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Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
Linus Torvalds1da177e2005-04-16 15:20:36 -07003
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
Stefan Richtera901ebb2006-04-01 01:43:18 +020020This 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
Stefan Richter6585fa82006-04-01 01:44:30 +020027The 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:
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32 ACPI ACPI support is enabled.
Chuck Ebbertc99c1082007-07-27 10:46:20 +100033 AGP AGP (Accelerated Graphics Port) is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +020037 AVR32 AVR32 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 AX25 Appropriate AX.25 support is enabled.
Robin Getz0ae53642007-10-09 17:24:49 +080039 BLACKFIN Blackfin architecture is enabled.
Randy Dunlapa9913042005-10-23 12:57:11 -070040 DRM Direct Rendering Management support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 IA-64 IA-64 architecture is enabled.
47 IOSCHED More than one I/O scheduler is enabled.
Adrian Bunk41e2e8b2005-07-12 13:58:33 -070048 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
Kristen Carlson Accardi11ef6972006-09-28 11:29:01 -070052 LIBATA Libata driver is enabled
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 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.
Matthew Wilcox309e57d2006-03-05 22:33:34 -070061 MSI Message Signaled Interrupts (PCI).
Randy Dunlapc8facbb2007-07-31 00:37:40 -070062 MTD MTD (Memory Technology Device) support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 NET Appropriate network support is enabled.
64 NUMA NUMA support is enabled.
john stultz734efb42006-06-26 00:25:05 -070065 GENERIC_TIME The generic timeofday code is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 NFS Appropriate NFS support is enabled.
67 OSS OSS sound support is enabled.
Randy Dunlapc8facbb2007-07-31 00:37:40 -070068 PV_OPS A paravirtualized kernel is enabled.
69 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 PARISC The PA-RISC architecture is enabled.
71 PCI PCI bus support is enabled.
Randy Dunlap7f785762007-10-05 13:17:58 -070072 PCIE PCI Express support is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 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.
James Morris20510f22007-10-16 23:31:32 -070079 ROOTPLUG The example Root Plug LSM is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 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/.
James Morris20510f22007-10-16 23:31:32 -070084 SECURITY Different security models are enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 SELINUX SELinux support is enabled.
86 SERIAL Serial support is enabled.
Paul Mundte523d932007-02-28 18:30:01 +090087 SH SuperH architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 SMP The kernel is an SMP kernel.
89 SPARC Sparc architecture is enabled.
Randy Dunlapa9913042005-10-23 12:57:11 -070090 SWSUSP Software suspend is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 TS Appropriate touchscreen support is enabled.
92 USB USB support is enabled.
93 USBHID USB Human Interface Device support is enabled.
94 V4L Video For Linux support is enabled.
95 VGA The VGA console has been enabled.
96 VT Virtual terminal support is enabled.
97 WDT Watchdog support is enabled.
98 XT IBM PC/XT MFM hard disk support is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -070099 X86-32 X86-32, aka i386 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 X86-64 X86-64 architecture is enabled.
101 More X86-64 boot options can be found in
102 Documentation/x86_64/boot-options.txt .
103
104In addition, the following text indicates that the option:
105
106 BUGS= Relates to possible processor bugs on the said processor.
107 KNL Is a kernel start-up parameter.
108 BOOT Is a boot loader parameter.
109
110Parameters denoted with BOOT are actually interpreted by the boot
111loader, and have no meaning to the kernel directly.
112Do not modify the syntax of boot loader parameters without extreme
113need or coordination with <Documentation/i386/boot.txt>.
114
Karsten Weiss55588702007-02-13 13:26:21 +0100115There are also arch-specific kernel-parameters not documented here.
116See for example <Documentation/x86_64/boot-options.txt>.
117
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
119a trailing = on the name of any parameter states that that parameter will
120be entered as an environment variable, whereas its absence indicates that
121it will appear as a kernel argument readable via /proc/cmdline by programs
122running once the system is up.
123
jens m. noedler9c4751f2006-09-29 02:00:27 -0700124The number of kernel parameters is not limited, but the length of the
125complete command line (parameters including spaces etc.) is limited to
126a fixed number of characters. This limit depends on the architecture
127and is between 256 and 4096 characters. It is defined in the file
128./include/asm/setup.h as COMMAND_LINE_SIZE.
129
130
Bernhard Walle03d926f2007-03-06 02:29:44 -0800131 acpi= [HW,ACPI,X86-64,i386]
132 Advanced Configuration and Power Interface
Randy Dunlapa9913042005-10-23 12:57:11 -0700133 Format: { force | off | ht | strict | noirq }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 force -- enable ACPI if default was off
135 off -- disable ACPI if default was on
136 noirq -- do not use ACPI for IRQ routing
137 ht -- run only enough ACPI to enable Hyper Threading
Randy Dunlapa9913042005-10-23 12:57:11 -0700138 strict -- Be less tolerant of platforms that are not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 strictly ACPI specification compliant.
140
Randy Dunlap53471122008-03-12 18:10:51 -0400141 See also Documentation/power/pm.txt, pci=noacpi
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
Len Browna1fdcc02007-03-11 03:26:14 -0400143 acpi_apic_instance= [ACPI, IOAPIC]
144 Format: <int>
145 2: use 2nd APIC table, if available
146 1,0: use 1st APIC table
Len Brown4e381a42007-03-30 14:16:10 -0400147 default: 0
Len Browna1fdcc02007-03-11 03:26:14 -0400148
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 acpi_sleep= [HW,ACPI] Sleep options
Pavel Machek23b168d2008-02-05 19:27:12 +0100150 Format: { s3_bios, s3_mode, s3_beep }
151 See Documentation/power/video.txt for s3_bios and s3_mode.
152 s3_beep is for debugging; it makes the PC's speaker beep
153 as soon as the kernel's real-mode entry point is called.
Randy Dunlapa9913042005-10-23 12:57:11 -0700154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Randy Dunlapa9913042005-10-23 12:57:11 -0700156 Format: { level | edge | high | low }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
Randy Dunlapa9913042005-10-23 12:57:11 -0700158 acpi_irq_balance [HW,ACPI]
159 ACPI will balance active IRQs
160 default in APIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
Randy Dunlapa9913042005-10-23 12:57:11 -0700162 acpi_irq_nobalance [HW,ACPI]
163 ACPI will not move active IRQs (default)
164 default in PIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
Randy Dunlapa9913042005-10-23 12:57:11 -0700166 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
167 use by PCI
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 Format: <irq>,<irq>...
169
Randy Dunlapa9913042005-10-23 12:57:11 -0700170 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 Format: <irq>,<irq>...
172
Len Brown67effe82007-07-26 00:50:06 -0400173 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
174
Len Browna1f9e652006-01-25 23:47:36 -0500175 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
176 Format: To spoof as Windows 98: ="Microsoft Windows"
177
Len Brownae00d812007-05-29 18:43:33 -0400178 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
179 acpi_osi="string1" # add string1 -- only one string
180 acpi_osi="!string2" # remove built-in string2
181 acpi_osi= # disable all strings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182
183 acpi_serialize [HW,ACPI] force serialization of AML methods
184
185 acpi_skip_timer_override [HW,ACPI]
186 Recognize and ignore IRQ0/pin2 Interrupt Override.
187 For broken nForce2 BIOS resulting in XT-PIC timer.
Andi Kleenfa18f472006-11-14 16:57:46 +0100188 acpi_use_timer_override [HW,ACPI}
189 Use timer override. For some broken Nvidia NF5 boards
190 that require a timer override, but don't have
191 HPET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192
Zhang Ruif9891062007-04-24 13:53:22 +0800193 acpi.debug_layer= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700195 Each bit of the <int> indicates an ACPI debug layer,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 1: enable, 0: disable. It is useful for boot time
197 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800198 via /sys/module/acpi/parameters/debug_layer.
199 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
200 Available bits (add the numbers together) to enable debug output
201 for specific parts of the ACPI subsystem:
202 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
203 0x10 namespace 0x20 parser 0x40 dispatcher
204 0x80 executer 0x100 resources 0x200 acpica debugger
205 0x400 os services 0x800 acpica disassembler.
206 The number can be in decimal or prefixed with 0x in hex.
207 Warning: Many of these options can produce a lot of
208 output and make your system unusable. Be very careful.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209
Zhang Ruif9891062007-04-24 13:53:22 +0800210 acpi.debug_level= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700212 Each bit of the <int> indicates an ACPI debug level,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 1: enable, 0: disable. It is useful for boot time
214 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800215 via /sys/module/acpi/parameters/debug_level.
216 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
217 Available bits (add the numbers together) to enable different
218 debug output levels of the ACPI subsystem:
219 0x01 error 0x02 warn 0x04 init 0x08 debug object
220 0x10 info 0x20 init names 0x40 parse 0x80 load
221 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
222 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
223 0x10000 resources 0x20000 user requests 0x40000 package.
224 The number can be in decimal or prefixed with 0x in hex.
225 Warning: Many of these options can produce a lot of
226 output and make your system unusable. Be very careful.
227
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700228 acpi_pm_good [X86-32,X86-64]
john stultz5d0cf412006-06-26 00:25:12 -0700229 Override the pmtimer bug detection: force the kernel
230 to assume that this machine's pmtimer latches its value
231 and always returns good values.
232
Chuck Ebbertc99c1082007-07-27 10:46:20 +1000233 agp= [AGP]
234 { off | try_unsupported }
235 off: disable AGP support
236 try_unsupported: try to drive unsupported chipsets
237 (may crash computer or cause data corruption)
238
Chuck Ebbert66759a02005-09-12 18:49:25 +0200239 enable_timer_pin_1 [i386,x86-64]
240 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700241 Can be useful to work around chipset bugs
242 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200243 The kernel tries to set a reasonable default.
244
245 disable_timer_pin_1 [i386,x86-64]
246 Disable PIN 1 of APIC timer
247 Can be useful to work around chipset bugs.
248
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 ad1848= [HW,OSS]
250 Format: <io>,<irq>,<dma>,<dma2>,<type>
251
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 advansys= [HW,SCSI]
253 See header of drivers/scsi/advansys.c.
254
255 advwdt= [HW,WDT] Advantech WDT
256 Format: <iostart>,<iostop>
257
258 aedsp16= [HW,OSS] Audio Excel DSP 16
259 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
260 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700261
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 aha152x= [HW,SCSI]
263 See Documentation/scsi/aha152x.txt.
264
265 aha1542= [HW,SCSI]
266 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
267
268 aic7xxx= [HW,SCSI]
269 See Documentation/scsi/aic7xxx.txt.
270
271 aic79xx= [HW,SCSI]
272 See Documentation/scsi/aic79xx.txt.
273
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200274 amd_iommu= [HW,X86-84]
275 Pass parameters to the AMD IOMMU driver in the system.
276 Possible values are:
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200277 isolate - enable device isolation (each device, as far
278 as possible, will get its own protection
279 domain)
280 amd_iommu_size= [HW,X86-64]
281 Define the size of the aperture for the AMD IOMMU
282 driver. Possible values are:
283 '32M', '64M' (default), '128M', '256M', '512M', '1G'
284
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 amijoy.map= [HW,JOY] Amiga joystick support
286 Map of devices attached to JOY0DAT and JOY1DAT
287 Format: <a>,<b>
288 See also Documentation/kernel/input/joystick.txt
289
290 analog.map= [HW,JOY] Analog joystick and gamepad support
291 Specifies type or capabilities of an analog joystick
292 connected to one of 16 gameports
293 Format: <type1>,<type2>,..<type16>
294
Randy Dunlapa9913042005-10-23 12:57:11 -0700295 apc= [HW,SPARC]
296 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 Format: noidle
298 Disable APC CPU standby support. SPARCstation-Fox does
299 not play well with APC CPU idle - disable it if you have
300 APC and your system crashes randomly.
301
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700302 apic= [APIC,i386] Advanced Programmable Interrupt Controller
303 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 Format: { quiet (default) | verbose | debug }
305 Change the amount of debugging information output
306 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700307
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700309 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
312 Format: <io>,<irq>,<nodeID>
313
314 ataflop= [HW,M68k]
315
316 atarimouse= [HW,MOUSE] Atari Mouse
317
318 atascsi= [HW,SCSI] Atari SCSI
319
320 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
321 EzKey and similar keyboards
322
323 atkbd.reset= [HW] Reset keyboard during initialization
324
Randy Dunlapa9913042005-10-23 12:57:11 -0700325 atkbd.set= [HW] Select keyboard code set
326 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
328 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
329 keyboards
330
331 atkbd.softraw= [HW] Choose between synthetic and real raw mode
332 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700333
334 atkbd.softrepeat= [HW]
335 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336
337 autotest [IA64]
338
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 baycom_epp= [HW,AX25]
340 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700341
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
343 Format: <io>,<mode>
344 See header of drivers/net/hamradio/baycom_par.c.
345
Randy Dunlapa9913042005-10-23 12:57:11 -0700346 baycom_ser_fdx= [HW,AX25]
347 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 Format: <io>,<irq>,<mode>[,<baud>]
349 See header of drivers/net/hamradio/baycom_ser_fdx.c.
350
Randy Dunlapa9913042005-10-23 12:57:11 -0700351 baycom_ser_hdx= [HW,AX25]
352 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 Format: <io>,<irq>,<mode>
354 See header of drivers/net/hamradio/baycom_ser_hdx.c.
355
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700356 boot_delay= Milliseconds to delay each printk during boot.
357 Values larger than 10 seconds (10000) are changed to
358 no delay (0).
359 Format: integer
360
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700362 bttv.radio= Most important insmod options are available as
363 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
365 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
366
367 BusLogic= [HW,SCSI]
368 See drivers/scsi/BusLogic.c, comment before function
369 BusLogic_ParseDriverOptions().
370
371 c101= [NET] Moxa C101 synchronous serial card
372
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700373 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 Sometimes CPU hardware bugs make them report the cache
375 size incorrectly. The kernel will attempt work arounds
376 to fix known problems, but for some CPUs it is not
377 possible to determine what the correct size should be.
378 This option provides an override for these situations.
379
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200380 security= [SECURITY] Choose a security module to enable at boot.
381 If this boot parameter is not specified, only the first
382 security module asking for security registration will be
383 loaded. An invalid security module name will be treated
384 as if no module has been chosen.
385
James Morris20510f22007-10-16 23:31:32 -0700386 capability.disable=
387 [SECURITY] Disable capabilities. This would normally
388 be used only if an alternative security model is to be
389 configured. Potentially dangerous and should only be
390 used if you are entirely sure of the consequences.
391
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100392 ccw_timeout_log [S390]
393 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394
Paul Menage8bab8dd2008-04-04 14:29:57 -0700395 cgroup_disable= [KNL] Disable a particular controller
396 Format: {name of the controller(s) to disable}
397 {Currently supported controllers - "memory"}
398
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 checkreqprot [SELINUX] Set initial checkreqprot flag value.
400 Format: { "0" | "1" }
401 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700402 0 -- check protection applied by kernel (includes
403 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 1 -- check protection requested by application.
405 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700406 Value can be changed at runtime via
407 /selinux/checkreqprot.
408
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100409 cio_ignore= [S390]
410 See Documentation/s390/CommonIO for details.
411
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700412 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700413 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200414 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700415 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200416 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 Format: { pit | tsc | cyclone | pmtmr }
418
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700419 clocksource= [GENERIC_TIME] Override the default clocksource
420 Format: <string>
421 Override the default clocksource and use the clocksource
422 with the name specified.
423 Some clocksource names to choose from, depending on
424 the platform:
425 [all] jiffies (this is the base, fallback clocksource)
426 [ACPI] acpi_pm
427 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
428 pxa_timer,timer3,32k_counter,timer0_1
429 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700430 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700431 scx200_hrt on Geode; cyclone on IBM x440
432 [MIPS] MIPS
433 [PARISC] cr16
434 [S390] tod
435 [SH] SuperH
436 [SPARC64] tick
437 [X86-64] hpet,tsc
438
Andi Kleenac72e782008-01-30 13:33:21 +0100439 clearcpuid=BITNUM [X86]
440 Disable CPUID feature X for the kernel. See
441 include/asm-x86/cpufeature.h for the valid bit numbers.
442 Note the Linux specific bits are not necessarily
443 stable over kernel options, but the vendor specific
444 ones should be.
445 Also note that user programs calling CPUID directly
446 or using the feature without checking anything
447 will still see it. This just prevents it from
448 being used by the kernel or shown in /proc/cpuinfo.
449 Also note the kernel might malfunction if you disable
450 some critical bits.
451
Arjan van de Vena25bd942008-01-30 13:33:08 +0100452 code_bytes [IA32/X86_64] How many bytes of object code to print
453 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100454 Range: 0 - 8192
455 Default: 64
456
Andi Kleenf9262c12006-03-08 17:57:25 -0800457 disable_8254_timer
458 enable_8254_timer
459 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
460 over the 8254 in addition to over the IO-APIC. The
461 kernel tries to set a sensible default.
462
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200463 hpet= [X86-32,HPET] option to control HPET usage
464 Format: { enable (default) | disable | force }
465 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100466 force: allow force enabled of undocumented chips (ICH4,
467 VIA, nVidia)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700470 Format:
471 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472
473 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
474 Format: <io>[,<irq>]
475
Randy Dunlapa9913042005-10-23 12:57:11 -0700476 com90xx= [HW,NET]
477 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 Format: <io>[,<irq>[,<memstart>]]
479
480 condev= [HW,S390] console device
481 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700482
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 console= [KNL] Output console device and options.
484
485 tty<n> Use the virtual console device <n>.
486
487 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800488 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800490 the form "bbbbpnf", where "bbbb" is the baud rate,
491 "p" is parity ("n", "o", or "e"), "n" is number of
492 bits, and "f" is flow control ("r" for RTS or
493 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800495 See Documentation/serial-console.txt for more
496 information. See
497 Documentation/networking/netconsole.txt for an
498 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700500 uart[8250],io,<addr>[,options]
501 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 Start an early, polled-mode console on the 8250/16550
503 UART at the specified I/O port or MMIO address,
504 switching to the matching ttyS device later. The
505 options are the same as for ttyS, above.
506
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700507 If the device connected to the port is not a TTY but a braille
508 device, prepend "brl," before the device type, for instance
509 console=brl,ttyS0
510 For now, only VisioBraille is supported.
511
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700512 earlycon= [KNL] Output early console device and options.
513 uart[8250],io,<addr>[,options]
514 uart[8250],mmio,<addr>[,options]
515 Start an early, polled-mode console on the 8250/16550
516 UART at the specified I/O port or MMIO address.
517 The options are the same as for ttyS, above.
518
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700519 no_console_suspend
520 [HW] Never suspend the console
521 Disable suspending of consoles during suspend and
522 hibernate operations. Once disabled, debugging
523 messages can reach various consoles while the rest
524 of the system is being put to sleep (ie, while
525 debugging driver suspend/resume hooks). This may
526 not work reliably with all consoles, but is known
527 to work with serial and VGA consoles.
528
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700530 Format:
531 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700533 crashkernel=nn[KMG]@ss[KMG]
534 [KNL] Reserve a chunk of physical memory to
535 hold a kernel to switch to with kexec on panic.
536
Bernhard Wallefb391592007-10-18 23:41:02 -0700537 crashkernel=range1:size1[,range2:size2,...][@offset]
538 [KNL] Same as above, but depends on the memory
539 in the running system. The syntax of range is
540 start-[end] where start and end are both
541 a memory unit (amount[KMG]). See also
542 Documentation/kdump/kdump.txt for a example.
543
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 cs4232= [HW,OSS]
545 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
546
547 cs89x0_dma= [HW,NET]
548 Format: <dma>
549
550 cs89x0_media= [HW,NET]
551 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700552
Randy Dunlapa9913042005-10-23 12:57:11 -0700553 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 See header of drivers/s390/block/dasd_devmap.c.
555
556 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
557 (one device per port)
558 Format: <port#>,<type>
559 See also Documentation/input/joystick-parport.txt
560
561 debug [KNL] Enable kernel debugging (events log level).
562
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700563 debug_locks_verbose=
564 [KNL] verbose self-tests
565 Format=<0|1>
566 Print debugging info while doing the locking API
567 self-tests.
568 We default to 0 (no extra messages), setting it to
569 1 will print _a lot_ more information - normally
570 only useful to kernel developers.
571
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700572 debug_objects [KNL] Enable object debugging
573
Thomas Gleixnerd3af01f2008-07-15 15:04:56 +0200574 debugpat [X86] Enable PAT debugging
575
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200576 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 Format: <area>[,<node>]
578 See also Documentation/networking/decnet.txt.
579
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000580 vt.default_blu= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700581 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
582 Change the default blue palette of the console.
583 This is a 16-member array composed of values
584 ranging from 0-255.
585
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000586 vt.default_grn= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700587 Format: <green0>,<green1>,<green2>,...,<green15>
588 Change the default green palette of the console.
589 This is a 16-member array composed of values
590 ranging from 0-255.
591
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000592 vt.default_red= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700593 Format: <red0>,<red1>,<red2>,...,<red15>
594 Change the default red palette of the console.
595 This is a 16-member array composed of values
596 ranging from 0-255.
597
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000598 vt.default_utf8=
599 [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700600 Format=<0|1>
601 Set system-wide default UTF-8 mode for all tty's.
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000602 Default is 1, i.e. UTF-8 mode is enabled for all
603 newly opened terminals.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700604
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 dhash_entries= [KNL]
606 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700607
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 digi= [HW,SERIAL]
609 IO parameters + enable/disable command.
610
611 digiepca= [HW,SERIAL]
612 See drivers/char/README.epca and
613 Documentation/digiepca.txt.
614
Yinghai Lu95ffa242008-04-29 03:52:33 -0700615 disable_mtrr_cleanup [X86]
616 enable_mtrr_cleanup [X86]
617 The kernel tries to adjust MTRR layout from continuous
618 to discrete, to make X server driver able to add WB
619 entry later. This parameter enables/disables that.
620
621 mtrr_chunk_size=nn[KMG] [X86]
622 used for mtrr cleanup. It is largest continous chunk
623 that could hold holes aka. UC entries.
624
625 mtrr_gran_size=nn[KMG] [X86]
Yinghai Lu12031a62008-05-02 02:40:22 -0700626 Used for mtrr cleanup. It is granularity of mtrr block.
627 Default is 1.
628 Large value could prevent small alignment from
629 using up MTRRs.
630
631 mtrr_spare_reg_nr=n [X86]
632 Format: <integer>
633 Range: 0,7 : spare reg number
634 Default : 1
635 Used for mtrr cleanup. It is spare mtrr entries number.
636 Set to 2 or more if your graphical card needs more.
Yinghai Lu95ffa242008-04-29 03:52:33 -0700637
Yinghai Lu093af8d2008-01-30 13:33:32 +0100638 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100639 By default the kernel will trim any uncacheable
640 memory out of your available memory pool based on
641 MTRR settings. This parameter disables that behavior,
642 possibly causing your machine to run very slowly.
643
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 dmasound= [HW,OSS] Sound subsystem buffers
645
646 dscc4.setup= [NET]
647
648 dtc3181e= [HW,SCSI]
649
Robin Getz0ae53642007-10-09 17:24:49 +0800650 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 earlyprintk=vga
652 earlyprintk=serial[,ttySn[,baudrate]]
653
Randy Dunlapa9913042005-10-23 12:57:11 -0700654 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 takes over.
656
657 Only vga or serial at a time, not both.
658
659 Currently only ttyS0 and ttyS1 are supported.
660
661 Interaction with the standard serial driver is not
662 very good.
663
664 The VGA output is eventually overwritten by the real
665 console.
666
667 eata= [HW,SCSI]
668
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700670 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 eisa_irq_edge= [PARISC,HW]
673 See header of drivers/parisc/eisa.c.
674
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700675 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700677 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678
679 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800680 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700681 See Documentation/block/as-iosched.txt and
682 Documentation/block/deadline-iosched.txt for details.
683
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700684 elfcorehdr= [X86-32, X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700685 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800686 image elf header. Generally kexec loader will
687 pass this option to capture kernel.
688 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689
690 enforcing [SELINUX] Set initial enforcing status.
691 Format: {"0" | "1"}
692 See security/selinux/Kconfig help text.
693 0 -- permissive (log only, no denials).
694 1 -- enforcing (deny and log).
695 Default value is 0.
696 Value can be changed at runtime via /selinux/enforce.
697
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 es1371= [HW,OSS]
699 Format: <spdif>,[<nomix>,[<amplifier>]]
700 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700701
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 ether= [HW,NET] Ethernet cards parameters
703 This option is obsoleted by the "netdev=" option, which
704 has equivalent usage. See its documentation for details.
705
706 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
707 Format: <io>[,<irq>]
708
Akinobu Mitade1ba092006-12-08 02:39:42 -0800709 failslab=
710 fail_page_alloc=
711 fail_make_request=[KNL]
712 General fault injection mechanism.
713 Format: <interval>,<probability>,<space>,<times>
714 See also /Documentation/fault-injection/.
715
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 fd_mcs= [HW,SCSI]
717 See header of drivers/scsi/fd_mcs.c.
718
719 fdomain= [HW,SCSI]
720 See header of drivers/scsi/fdomain.c.
721
722 floppy= [HW]
723 See Documentation/floppy.txt.
724
Alex Chiangf13ae302008-05-08 14:03:23 -0600725 force_pal_cache_flush
726 [IA-64] Avoid check_sal_cache_flush which may hang on
727 buggy SAL_CACHE_FLUSH implementations. Using this
728 parameter will force ia64_sal_cache_flush to call
729 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
730
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 gamecon.map[2|3]=
732 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
733 support via parallel port (up to 5 devices per port)
734 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
735 See also Documentation/input/joystick-parport.txt
736
737 gamma= [HW,DRM]
738
Yinghai Luaaf23042008-01-30 13:33:09 +0100739 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
740 Format: off | on
741 default: on
742
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 gdth= [HW,SCSI]
744 See header of drivers/scsi/gdth.c.
745
746 gpt [EFI] Forces disk with valid GPT signature but
747 invalid Protective MBR to be treated as GPT.
748
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 gvp11= [HW,SCSI]
750
751 hashdist= [KNL,NUMA] Large hashes allocated during boot
752 are distributed across NUMA nodes. Defaults on
753 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700754 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755
756 hcl= [IA-64] SGI's Hardware Graph compatibility layer
757
758 hd= [EIDE] (E)IDE hard drive subsystem geometry
759 Format: <cyl>,<head>,<sect>
760
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
762 size of <nn>. This works even on boxes that have no
763 highmem otherwise. This also works to reduce highmem
764 size on bigger boxes.
765
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800766 highres= [KNL] Enable/disable high resolution timer mode.
767 Valid parameters: "on", "off"
768 Default: "on"
769
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 hisax= [HW,ISDN]
771 See Documentation/isdn/README.HiSax.
772
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700773 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
Jon Tollefson4ec161c2008-01-04 09:59:50 +1100774 hugepagesz= [HW,IA-64,PPC] The size of the HugeTLB pages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200777 i8042.dumbkbd [HW] Pretend that controller can only read data from
778 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 (Don't attempt to blink the leds)
780 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500781 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400782 i8042.noloop [HW] Disable the AUX Loopback command while probing
783 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784 i8042.nomux [HW] Don't check presence of an active multiplexing
785 controller
786 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
787 controllers
788 i8042.panicblink=
789 [HW] Frequency with which keyboard LEDs should blink
790 when kernel panics (default is 0.5 sec)
791 i8042.reset [HW] Reset the controller during init and cleanup
792 i8042.unlock [HW] Unlock (ignore) the keylock
793
794 i810= [HW,DRM]
795
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700796 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
797 indicates that the driver is running on unsupported
798 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
800 does not match list of supported models.
801 i8k.power_status
802 [HW] Report power status in /proc/i8k
803 (disabled by default)
804 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
805 capability is set.
806
807 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
808 See Documentation/mca.txt.
809
810 icn= [HW,ISDN]
811 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
812
813 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200814 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100815 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100818 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819
Andi Kleenf039b752007-05-02 19:27:12 +0200820 idle= [X86]
821 Format: idle=poll or idle=mwait
822 Poll forces a polling idle loop that can slightly improves the performance
823 of waking up a idle CPU, but will use a lot of power and make the system
824 run hot. Not recommended.
825 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
826 to not use it because it doesn't save as much power as a normal idle
827 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
828 as idle=poll.
Randy Dunlapa9913042005-10-23 12:57:11 -0700829
Denis Cheng594765a2008-02-06 02:57:49 +0100830 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
831 Claim all unknown PCI IDE storage controllers.
832
Ingo Molnar792908222006-12-06 20:40:51 -0800833 ignore_loglevel [KNL]
834 Ignore loglevel setting - this will print /all/
835 kernel messages to the console. Useful for debugging.
836
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 ihash_entries= [KNL]
838 Set number of hash buckets for inode cache.
839
840 in2000= [HW,SCSI]
841 See header of drivers/scsi/in2000.c.
842
843 init= [KNL]
844 Format: <full_path>
845 Run specified binary instead of /sbin/init as init
846 process.
847
848 initcall_debug [KNL] Trace initcalls as they are executed. Useful
849 for working out where the kernel is dying during
850 startup.
851
852 initrd= [BOOT] Specify the location of the initial ramdisk
853
854 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
855 Format: <irq>
856
857 inttest= [IA64]
858
Pavel Machekb552da82008-03-19 15:58:11 +0100859 iommu= [x86]
860 off
861 force
862 noforce
863 biomerge
864 panic
865 nopanic
866 merge
867 nomerge
868 forcesac
869 soft
870
871
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700872 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
873 off
874 Disable intel iommu driver.
875 igfx_off [Default Off]
876 By default, gfx is mapped as normal device. If a gfx
877 device has a dedicated DMAR unit, the DMAR unit is
878 bypassed by not enabling DMAR with this option. In
879 this case, gfx device will use physical address for
880 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700881 forcedac [x86_64]
882 With this option iommu will not optimize to look
883 for io virtual address below 32 bit forcing dual
884 address cycle on pci bus for cards supporting greater
885 than 32 bit addressing. The default is to look
886 for translation below 32 bit and if not available
887 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800888 strict [Default Off]
889 With this option on every unmap_single operation will
890 result in a hardware IOTLB flush operation as opposed
891 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700892
Rene Hermanb02aae92008-01-30 13:30:05 +0100893 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100894 0x80
895 Standard port 0x80 based delay
896 0xed
897 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100898 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100899 Simple two microseconds delay
900 none
901 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100902
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 io7= [HW] IO7 for Marvel based alpha systems
904 See comment before marvel_specify_io7 in
905 arch/alpha/kernel/core_marvel.c.
906
907 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400908 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909
910 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700911 See comment before ip2_setup() in
912 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913
914 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
915 See header of drivers/scsi/ips.c.
916
Simon Horman72c4a132006-09-13 19:57:18 -0700917 ports= [IP_VS_FTP] IPVS ftp helper module
918 Default is 21.
919 Up to 8 (IP_VS_APP_MAX_PORTS) ports
920 may be specified.
921 Format: <port>,<port>....
922
Alan Cox200803d2005-06-28 20:45:18 -0700923 irqfixup [HW]
924 When an interrupt is not handled search all handlers
925 for it. Intended to get systems with badly broken
926 firmware running.
927
928 irqpoll [HW]
929 When an interrupt is not handled search all handlers
930 for it. Also check all handlers each timer
931 interrupt. Intended to get systems with badly broken
932 firmware running.
933
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700935 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936
937 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800938 Format:
939 <cpu number>,...,<cpu number>
940 or
941 <cpu number>-<cpu number> (must be a positive range in ascending order)
942 or a mixture
943 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944 This option can be used to specify one or more CPUs
945 to isolate from the general SMP balancing and scheduling
946 algorithms. The only way to move a process onto or off
947 an "isolated" CPU is via the CPU affinity syscalls.
948 <cpu number> begins at 0 and the maximum value is
949 "number of CPUs in system - 1".
950
951 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700952 alternative -- manually setting the CPU mask of all
953 tasks in the system -- can cause problems and
954 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955
Randy Dunlapa9913042005-10-23 12:57:11 -0700956 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957
958 js= [HW,JOY] Analog joystick
959 See Documentation/input/joystick.txt.
960
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700961 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700962 specifies the amount of memory usable by the kernel
963 for non-movable allocations. The requested amount is
964 spread evenly throughout all nodes in the system. The
965 remaining memory in each node is used for Movable
966 pages. In the event, a node is too small to have both
967 kernelcore and Movable pages, kernelcore pages will
968 take priority and other nodes will have a larger number
969 of kernelcore pages. The Movable zone is used for the
970 allocation of pages that may be reclaimed or moved
971 by the page migration subsystem. This means that
972 HugeTLB pages may not be allocated from this zone.
973 Note that allocations like PTEs-from-HighMem still
974 use the HighMem zone if it exists, and the Normal
975 zone if it does not.
976
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700977 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -0700978 is similar to kernelcore except it specifies the
979 amount of memory used for migratable allocations.
980 If both kernelcore and movablecore is specified,
981 then kernelcore will be at *least* the specified
982 value but may be more. If movablecore on its own
983 is specified, the administrator must be careful
984 that the amount of memory usable for all allocations
985 is not too small.
986
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 keepinitrd [HW,ARM]
988
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700989 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -0700990 in oops dumps.
991
Jason Wessel6cdf6e02008-04-17 20:05:38 +0200992 kgdboc= [HW] kgdb over consoles.
993 Requires a tty driver that supports console polling.
994 (only serial suported for now)
995 Format: <serial_device>[,baud]
996
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 l2cr= [PPC]
998
Robert Brosea78bfbf2008-03-29 07:20:23 +1100999 l3cr= [PPC]
1000
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001001 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001002 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001004 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001005 C2 power state.
1006
FD Camifcb71f62008-01-06 19:08:56 +01001007 libata.dma= [LIBATA] DMA control
1008 libata.dma=0 Disable all PATA and SATA DMA
1009 libata.dma=1 PATA and SATA Disk DMA only
1010 libata.dma=2 ATAPI (CDROM) DMA only
1011 libata.dma=4 Compact Flash DMA only
1012 Combinations also work, so libata.dma=3 enables DMA
1013 for disks and CDROMs, but not CFs.
1014
Dave Jones78e70c22007-09-27 11:50:13 -04001015 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1016 when set.
1017 Format: <int>
1018
Tejun Heo33267322008-02-13 09:15:09 +09001019 libata.force= [LIBATA] Force configurations. The format is comma
1020 separated list of "[ID:]VAL" where ID is
1021 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1022 matching port, link or device. Basically, it matches
1023 the ATA ID string printed on console by libata. If
1024 the whole ID part is omitted, the last PORT and DEVICE
1025 values are used. If ID hasn't been specified yet, the
1026 configuration applies to all ports, links and devices.
1027
1028 If only DEVICE is omitted, the parameter applies to
1029 the port and all links and devices behind it. DEVICE
1030 number of 0 either selects the first device or the
1031 first fan-out link behind PMP device. It does not
1032 select the host link. DEVICE number of 15 selects the
1033 host link and device attached to it.
1034
1035 The VAL specifies the configuration to force. As long
1036 as there's no ambiguity shortcut notation is allowed.
1037 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1038 The following configurations can be forced.
1039
1040 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1041 Any ID with matching PORT is used.
1042
1043 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1044
1045 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1046 udma[/][16,25,33,44,66,100,133] notation is also
1047 allowed.
1048
1049 * [no]ncq: Turn on or off NCQ.
1050
1051 If there are multiple matching configurations changing
1052 the same attribute, the last one is used.
1053
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054 load_ramdisk= [RAM] List of ramdisks to load from floppy
1055 See Documentation/ramdisk.txt.
1056
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001057 lockd.nlm_grace_period=P [NFS] Assign grace period.
1058 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001060 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1061 Format: <integer>
1062
1063 lockd.nlm_timeout=T [NFS] Assign timeout value.
1064 Format: <integer>
1065
1066 lockd.nlm_udpport=M [NFS] Assign UDP port.
1067 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068
1069 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1070 Format: <irq>
1071
1072 loglevel= All Kernel Messages with a loglevel smaller than the
1073 console loglevel will be printed to the console. It can
1074 also be changed with klogd or other programs. The
1075 loglevels are defined as follows:
1076
1077 0 (KERN_EMERG) system is unusable
1078 1 (KERN_ALERT) action must be taken immediately
1079 2 (KERN_CRIT) critical conditions
1080 3 (KERN_ERR) error conditions
1081 4 (KERN_WARNING) warning conditions
1082 5 (KERN_NOTICE) normal but significant condition
1083 6 (KERN_INFO) informational
1084 7 (KERN_DEBUG) debug-level messages
1085
1086 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001087 Format: { n | nk | nM }
1088 n must be a power of two. The default size
1089 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090
Randy Dunlapaccaa242007-10-16 01:29:37 -07001091 logo.nologo [FB] Disables display of the built-in Linux logo.
1092 This may be used to provide more screen space for
1093 kernel log messages and is useful when debugging
1094 kernel boot problems.
1095
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 lp=0 [LP] Specify parallel ports to use, e.g,
1097 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1098 lp=reset first parallel port). 'lp=0' disables the
1099 lp=auto printer driver. 'lp=reset' (which can be
1100 specified in addition to the ports) causes
1101 attached printers to be reset. Using
1102 lp=port1,port2,... specifies the parallel ports
1103 to associate lp devices with, starting with
1104 lp0. A port specification may be 'none' to skip
1105 that lp device, or a parport name such as
1106 'parport0'. Specifying 'lp=auto' instead of a
1107 port specification list means that device IDs
1108 from each port should be examined, to see if
1109 an IEEE 1284-compliant printer is attached; if
1110 so, the driver will manage that printer.
1111 See also header of drivers/char/lp.c.
1112
1113 lpj=n [KNL]
1114 Sets loops_per_jiffy to given constant, thus avoiding
1115 time-consuming boot-time autodetection (up to 250 ms per
1116 CPU). 0 enables autodetection (default). To determine
1117 the correct value for your kernel, boot with normal
1118 autodetection and see what value is printed. Note that
1119 on SMP systems the preset will be applied to all CPUs,
1120 which is likely to cause problems if your CPUs need
1121 significantly divergent settings. An incorrect value
1122 will cause delays in the kernel to be wrong, leading to
1123 unpredictable I/O errors and other breakage. Although
1124 unlikely, in the extreme case this might damage your
1125 hardware.
1126
1127 ltpc= [NET]
1128 Format: <io>,<irq>,<dma>
1129
Randy Dunlapa9913042005-10-23 12:57:11 -07001130 mac5380= [HW,SCSI] Format:
1131 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132
Randy Dunlapa9913042005-10-23 12:57:11 -07001133 machvec= [IA64] Force the use of a particular machine-vector
1134 (machvec) in a generic kernel.
1135 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136
Randy Dunlapa9913042005-10-23 12:57:11 -07001137 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138 be mounted
1139 Format: <1-256>
1140
1141 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001142 should make use of. maxcpus=n : n >= 0 limits the
1143 kernel to using 'n' processors. n=0 is a special case,
1144 it is equivalent to "nosmp", which also disables
1145 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146
Bob Picco2b2c3752005-06-29 18:00:00 -07001147 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1148 equal to this physical address is ignored.
1149
Randy Dunlapa9913042005-10-23 12:57:11 -07001150 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 Should be between 1 and 2^32-1.
1152
1153 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001154 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 Should be between 1 and 16384.
1156
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157 mcatest= [IA-64]
1158
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001159 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160
Andi Kleen909dd322007-10-17 18:04:38 +02001161 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1162
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 md= [HW] RAID subsystems devices and level
1164 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001165
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166 mdacon= [MDA]
1167 Format: <first>,<last>
1168 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001169
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1171 Amount of memory to be used when the kernel is not able
1172 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001173 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 address space collisions. Without memmap= PCI devices
1175 could be placed at addresses belonging to unused RAM.
1176
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001177 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 memory.
1179
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001180 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181 E820 memory map, as specified by the user.
1182 Such memmap=exactmap lines can be constructed based on
1183 BIOS output or other requirements. See the memmap=nn@ss
1184 option description.
1185
1186 memmap=nn[KMG]@ss[KMG]
1187 [KNL] Force usage of a specific region of memory
1188 Region of memory to be used, from ss to ss+nn.
1189
1190 memmap=nn[KMG]#ss[KMG]
1191 [KNL,ACPI] Mark specific memory as ACPI data.
1192 Region of memory to be used, from ss to ss+nn.
1193
1194 memmap=nn[KMG]$ss[KMG]
1195 [KNL,ACPI] Mark specific memory as reserved.
1196 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001197 Example: Exclude memory from 0x18690000-0x1869ffff
1198 memmap=64K$0x18690000
1199 or
1200 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201
Yinghai Luc64df702008-03-21 18:56:19 -07001202 memtest= [KNL,X86_64] Enable memtest
1203 Format: <integer>
1204 range: 0,4 : pattern number
1205 default : 0 <disable>
1206
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 meye.*= [HW] Set MotionEye Camera parameters
1208 See Documentation/video4linux/meye.txt.
1209
Andres Salomon8f368812007-10-12 23:04:06 +02001210 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1211 Multi-Function General Purpose Timers on AMD Geode
1212 platforms.
1213
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001214 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1215 the BIOS has incorrectly applied a workaround. TinyBIOS
1216 version 0.98 is known to be affected, 0.99 fixes the
1217 problem by letting the user disable the workaround.
1218
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219 mga= [HW,DRM]
1220
1221 mousedev.tap_time=
1222 [MOUSE] Maximum time between finger touching and
1223 leaving touchpad surface for touch to be considered
1224 a tap and be reported as a left button click (for
1225 touchpads working in absolute mode only).
1226 Format: <msecs>
1227 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1228 reporting absolute coordinates, such as tablets
1229 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1230 reporting absolute coordinates, such as tablets
1231
1232 mpu401= [HW,OSS]
1233 Format: <io>,<irq>
1234
1235 MTD_Partition= [MTD]
1236 Format: <name>,<region-number>,<size>,<offset>
1237
Randy Dunlapa9913042005-10-23 12:57:11 -07001238 MTD_Region= [MTD] Format:
1239 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240
1241 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001242 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243
Ben Dooks9db829f2008-07-03 11:24:29 +01001244 mtdset= [ARM]
1245 ARM/S3C2412 JIVE boot control
1246
1247 See arch/arm/mach-s3c2412/mach-jive.c
1248
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001250 [HW] Make the MicroTouch USB driver use raw coordinates
1251 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001252
1253 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1254
1255 NCR_D700= [HW,SCSI]
1256 See header of drivers/scsi/NCR_D700.c.
1257
1258 ncr5380= [HW,SCSI]
1259
1260 ncr53c400= [HW,SCSI]
1261
1262 ncr53c400a= [HW,SCSI]
1263
1264 ncr53c406a= [HW,SCSI]
1265
1266 ncr53c8xx= [HW,SCSI]
1267
1268 netdev= [NET] Network devices parameters
1269 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1270 Note that mem_start is often overloaded to mean
1271 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001272 This usage is only documented in each driver source
1273 file if at all.
1274
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001276 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277
1278 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001279 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280
Trond Myklebusta72b4422006-01-03 09:55:41 +01001281 nfs.callback_tcpport=
1282 [NFS] set the TCP port on which the NFSv4 callback
1283 channel should listen.
1284
Trond Myklebust58df0952006-01-03 09:55:57 +01001285 nfs.idmap_cache_timeout=
1286 [NFS] set the maximum lifetime for idmapper cache
1287 entries.
1288
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001289 nfs.enable_ino64=
1290 [NFS] enable 64-bit inode numbers.
1291 If zero, the NFS client will fake up a 32-bit inode
1292 number for the readdir() and stat() syscalls instead
1293 of returning the full 64-bit number.
1294 The default is to return 64-bit inode numbers.
1295
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001296 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1297 when a NMI is triggered.
1298 Format: [state][,regs][,debounce][,die]
1299
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001300 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001301
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001302 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303 emulation library even if a 387 maths coprocessor
1304 is present.
1305
Christoph Lameterc1aee212007-05-31 00:40:47 -07001306 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1307 caches in the slab allocator. Saves per-node memory,
1308 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001309
Randy Dunlapa9913042005-10-23 12:57:11 -07001310 noalign [KNL,ARM]
1311
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312 noapic [SMP,APIC] Tells the kernel to not make use of any
1313 IOAPICs that may be present in the system.
1314
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315 nobats [PPC] Do not use BATs for mapping kernel lowmem
1316 on "Classic" PPC cores.
1317
1318 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001319
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001320 nodelayacct [KNL] Disable per-task delay accounting
1321
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1323
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001324 noefi [X86-32,X86-64] Disable EFI runtime services support.
1325
Linus Torvalds1da177e2005-04-16 15:20:36 -07001326 noexec [IA-64]
1327
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001328 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001329 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001331 noexec=off: disable non-executable mappings
1332
1333 noexec32 [X86-64]
1334 This affects only 32-bit executables.
1335 noexec32=on: enable non-executable mappings (default)
1336 read doesn't imply executable mappings
1337 noexec32=off: disable non-executable mappings
1338 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001340 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001341 register save and restore. The kernel will only save
1342 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343
Andi Kleen191679f2008-01-30 13:33:21 +01001344 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1345
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001347
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001348 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349 instruction doesn't work correctly and not to
1350 use it.
1351
1352 nohalt [IA-64] Tells the kernel not to use the power saving
1353 function PAL_HALT_LIGHT when idle. This increases
1354 power-consumption. On the positive side, it reduces
1355 interrupt wake-up latency, which may improve performance
1356 in certain environments such as networked servers or
1357 real-time systems.
1358
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001359 nohz= [KNL] Boottime enable/disable dynamic ticks
1360 Valid arguments: on, off
1361 Default: on
1362
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001363 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001364
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001365 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366 disable unhandled interrupt sources.
1367
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001368 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001369 broken timer IRQ sources.
1370
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371 noisapnp [ISAPNP] Disables ISA PnP code.
1372
1373 noinitrd [RAM] Tells the kernel not to load any configured
1374 initial RAM disk.
1375
1376 nointroute [IA-64]
1377
Tony Luck0aa366f2007-07-20 11:22:30 -07001378 nojitter [IA64] Disables jitter checking for ITC timers.
1379
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001380 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001382 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001383
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384 noltlbs [PPC] Do not use large page/tlb entries for kernel
1385 lowmem mapping on PPC40x.
1386
Horms312f1f02006-02-22 09:57:55 +09001387 nomca [IA-64] Disable machine check abort handling
1388
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001389 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001390
Andres Salomon83d73842007-10-12 23:04:06 +02001391 nomfgpt [X86-32] Disable Multi-Function General Purpose
1392 Timer usage (for AMD Geode machines).
1393
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001394 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001395
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001396 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001397 with UP alternatives
1398
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399 noresidual [PPC] Don't use residual data on PReP machines.
1400
Randy Dunlapa9913042005-10-23 12:57:11 -07001401 noresume [SWSUSP] Disables resume and restores original swap
1402 space.
1403
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404 no-scroll [VGA] Disables scrollback.
1405 This is required for the Braillex ib80-piezo Braille
1406 reader made by F.H. Papenmeier (Germany).
1407
1408 nosbagart [IA-64]
1409
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001410 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001411
Len Brown61ec7562007-08-16 03:34:22 -04001412 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1413 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414
Dave Jones97842212007-07-15 23:41:05 -07001415 nosoftlockup [KNL] Disable the soft-lockup detector.
1416
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 nosync [HW,M68K] Disables sync negotiation for all devices.
1418
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001419 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420
1421 nousb [USB] Disable the USB subsystem
1422
1423 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001424
Fenghua Yua6c75b862008-03-14 13:57:08 -07001425 nptcg= [IA64] Override max number of concurrent global TLB
1426 purges which is reported from either PAL_VM_SUMMARY or
1427 SAL PALO.
1428
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001429 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1430 one of ['zone', 'node', 'default'] can be specified
1431 This can be set from sysctl after boot.
1432 See Documentation/sysctl/vm.txt for details.
1433
Dave Jonesa61c2d72006-01-07 23:18:19 +00001434 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1435
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001436 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1437 Rather than timing out after 20 ms if an EC
1438 command is not properly ACKed, override the length
1439 of the timeout. We have interrupts disabled while
1440 waiting for the ACK, so if this is set too high
1441 interrupts *may* be lost!
1442
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 opl3= [HW,OSS]
1444 Format: <io>
1445
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446 oprofile.timer= [HW]
1447 Use timer interrupt instead of performance counters
1448
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449 osst= [HW,SCSI] SCSI Tape Driver
1450 Format: <buffer_size>,<write_threshold>
1451 See also Documentation/scsi/st.txt.
1452
1453 panic= [KNL] Kernel behaviour on panic
1454 Format: <timeout>
1455
1456 parkbd.port= [HW] Parallel port number the keyboard adapter is
1457 connected to, default is 0.
1458 Format: <parport#>
1459 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1460 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001461 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462
Randy Dunlapa9913042005-10-23 12:57:11 -07001463 parport= [HW,PPT] Specify parallel ports. 0 disables.
1464 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1465 Use 'auto' to force the driver to use any
1466 IRQ/DMA settings detected (the default is to
1467 ignore detected IRQ/DMA settings because of
1468 possible conflicts). You can specify the base
1469 address, IRQ, and DMA settings; IRQ and DMA
1470 should be numbers, or 'auto' (for using detected
1471 settings on that particular port), or 'nofifo'
1472 (to avoid using a FIFO even if it is detected).
1473 Parallel ports are assigned in the order they
1474 are specified on the command line, starting
1475 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476
Randy Dunlapa9913042005-10-23 12:57:11 -07001477 parport_init_mode= [HW,PPT]
1478 Configure VIA parallel port to operate in
1479 a specific mode. This is necessary on Pegasos
1480 computer where firmware has no options for setting
1481 up parallel port mode and sets it to spp.
1482 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483 Format: [spp|ps2|epp|ecp|ecpepp]
1484
Randy Dunlapa9913042005-10-23 12:57:11 -07001485 pas2= [HW,OSS] Format:
1486 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1487
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 pas16= [HW,SCSI]
1489 See header of drivers/scsi/pas16.c.
1490
Andrew Mortondd287792006-03-23 03:00:57 -08001491 pause_on_oops=
1492 Halt all CPUs after the first oops has been printed for
1493 the specified number of seconds. This is to be used if
1494 your oopses keep scrolling off the screen.
1495
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496 pcbit= [HW,ISDN]
1497
1498 pcd. [PARIDE]
1499 See header of drivers/block/paride/pcd.c.
1500 See also Documentation/paride.txt.
1501
Randy Dunlapa9913042005-10-23 12:57:11 -07001502 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001503 off [X86-32] don't probe for the PCI bus
1504 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001505 the hardware directly. Use this if your machine
1506 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001507 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001508 hardware access methods are allowed. Use this
1509 if you experience crashes upon bootup and you
1510 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001511 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001512 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001513 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001514 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001515 noaer [PCIE] If the PCIEAER kernel config parameter is
1516 enabled, this kernel boot option can be used to
1517 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001518 nodomains [PCI] Disable support for multiple PCI
1519 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001520 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001521 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001522 nomsi [MSI] If the PCI_MSI kernel config parameter is
1523 enabled, this kernel boot option can be used to
1524 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001525 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001526 routing table. These calls are known to be buggy
1527 on several machines and they hang the machine
1528 when used, but on other computers it's the only
1529 way to get the interrupt routing table. Try
1530 this option if the kernel is unable to allocate
1531 IRQs or discover secondary PCI buses on your
1532 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001533 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001534 Use with caution as certain devices share
1535 address decoders between ROMs and other
1536 resources.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001537 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001538 assigned automatically to PCI devices. You can
1539 make the kernel exclude IRQs of your ISA cards
1540 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001541 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001542 of the PIRQ table (normally generated
1543 by the BIOS) if it is outside the
1544 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001545 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001546 useful if the kernel is unable to find your
1547 secondary buses and you want to tell it
1548 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001549 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001550 numbers ourselves, overriding
1551 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001552 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001553 in the BIOS $PIR table. This is needed on
1554 some systems with broken BIOSes, notably
1555 some HP Pavilion N5400 and Omnibook XE3
1556 notebooks. This will have no effect if ACPI
1557 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001558 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001559 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001560 use_crs [X86-32] Use _CRS for PCI resource
1561 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001562 routeirq Do IRQ routing for all PCI devices.
1563 This is normally done in pci_enable_device(),
1564 so this option is a temporary workaround
1565 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001566 skip_isa_align [X86] do not align io start addr, so can
1567 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001568 firmware [ARM] Do not re-enumerate the bus but instead
1569 just use the configuration from the
1570 bootloader. This is currently used on
1571 IXP2000 systems where the bus has to be
1572 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001573 noearly [X86] Don't do any early type 1 scanning.
1574 This might help on some broken boards which
1575 machine check when some devices' config space
1576 is read. But various workarounds are disabled
1577 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001578 bfsort Sort PCI devices into breadth-first order.
1579 This sorting is done to get a device
1580 order compatible with older (<= 2.4) kernels.
1581 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001582 cbiosize=nn[KMG] The fixed amount of bus space which is
1583 reserved for the CardBus bridge's IO window.
1584 The default value is 256 bytes.
1585 cbmemsize=nn[KMG] The fixed amount of bus space which is
1586 reserved for the CardBus bridge's memory
1587 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001588
Linus Torvalds1da177e2005-04-16 15:20:36 -07001589 pcmv= [HW,PCMCIA] BadgePAD 4
1590
1591 pd. [PARIDE]
1592 See Documentation/paride.txt.
1593
1594 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1595 boot time.
1596 Format: { 0 | 1 }
1597 See arch/parisc/kernel/pdc_chassis.c
1598
1599 pf. [PARIDE]
1600 See Documentation/paride.txt.
1601
1602 pg. [PARIDE]
1603 See Documentation/paride.txt.
1604
1605 pirq= [SMP,APIC] Manual mp-table setup
1606 See Documentation/i386/IO-APIC.txt.
1607
1608 plip= [PPT,NET] Parallel port network link
1609 Format: { parport<nr> | timid | 0 }
1610 See also Documentation/parport.txt.
1611
Thomas Gleixnerde32a2432008-07-12 05:33:30 +02001612 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1613 Override pmtimer IOPort with a hex value.
1614 e.g. pmtmr=0x508
1615
Linus Torvalds1da177e2005-04-16 15:20:36 -07001616 pnpacpi= [ACPI]
1617 { off }
1618
1619 pnpbios= [ISAPNP]
1620 { on | off | curr | res | no-curr | no-res }
1621
1622 pnp_reserve_irq=
1623 [ISAPNP] Exclude IRQs for the autoconfiguration
1624
1625 pnp_reserve_dma=
1626 [ISAPNP] Exclude DMAs for the autoconfiguration
1627
1628 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001629 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001630
1631 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001632 [ISAPNP] Exclude memory regions for the
1633 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001634 Ranges are in pairs (memory base and size).
1635
Ingo Molnar45807a12007-07-15 23:40:10 -07001636 print-fatal-signals=
1637 [KNL] debug: print fatal signals
1638 print-fatal-signals=1: print segfault info to
1639 the kernel console.
1640 default: off.
1641
Randy Dunlape84845c2007-07-15 23:40:25 -07001642 printk.time= Show timing data prefixed to each printk message line
1643 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1644
Linus Torvalds1da177e2005-04-16 15:20:36 -07001645 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001646 Format: [schedule,]<number>
1647 Param: "schedule" - profile schedule points.
1648 Param: <number> - step/bucket size as a power of 2 for
1649 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001650 Param: "sleep" - profile D-state sleeping (millisecs).
1651 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001652 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001653
Randy Dunlapa9913042005-10-23 12:57:11 -07001654 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001655 Limit processor to maximum C-state
1656 max_cstate=9 overrides any DMI blacklist limit.
1657
Len Brown41c0d862005-12-28 12:43:51 -05001658 processor.nocst [HW,ACPI]
1659 Ignore the _CST method to determine C-states,
1660 instead using the legacy FADT method
1661
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1663 before loading.
1664 See Documentation/ramdisk.txt.
1665
Randy Dunlapa9913042005-10-23 12:57:11 -07001666 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1667 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001668 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1669 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001670 psmouse.resetafter= [HW,MOUSE]
1671 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001672 (0 = never).
1673 psmouse.resolution=
1674 [HW,MOUSE] Set desired mouse resolution, in dpi.
1675 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001676 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677 0 = disabled, 1 = enabled (default).
1678
1679 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001680 Format:
1681 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001682
1683 pt. [PARIDE]
1684 See Documentation/paride.txt.
1685
Kay Sieversdc8c8582007-08-15 12:25:38 +02001686 pty.legacy_count=
1687 [KNL] Number of legacy pty's. Overwrites compiled-in
1688 default number.
1689
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001690 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001691
Linus Torvalds1da177e2005-04-16 15:20:36 -07001692 r128= [HW,DRM]
1693
1694 raid= [HW,RAID]
1695 See Documentation/md.txt.
1696
Randy Dunlapa9913042005-10-23 12:57:11 -07001697 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001698 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001699
Linus Torvalds1da177e2005-04-16 15:20:36 -07001700 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701 See Documentation/ramdisk.txt.
1702
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001703 rcupdate.blimit= [KNL,BOOT]
1704 Set maximum number of finished RCU callbacks to process
1705 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001706
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001707 rcupdate.qhimark= [KNL,BOOT]
1708 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001709 RCU callbacks over which batch limiting is disabled.
1710
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001711 rcupdate.qlowmark= [KNL,BOOT]
1712 Set threshold of queued RCU callbacks below which
1713 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001714
Olof Johanssonffdfc402005-09-06 15:17:19 -07001715 rdinit= [KNL]
1716 Format: <full_path>
1717 Run specified binary instead of /init from the ramdisk,
1718 used for early userspace startup. See initrd.
1719
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001720 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001721 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001722 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001723
Paul Jackson46b6d942008-07-04 10:00:09 -07001724 relax_domain_level=
1725 [KNL, SMP] Set scheduler's default relax_domain_level.
1726 See Documentation/cpusets.txt.
1727
Linus Torvalds1da177e2005-04-16 15:20:36 -07001728 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1729
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001730 reservetop= [X86-32]
Zachary Amsden461a9aff2006-09-25 23:32:25 -07001731 Format: nn[KMG]
1732 Reserves a hole at the top of the kernel virtual
1733 address space.
1734
Vivek Goyal7e962872006-09-27 01:50:44 -07001735 reset_devices [KNL] Force drivers to reset the underlying device
1736 during initialization.
1737
Randy Dunlapa9913042005-10-23 12:57:11 -07001738 resume= [SWSUSP]
1739 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001741 resume_offset= [SWSUSP]
1742 Specify the offset from the beginning of the partition
1743 given by "resume=" at which the swap header is located,
1744 in <PAGE_SIZE> units (needed only for swap files).
1745 See Documentation/power/swsusp-and-swap-files.txt
1746
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001747 retain_initrd [RAM] Keep initrd memory after extraction
1748
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749 rhash_entries= [KNL,NET]
1750 Set number of hash buckets for route cache
1751
1752 riscom8= [HW,SERIAL]
1753 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1754
1755 ro [KNL] Mount root device read-only on boot
1756
1757 root= [KNL] Root filesystem
1758
1759 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1760 mount the root filesystem
1761
1762 rootflags= [KNL] Set root filesystem mount option string
1763
1764 rootfstype= [KNL] Set root filesystem type
1765
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001766 rootwait [KNL] Wait (indefinitely) for root device to show up.
1767 Useful for devices that are detected asynchronously
1768 (e.g. USB and MMC devices).
1769
James Morris20510f22007-10-16 23:31:32 -07001770 root_plug.vendor_id=
1771 [ROOTPLUG] Override the default vendor ID
1772
1773 root_plug.product_id=
1774 [ROOTPLUG] Override the default product ID
1775
1776 root_plug.debug=
1777 [ROOTPLUG] Enable debugging output
1778
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779 rw [KNL] Mount root device read-write on boot
1780
1781 S [KNL] Run init in single mode
1782
1783 sa1100ir [NET]
1784 See drivers/net/irda/sa1100_ir.c.
1785
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001787
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1789 Format: <io>[,<timeout>[,<isapnp>]]
1790
1791 scsi_debug_*= [SCSI]
1792 See drivers/scsi/scsi_debug.c.
1793
1794 scsi_default_dev_flags=
1795 [SCSI] SCSI default device flags
1796 Format: <integer>
1797
1798 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1799 Format: <vendor>:<model>:<flags>
1800 (flags are integer value)
1801
Randy Dunlap6af66322007-11-14 16:52:25 -08001802 scsi_logging_level= [SCSI] a bit mask of logging levels
1803 See drivers/scsi/scsi_logging.h for bits. Also
1804 settable via sysctl at dev.scsi.logging_level
1805 (/proc/sys/dev/scsi/logging_level).
1806 There is also a nice 'scsi_logging_level' script in the
1807 S390-tools package, available for download at
1808 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001810 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1811 discovered. async scans them in kernel threads,
1812 allowing boot to proceed. none ignores them, expecting
1813 user space to do the scan.
1814
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815 selinux [SELINUX] Disable or enable SELinux at boot time.
1816 Format: { "0" | "1" }
1817 See security/selinux/Kconfig help text.
1818 0 -- disable.
1819 1 -- enable.
1820 Default value is set via kernel config option.
1821 If enabled at boot time, /selinux/disable can be used
1822 later to disable prior to initial policy load.
1823
James Morris4e5ab4c2006-06-09 00:33:33 -07001824 selinux_compat_net =
1825 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001826 Format: { "0" | "1" }
1827 0 -- use new secmark-based packet controls
1828 1 -- use legacy packet controls
1829 Default value is 0 (preferred).
1830 Value can be changed at runtime via
1831 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001832
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001833 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835 shapers= [NET]
1836 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001837
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838 sim710= [SCSI,HW]
1839 See header of drivers/scsi/sim710.c.
1840
1841 simeth= [IA-64]
1842 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001843
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844 slram= [HW,MTD]
1845
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001846 slub_debug[=options[,slabs]] [MM, SLUB]
1847 Enabling slub_debug allows one to determine the
1848 culprit if slab objects become corrupted. Enabling
1849 slub_debug can create guard zones around objects and
1850 may poison objects when not in use. Also tracks the
1851 last alloc / free. For more information see
1852 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001853
1854 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001855 Determines the maximum allowed order for slabs.
1856 A high setting may cause OOMs due to memory
1857 fragmentation. For more information see
1858 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001859
1860 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001861 The minimum number of objects per slab. SLUB will
1862 increase the slab order up to slub_max_order to
1863 generate a sufficiently large slab able to contain
1864 the number of objects indicated. The higher the number
1865 of objects the smaller the overhead of tracking slabs
1866 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001867 For more information see Documentation/vm/slub.txt.
1868
1869 slub_min_order= [MM, SLUB]
1870 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001871 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001872 For more information see Documentation/vm/slub.txt.
1873
1874 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001875 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001876 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001877 allocs to different slabs. Debug options disable
1878 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001879 For more information see Documentation/vm/slub.txt.
1880
Linus Torvalds1da177e2005-04-16 15:20:36 -07001881 smart2= [HW]
1882 Format: <io1>[,<io2>[,...,<io8>]]
1883
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001884 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001885 attempt to substitute SMP alternatives once at boot.
1886
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001887 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1888 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1889 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1890 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1891 smsc-ircc2.ircc_irq= [HW] IRQ line
1892 smsc-ircc2.ircc_dma= [HW] DMA channel
1893 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1894 0: Toshiba Satellite 1800 (GP data pin select)
1895 1: Fast pin select (default)
1896 2: ATC IRMode
1897
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898 snd-ad1816a= [HW,ALSA]
1899
1900 snd-ad1848= [HW,ALSA]
1901
1902 snd-ali5451= [HW,ALSA]
1903
1904 snd-als100= [HW,ALSA]
1905
1906 snd-als4000= [HW,ALSA]
1907
1908 snd-azt2320= [HW,ALSA]
1909
1910 snd-cmi8330= [HW,ALSA]
1911
1912 snd-cmipci= [HW,ALSA]
1913
1914 snd-cs4231= [HW,ALSA]
1915
1916 snd-cs4232= [HW,ALSA]
1917
1918 snd-cs4236= [HW,ALSA]
1919
1920 snd-cs4281= [HW,ALSA]
1921
1922 snd-cs46xx= [HW,ALSA]
1923
1924 snd-dt019x= [HW,ALSA]
1925
1926 snd-dummy= [HW,ALSA]
1927
1928 snd-emu10k1= [HW,ALSA]
1929
1930 snd-ens1370= [HW,ALSA]
1931
1932 snd-ens1371= [HW,ALSA]
1933
1934 snd-es968= [HW,ALSA]
1935
1936 snd-es1688= [HW,ALSA]
1937
1938 snd-es18xx= [HW,ALSA]
1939
1940 snd-es1938= [HW,ALSA]
1941
1942 snd-es1968= [HW,ALSA]
1943
1944 snd-fm801= [HW,ALSA]
1945
1946 snd-gusclassic= [HW,ALSA]
1947
1948 snd-gusextreme= [HW,ALSA]
1949
1950 snd-gusmax= [HW,ALSA]
1951
1952 snd-hdsp= [HW,ALSA]
1953
1954 snd-ice1712= [HW,ALSA]
1955
1956 snd-intel8x0= [HW,ALSA]
1957
1958 snd-interwave= [HW,ALSA]
1959
1960 snd-interwave-stb=
1961 [HW,ALSA]
1962
1963 snd-korg1212= [HW,ALSA]
1964
1965 snd-maestro3= [HW,ALSA]
1966
1967 snd-mpu401= [HW,ALSA]
1968
1969 snd-mtpav= [HW,ALSA]
1970
1971 snd-nm256= [HW,ALSA]
1972
1973 snd-opl3sa2= [HW,ALSA]
1974
1975 snd-opti92x-ad1848=
1976 [HW,ALSA]
1977
1978 snd-opti92x-cs4231=
1979 [HW,ALSA]
1980
1981 snd-opti93x= [HW,ALSA]
1982
1983 snd-pmac= [HW,ALSA]
1984
1985 snd-rme32= [HW,ALSA]
1986
1987 snd-rme96= [HW,ALSA]
1988
1989 snd-rme9652= [HW,ALSA]
1990
1991 snd-sb8= [HW,ALSA]
1992
1993 snd-sb16= [HW,ALSA]
1994
1995 snd-sbawe= [HW,ALSA]
1996
1997 snd-serial= [HW,ALSA]
1998
1999 snd-sgalaxy= [HW,ALSA]
2000
2001 snd-sonicvibes= [HW,ALSA]
2002
2003 snd-sun-amd7930=
2004 [HW,ALSA]
2005
2006 snd-sun-cs4231= [HW,ALSA]
2007
2008 snd-trident= [HW,ALSA]
2009
2010 snd-usb-audio= [HW,ALSA,USB]
2011
2012 snd-via82xx= [HW,ALSA]
2013
2014 snd-virmidi= [HW,ALSA]
2015
2016 snd-wavefront= [HW,ALSA]
2017
2018 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002019
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2021 See Documentation/sonypi.txt
2022
2023 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2024 See Documentation/specialix.txt.
2025
2026 spia_io_base= [HW,MTD]
2027 spia_fio_base=
2028 spia_pedr=
2029 spia_peddr=
2030
2031 sscape= [HW,OSS]
2032 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002033
Linus Torvalds1da177e2005-04-16 15:20:36 -07002034 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2035 See Documentation/scsi/st.txt.
2036
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037 sti= [PARISC,HW]
2038 Format: <num>
2039 Set the STI (builtin display/keyboard on the HP-PARISC
2040 machines) console (graphic card) which should be used
2041 as the initial boot-console.
2042 See also comment in drivers/video/console/sticore.c.
2043
2044 sti_font= [HW]
2045 See comment in drivers/video/console/sticore.c.
2046
2047 stifb= [HW]
2048 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2049
Greg Banks42a7fc42007-03-06 01:42:23 -08002050 sunrpc.pool_mode=
2051 [NFS]
2052 Control how the NFS server code allocates CPUs to
2053 service thread pools. Depending on how many NICs
2054 you have and where their interrupts are bound, this
2055 option will affect which CPUs will do NFS serving.
2056 Note: this parameter cannot be changed while the
2057 NFS server is running.
2058
2059 auto the server chooses an appropriate mode
2060 automatically using heuristics
2061 global a single global pool contains all CPUs
2062 percpu one pool for each CPU
2063 pernode one pool for each NUMA node (equivalent
2064 to global on non-NUMA machines)
2065
Linus Torvalds1da177e2005-04-16 15:20:36 -07002066 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002067
Linus Torvalds1da177e2005-04-16 15:20:36 -07002068 switches= [HW,M68k]
2069
2070 sym53c416= [HW,SCSI]
2071 See header of drivers/scsi/sym53c416.c.
2072
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002073 sysrq_always_enabled
2074 [KNL]
2075 Ignore sysrq setting - this boot parameter will
2076 neutralize any effect of /proc/sys/kernel/sysrq.
2077 Useful for debugging.
2078
Linus Torvalds1da177e2005-04-16 15:20:36 -07002079 t128= [HW,SCSI]
2080 See header of drivers/scsi/t128.c.
2081
2082 tdfx= [HW,DRM]
2083
2084 thash_entries= [KNL,NET]
2085 Set number of hash buckets for TCP connection
2086
Len Brownf8707ec2007-08-12 00:12:54 -04002087 thermal.act= [HW,ACPI]
2088 -1: disable all active trip points in all thermal zones
2089 <degrees C>: override all lowest active trip points
2090
Len Brownc52a7412007-08-14 15:49:32 -04002091 thermal.crt= [HW,ACPI]
2092 -1: disable all critical trip points in all thermal zones
2093 <degrees C>: lower all critical trip points
2094
Len Brownf5487142007-08-12 00:12:44 -04002095 thermal.nocrt= [HW,ACPI]
2096 Set to disable actions on ACPI thermal zone
2097 critical and hot trip points.
2098
Len Brown72b33ef2007-08-12 00:12:17 -04002099 thermal.off= [HW,ACPI]
2100 1: disable ACPI thermal control
2101
Len Browna70cdc52007-08-12 00:12:35 -04002102 thermal.psv= [HW,ACPI]
2103 -1: disable all passive trip points
2104 <degrees C>: override all passive trip points to this value
2105
Len Brown730ff342007-08-12 00:12:26 -04002106 thermal.tzp= [HW,ACPI]
2107 Specify global default ACPI thermal zone polling rate
2108 <deci-seconds>: poll all this frequency
2109 0: no polling (default)
2110
Linus Torvalds1da177e2005-04-16 15:20:36 -07002111 tipar.timeout= [HW,PPT]
2112 Set communications timeout in tenths of a second
2113 (default 15).
2114
2115 tipar.delay= [HW,PPT]
2116 Set inter-bit delay in microseconds (default 10).
2117
Linus Torvalds1da177e2005-04-16 15:20:36 -07002118 tmscsim= [HW,SCSI]
2119 See comment before function dc390_setup() in
2120 drivers/scsi/tmscsim.c.
2121
2122 tp720= [HW,PS2]
2123
2124 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002125 Format:
2126 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2127
Randy Dunlapa9913042005-10-23 12:57:11 -07002128 turbografx.map[2|3]= [HW,JOY]
2129 TurboGraFX parallel port interface
2130 Format:
2131 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002132 See also Documentation/input/joystick-parport.txt
2133
2134 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2135 See header of drivers/scsi/u14-34f.c.
2136
2137 uart401= [HW,OSS]
2138 Format: <io>,<irq>
2139
2140 uart6850= [HW,OSS]
2141 Format: <io>,<irq>
2142
Alan Stern5f8364b2006-12-05 16:29:55 -05002143 uhci-hcd.ignore_oc=
2144 [USB] Ignore overcurrent events (default N).
2145 Some badly-designed motherboards generate lots of
2146 bogus events, for ports that aren't wired to
2147 anything. Set this parameter to avoid log spamming.
2148 Note that genuine overcurrent events won't be
2149 reported either.
2150
Alan Sternb5e795f2007-02-20 15:00:53 -05002151 usbcore.autosuspend=
2152 [USB] The autosuspend time delay (in seconds) used
2153 for newly-detected USB devices (default 2). This
2154 is the time required before an idle device will be
2155 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002156 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002157
Linus Torvalds1da177e2005-04-16 15:20:36 -07002158 usbhid.mousepoll=
2159 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002160
Paul Jackson200001e2008-06-25 05:44:46 -07002161 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2162 kernel's map of available physical RAM.
2163
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002164 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002165 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002166 vdso=1: enable VDSO (default)
2167 vdso=0: disable VDSO mapping
2168
Roland McGrathaf65d642008-01-30 13:30:43 +01002169 vdso32= [X86-32,X86-64]
2170 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2171 vdso32=1: enable 32-bit VDSO (default)
2172 vdso32=0: disable 32-bit VDSO mapping
2173
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002174 vector= [IA-64,SMP]
2175 vector=percpu: enable percpu vector domain
2176
Linus Torvalds1da177e2005-04-16 15:20:36 -07002177 video= [FB] Frame buffer configuration
2178 See Documentation/fb/modedb.txt.
2179
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002180 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002181 See Documentation/i386/boot.txt and
2182 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002183 Use vga=ask for menu.
2184 This is actually a boot loader parameter; the value is
2185 passed to the kernel using a special protocol.
2186
Randy Dunlapa9913042005-10-23 12:57:11 -07002187 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002188 size of <nn>. This can be used to increase the
2189 minimum size (128MB on x86). It can also be used to
2190 decrease the size and leave more room for directly
2191 mapped kernel RAM.
2192
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002193 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2194 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002195
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002196 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2197 Format: <command>
2198
2199 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2200 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002201
Linus Torvalds1da177e2005-04-16 15:20:36 -07002202 waveartist= [HW,OSS]
2203 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002204
Linus Torvalds1da177e2005-04-16 15:20:36 -07002205 wd33c93= [HW,SCSI]
2206 See header of drivers/scsi/wd33c93.c.
2207
2208 wd7000= [HW,SCSI]
2209 See header of drivers/scsi/wd7000.c.
2210
2211 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002212 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213
2214 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2215 xd_geo= See header of drivers/block/xd.c.
2216
2217 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002218 Format:
2219 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002220
Andi Kleena62eaf12006-02-16 23:41:58 +01002221 norandmaps Don't use address space randomization
2222 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2223
Randy Dunlapa9913042005-10-23 12:57:11 -07002224______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002225
2226TODO:
2227
2228 Add documentation for ALSA options.
2229 Add more DRM drivers.