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475 force: allow force enabled of undocumented chips (ICH4,
476 VIA, nVidia)
1da177e4 477
1da177e4 478 com20020= [HW,NET] ARCnet - COM20020 chipset
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479 Format:
480 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
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481
482 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
483 Format: <io>[,<irq>]
484
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485 com90xx= [HW,NET]
486 ARCnet - COM90xx chipset (memory-mapped buffers)
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487 Format: <io>[,<irq>[,<memstart>]]
488
489 condev= [HW,S390] console device
490 conmode=
a9913044 491
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492 console= [KNL] Output console device and options.
493
494 tty<n> Use the virtual console device <n>.
495
496 ttyS<n>[,options]
f1a1c2dc 497 ttyUSB0[,options]
1da177e4 498 Use the specified serial port. The options are of
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499 the form "bbbbpnf", where "bbbb" is the baud rate,
500 "p" is parity ("n", "o", or "e"), "n" is number of
501 bits, and "f" is flow control ("r" for RTS or
502 omit it). Default is "9600n8".
503
504 See Documentation/serial-console.txt for more
505 information. See
506 Documentation/networking/netconsole.txt for an
507 alternative.
1da177e4 508
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509 uart[8250],io,<addr>[,options]
510 uart[8250],mmio,<addr>[,options]
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LT
511 Start an early, polled-mode console on the 8250/16550
512 UART at the specified I/O port or MMIO address,
513 switching to the matching ttyS device later. The
514 options are the same as for ttyS, above.
515
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ST
516 If the device connected to the port is not a TTY but a braille
517 device, prepend "brl," before the device type, for instance
518 console=brl,ttyS0
519 For now, only VisioBraille is supported.
520
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521 earlycon= [KNL] Output early console device and options.
522 uart[8250],io,<addr>[,options]
523 uart[8250],mmio,<addr>[,options]
524 Start an early, polled-mode console on the 8250/16550
525 UART at the specified I/O port or MMIO address.
526 The options are the same as for ttyS, above.
527
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528 no_console_suspend
529 [HW] Never suspend the console
530 Disable suspending of consoles during suspend and
531 hibernate operations. Once disabled, debugging
532 messages can reach various consoles while the rest
533 of the system is being put to sleep (ie, while
534 debugging driver suspend/resume hooks). This may
535 not work reliably with all consoles, but is known
536 to work with serial and VGA consoles.
537
1da177e4 538 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
a9913044
RD
539 Format:
540 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
1da177e4 541
dc009d92
EB
542 crashkernel=nn[KMG]@ss[KMG]
543 [KNL] Reserve a chunk of physical memory to
544 hold a kernel to switch to with kexec on panic.
545
fb391599
BW
546 crashkernel=range1:size1[,range2:size2,...][@offset]
547 [KNL] Same as above, but depends on the memory
548 in the running system. The syntax of range is
549 start-[end] where start and end are both
550 a memory unit (amount[KMG]). See also
551 Documentation/kdump/kdump.txt for a example.
552
1da177e4
LT
553 cs4232= [HW,OSS]
554 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
555
556 cs89x0_dma= [HW,NET]
557 Format: <dma>
558
559 cs89x0_media= [HW,NET]
560 Format: { rj45 | aui | bnc }
a9913044 561
a9913044 562 dasd= [HW,NET]
1da177e4
LT
563 See header of drivers/s390/block/dasd_devmap.c.
564
565 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
566 (one device per port)
567 Format: <port#>,<type>
568 See also Documentation/input/joystick-parport.txt
569
570 debug [KNL] Enable kernel debugging (events log level).
571
cae2ed9a
IM
572 debug_locks_verbose=
573 [KNL] verbose self-tests
574 Format=<0|1>
575 Print debugging info while doing the locking API
576 self-tests.
577 We default to 0 (no extra messages), setting it to
578 1 will print _a lot_ more information - normally
579 only useful to kernel developers.
580
3ac7fe5a
TG
581 debug_objects [KNL] Enable object debugging
582
d3af01f1
TG
583 debugpat [X86] Enable PAT debugging
584
2d27a966 585 decnet.addr= [HW,NET]
1da177e4
LT
586 Format: <area>[,<node>]
587 See also Documentation/networking/decnet.txt.
588
ecb77fa9 589 vt.default_blu= [VT]
55ff9780
AD
590 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
591 Change the default blue palette of the console.
592 This is a 16-member array composed of values
593 ranging from 0-255.
594
ecb77fa9 595 vt.default_grn= [VT]
55ff9780
AD
596 Format: <green0>,<green1>,<green2>,...,<green15>
597 Change the default green palette of the console.
598 This is a 16-member array composed of values
599 ranging from 0-255.
600
ecb77fa9 601 vt.default_red= [VT]
55ff9780
AD
602 Format: <red0>,<red1>,<red2>,...,<red15>
603 Change the default red palette of the console.
604 This is a 16-member array composed of values
605 ranging from 0-255.
606
ecb77fa9
ST
607 vt.default_utf8=
608 [VT]
55ff9780
AD
609 Format=<0|1>
610 Set system-wide default UTF-8 mode for all tty's.
ecb77fa9
ST
611 Default is 1, i.e. UTF-8 mode is enabled for all
612 newly opened terminals.
55ff9780 613
1da177e4
LT
614 dhash_entries= [KNL]
615 Set number of hash buckets for dentry cache.
a9913044 616
1da177e4
LT
617 digi= [HW,SERIAL]
618 IO parameters + enable/disable command.
619
620 digiepca= [HW,SERIAL]
621 See drivers/char/README.epca and
622 Documentation/digiepca.txt.
623
95ffa243
YL
624 disable_mtrr_cleanup [X86]
625 enable_mtrr_cleanup [X86]
626 The kernel tries to adjust MTRR layout from continuous
627 to discrete, to make X server driver able to add WB
628 entry later. This parameter enables/disables that.
629
630 mtrr_chunk_size=nn[KMG] [X86]
631 used for mtrr cleanup. It is largest continous chunk
632 that could hold holes aka. UC entries.
633
634 mtrr_gran_size=nn[KMG] [X86]
12031a62
YL
635 Used for mtrr cleanup. It is granularity of mtrr block.
636 Default is 1.
637 Large value could prevent small alignment from
638 using up MTRRs.
639
640 mtrr_spare_reg_nr=n [X86]
641 Format: <integer>
642 Range: 0,7 : spare reg number
643 Default : 1
644 Used for mtrr cleanup. It is spare mtrr entries number.
645 Set to 2 or more if your graphical card needs more.
95ffa243 646
093af8d7 647 disable_mtrr_trim [X86, Intel and AMD only]
99fc8d42
JB
648 By default the kernel will trim any uncacheable
649 memory out of your available memory pool based on
650 MTRR settings. This parameter disables that behavior,
651 possibly causing your machine to run very slowly.
652
1da177e4
LT
653 dmasound= [HW,OSS] Sound subsystem buffers
654
655 dscc4.setup= [NET]
656
657 dtc3181e= [HW,SCSI]
658
0ae53640 659 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
1da177e4
LT
660 earlyprintk=vga
661 earlyprintk=serial[,ttySn[,baudrate]]
662
a9913044 663 Append ",keep" to not disable it when the real console
1da177e4
LT
664 takes over.
665
666 Only vga or serial at a time, not both.
667
668 Currently only ttyS0 and ttyS1 are supported.
669
670 Interaction with the standard serial driver is not
671 very good.
672
673 The VGA output is eventually overwritten by the real
674 console.
675
676 eata= [HW,SCSI]
677
1da177e4 678 edd= [EDD]
8c4dd606 679 Format: {"off" | "on" | "skip[mbr]"}
1da177e4 680
1da177e4
LT
681 eisa_irq_edge= [PARISC,HW]
682 See header of drivers/parisc/eisa.c.
683
cd4f0ef7 684 elanfreq= [X86-32]
1da177e4 685 See comment before function elanfreq_setup() in
71f77055 686 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
1da177e4
LT
687
688 elevator= [IOSCHED]
16ab3adf 689 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
a9913044
RD
690 See Documentation/block/as-iosched.txt and
691 Documentation/block/deadline-iosched.txt for details.
692
cd4f0ef7 693 elfcorehdr= [X86-32, X86_64]
a9913044 694 Specifies physical address of start of kernel core
aac04b32
VG
695 image elf header. Generally kexec loader will
696 pass this option to capture kernel.
697 See Documentation/kdump/kdump.txt for details.
1da177e4
LT
698
699 enforcing [SELINUX] Set initial enforcing status.
700 Format: {"0" | "1"}
701 See security/selinux/Kconfig help text.
702 0 -- permissive (log only, no denials).
703 1 -- enforcing (deny and log).
704 Default value is 0.
705 Value can be changed at runtime via /selinux/enforce.
706
1da177e4
LT
707 es1371= [HW,OSS]
708 Format: <spdif>,[<nomix>,[<amplifier>]]
709 See also header of sound/oss/es1371.c.
a9913044 710
1da177e4
LT
711 ether= [HW,NET] Ethernet cards parameters
712 This option is obsoleted by the "netdev=" option, which
713 has equivalent usage. See its documentation for details.
714
715 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
716 Format: <io>[,<irq>]
717
de1ba09b
AM
718 failslab=
719 fail_page_alloc=
720 fail_make_request=[KNL]
721 General fault injection mechanism.
722 Format: <interval>,<probability>,<space>,<times>
723 See also /Documentation/fault-injection/.
724
1da177e4
LT
725 fd_mcs= [HW,SCSI]
726 See header of drivers/scsi/fd_mcs.c.
727
728 fdomain= [HW,SCSI]
729 See header of drivers/scsi/fdomain.c.
730
731 floppy= [HW]
732 See Documentation/floppy.txt.
733
f13ae30e
AC
734 force_pal_cache_flush
735 [IA-64] Avoid check_sal_cache_flush which may hang on
736 buggy SAL_CACHE_FLUSH implementations. Using this
737 parameter will force ia64_sal_cache_flush to call
738 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
739
1da177e4
LT
740 gamecon.map[2|3]=
741 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
742 support via parallel port (up to 5 devices per port)
743 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
744 See also Documentation/input/joystick-parport.txt
745
746 gamma= [HW,DRM]
747
aaf23042
YL
748 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
749 Format: off | on
750 default: on
751
1da177e4
LT
752 gdth= [HW,SCSI]
753 See header of drivers/scsi/gdth.c.
754
755 gpt [EFI] Forces disk with valid GPT signature but
756 invalid Protective MBR to be treated as GPT.
757
1da177e4
LT
758 gvp11= [HW,SCSI]
759
760 hashdist= [KNL,NUMA] Large hashes allocated during boot
761 are distributed across NUMA nodes. Defaults on
762 for IA-64, off otherwise.
a9913044 763 Format: 0 | 1 (for off | on)
1da177e4
LT
764
765 hcl= [IA-64] SGI's Hardware Graph compatibility layer
766
767 hd= [EIDE] (E)IDE hard drive subsystem geometry
768 Format: <cyl>,<head>,<sect>
769
1da177e4
LT
770 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
771 size of <nn>. This works even on boxes that have no
772 highmem otherwise. This also works to reduce highmem
773 size on bigger boxes.
774
54cdfdb4
TG
775 highres= [KNL] Enable/disable high resolution timer mode.
776 Valid parameters: "on", "off"
777 Default: "on"
778
1da177e4
LT
779 hisax= [HW,ISDN]
780 See Documentation/isdn/README.HiSax.
781
b4718e62
AK
782 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
783 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
0d9ea754
JT
784 On x86-64 and powerpc, this option can be specified
785 multiple times interleaved with hugepages= to reserve
786 huge pages of different sizes. Valid pages sizes on
787 x86-64 are 2M (when the CPU supports "pse") and 1G
788 (when the CPU supports the "pdpe1gb" cpuinfo flag)
b4718e62
AK
789 Note that 1GB pages can only be allocated at boot time
790 using hugepages= and not freed afterwards.
e11bfbfc
NP
791 default_hugepagesz=
792 [same as hugepagesz=] The size of the default
793 HugeTLB page size. This is the size represented by
794 the legacy /proc/ hugepages APIs, used for SHM, and
795 default size when mounting hugetlbfs filesystems.
796 Defaults to the default architecture's huge page size
797 if not specified.
1da177e4 798
1da177e4 799 i8042.direct [HW] Put keyboard port into non-translated mode
84eb8d06
ML
800 i8042.dumbkbd [HW] Pretend that controller can only read data from
801 keyboard and cannot control its state
1da177e4
LT
802 (Don't attempt to blink the leds)
803 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
945ef0d4 804 i8042.nokbd [HW] Don't check/create keyboard port
75d08c78
JK
805 i8042.noloop [HW] Disable the AUX Loopback command while probing
806 for the AUX port
1da177e4
LT
807 i8042.nomux [HW] Don't check presence of an active multiplexing
808 controller
809 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
810 controllers
811 i8042.panicblink=
812 [HW] Frequency with which keyboard LEDs should blink
813 when kernel panics (default is 0.5 sec)
814 i8042.reset [HW] Reset the controller during init and cleanup
815 i8042.unlock [HW] Unlock (ignore) the keylock
816
817 i810= [HW,DRM]
818
e70c9d5e
DT
819 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
820 indicates that the driver is running on unsupported
821 hardware.
1da177e4
LT
822 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
823 does not match list of supported models.
824 i8k.power_status
825 [HW] Report power status in /proc/i8k
826 (disabled by default)
827 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
828 capability is set.
829
830 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
831 See Documentation/mca.txt.
832
833 icn= [HW,ISDN]
834 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
835
836 ide= [HW] (E)IDE subsystem
a594eeb1 837 Format: ide=nodma or ide=doubler
1c10e938 838 See Documentation/ide/ide.txt.
1da177e4 839
1da177e4 840 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
1c10e938 841 See Documentation/ide/ide.txt.
1da177e4 842
f039b754 843 idle= [X86]
da5e09a1 844 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
f039b754
AK
845 Poll forces a polling idle loop that can slightly improves the performance
846 of waking up a idle CPU, but will use a lot of power and make the system
847 run hot. Not recommended.
848 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
849 to not use it because it doesn't save as much power as a normal idle
850 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
851 as idle=poll.
c1e3b377
ZY
852 idle=halt. Halt is forced to be used for CPU idle.
853 In such case C2/C3 won't be used again.
da5e09a1 854 idle=nomwait. Disable mwait for CPU C-states
a9913044 855
594765a7
DC
856 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
857 Claim all unknown PCI IDE storage controllers.
858
79290822
IM
859 ignore_loglevel [KNL]
860 Ignore loglevel setting - this will print /all/
861 kernel messages to the console. Useful for debugging.
862
1da177e4
LT
863 ihash_entries= [KNL]
864 Set number of hash buckets for inode cache.
865
866 in2000= [HW,SCSI]
867 See header of drivers/scsi/in2000.c.
868
869 init= [KNL]
870 Format: <full_path>
871 Run specified binary instead of /sbin/init as init
872 process.
873
874 initcall_debug [KNL] Trace initcalls as they are executed. Useful
875 for working out where the kernel is dying during
876 startup.
877
878 initrd= [BOOT] Specify the location of the initial ramdisk
879
880 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
881 Format: <irq>
882
883 inttest= [IA64]
884
b552da87
PM
885 iommu= [x86]
886 off
887 force
888 noforce
889 biomerge
890 panic
891 nopanic
892 merge
893 nomerge
894 forcesac
895 soft
2842e5bf
JR
896 fullflush
897 Flush IO/TLB at every deallocation
898 nofullflush
899 Flush IO/TLB only when addresses are reused (default)
b552da87
PM
900
901
ba395927
KA
902 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
903 off
904 Disable intel iommu driver.
905 igfx_off [Default Off]
906 By default, gfx is mapped as normal device. If a gfx
907 device has a dedicated DMAR unit, the DMAR unit is
908 bypassed by not enabling DMAR with this option. In
909 this case, gfx device will use physical address for
910 DMA.
7d3b03ce
KA
911 forcedac [x86_64]
912 With this option iommu will not optimize to look
913 for io virtual address below 32 bit forcing dual
914 address cycle on pci bus for cards supporting greater
915 than 32 bit addressing. The default is to look
916 for translation below 32 bit and if not available
917 then look in the higher range.
5e0d2a6f 918 strict [Default Off]
919 With this option on every unmap_single operation will
920 result in a hardware IOTLB flush operation as opposed
921 to batching them for performance.
ba395927 922
b02aae9c 923 io_delay= [X86-32,X86-64] I/O delay method
6e7c4025
IM
924 0x80
925 Standard port 0x80 based delay
926 0xed
927 Alternate port 0xed based delay (needed on some systems)
b02aae9c 928 udelay
6e7c4025
IM
929 Simple two microseconds delay
930 none
931 No delay
b02aae9c 932
1da177e4
LT
933 io7= [HW] IO7 for Marvel based alpha systems
934 See comment before marvel_specify_io7 in
935 arch/alpha/kernel/core_marvel.c.
936
937 ip= [IP_PNP]
6ded55da 938 See Documentation/filesystems/nfsroot.txt.
1da177e4
LT
939
940 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
c8facbb6
RD
941 See comment before ip2_setup() in
942 drivers/char/ip2/ip2base.c.
1da177e4
LT
943
944 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
945 See header of drivers/scsi/ips.c.
946
72c4a13a
SH
947 ports= [IP_VS_FTP] IPVS ftp helper module
948 Default is 21.
949 Up to 8 (IP_VS_APP_MAX_PORTS) ports
950 may be specified.
951 Format: <port>,<port>....
952
200803df
AC
953 irqfixup [HW]
954 When an interrupt is not handled search all handlers
955 for it. Intended to get systems with badly broken
956 firmware running.
957
958 irqpoll [HW]
959 When an interrupt is not handled search all handlers
960 for it. Also check all handlers each timer
961 interrupt. Intended to get systems with badly broken
962 firmware running.
963
1da177e4 964 isapnp= [ISAPNP]
a9913044 965 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
1da177e4
LT
966
967 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
22f2e280
DF
968 Format:
969 <cpu number>,...,<cpu number>
970 or
971 <cpu number>-<cpu number> (must be a positive range in ascending order)
972 or a mixture
973 <cpu number>,...,<cpu number>-<cpu number>
1da177e4
LT
974 This option can be used to specify one or more CPUs
975 to isolate from the general SMP balancing and scheduling
976 algorithms. The only way to move a process onto or off
977 an "isolated" CPU is via the CPU affinity syscalls.
978 <cpu number> begins at 0 and the maximum value is
979 "number of CPUs in system - 1".
980
981 This option is the preferred way to isolate CPUs. The
a9913044
RD
982 alternative -- manually setting the CPU mask of all
983 tasks in the system -- can cause problems and
984 suboptimal load balancer performance.
1da177e4 985
a9913044 986 iucv= [HW,NET]
1da177e4
LT
987
988 js= [HW,JOY] Analog joystick
989 See Documentation/input/joystick.txt.
990
cd4f0ef7 991 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
ed7ed365
MG
992 specifies the amount of memory usable by the kernel
993 for non-movable allocations. The requested amount is
994 spread evenly throughout all nodes in the system. The
995 remaining memory in each node is used for Movable
996 pages. In the event, a node is too small to have both
997 kernelcore and Movable pages, kernelcore pages will
998 take priority and other nodes will have a larger number
999 of kernelcore pages. The Movable zone is used for the
1000 allocation of pages that may be reclaimed or moved
1001 by the page migration subsystem. This means that
1002 HugeTLB pages may not be allocated from this zone.
1003 Note that allocations like PTEs-from-HighMem still
1004 use the HighMem zone if it exists, and the Normal
1005 zone if it does not.
1006
cd4f0ef7 1007 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
7e63efef
MG
1008 is similar to kernelcore except it specifies the
1009 amount of memory used for migratable allocations.
1010 If both kernelcore and movablecore is specified,
1011 then kernelcore will be at *least* the specified
1012 value but may be more. If movablecore on its own
1013 is specified, the administrator must be careful
1014 that the amount of memory usable for all allocations
1015 is not too small.
1016
1da177e4
LT
1017 keepinitrd [HW,ARM]
1018
cd4f0ef7 1019 kstack=N [X86-32,X86-64] Print N words from the kernel stack
1da177e4
LT
1020 in oops dumps.
1021
6cdf6e06
JW
1022 kgdboc= [HW] kgdb over consoles.
1023 Requires a tty driver that supports console polling.
1024 (only serial suported for now)
1025 Format: <serial_device>[,baud]
1026
1da177e4
LT
1027 l2cr= [PPC]
1028
a78bfbfc
RB
1029 l3cr= [PPC]
1030
cd4f0ef7 1031 lapic [X86-32,APIC] Enable the local APIC even if BIOS
a9913044 1032 disabled it.
1da177e4 1033
cd4f0ef7 1034 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
e585bef8
TG
1035 C2 power state.
1036
fcb71f6f
FC
1037 libata.dma= [LIBATA] DMA control
1038 libata.dma=0 Disable all PATA and SATA DMA
1039 libata.dma=1 PATA and SATA Disk DMA only
1040 libata.dma=2 ATAPI (CDROM) DMA only
1041 libata.dma=4 Compact Flash DMA only
1042 Combinations also work, so libata.dma=3 enables DMA
1043 for disks and CDROMs, but not CFs.
1044
78e70c23
DJ
1045 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1046 when set.
1047 Format: <int>
1048
33267325
TH
1049 libata.force= [LIBATA] Force configurations. The format is comma
1050 separated list of "[ID:]VAL" where ID is
1051 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1052 matching port, link or device. Basically, it matches
1053 the ATA ID string printed on console by libata. If
1054 the whole ID part is omitted, the last PORT and DEVICE
1055 values are used. If ID hasn't been specified yet, the
1056 configuration applies to all ports, links and devices.
1057
1058 If only DEVICE is omitted, the parameter applies to
1059 the port and all links and devices behind it. DEVICE
1060 number of 0 either selects the first device or the
1061 first fan-out link behind PMP device. It does not
1062 select the host link. DEVICE number of 15 selects the
1063 host link and device attached to it.
1064
1065 The VAL specifies the configuration to force. As long
1066 as there's no ambiguity shortcut notation is allowed.
1067 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1068 The following configurations can be forced.
1069
1070 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1071 Any ID with matching PORT is used.
1072
1073 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1074
1075 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1076 udma[/][16,25,33,44,66,100,133] notation is also
1077 allowed.
1078
1079 * [no]ncq: Turn on or off NCQ.
1080
05944bdf
TH
1081 * nohrst, nosrst, norst: suppress hard, soft
1082 and both resets.
1083
33267325
TH
1084 If there are multiple matching configurations changing
1085 the same attribute, the last one is used.
1086
1da177e4
LT
1087 load_ramdisk= [RAM] List of ramdisks to load from floppy
1088 See Documentation/ramdisk.txt.
1089
a6b25b67
RD
1090 lockd.nlm_grace_period=P [NFS] Assign grace period.
1091 Format: <integer>
1da177e4 1092
a6b25b67
RD
1093 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1094 Format: <integer>
1095
1096 lockd.nlm_timeout=T [NFS] Assign timeout value.
1097 Format: <integer>
1098
1099 lockd.nlm_udpport=M [NFS] Assign UDP port.
1100 Format: <integer>
1da177e4
LT
1101
1102 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1103 Format: <irq>
1104
1105 loglevel= All Kernel Messages with a loglevel smaller than the
1106 console loglevel will be printed to the console. It can
1107 also be changed with klogd or other programs. The
1108 loglevels are defined as follows:
1109
1110 0 (KERN_EMERG) system is unusable
1111 1 (KERN_ALERT) action must be taken immediately
1112 2 (KERN_CRIT) critical conditions
1113 3 (KERN_ERR) error conditions
1114 4 (KERN_WARNING) warning conditions
1115 5 (KERN_NOTICE) normal but significant condition
1116 6 (KERN_INFO) informational
1117 7 (KERN_DEBUG) debug-level messages
1118
1119 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
a9913044
RD
1120 Format: { n | nk | nM }
1121 n must be a power of two. The default size
1122 is set in the kernel config file.
1da177e4 1123
accaa24c
RD
1124 logo.nologo [FB] Disables display of the built-in Linux logo.
1125 This may be used to provide more screen space for
1126 kernel log messages and is useful when debugging
1127 kernel boot problems.
1128
1da177e4
LT
1129 lp=0 [LP] Specify parallel ports to use, e.g,
1130 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1131 lp=reset first parallel port). 'lp=0' disables the
1132 lp=auto printer driver. 'lp=reset' (which can be
1133 specified in addition to the ports) causes
1134 attached printers to be reset. Using
1135 lp=port1,port2,... specifies the parallel ports
1136 to associate lp devices with, starting with
1137 lp0. A port specification may be 'none' to skip
1138 that lp device, or a parport name such as
1139 'parport0'. Specifying 'lp=auto' instead of a
1140 port specification list means that device IDs
1141 from each port should be examined, to see if
1142 an IEEE 1284-compliant printer is attached; if
1143 so, the driver will manage that printer.
1144 See also header of drivers/char/lp.c.
1145
1146 lpj=n [KNL]
1147 Sets loops_per_jiffy to given constant, thus avoiding
1148 time-consuming boot-time autodetection (up to 250 ms per
1149 CPU). 0 enables autodetection (default). To determine
1150 the correct value for your kernel, boot with normal
1151 autodetection and see what value is printed. Note that
1152 on SMP systems the preset will be applied to all CPUs,
1153 which is likely to cause problems if your CPUs need
1154 significantly divergent settings. An incorrect value
1155 will cause delays in the kernel to be wrong, leading to
1156 unpredictable I/O errors and other breakage. Although
1157 unlikely, in the extreme case this might damage your
1158 hardware.
1159
1160 ltpc= [NET]
1161 Format: <io>,<irq>,<dma>
1162
a9913044
RD
1163 mac5380= [HW,SCSI] Format:
1164 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1da177e4 1165
a9913044
RD
1166 machvec= [IA64] Force the use of a particular machine-vector
1167 (machvec) in a generic kernel.
1168 Example: machvec=hpzx1_swiotlb
1da177e4 1169
a9913044 1170 max_loop= [LOOP] Maximum number of loopback devices that can
1da177e4
LT
1171 be mounted
1172 Format: <1-256>
1173
1174 maxcpus= [SMP] Maximum number of processors that an SMP kernel
61ec7567
LB
1175 should make use of. maxcpus=n : n >= 0 limits the
1176 kernel to using 'n' processors. n=0 is a special case,
1177 it is equivalent to "nosmp", which also disables
1178 the IO APIC.
1da177e4 1179
2b2c3750
BP
1180 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1181 equal to this physical address is ignored.
1182
a9913044 1183 max_luns= [SCSI] Maximum number of LUNs to probe.
1da177e4
LT
1184 Should be between 1 and 2^32-1.
1185
1186 max_report_luns=
a9913044 1187 [SCSI] Maximum number of LUNs received.
1da177e4
LT
1188 Should be between 1 and 16384.
1189
1da177e4
LT
1190 mcatest= [IA-64]
1191
cd4f0ef7 1192 mce [X86-32] Machine Check Exception
1da177e4 1193
909dd324
AK
1194 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1195
1da177e4
LT
1196 md= [HW] RAID subsystems devices and level
1197 See Documentation/md.txt.
a9913044 1198
1da177e4
LT
1199 mdacon= [MDA]
1200 Format: <first>,<last>
1201 Specifies range of consoles to be captured by the MDA.
a9913044 1202
1da177e4
LT
1203 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1204 Amount of memory to be used when the kernel is not able
1205 to see the whole system memory or for test.
cd4f0ef7 1206 [X86-32] Use together with memmap= to avoid physical
1da177e4
LT
1207 address space collisions. Without memmap= PCI devices
1208 could be placed at addresses belonging to unused RAM.
1209
cd4f0ef7 1210 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1da177e4
LT
1211 memory.
1212
cd4f0ef7 1213 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1da177e4
LT
1214 E820 memory map, as specified by the user.
1215 Such memmap=exactmap lines can be constructed based on
1216 BIOS output or other requirements. See the memmap=nn@ss
1217 option description.
1218
1219 memmap=nn[KMG]@ss[KMG]
1220 [KNL] Force usage of a specific region of memory
1221 Region of memory to be used, from ss to ss+nn.
1222
1223 memmap=nn[KMG]#ss[KMG]
1224 [KNL,ACPI] Mark specific memory as ACPI data.
1225 Region of memory to be used, from ss to ss+nn.
1226
1227 memmap=nn[KMG]$ss[KMG]
1228 [KNL,ACPI] Mark specific memory as reserved.
1229 Region of memory to be used, from ss to ss+nn.
1312848e
PM
1230 Example: Exclude memory from 0x18690000-0x1869ffff
1231 memmap=64K$0x18690000
1232 or
1233 memmap=0x10000$0x18690000
1da177e4 1234
caadbdce 1235 memtest= [KNL,X86] Enable memtest
c64df707
YL
1236 Format: <integer>
1237 range: 0,4 : pattern number
1238 default : 0 <disable>
1239
1da177e4
LT
1240 meye.*= [HW] Set MotionEye Camera parameters
1241 See Documentation/video4linux/meye.txt.
1242
8f36881b
AS
1243 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1244 Multi-Function General Purpose Timers on AMD Geode
1245 platforms.
1246
e6c4dc6c
WT
1247 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1248 the BIOS has incorrectly applied a workaround. TinyBIOS
1249 version 0.98 is known to be affected, 0.99 fixes the
1250 problem by letting the user disable the workaround.
1251
1da177e4
LT
1252 mga= [HW,DRM]
1253
6b74ab97
MG
1254 mminit_loglevel=
1255 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1256 parameter allows control of the logging verbosity for
1257 the additional memory initialisation checks. A value
1258 of 0 disables mminit logging and a level of 4 will
1259 log everything. Information is printed at KERN_DEBUG
1260 so loglevel=8 may also need to be specified.
1261
1da177e4
LT
1262 mousedev.tap_time=
1263 [MOUSE] Maximum time between finger touching and
1264 leaving touchpad surface for touch to be considered
1265 a tap and be reported as a left button click (for
1266 touchpads working in absolute mode only).
1267 Format: <msecs>
1268 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1269 reporting absolute coordinates, such as tablets
1270 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1271 reporting absolute coordinates, such as tablets
1272
1273 mpu401= [HW,OSS]
1274 Format: <io>,<irq>
1275
1276 MTD_Partition= [MTD]
1277 Format: <name>,<region-number>,<size>,<offset>
1278
a9913044
RD
1279 MTD_Region= [MTD] Format:
1280 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1da177e4
LT
1281
1282 mtdparts= [MTD]
c8facbb6 1283 See drivers/mtd/cmdlinepart.c.
1da177e4 1284
9db829f4
BD
1285 mtdset= [ARM]
1286 ARM/S3C2412 JIVE boot control
1287
1288 See arch/arm/mach-s3c2412/mach-jive.c
1289
1da177e4 1290 mtouchusb.raw_coordinates=
a9913044
RD
1291 [HW] Make the MicroTouch USB driver use raw coordinates
1292 ('y', default) or cooked coordinates ('n')
1da177e4
LT
1293
1294 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1295
1296 NCR_D700= [HW,SCSI]
1297 See header of drivers/scsi/NCR_D700.c.
1298
1299 ncr5380= [HW,SCSI]
1300
1301 ncr53c400= [HW,SCSI]
1302
1303 ncr53c400a= [HW,SCSI]
1304
1305 ncr53c406a= [HW,SCSI]
1306
1307 ncr53c8xx= [HW,SCSI]
1308
1309 netdev= [NET] Network devices parameters
1310 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1311 Note that mem_start is often overloaded to mean
1312 something different and driver-specific.
a9913044
RD
1313 This usage is only documented in each driver source
1314 file if at all.
1315
58401572
KPO
1316 nf_conntrack.acct=
1317 [NETFILTER] Enable connection tracking flow accounting
1318 0 to disable accounting
1319 1 to enable accounting
1320 Default value depends on CONFIG_NF_CT_ACCT that is
1321 going to be removed in 2.6.29.
1322
1da177e4 1323 nfsaddrs= [NFS]
6ded55da 1324 See Documentation/filesystems/nfsroot.txt.
1da177e4
LT
1325
1326 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
6ded55da 1327 See Documentation/filesystems/nfsroot.txt.
1da177e4 1328
a72b4422
TM
1329 nfs.callback_tcpport=
1330 [NFS] set the TCP port on which the NFSv4 callback
1331 channel should listen.
1332
58df095b
TM
1333 nfs.idmap_cache_timeout=
1334 [NFS] set the maximum lifetime for idmapper cache
1335 entries.
1336
f43bf0be
TM
1337 nfs.enable_ino64=
1338 [NFS] enable 64-bit inode numbers.
1339 If zero, the NFS client will fake up a 32-bit inode
1340 number for the readdir() and stat() syscalls instead
1341 of returning the full 64-bit number.
1342 The default is to return 64-bit inode numbers.
1343
e7ba176b
HS
1344 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1345 when a NMI is triggered.
1346 Format: [state][,regs][,debounce][,die]
1347
cd4f0ef7 1348 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1da177e4 1349
cd4f0ef7 1350 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1da177e4
LT
1351 emulation library even if a 387 maths coprocessor
1352 is present.
1353
c1aee215
CL
1354 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1355 caches in the slab allocator. Saves per-node memory,
1356 but will impact performance.
3395ee05 1357
a9913044
RD
1358 noalign [KNL,ARM]
1359
1da177e4
LT
1360 noapic [SMP,APIC] Tells the kernel to not make use of any
1361 IOAPICs that may be present in the system.
1362
1da177e4
LT
1363 nobats [PPC] Do not use BATs for mapping kernel lowmem
1364 on "Classic" PPC cores.
1365
1366 nocache [ARM]
a9913044 1367
163ecdff
SN
1368 nodelayacct [KNL] Disable per-task delay accounting
1369
1da177e4
LT
1370 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1371
8b2cb7a8
HY
1372 noefi [X86-32,X86-64] Disable EFI runtime services support.
1373
1da177e4
LT
1374 noexec [IA-64]
1375
cd4f0ef7 1376 noexec [X86-32,X86-64]
f5a1b191 1377 On X86-32 available only on PAE configured kernels.
1da177e4 1378 noexec=on: enable non-executable mappings (default)
f5a1b191
JS
1379 noexec=off: disable non-executable mappings
1380
1381 noexec32 [X86-64]
1382 This affects only 32-bit executables.
1383 noexec32=on: enable non-executable mappings (default)
1384 read doesn't imply executable mappings
1385 noexec32=off: disable non-executable mappings
1386 read implies executable mappings
1da177e4 1387
cd4f0ef7 1388 nofxsr [BUGS=X86-32] Disables x86 floating point extended
4f886511
CE
1389 register save and restore. The kernel will only save
1390 legacy floating-point registers on task switch.
1da177e4 1391
191679fd
AK
1392 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1393
1da177e4 1394 nohlt [BUGS=ARM]
a9913044 1395
cd4f0ef7 1396 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1da177e4
LT
1397 instruction doesn't work correctly and not to
1398 use it.
1399
1400 nohalt [IA-64] Tells the kernel not to use the power saving
1401 function PAL_HALT_LIGHT when idle. This increases
1402 power-consumption. On the positive side, it reduces
1403 interrupt wake-up latency, which may improve performance
1404 in certain environments such as networked servers or
1405 real-time systems.
1406
79bf2bb3
TG
1407 nohz= [KNL] Boottime enable/disable dynamic ticks
1408 Valid arguments: on, off
1409 Default: on
1410
cd4f0ef7 1411 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
8542b200 1412
cd4f0ef7 1413 noirqdebug [X86-32] Disables the code which attempts to detect and
1da177e4
LT
1414 disable unhandled interrupt sources.
1415
cd4f0ef7 1416 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
8542b200
ZA
1417 broken timer IRQ sources.
1418
1da177e4
LT
1419 noisapnp [ISAPNP] Disables ISA PnP code.
1420
1421 noinitrd [RAM] Tells the kernel not to load any configured
1422 initial RAM disk.
1423
1424 nointroute [IA-64]
1425
0aa366f3
TL
1426 nojitter [IA64] Disables jitter checking for ITC timers.
1427
cd4f0ef7 1428 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1da177e4 1429
cd4f0ef7 1430 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
ad62ca2b 1431
1da177e4
LT
1432 noltlbs [PPC] Do not use large page/tlb entries for kernel
1433 lowmem mapping on PPC40x.
1434
312f1f01
H
1435 nomca [IA-64] Disable machine check abort handling
1436
cd4f0ef7 1437 nomce [X86-32] Machine Check Exception
abe37e5a 1438
83d7384f
AS
1439 nomfgpt [X86-32] Disable Multi-Function General Purpose
1440 Timer usage (for AMD Geode machines).
1441
cd4f0ef7 1442 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
959b4fdf 1443
cd4f0ef7 1444 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
b7fb4af0
JF
1445 with UP alternatives
1446
1da177e4
LT
1447 noresidual [PPC] Don't use residual data on PReP machines.
1448
a9913044
RD
1449 noresume [SWSUSP] Disables resume and restores original swap
1450 space.
1451
1da177e4
LT
1452 no-scroll [VGA] Disables scrollback.
1453 This is required for the Braillex ib80-piezo Braille
1454 reader made by F.H. Papenmeier (Germany).
1455
1456 nosbagart [IA-64]
1457
cd4f0ef7 1458 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
4f886511 1459
61ec7567
LB
1460 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1461 and disable the IO APIC. legacy for "maxcpus=0".
1da177e4 1462
97842216
DJ
1463 nosoftlockup [KNL] Disable the soft-lockup detector.
1464
1da177e4
LT
1465 nosync [HW,M68K] Disables sync negotiation for all devices.
1466
cd4f0ef7 1467 notsc [BUGS=X86-32] Disable Time Stamp Counter
1da177e4
LT
1468
1469 nousb [USB] Disable the USB subsystem
1470
1471 nowb [ARM]
a9913044 1472
a6c75b86
FY
1473 nptcg= [IA64] Override max number of concurrent global TLB
1474 purges which is reported from either PAL_VM_SUMMARY or
1475 SAL PALO.
1476
f0c0b2b8
KH
1477 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1478 one of ['zone', 'node', 'default'] can be specified
1479 This can be set from sysctl after boot.
1480 See Documentation/sysctl/vm.txt for details.
1481
a61c2d78
DJ
1482 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1483
3ef0e1f8
AS
1484 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1485 Rather than timing out after 20 ms if an EC
1486 command is not properly ACKed, override the length
1487 of the timeout. We have interrupts disabled while
1488 waiting for the ACK, so if this is set too high
1489 interrupts *may* be lost!
1490
1da177e4
LT
1491 opl3= [HW,OSS]
1492 Format: <io>
1493
1da177e4
LT
1494 oprofile.timer= [HW]
1495 Use timer interrupt instead of performance counters
1496
1da177e4
LT
1497 osst= [HW,SCSI] SCSI Tape Driver
1498 Format: <buffer_size>,<write_threshold>
1499 See also Documentation/scsi/st.txt.
1500
1501 panic= [KNL] Kernel behaviour on panic
1502 Format: <timeout>
1503
1504 parkbd.port= [HW] Parallel port number the keyboard adapter is
1505 connected to, default is 0.
1506 Format: <parport#>
1507 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1508 0 for XT, 1 for AT (default is AT).
a9913044
RD
1509 Format: <mode>
1510
1511 parport= [HW,PPT] Specify parallel ports. 0 disables.
1512 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1513 Use 'auto' to force the driver to use any
1514 IRQ/DMA settings detected (the default is to
1515 ignore detected IRQ/DMA settings because of
1516 possible conflicts). You can specify the base
1517 address, IRQ, and DMA settings; IRQ and DMA
1518 should be numbers, or 'auto' (for using detected
1519 settings on that particular port), or 'nofifo'
1520 (to avoid using a FIFO even if it is detected).
1521 Parallel ports are assigned in the order they
1522 are specified on the command line, starting
1523 with parport0.
1524
1525 parport_init_mode= [HW,PPT]
1526 Configure VIA parallel port to operate in
1527 a specific mode. This is necessary on Pegasos
1528 computer where firmware has no options for setting
1529 up parallel port mode and sets it to spp.
1530 Currently this function knows 686a and 8231 chips.
1da177e4
LT
1531 Format: [spp|ps2|epp|ecp|ecpepp]
1532
a9913044
RD
1533 pas2= [HW,OSS] Format:
1534 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1535
1da177e4
LT
1536 pas16= [HW,SCSI]
1537 See header of drivers/scsi/pas16.c.
1538
dd287796
AM
1539 pause_on_oops=
1540 Halt all CPUs after the first oops has been printed for
1541 the specified number of seconds. This is to be used if
1542 your oopses keep scrolling off the screen.
1543
1da177e4
LT
1544 pcbit= [HW,ISDN]
1545
1546 pcd. [PARIDE]
1547 See header of drivers/block/paride/pcd.c.
1548 See also Documentation/paride.txt.
1549
a9913044 1550 pci=option[,option...] [PCI] various PCI subsystem options:
cd4f0ef7
AC
1551 off [X86-32] don't probe for the PCI bus
1552 bios [X86-32] force use of PCI BIOS, don't access
a9913044
RD
1553 the hardware directly. Use this if your machine
1554 has a non-standard PCI host bridge.
cd4f0ef7 1555 nobios [X86-32] disallow use of PCI BIOS, only direct
a9913044
RD
1556 hardware access methods are allowed. Use this
1557 if you experience crashes upon bootup and you
1558 suspect they are caused by the BIOS.
cd4f0ef7 1559 conf1 [X86-32] Force use of PCI Configuration
a9913044 1560 Mechanism 1.
cd4f0ef7 1561 conf2 [X86-32] Force use of PCI Configuration
a9913044 1562 Mechanism 2.
7f785763
RD
1563 noaer [PCIE] If the PCIEAER kernel config parameter is
1564 enabled, this kernel boot option can be used to
1565 disable the use of PCIE advanced error reporting.
32a2eea7
JG
1566 nodomains [PCI] Disable support for multiple PCI
1567 root domains (aka PCI segments, in ACPI-speak).
cd4f0ef7 1568 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
61be6d66 1569 Configuration
309e57df
MW
1570 nomsi [MSI] If the PCI_MSI kernel config parameter is
1571 enabled, this kernel boot option can be used to
1572 disable the use of MSI interrupts system-wide.
cd4f0ef7 1573 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
a9913044
RD
1574 routing table. These calls are known to be buggy
1575 on several machines and they hang the machine
1576 when used, but on other computers it's the only
1577 way to get the interrupt routing table. Try
1578 this option if the kernel is unable to allocate
1579 IRQs or discover secondary PCI buses on your
1580 motherboard.
cd4f0ef7 1581 rom [X86-32] Assign address space to expansion ROMs.
a9913044
RD
1582 Use with caution as certain devices share
1583 address decoders between ROMs and other
1584 resources.
bb71ad88
GH
1585 norom [X86-32,X86_64] Do not assign address space to
1586 expansion ROMs that do not already have
1587 BIOS assigned address ranges.
cd4f0ef7 1588 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
a9913044
RD
1589 assigned automatically to PCI devices. You can
1590 make the kernel exclude IRQs of your ISA cards
1591 this way.
cd4f0ef7 1592 pirqaddr=0xAAAAA [X86-32] Specify the physical address
a9913044
RD
1593 of the PIRQ table (normally generated
1594 by the BIOS) if it is outside the
1595 F0000h-100000h range.
cd4f0ef7 1596 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
a9913044
RD
1597 useful if the kernel is unable to find your
1598 secondary buses and you want to tell it
1599 explicitly which ones they are.
cd4f0ef7 1600 assign-busses [X86-32] Always assign all PCI bus
a9913044
RD
1601 numbers ourselves, overriding
1602 whatever the firmware may have done.
cd4f0ef7 1603 usepirqmask [X86-32] Honor the possible IRQ mask stored
a9913044
RD
1604 in the BIOS $PIR table. This is needed on
1605 some systems with broken BIOSes, notably
1606 some HP Pavilion N5400 and Omnibook XE3
1607 notebooks. This will have no effect if ACPI
1608 IRQ routing is enabled.
cd4f0ef7 1609 noacpi [X86-32] Do not use ACPI for IRQ routing
a9913044 1610 or for PCI scanning.
62f420f8
GH
1611 use_crs [X86-32] Use _CRS for PCI resource
1612 allocation.
a9913044
RD
1613 routeirq Do IRQ routing for all PCI devices.
1614 This is normally done in pci_enable_device(),
1615 so this option is a temporary workaround
1616 for broken drivers that don't call it.
13a6ddb0
YL
1617 skip_isa_align [X86] do not align io start addr, so can
1618 handle more pci cards
a9913044
RD
1619 firmware [ARM] Do not re-enumerate the bus but instead
1620 just use the configuration from the
1621 bootloader. This is currently used on
1622 IXP2000 systems where the bus has to be
1623 configured a certain way for adjunct CPUs.
0637a70a
AK
1624 noearly [X86] Don't do any early type 1 scanning.
1625 This might help on some broken boards which
1626 machine check when some devices' config space
1627 is read. But various workarounds are disabled
1628 and some IOMMU drivers will not work.
6b4b78fe
MD
1629 bfsort Sort PCI devices into breadth-first order.
1630 This sorting is done to get a device
1631 order compatible with older (<= 2.4) kernels.
1632 nobfsort Don't sort PCI devices into breadth-first order.
4516a618
AN
1633 cbiosize=nn[KMG] The fixed amount of bus space which is
1634 reserved for the CardBus bridge's IO window.
1635 The default value is 256 bytes.
1636 cbmemsize=nn[KMG] The fixed amount of bus space which is
1637 reserved for the CardBus bridge's memory
1638 window. The default value is 64 megabytes.
6b4b78fe 1639
1da177e4
LT
1640 pcmv= [HW,PCMCIA] BadgePAD 4
1641
1642 pd. [PARIDE]
1643 See Documentation/paride.txt.
1644
1645 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1646 boot time.
1647 Format: { 0 | 1 }
1648 See arch/parisc/kernel/pdc_chassis.c
1649
1650 pf. [PARIDE]
1651 See Documentation/paride.txt.
1652
1653 pg. [PARIDE]
1654 See Documentation/paride.txt.
1655
1656 pirq= [SMP,APIC] Manual mp-table setup
1657 See Documentation/i386/IO-APIC.txt.
1658
1659 plip= [PPT,NET] Parallel port network link
1660 Format: { parport<nr> | timid | 0 }
1661 See also Documentation/parport.txt.
1662
de32a243
TG
1663 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1664 Override pmtimer IOPort with a hex value.
1665 e.g. pmtmr=0x508
1666
1da177e4
LT
1667 pnpacpi= [ACPI]
1668 { off }
1669
1670 pnpbios= [ISAPNP]
1671 { on | off | curr | res | no-curr | no-res }
1672
1673 pnp_reserve_irq=
1674 [ISAPNP] Exclude IRQs for the autoconfiguration
1675
1676 pnp_reserve_dma=
1677 [ISAPNP] Exclude DMAs for the autoconfiguration
1678
1679 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
a9913044 1680 Ranges are in pairs (I/O port base and size).
1da177e4
LT
1681
1682 pnp_reserve_mem=
a9913044
RD
1683 [ISAPNP] Exclude memory regions for the
1684 autoconfiguration.
1da177e4
LT
1685 Ranges are in pairs (memory base and size).
1686
45807a1d
IM
1687 print-fatal-signals=
1688 [KNL] debug: print fatal signals
1689 print-fatal-signals=1: print segfault info to
1690 the kernel console.
1691 default: off.
1692
e84845c4
RD
1693 printk.time= Show timing data prefixed to each printk message line
1694 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1695
1da177e4 1696 profile= [KNL] Enable kernel profiling via /proc/profile
a9913044
RD
1697 Format: [schedule,]<number>
1698 Param: "schedule" - profile schedule points.
1699 Param: <number> - step/bucket size as a power of 2 for
1700 statistical time based profiling.
b3da2a73
MG
1701 Param: "sleep" - profile D-state sleeping (millisecs).
1702 Requires CONFIG_SCHEDSTATS
c0fe2e69 1703 Param: "kvm" - profile VM exits.
1da177e4 1704
a9913044 1705 processor.max_cstate= [HW,ACPI]
1da177e4
LT
1706 Limit processor to maximum C-state
1707 max_cstate=9 overrides any DMI blacklist limit.
1708
41c0d868
LB
1709 processor.nocst [HW,ACPI]
1710 Ignore the _CST method to determine C-states,
1711 instead using the legacy FADT method
1712
1da177e4
LT
1713 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1714 before loading.
1715 See Documentation/ramdisk.txt.
1716
a9913044
RD
1717 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1718 probe for; one of (bare|imps|exps|lifebook|any).
1da177e4
LT
1719 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1720 per second.
a9913044
RD
1721 psmouse.resetafter= [HW,MOUSE]
1722 Try to reset the device after so many bad packets
1da177e4
LT
1723 (0 = never).
1724 psmouse.resolution=
1725 [HW,MOUSE] Set desired mouse resolution, in dpi.
1726 psmouse.smartscroll=
a9913044 1727 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1da177e4
LT
1728 0 = disabled, 1 = enabled (default).
1729
1730 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
a9913044
RD
1731 Format:
1732 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1da177e4
LT
1733
1734 pt. [PARIDE]
1735 See Documentation/paride.txt.
1736
dc8c8587
KS
1737 pty.legacy_count=
1738 [KNL] Number of legacy pty's. Overwrites compiled-in
1739 default number.
1740
7d2c502f 1741 quiet [KNL] Disable most log messages
a9913044 1742
1da177e4
LT
1743 r128= [HW,DRM]
1744
1745 raid= [HW,RAID]
1746 See Documentation/md.txt.
1747
a9913044 1748 ramdisk_blocksize= [RAM]
1da177e4 1749 See Documentation/ramdisk.txt.
a9913044 1750
1da177e4 1751 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1da177e4
LT
1752 See Documentation/ramdisk.txt.
1753
24aaef8d
RD
1754 rcupdate.blimit= [KNL,BOOT]
1755 Set maximum number of finished RCU callbacks to process
1756 in one batch.
21a1ea9e 1757
24aaef8d
RD
1758 rcupdate.qhimark= [KNL,BOOT]
1759 Set threshold of queued
21a1ea9e
DS
1760 RCU callbacks over which batch limiting is disabled.
1761
24aaef8d
RD
1762 rcupdate.qlowmark= [KNL,BOOT]
1763 Set threshold of queued RCU callbacks below which
1764 batch limiting is re-enabled.
21a1ea9e 1765
ffdfc409
OJ
1766 rdinit= [KNL]
1767 Format: <full_path>
1768 Run specified binary instead of /init from the ramdisk,
1769 used for early userspace startup. See initrd.
1770
cd4f0ef7 1771 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1da177e4 1772 Format: <reboot_mode>[,<reboot_mode2>[,...]]
e53dd083 1773 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1da177e4 1774
46b6d94e
PJ
1775 relax_domain_level=
1776 [KNL, SMP] Set scheduler's default relax_domain_level.
1777 See Documentation/cpusets.txt.
1778
1da177e4
LT
1779 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1780
cd4f0ef7 1781 reservetop= [X86-32]
461a9aff
ZA
1782 Format: nn[KMG]
1783 Reserves a hole at the top of the kernel virtual
1784 address space.
1785
7e96287d
VG
1786 reset_devices [KNL] Force drivers to reset the underlying device
1787 during initialization.
1788
a9913044
RD
1789 resume= [SWSUSP]
1790 Specify the partition device for software suspend
1da177e4 1791
ecbd0da1
RW
1792 resume_offset= [SWSUSP]
1793 Specify the offset from the beginning of the partition
1794 given by "resume=" at which the swap header is located,
1795 in <PAGE_SIZE> units (needed only for swap files).
1796 See Documentation/power/swsusp-and-swap-files.txt
1797
0a7b35cb
MN
1798 retain_initrd [RAM] Keep initrd memory after extraction
1799
1da177e4
LT
1800 rhash_entries= [KNL,NET]
1801 Set number of hash buckets for route cache
1802
1803 riscom8= [HW,SERIAL]
1804 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1805
1806 ro [KNL] Mount root device read-only on boot
1807
1808 root= [KNL] Root filesystem
1809
1810 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1811 mount the root filesystem
1812
1813 rootflags= [KNL] Set root filesystem mount option string
1814
1815 rootfstype= [KNL] Set root filesystem type
1816
cc1ed754
PO
1817 rootwait [KNL] Wait (indefinitely) for root device to show up.
1818 Useful for devices that are detected asynchronously
1819 (e.g. USB and MMC devices).
1820
20510f2f
JM
1821 root_plug.vendor_id=
1822 [ROOTPLUG] Override the default vendor ID
1823
1824 root_plug.product_id=
1825 [ROOTPLUG] Override the default product ID
1826
1827 root_plug.debug=
1828 [ROOTPLUG] Enable debugging output
1829
1da177e4
LT
1830 rw [KNL] Mount root device read-write on boot
1831
1832 S [KNL] Run init in single mode
1833
1834 sa1100ir [NET]
1835 See drivers/net/irda/sa1100_ir.c.
1836
1da177e4 1837 sbni= [NET] Granch SBNI12 leased line adapter
a9913044 1838
1da177e4
LT
1839 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1840 Format: <io>[,<timeout>[,<isapnp>]]
1841
1842 scsi_debug_*= [SCSI]
1843 See drivers/scsi/scsi_debug.c.
1844
1845 scsi_default_dev_flags=
1846 [SCSI] SCSI default device flags
1847 Format: <integer>
1848
1849 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1850 Format: <vendor>:<model>:<flags>
1851 (flags are integer value)
1852
6af6632a
RD
1853 scsi_logging_level= [SCSI] a bit mask of logging levels
1854 See drivers/scsi/scsi_logging.h for bits. Also
1855 settable via sysctl at dev.scsi.logging_level
1856 (/proc/sys/dev/scsi/logging_level).
1857 There is also a nice 'scsi_logging_level' script in the
1858 S390-tools package, available for download at
1859 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1da177e4 1860
3e082a91
MW
1861 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1862 discovered. async scans them in kernel threads,
1863 allowing boot to proceed. none ignores them, expecting
1864 user space to do the scan.
1865
1da177e4
LT
1866 selinux [SELINUX] Disable or enable SELinux at boot time.
1867 Format: { "0" | "1" }
1868 See security/selinux/Kconfig help text.
1869 0 -- disable.
1870 1 -- enable.
1871 Default value is set via kernel config option.
1872 If enabled at boot time, /selinux/disable can be used
1873 later to disable prior to initial policy load.
1874
4e5ab4cb
JM
1875 selinux_compat_net =
1876 [SELINUX] Set initial selinux_compat_net flag value.
e53dd083
MCC
1877 Format: { "0" | "1" }
1878 0 -- use new secmark-based packet controls
1879 1 -- use legacy packet controls
1880 Default value is 0 (preferred).
1881 Value can be changed at runtime via
1882 /selinux/compat_net.
4e5ab4cb 1883
cd4f0ef7 1884 serialnumber [BUGS=X86-32]
1da177e4 1885
1da177e4
LT
1886 shapers= [NET]
1887 Maximal number of shapers.
a9913044 1888
1da177e4
LT
1889 sim710= [SCSI,HW]
1890 See header of drivers/scsi/sim710.c.
1891
1892 simeth= [IA-64]
1893 simscsi=
a9913044 1894
1da177e4
LT
1895 slram= [HW,MTD]
1896
f0630fff
CL
1897 slub_debug[=options[,slabs]] [MM, SLUB]
1898 Enabling slub_debug allows one to determine the
1899 culprit if slab objects become corrupted. Enabling
1900 slub_debug can create guard zones around objects and
1901 may poison objects when not in use. Also tracks the
1902 last alloc / free. For more information see
1903 Documentation/vm/slub.txt.
c1aee215
CL
1904
1905 slub_max_order= [MM, SLUB]
f0630fff
CL
1906 Determines the maximum allowed order for slabs.
1907 A high setting may cause OOMs due to memory
1908 fragmentation. For more information see
1909 Documentation/vm/slub.txt.
c1aee215
CL
1910
1911 slub_min_objects= [MM, SLUB]
f0630fff
CL
1912 The minimum number of objects per slab. SLUB will
1913 increase the slab order up to slub_max_order to
1914 generate a sufficiently large slab able to contain
1915 the number of objects indicated. The higher the number
1916 of objects the smaller the overhead of tracking slabs
1917 and the less frequently locks need to be acquired.
c1aee215
CL
1918 For more information see Documentation/vm/slub.txt.
1919
1920 slub_min_order= [MM, SLUB]
1921 Determines the mininum page order for slabs. Must be
f0630fff 1922 lower than slub_max_order.
c1aee215
CL
1923 For more information see Documentation/vm/slub.txt.
1924
1925 slub_nomerge [MM, SLUB]
f0630fff 1926 Disable merging of slabs with similar size. May be
c1aee215 1927 necessary if there is some reason to distinguish
f0630fff
CL
1928 allocs to different slabs. Debug options disable
1929 merging on their own.
c1aee215
CL
1930 For more information see Documentation/vm/slub.txt.
1931
1da177e4
LT
1932 smart2= [HW]
1933 Format: <io1>[,<io2>[,...,<io8>]]
1934
cd4f0ef7 1935 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
b7fb4af0
JF
1936 attempt to substitute SMP alternatives once at boot.
1937
d0d4f69b
BH
1938 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1939 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1940 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1941 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1942 smsc-ircc2.ircc_irq= [HW] IRQ line
1943 smsc-ircc2.ircc_dma= [HW] DMA channel
1944 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1945 0: Toshiba Satellite 1800 (GP data pin select)
1946 1: Fast pin select (default)
1947 2: ATC IRMode
1948
1da177e4
LT
1949 snd-ad1816a= [HW,ALSA]
1950
1951 snd-ad1848= [HW,ALSA]
1952
1953 snd-ali5451= [HW,ALSA]
1954
1955 snd-als100= [HW,ALSA]
1956
1957 snd-als4000= [HW,ALSA]
1958
1959 snd-azt2320= [HW,ALSA]
1960
1961 snd-cmi8330= [HW,ALSA]
1962
1963 snd-cmipci= [HW,ALSA]
1964
1965 snd-cs4231= [HW,ALSA]
1966
1967 snd-cs4232= [HW,ALSA]
1968
1969 snd-cs4236= [HW,ALSA]
1970
1971 snd-cs4281= [HW,ALSA]
1972
1973 snd-cs46xx= [HW,ALSA]
1974
1975 snd-dt019x= [HW,ALSA]
1976
1977 snd-dummy= [HW,ALSA]
1978
1979 snd-emu10k1= [HW,ALSA]
1980
1981 snd-ens1370= [HW,ALSA]
1982
1983 snd-ens1371= [HW,ALSA]
1984
1985 snd-es968= [HW,ALSA]
1986
1987 snd-es1688= [HW,ALSA]
1988
1989 snd-es18xx= [HW,ALSA]
1990
1991 snd-es1938= [HW,ALSA]
1992
1993 snd-es1968= [HW,ALSA]
1994
1995 snd-fm801= [HW,ALSA]
1996
1997 snd-gusclassic= [HW,ALSA]
1998
1999 snd-gusextreme= [HW,ALSA]
2000
2001 snd-gusmax= [HW,ALSA]
2002
2003 snd-hdsp= [HW,ALSA]
2004
2005 snd-ice1712= [HW,ALSA]
2006
2007 snd-intel8x0= [HW,ALSA]
2008
2009 snd-interwave= [HW,ALSA]
2010
2011 snd-interwave-stb=
2012 [HW,ALSA]
2013
2014 snd-korg1212= [HW,ALSA]
2015
2016 snd-maestro3= [HW,ALSA]
2017
2018 snd-mpu401= [HW,ALSA]
2019
2020 snd-mtpav= [HW,ALSA]
2021
2022 snd-nm256= [HW,ALSA]
2023
2024 snd-opl3sa2= [HW,ALSA]
2025
2026 snd-opti92x-ad1848=
2027 [HW,ALSA]
2028
2029 snd-opti92x-cs4231=
2030 [HW,ALSA]
2031
2032 snd-opti93x= [HW,ALSA]
2033
2034 snd-pmac= [HW,ALSA]
2035
2036 snd-rme32= [HW,ALSA]
2037
2038 snd-rme96= [HW,ALSA]
2039
2040 snd-rme9652= [HW,ALSA]
2041
2042 snd-sb8= [HW,ALSA]
2043
2044 snd-sb16= [HW,ALSA]
2045
2046 snd-sbawe= [HW,ALSA]
2047
2048 snd-serial= [HW,ALSA]
2049
2050 snd-sgalaxy= [HW,ALSA]
2051
2052 snd-sonicvibes= [HW,ALSA]
2053
2054 snd-sun-amd7930=
2055 [HW,ALSA]
2056
2057 snd-sun-cs4231= [HW,ALSA]
2058
2059 snd-trident= [HW,ALSA]
2060
2061 snd-usb-audio= [HW,ALSA,USB]
2062
2063 snd-via82xx= [HW,ALSA]
2064
2065 snd-virmidi= [HW,ALSA]
2066
2067 snd-wavefront= [HW,ALSA]
2068
2069 snd-ymfpci= [HW,ALSA]
a9913044 2070
9c44bc03
IM
2071 softlockup_panic=
2072 [KNL] Should the soft-lockup detector generate panics.
2073
1da177e4
LT
2074 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2075 See Documentation/sonypi.txt
2076
2077 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2078 See Documentation/specialix.txt.
2079
2080 spia_io_base= [HW,MTD]
2081 spia_fio_base=
2082 spia_pedr=
2083 spia_peddr=
2084
2085 sscape= [HW,OSS]
2086 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
a9913044 2087
1da177e4
LT
2088 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2089 See Documentation/scsi/st.txt.
2090
1da177e4
LT
2091 sti= [PARISC,HW]
2092 Format: <num>
2093 Set the STI (builtin display/keyboard on the HP-PARISC
2094 machines) console (graphic card) which should be used
2095 as the initial boot-console.
2096 See also comment in drivers/video/console/sticore.c.
2097
2098 sti_font= [HW]
2099 See comment in drivers/video/console/sticore.c.
2100
2101 stifb= [HW]
2102 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2103
42a7fc4a
GB
2104 sunrpc.pool_mode=
2105 [NFS]
2106 Control how the NFS server code allocates CPUs to
2107 service thread pools. Depending on how many NICs
2108 you have and where their interrupts are bound, this
2109 option will affect which CPUs will do NFS serving.
2110 Note: this parameter cannot be changed while the
2111 NFS server is running.
2112
2113 auto the server chooses an appropriate mode
2114 automatically using heuristics
2115 global a single global pool contains all CPUs
2116 percpu one pool for each CPU
2117 pernode one pool for each NUMA node (equivalent
2118 to global on non-NUMA machines)
2119
1da177e4 2120 swiotlb= [IA-64] Number of I/O TLB slabs
a9913044 2121
1da177e4
LT
2122 switches= [HW,M68k]
2123
2124 sym53c416= [HW,SCSI]
2125 See header of drivers/scsi/sym53c416.c.
2126
5d6f647f
IM
2127 sysrq_always_enabled
2128 [KNL]
2129 Ignore sysrq setting - this boot parameter will
2130 neutralize any effect of /proc/sys/kernel/sysrq.
2131 Useful for debugging.
2132
1da177e4
LT
2133 t128= [HW,SCSI]
2134 See header of drivers/scsi/t128.c.
2135
2136 tdfx= [HW,DRM]
2137
77437fd4
DB
2138 test_suspend= [SUSPEND]
2139 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2140 standby suspend) as the system sleep state to briefly
2141 enter during system startup. The system is woken from
2142 this state using a wakeup-capable RTC alarm.
2143
1da177e4
LT
2144 thash_entries= [KNL,NET]
2145 Set number of hash buckets for TCP connection
2146
f8707ec9
LB
2147 thermal.act= [HW,ACPI]
2148 -1: disable all active trip points in all thermal zones
2149 <degrees C>: override all lowest active trip points
2150
c52a7419
LB
2151 thermal.crt= [HW,ACPI]
2152 -1: disable all critical trip points in all thermal zones
2153 <degrees C>: lower all critical trip points
2154
f5487145
LB
2155 thermal.nocrt= [HW,ACPI]
2156 Set to disable actions on ACPI thermal zone
2157 critical and hot trip points.
2158
72b33ef8
LB
2159 thermal.off= [HW,ACPI]
2160 1: disable ACPI thermal control
2161
a70cdc52
LB
2162 thermal.psv= [HW,ACPI]
2163 -1: disable all passive trip points
2164 <degrees C>: override all passive trip points to this value
2165
730ff34d
LB
2166 thermal.tzp= [HW,ACPI]
2167 Specify global default ACPI thermal zone polling rate
2168 <deci-seconds>: poll all this frequency
2169 0: no polling (default)
2170
1da177e4
LT
2171 tmscsim= [HW,SCSI]
2172 See comment before function dc390_setup() in
2173 drivers/scsi/tmscsim.c.
2174
2175 tp720= [HW,PS2]
2176
2177 trix= [HW,OSS] MediaTrix AudioTrix Pro
a9913044
RD
2178 Format:
2179 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2180
a9913044
RD
2181 turbografx.map[2|3]= [HW,JOY]
2182 TurboGraFX parallel port interface
2183 Format:
2184 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1da177e4
LT
2185 See also Documentation/input/joystick-parport.txt
2186
2187 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2188 See header of drivers/scsi/u14-34f.c.
2189
2190 uart401= [HW,OSS]
2191 Format: <io>,<irq>
2192
2193 uart6850= [HW,OSS]
2194 Format: <io>,<irq>
2195
5f8364b7
AS
2196 uhci-hcd.ignore_oc=
2197 [USB] Ignore overcurrent events (default N).
2198 Some badly-designed motherboards generate lots of
2199 bogus events, for ports that aren't wired to
2200 anything. Set this parameter to avoid log spamming.
2201 Note that genuine overcurrent events won't be
2202 reported either.
2203
e3a61b0a
SA
2204 unknown_nmi_panic
2205 [X86-32,X86-64]
2206 Set unknown_nmi_panic=1 early on boot.
2207
b5e795f8
AS
2208 usbcore.autosuspend=
2209 [USB] The autosuspend time delay (in seconds) used
2210 for newly-detected USB devices (default 2). This
2211 is the time required before an idle device will be
2212 autosuspended. Devices for which the delay is set
eaafbc3a 2213 to a negative value won't be autosuspended at all.
b5e795f8 2214
1da177e4
LT
2215 usbhid.mousepoll=
2216 [USBHID] The interval which mice are to be polled at.
a9913044 2217
200001eb
PJ
2218 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2219 kernel's map of available physical RAM.
2220
cd4f0ef7 2221 vdso= [X86-32,SH,x86-64]
1dbf527c 2222 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
e6e5494c
IM
2223 vdso=1: enable VDSO (default)
2224 vdso=0: disable VDSO mapping
2225
af65d648
RM
2226 vdso32= [X86-32,X86-64]
2227 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2228 vdso32=1: enable 32-bit VDSO (default)
2229 vdso32=0: disable 32-bit VDSO mapping
2230
d080d397
YI
2231 vector= [IA-64,SMP]
2232 vector=percpu: enable percpu vector domain
2233
1da177e4
LT
2234 video= [FB] Frame buffer configuration
2235 See Documentation/fb/modedb.txt.
2236
cd4f0ef7 2237 vga= [BOOT,X86-32] Select a particular video mode
a9913044
RD
2238 See Documentation/i386/boot.txt and
2239 Documentation/svga.txt.
1da177e4
LT
2240 Use vga=ask for menu.
2241 This is actually a boot loader parameter; the value is
2242 passed to the kernel using a special protocol.
2243
a9913044 2244 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1da177e4
LT
2245 size of <nn>. This can be used to increase the
2246 minimum size (128MB on x86). It can also be used to
2247 decrease the size and leave more room for directly
2248 mapped kernel RAM.
2249
585c3047
PO
2250 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2251 Format: <command>
1da177e4 2252
585c3047
PO
2253 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2254 Format: <command>
2255
2256 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2257 Format: <command>
a9913044 2258
1da177e4
LT
2259 waveartist= [HW,OSS]
2260 Format: <io>,<irq>,<dma>,<dma2>
a9913044 2261
1da177e4
LT
2262 wd33c93= [HW,SCSI]
2263 See header of drivers/scsi/wd33c93.c.
2264
2265 wd7000= [HW,SCSI]
2266 See header of drivers/scsi/wd7000.c.
2267
2268 wdt= [WDT] Watchdog
8dfe9c21 2269 See Documentation/watchdog/wdt.txt.
1da177e4
LT
2270
2271 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2272 xd_geo= See header of drivers/block/xd.c.
2273
2274 xirc2ps_cs= [NET,PCMCIA]
a9913044
RD
2275 Format:
2276 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1da177e4 2277
a62eaf15
AK
2278 norandmaps Don't use address space randomization
2279 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2280
a9913044 2281______________________________________________________________________
1da177e4
LT
2282
2283TODO:
2284
2285 Add documentation for ALSA options.
2286 Add more DRM drivers.