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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.
David Brownell77437fd2008-07-23 21:28:33 -070090 SWSUSP Software suspend (hibernation) is enabled.
91 SUSPEND System suspend states are enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 TS Appropriate touchscreen support is enabled.
93 USB USB support is enabled.
94 USBHID USB Human Interface Device support is enabled.
95 V4L Video For Linux support is enabled.
96 VGA The VGA console has been enabled.
97 VT Virtual terminal support is enabled.
98 WDT Watchdog support is enabled.
99 XT IBM PC/XT MFM hard disk support is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700100 X86-32 X86-32, aka i386 architecture is enabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 X86-64 X86-64 architecture is enabled.
102 More X86-64 boot options can be found in
103 Documentation/x86_64/boot-options.txt .
104
105In addition, the following text indicates that the option:
106
107 BUGS= Relates to possible processor bugs on the said processor.
108 KNL Is a kernel start-up parameter.
109 BOOT Is a boot loader parameter.
110
111Parameters denoted with BOOT are actually interpreted by the boot
112loader, and have no meaning to the kernel directly.
113Do not modify the syntax of boot loader parameters without extreme
114need or coordination with <Documentation/i386/boot.txt>.
115
Karsten Weiss55588702007-02-13 13:26:21 +0100116There are also arch-specific kernel-parameters not documented here.
117See for example <Documentation/x86_64/boot-options.txt>.
118
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
120a trailing = on the name of any parameter states that that parameter will
121be entered as an environment variable, whereas its absence indicates that
122it will appear as a kernel argument readable via /proc/cmdline by programs
123running once the system is up.
124
jens m. noedler9c4751f2006-09-29 02:00:27 -0700125The number of kernel parameters is not limited, but the length of the
126complete command line (parameters including spaces etc.) is limited to
127a fixed number of characters. This limit depends on the architecture
128and is between 256 and 4096 characters. It is defined in the file
129./include/asm/setup.h as COMMAND_LINE_SIZE.
130
131
Bernhard Walle03d926f2007-03-06 02:29:44 -0800132 acpi= [HW,ACPI,X86-64,i386]
133 Advanced Configuration and Power Interface
Randy Dunlapa9913042005-10-23 12:57:11 -0700134 Format: { force | off | ht | strict | noirq }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 force -- enable ACPI if default was off
136 off -- disable ACPI if default was on
137 noirq -- do not use ACPI for IRQ routing
138 ht -- run only enough ACPI to enable Hyper Threading
Randy Dunlapa9913042005-10-23 12:57:11 -0700139 strict -- Be less tolerant of platforms that are not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 strictly ACPI specification compliant.
141
Randy Dunlap53471122008-03-12 18:10:51 -0400142 See also Documentation/power/pm.txt, pci=noacpi
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
Len Browna1fdcc02007-03-11 03:26:14 -0400144 acpi_apic_instance= [ACPI, IOAPIC]
145 Format: <int>
146 2: use 2nd APIC table, if available
147 1,0: use 1st APIC table
Len Brown4e381a42007-03-30 14:16:10 -0400148 default: 0
Len Browna1fdcc02007-03-11 03:26:14 -0400149
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 acpi_sleep= [HW,ACPI] Sleep options
Shaohua Libdfe6b72008-07-23 21:28:41 -0700151 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
Pavel Machek23b168d2008-02-05 19:27:12 +0100152 See Documentation/power/video.txt for s3_bios and s3_mode.
153 s3_beep is for debugging; it makes the PC's speaker beep
154 as soon as the kernel's real-mode entry point is called.
Shaohua Libdfe6b72008-07-23 21:28:41 -0700155 s4_nohwsig prevents ACPI hardware signature from being
156 used during resume from hibernation.
Rafael J. Wysockid8f3de02008-06-12 23:24:06 +0200157 old_ordering causes the ACPI 1.0 ordering of the _PTS
158 control method, wrt putting devices into low power
159 states, to be enforced (the ACPI 2.0 ordering of _PTS is
160 used by default).
Randy Dunlapa9913042005-10-23 12:57:11 -0700161
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Randy Dunlapa9913042005-10-23 12:57:11 -0700163 Format: { level | edge | high | low }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164
Randy Dunlapa9913042005-10-23 12:57:11 -0700165 acpi_irq_balance [HW,ACPI]
166 ACPI will balance active IRQs
167 default in APIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168
Randy Dunlapa9913042005-10-23 12:57:11 -0700169 acpi_irq_nobalance [HW,ACPI]
170 ACPI will not move active IRQs (default)
171 default in PIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172
Randy Dunlapa9913042005-10-23 12:57:11 -0700173 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
174 use by PCI
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 Format: <irq>,<irq>...
176
Randy Dunlapa9913042005-10-23 12:57:11 -0700177 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 Format: <irq>,<irq>...
179
Len Brown67effe82007-07-26 00:50:06 -0400180 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
181
Len Browna1f9e652006-01-25 23:47:36 -0500182 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
183 Format: To spoof as Windows 98: ="Microsoft Windows"
184
Len Brownae00d812007-05-29 18:43:33 -0400185 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
186 acpi_osi="string1" # add string1 -- only one string
187 acpi_osi="!string2" # remove built-in string2
188 acpi_osi= # disable all strings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
190 acpi_serialize [HW,ACPI] force serialization of AML methods
191
192 acpi_skip_timer_override [HW,ACPI]
193 Recognize and ignore IRQ0/pin2 Interrupt Override.
194 For broken nForce2 BIOS resulting in XT-PIC timer.
Andi Kleenfa18f472006-11-14 16:57:46 +0100195 acpi_use_timer_override [HW,ACPI}
196 Use timer override. For some broken Nvidia NF5 boards
197 that require a timer override, but don't have
198 HPET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199
Zhang Ruif9891062007-04-24 13:53:22 +0800200 acpi.debug_layer= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700202 Each bit of the <int> indicates an ACPI debug layer,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 1: enable, 0: disable. It is useful for boot time
204 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800205 via /sys/module/acpi/parameters/debug_layer.
206 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
207 Available bits (add the numbers together) to enable debug output
208 for specific parts of the ACPI subsystem:
209 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
210 0x10 namespace 0x20 parser 0x40 dispatcher
211 0x80 executer 0x100 resources 0x200 acpica debugger
212 0x400 os services 0x800 acpica disassembler.
213 The number can be in decimal or prefixed with 0x in hex.
214 Warning: Many of these options can produce a lot of
215 output and make your system unusable. Be very careful.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
Zhang Ruif9891062007-04-24 13:53:22 +0800217 acpi.debug_level= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 Format: <int>
Randy Dunlapa9913042005-10-23 12:57:11 -0700219 Each bit of the <int> indicates an ACPI debug level,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 1: enable, 0: disable. It is useful for boot time
221 debugging. After system has booted up, it can be set
Zhang Ruif9891062007-04-24 13:53:22 +0800222 via /sys/module/acpi/parameters/debug_level.
223 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
224 Available bits (add the numbers together) to enable different
225 debug output levels of the ACPI subsystem:
226 0x01 error 0x02 warn 0x04 init 0x08 debug object
227 0x10 info 0x20 init names 0x40 parse 0x80 load
228 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
229 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
230 0x10000 resources 0x20000 user requests 0x40000 package.
231 The number can be in decimal or prefixed with 0x in hex.
232 Warning: Many of these options can produce a lot of
233 output and make your system unusable. Be very careful.
234
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700235 acpi_pm_good [X86-32,X86-64]
john stultz5d0cf412006-06-26 00:25:12 -0700236 Override the pmtimer bug detection: force the kernel
237 to assume that this machine's pmtimer latches its value
238 and always returns good values.
239
Chuck Ebbertc99c1082007-07-27 10:46:20 +1000240 agp= [AGP]
241 { off | try_unsupported }
242 off: disable AGP support
243 try_unsupported: try to drive unsupported chipsets
244 (may crash computer or cause data corruption)
245
Chuck Ebbert66759a02005-09-12 18:49:25 +0200246 enable_timer_pin_1 [i386,x86-64]
247 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700248 Can be useful to work around chipset bugs
249 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200250 The kernel tries to set a reasonable default.
251
252 disable_timer_pin_1 [i386,x86-64]
253 Disable PIN 1 of APIC timer
254 Can be useful to work around chipset bugs.
255
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 ad1848= [HW,OSS]
257 Format: <io>,<irq>,<dma>,<dma2>,<type>
258
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 advansys= [HW,SCSI]
260 See header of drivers/scsi/advansys.c.
261
262 advwdt= [HW,WDT] Advantech WDT
263 Format: <iostart>,<iostop>
264
265 aedsp16= [HW,OSS] Audio Excel DSP 16
266 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
267 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700268
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 aha152x= [HW,SCSI]
270 See Documentation/scsi/aha152x.txt.
271
272 aha1542= [HW,SCSI]
273 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
274
275 aic7xxx= [HW,SCSI]
276 See Documentation/scsi/aic7xxx.txt.
277
278 aic79xx= [HW,SCSI]
279 See Documentation/scsi/aic79xx.txt.
280
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200281 amd_iommu= [HW,X86-84]
282 Pass parameters to the AMD IOMMU driver in the system.
283 Possible values are:
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200284 isolate - enable device isolation (each device, as far
285 as possible, will get its own protection
286 domain)
FUJITA Tomonoriafa9fdc2008-09-20 01:23:30 +0900287 fullflush - enable flushing of IO/TLB entries when
288 they are unmapped. Otherwise they are
289 flushed before they will be reused, which
290 is a lot of faster
291
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200292 amd_iommu_size= [HW,X86-64]
293 Define the size of the aperture for the AMD IOMMU
294 driver. Possible values are:
295 '32M', '64M' (default), '128M', '256M', '512M', '1G'
296
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 amijoy.map= [HW,JOY] Amiga joystick support
298 Map of devices attached to JOY0DAT and JOY1DAT
299 Format: <a>,<b>
300 See also Documentation/kernel/input/joystick.txt
301
302 analog.map= [HW,JOY] Analog joystick and gamepad support
303 Specifies type or capabilities of an analog joystick
304 connected to one of 16 gameports
305 Format: <type1>,<type2>,..<type16>
306
Randy Dunlapa9913042005-10-23 12:57:11 -0700307 apc= [HW,SPARC]
308 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 Format: noidle
310 Disable APC CPU standby support. SPARCstation-Fox does
311 not play well with APC CPU idle - disable it if you have
312 APC and your system crashes randomly.
313
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700314 apic= [APIC,i386] Advanced Programmable Interrupt Controller
315 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 Format: { quiet (default) | verbose | debug }
317 Change the amount of debugging information output
318 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700319
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700321 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
324 Format: <io>,<irq>,<nodeID>
325
326 ataflop= [HW,M68k]
327
328 atarimouse= [HW,MOUSE] Atari Mouse
329
330 atascsi= [HW,SCSI] Atari SCSI
331
332 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
333 EzKey and similar keyboards
334
335 atkbd.reset= [HW] Reset keyboard during initialization
336
Randy Dunlapa9913042005-10-23 12:57:11 -0700337 atkbd.set= [HW] Select keyboard code set
338 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339
340 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
341 keyboards
342
343 atkbd.softraw= [HW] Choose between synthetic and real raw mode
344 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700345
346 atkbd.softrepeat= [HW]
347 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348
349 autotest [IA64]
350
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 baycom_epp= [HW,AX25]
352 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700353
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
355 Format: <io>,<mode>
356 See header of drivers/net/hamradio/baycom_par.c.
357
Randy Dunlapa9913042005-10-23 12:57:11 -0700358 baycom_ser_fdx= [HW,AX25]
359 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 Format: <io>,<irq>,<mode>[,<baud>]
361 See header of drivers/net/hamradio/baycom_ser_fdx.c.
362
Randy Dunlapa9913042005-10-23 12:57:11 -0700363 baycom_ser_hdx= [HW,AX25]
364 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 Format: <io>,<irq>,<mode>
366 See header of drivers/net/hamradio/baycom_ser_hdx.c.
367
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700368 boot_delay= Milliseconds to delay each printk during boot.
369 Values larger than 10 seconds (10000) are changed to
370 no delay (0).
371 Format: integer
372
Andreas Herrmann35fc9082008-08-20 14:08:58 -0700373 bootmem_debug [KNL] Enable bootmem allocator debug messages.
374
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700376 bttv.radio= Most important insmod options are available as
377 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
379 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
380
381 BusLogic= [HW,SCSI]
382 See drivers/scsi/BusLogic.c, comment before function
383 BusLogic_ParseDriverOptions().
384
385 c101= [NET] Moxa C101 synchronous serial card
386
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700387 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 Sometimes CPU hardware bugs make them report the cache
389 size incorrectly. The kernel will attempt work arounds
390 to fix known problems, but for some CPUs it is not
391 possible to determine what the correct size should be.
392 This option provides an override for these situations.
393
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200394 security= [SECURITY] Choose a security module to enable at boot.
395 If this boot parameter is not specified, only the first
396 security module asking for security registration will be
397 loaded. An invalid security module name will be treated
398 as if no module has been chosen.
399
James Morris20510f22007-10-16 23:31:32 -0700400 capability.disable=
401 [SECURITY] Disable capabilities. This would normally
402 be used only if an alternative security model is to be
403 configured. Potentially dangerous and should only be
404 used if you are entirely sure of the consequences.
405
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100406 ccw_timeout_log [S390]
407 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408
Paul Menage8bab8dd2008-04-04 14:29:57 -0700409 cgroup_disable= [KNL] Disable a particular controller
410 Format: {name of the controller(s) to disable}
411 {Currently supported controllers - "memory"}
412
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 checkreqprot [SELINUX] Set initial checkreqprot flag value.
414 Format: { "0" | "1" }
415 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700416 0 -- check protection applied by kernel (includes
417 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 1 -- check protection requested by application.
419 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700420 Value can be changed at runtime via
421 /selinux/checkreqprot.
422
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100423 cio_ignore= [S390]
424 See Documentation/s390/CommonIO for details.
425
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700426 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700427 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200428 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700429 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200430 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 Format: { pit | tsc | cyclone | pmtmr }
432
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700433 clocksource= [GENERIC_TIME] Override the default clocksource
434 Format: <string>
435 Override the default clocksource and use the clocksource
436 with the name specified.
437 Some clocksource names to choose from, depending on
438 the platform:
439 [all] jiffies (this is the base, fallback clocksource)
440 [ACPI] acpi_pm
441 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
442 pxa_timer,timer3,32k_counter,timer0_1
443 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700444 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700445 scx200_hrt on Geode; cyclone on IBM x440
446 [MIPS] MIPS
447 [PARISC] cr16
448 [S390] tod
449 [SH] SuperH
450 [SPARC64] tick
451 [X86-64] hpet,tsc
452
Andi Kleenac72e782008-01-30 13:33:21 +0100453 clearcpuid=BITNUM [X86]
454 Disable CPUID feature X for the kernel. See
455 include/asm-x86/cpufeature.h for the valid bit numbers.
456 Note the Linux specific bits are not necessarily
457 stable over kernel options, but the vendor specific
458 ones should be.
459 Also note that user programs calling CPUID directly
460 or using the feature without checking anything
461 will still see it. This just prevents it from
462 being used by the kernel or shown in /proc/cpuinfo.
463 Also note the kernel might malfunction if you disable
464 some critical bits.
465
Arjan van de Vena25bd942008-01-30 13:33:08 +0100466 code_bytes [IA32/X86_64] How many bytes of object code to print
467 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100468 Range: 0 - 8192
469 Default: 64
470
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200471 hpet= [X86-32,HPET] option to control HPET usage
472 Format: { enable (default) | disable | force }
473 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100474 force: allow force enabled of undocumented chips (ICH4,
475 VIA, nVidia)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700478 Format:
479 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480
481 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
482 Format: <io>[,<irq>]
483
Randy Dunlapa9913042005-10-23 12:57:11 -0700484 com90xx= [HW,NET]
485 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 Format: <io>[,<irq>[,<memstart>]]
487
488 condev= [HW,S390] console device
489 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700490
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 console= [KNL] Output console device and options.
492
493 tty<n> Use the virtual console device <n>.
494
495 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800496 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800498 the form "bbbbpnf", where "bbbb" is the baud rate,
499 "p" is parity ("n", "o", or "e"), "n" is number of
500 bits, and "f" is flow control ("r" for RTS or
501 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800503 See Documentation/serial-console.txt for more
504 information. See
505 Documentation/networking/netconsole.txt for an
506 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700508 uart[8250],io,<addr>[,options]
509 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 Start an early, polled-mode console on the 8250/16550
511 UART at the specified I/O port or MMIO address,
512 switching to the matching ttyS device later. The
513 options are the same as for ttyS, above.
514
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700515 If the device connected to the port is not a TTY but a braille
516 device, prepend "brl," before the device type, for instance
517 console=brl,ttyS0
518 For now, only VisioBraille is supported.
519
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700520 earlycon= [KNL] Output early console device and options.
521 uart[8250],io,<addr>[,options]
522 uart[8250],mmio,<addr>[,options]
523 Start an early, polled-mode console on the 8250/16550
524 UART at the specified I/O port or MMIO address.
525 The options are the same as for ttyS, above.
526
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700527 no_console_suspend
528 [HW] Never suspend the console
529 Disable suspending of consoles during suspend and
530 hibernate operations. Once disabled, debugging
531 messages can reach various consoles while the rest
532 of the system is being put to sleep (ie, while
533 debugging driver suspend/resume hooks). This may
534 not work reliably with all consoles, but is known
535 to work with serial and VGA consoles.
536
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700538 Format:
539 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700541 crashkernel=nn[KMG]@ss[KMG]
542 [KNL] Reserve a chunk of physical memory to
543 hold a kernel to switch to with kexec on panic.
544
Bernhard Wallefb391592007-10-18 23:41:02 -0700545 crashkernel=range1:size1[,range2:size2,...][@offset]
546 [KNL] Same as above, but depends on the memory
547 in the running system. The syntax of range is
548 start-[end] where start and end are both
549 a memory unit (amount[KMG]). See also
550 Documentation/kdump/kdump.txt for a example.
551
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 cs4232= [HW,OSS]
553 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
554
555 cs89x0_dma= [HW,NET]
556 Format: <dma>
557
558 cs89x0_media= [HW,NET]
559 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700560
Randy Dunlapa9913042005-10-23 12:57:11 -0700561 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 See header of drivers/s390/block/dasd_devmap.c.
563
564 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
565 (one device per port)
566 Format: <port#>,<type>
567 See also Documentation/input/joystick-parport.txt
568
569 debug [KNL] Enable kernel debugging (events log level).
570
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700571 debug_locks_verbose=
572 [KNL] verbose self-tests
573 Format=<0|1>
574 Print debugging info while doing the locking API
575 self-tests.
576 We default to 0 (no extra messages), setting it to
577 1 will print _a lot_ more information - normally
578 only useful to kernel developers.
579
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700580 debug_objects [KNL] Enable object debugging
581
Thomas Gleixnerd3af01f2008-07-15 15:04:56 +0200582 debugpat [X86] Enable PAT debugging
583
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200584 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 Format: <area>[,<node>]
586 See also Documentation/networking/decnet.txt.
587
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000588 vt.default_blu= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700589 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
590 Change the default blue palette of the console.
591 This is a 16-member array composed of values
592 ranging from 0-255.
593
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000594 vt.default_grn= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700595 Format: <green0>,<green1>,<green2>,...,<green15>
596 Change the default green palette of the console.
597 This is a 16-member array composed of values
598 ranging from 0-255.
599
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000600 vt.default_red= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700601 Format: <red0>,<red1>,<red2>,...,<red15>
602 Change the default red palette of the console.
603 This is a 16-member array composed of values
604 ranging from 0-255.
605
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000606 vt.default_utf8=
607 [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700608 Format=<0|1>
609 Set system-wide default UTF-8 mode for all tty's.
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000610 Default is 1, i.e. UTF-8 mode is enabled for all
611 newly opened terminals.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700612
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 dhash_entries= [KNL]
614 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700615
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 digi= [HW,SERIAL]
617 IO parameters + enable/disable command.
618
619 digiepca= [HW,SERIAL]
620 See drivers/char/README.epca and
621 Documentation/digiepca.txt.
622
Yinghai Lu95ffa242008-04-29 03:52:33 -0700623 disable_mtrr_cleanup [X86]
624 enable_mtrr_cleanup [X86]
625 The kernel tries to adjust MTRR layout from continuous
626 to discrete, to make X server driver able to add WB
627 entry later. This parameter enables/disables that.
628
629 mtrr_chunk_size=nn[KMG] [X86]
630 used for mtrr cleanup. It is largest continous chunk
631 that could hold holes aka. UC entries.
632
633 mtrr_gran_size=nn[KMG] [X86]
Yinghai Lu12031a62008-05-02 02:40:22 -0700634 Used for mtrr cleanup. It is granularity of mtrr block.
635 Default is 1.
636 Large value could prevent small alignment from
637 using up MTRRs.
638
639 mtrr_spare_reg_nr=n [X86]
640 Format: <integer>
641 Range: 0,7 : spare reg number
642 Default : 1
643 Used for mtrr cleanup. It is spare mtrr entries number.
644 Set to 2 or more if your graphical card needs more.
Yinghai Lu95ffa242008-04-29 03:52:33 -0700645
Yinghai Lu093af8d2008-01-30 13:33:32 +0100646 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100647 By default the kernel will trim any uncacheable
648 memory out of your available memory pool based on
649 MTRR settings. This parameter disables that behavior,
650 possibly causing your machine to run very slowly.
651
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 dmasound= [HW,OSS] Sound subsystem buffers
653
654 dscc4.setup= [NET]
655
656 dtc3181e= [HW,SCSI]
657
Robin Getz0ae53642007-10-09 17:24:49 +0800658 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 earlyprintk=vga
660 earlyprintk=serial[,ttySn[,baudrate]]
Yinghai Lu5c059172008-07-24 17:29:40 -0700661 earlyprintk=dbgp
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662
Randy Dunlapa9913042005-10-23 12:57:11 -0700663 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 takes over.
665
Yinghai Lu5c059172008-07-24 17:29:40 -0700666 Only vga or serial or usb debug port at a time.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667
668 Currently only ttyS0 and ttyS1 are supported.
669
670 Interaction with the standard serial driver is not
671 very good.
672
673 The VGA output is eventually overwritten by the real
674 console.
675
676 eata= [HW,SCSI]
677
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700679 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 eisa_irq_edge= [PARISC,HW]
682 See header of drivers/parisc/eisa.c.
683
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700684 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700686 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687
688 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800689 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700690 See Documentation/block/as-iosched.txt and
691 Documentation/block/deadline-iosched.txt for details.
692
Simon Hormane515a0d2008-10-18 20:28:27 -0700693 elfcorehdr= [IA64,PPC,SH,X86-32,X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700694 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800695 image elf header. Generally kexec loader will
696 pass this option to capture kernel.
697 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698
699 enforcing [SELINUX] Set initial enforcing status.
700 Format: {"0" | "1"}
701 See security/selinux/Kconfig help text.
702 0 -- permissive (log only, no denials).
703 1 -- enforcing (deny and log).
704 Default value is 0.
705 Value can be changed at runtime via /selinux/enforce.
706
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 es1371= [HW,OSS]
708 Format: <spdif>,[<nomix>,[<amplifier>]]
709 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700710
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 ether= [HW,NET] Ethernet cards parameters
712 This option is obsoleted by the "netdev=" option, which
713 has equivalent usage. See its documentation for details.
714
715 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
716 Format: <io>[,<irq>]
717
Akinobu Mitade1ba092006-12-08 02:39:42 -0800718 failslab=
719 fail_page_alloc=
720 fail_make_request=[KNL]
721 General fault injection mechanism.
722 Format: <interval>,<probability>,<space>,<times>
723 See also /Documentation/fault-injection/.
724
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 fd_mcs= [HW,SCSI]
726 See header of drivers/scsi/fd_mcs.c.
727
728 fdomain= [HW,SCSI]
729 See header of drivers/scsi/fdomain.c.
730
731 floppy= [HW]
732 See Documentation/floppy.txt.
733
Alex Chiangf13ae302008-05-08 14:03:23 -0600734 force_pal_cache_flush
735 [IA-64] Avoid check_sal_cache_flush which may hang on
736 buggy SAL_CACHE_FLUSH implementations. Using this
737 parameter will force ia64_sal_cache_flush to call
738 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
739
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 gamecon.map[2|3]=
741 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
742 support via parallel port (up to 5 devices per port)
743 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
744 See also Documentation/input/joystick-parport.txt
745
746 gamma= [HW,DRM]
747
Yinghai Luaaf23042008-01-30 13:33:09 +0100748 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
749 Format: off | on
750 default: on
751
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752 gdth= [HW,SCSI]
753 See header of drivers/scsi/gdth.c.
754
755 gpt [EFI] Forces disk with valid GPT signature but
756 invalid Protective MBR to be treated as GPT.
757
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 gvp11= [HW,SCSI]
759
760 hashdist= [KNL,NUMA] Large hashes allocated during boot
761 are distributed across NUMA nodes. Defaults on
762 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700763 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764
765 hcl= [IA-64] SGI's Hardware Graph compatibility layer
766
767 hd= [EIDE] (E)IDE hard drive subsystem geometry
768 Format: <cyl>,<head>,<sect>
769
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
771 size of <nn>. This works even on boxes that have no
772 highmem otherwise. This also works to reduce highmem
773 size on bigger boxes.
774
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800775 highres= [KNL] Enable/disable high resolution timer mode.
776 Valid parameters: "on", "off"
777 Default: "on"
778
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 hisax= [HW,ISDN]
780 See Documentation/isdn/README.HiSax.
781
Andi Kleenb4718e62008-07-23 21:27:51 -0700782 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
783 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
Jon Tollefson0d9ea752008-07-23 21:27:56 -0700784 On x86-64 and powerpc, this option can be specified
785 multiple times interleaved with hugepages= to reserve
786 huge pages of different sizes. Valid pages sizes on
787 x86-64 are 2M (when the CPU supports "pse") and 1G
788 (when the CPU supports the "pdpe1gb" cpuinfo flag)
Andi Kleenb4718e62008-07-23 21:27:51 -0700789 Note that 1GB pages can only be allocated at boot time
790 using hugepages= and not freed afterwards.
Nick Piggine11bfbf2008-07-23 21:27:52 -0700791 default_hugepagesz=
792 [same as hugepagesz=] The size of the default
793 HugeTLB page size. This is the size represented by
794 the legacy /proc/ hugepages APIs, used for SHM, and
795 default size when mounting hugetlbfs filesystems.
796 Defaults to the default architecture's huge page size
797 if not specified.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798
Paul Mundt6902aa82008-09-21 17:14:42 +0900799 hlt [BUGS=ARM,SH]
800
Jiri Kosina36d95732008-10-06 02:51:09 -0400801 i8042.debug [HW] Toggle i8042 debug mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200803 i8042.dumbkbd [HW] Pretend that controller can only read data from
804 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 (Don't attempt to blink the leds)
806 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500807 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400808 i8042.noloop [HW] Disable the AUX Loopback command while probing
809 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 i8042.nomux [HW] Don't check presence of an active multiplexing
811 controller
812 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
813 controllers
814 i8042.panicblink=
815 [HW] Frequency with which keyboard LEDs should blink
816 when kernel panics (default is 0.5 sec)
817 i8042.reset [HW] Reset the controller during init and cleanup
818 i8042.unlock [HW] Unlock (ignore) the keylock
819
820 i810= [HW,DRM]
821
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700822 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
823 indicates that the driver is running on unsupported
824 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
826 does not match list of supported models.
827 i8k.power_status
828 [HW] Report power status in /proc/i8k
829 (disabled by default)
830 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
831 capability is set.
832
833 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
834 See Documentation/mca.txt.
835
836 icn= [HW,ISDN]
837 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
838
839 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200840 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100841 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100844 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845
Andi Kleenf039b752007-05-02 19:27:12 +0200846 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800847 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200848 Poll forces a polling idle loop that can slightly improves the performance
849 of waking up a idle CPU, but will use a lot of power and make the system
850 run hot. Not recommended.
851 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
852 to not use it because it doesn't save as much power as a normal idle
853 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
854 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800855 idle=halt. Halt is forced to be used for CPU idle.
856 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800857 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700858
Denis Cheng594765a2008-02-06 02:57:49 +0100859 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
860 Claim all unknown PCI IDE storage controllers.
861
Ingo Molnar792908222006-12-06 20:40:51 -0800862 ignore_loglevel [KNL]
863 Ignore loglevel setting - this will print /all/
864 kernel messages to the console. Useful for debugging.
865
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 ihash_entries= [KNL]
867 Set number of hash buckets for inode cache.
868
869 in2000= [HW,SCSI]
870 See header of drivers/scsi/in2000.c.
871
872 init= [KNL]
873 Format: <full_path>
874 Run specified binary instead of /sbin/init as init
875 process.
876
877 initcall_debug [KNL] Trace initcalls as they are executed. Useful
878 for working out where the kernel is dying during
879 startup.
880
881 initrd= [BOOT] Specify the location of the initial ramdisk
882
883 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
884 Format: <irq>
885
886 inttest= [IA64]
887
Pavel Machekb552da82008-03-19 15:58:11 +0100888 iommu= [x86]
889 off
890 force
891 noforce
892 biomerge
893 panic
894 nopanic
895 merge
896 nomerge
897 forcesac
898 soft
899
900
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700901 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
902 off
903 Disable intel iommu driver.
904 igfx_off [Default Off]
905 By default, gfx is mapped as normal device. If a gfx
906 device has a dedicated DMAR unit, the DMAR unit is
907 bypassed by not enabling DMAR with this option. In
908 this case, gfx device will use physical address for
909 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700910 forcedac [x86_64]
911 With this option iommu will not optimize to look
912 for io virtual address below 32 bit forcing dual
913 address cycle on pci bus for cards supporting greater
914 than 32 bit addressing. The default is to look
915 for translation below 32 bit and if not available
916 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800917 strict [Default Off]
918 With this option on every unmap_single operation will
919 result in a hardware IOTLB flush operation as opposed
920 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700921
Rene Hermanb02aae92008-01-30 13:30:05 +0100922 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100923 0x80
924 Standard port 0x80 based delay
925 0xed
926 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100927 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100928 Simple two microseconds delay
929 none
930 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100931
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 io7= [HW] IO7 for Marvel based alpha systems
933 See comment before marvel_specify_io7 in
934 arch/alpha/kernel/core_marvel.c.
935
936 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400937 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938
939 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700940 See comment before ip2_setup() in
941 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942
943 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
944 See header of drivers/scsi/ips.c.
945
Simon Horman72c4a132006-09-13 19:57:18 -0700946 ports= [IP_VS_FTP] IPVS ftp helper module
947 Default is 21.
948 Up to 8 (IP_VS_APP_MAX_PORTS) ports
949 may be specified.
950 Format: <port>,<port>....
951
Alan Cox200803d2005-06-28 20:45:18 -0700952 irqfixup [HW]
953 When an interrupt is not handled search all handlers
954 for it. Intended to get systems with badly broken
955 firmware running.
956
957 irqpoll [HW]
958 When an interrupt is not handled search all handlers
959 for it. Also check all handlers each timer
960 interrupt. Intended to get systems with badly broken
961 firmware running.
962
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700964 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965
966 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800967 Format:
968 <cpu number>,...,<cpu number>
969 or
970 <cpu number>-<cpu number> (must be a positive range in ascending order)
971 or a mixture
972 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973 This option can be used to specify one or more CPUs
974 to isolate from the general SMP balancing and scheduling
975 algorithms. The only way to move a process onto or off
976 an "isolated" CPU is via the CPU affinity syscalls.
977 <cpu number> begins at 0 and the maximum value is
978 "number of CPUs in system - 1".
979
980 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700981 alternative -- manually setting the CPU mask of all
982 tasks in the system -- can cause problems and
983 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984
Randy Dunlapa9913042005-10-23 12:57:11 -0700985 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986
987 js= [HW,JOY] Analog joystick
988 See Documentation/input/joystick.txt.
989
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700990 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700991 specifies the amount of memory usable by the kernel
992 for non-movable allocations. The requested amount is
993 spread evenly throughout all nodes in the system. The
994 remaining memory in each node is used for Movable
995 pages. In the event, a node is too small to have both
996 kernelcore and Movable pages, kernelcore pages will
997 take priority and other nodes will have a larger number
998 of kernelcore pages. The Movable zone is used for the
999 allocation of pages that may be reclaimed or moved
1000 by the page migration subsystem. This means that
1001 HugeTLB pages may not be allocated from this zone.
1002 Note that allocations like PTEs-from-HighMem still
1003 use the HighMem zone if it exists, and the Normal
1004 zone if it does not.
1005
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001006 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -07001007 is similar to kernelcore except it specifies the
1008 amount of memory used for migratable allocations.
1009 If both kernelcore and movablecore is specified,
1010 then kernelcore will be at *least* the specified
1011 value but may be more. If movablecore on its own
1012 is specified, the administrator must be careful
1013 that the amount of memory usable for all allocations
1014 is not too small.
1015
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 keepinitrd [HW,ARM]
1017
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001018 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019 in oops dumps.
1020
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001021 kgdboc= [HW] kgdb over consoles.
1022 Requires a tty driver that supports console polling.
1023 (only serial suported for now)
1024 Format: <serial_device>[,baud]
1025
Florian Fainelli9bed90c62008-08-23 18:54:37 +02001026 kmac= [MIPS] korina ethernet MAC address.
1027 Configure the RouterBoard 532 series on-chip
1028 Ethernet adapter MAC address.
1029
Linus Torvalds1da177e2005-04-16 15:20:36 -07001030 l2cr= [PPC]
1031
Robert Brosea78bfbf2008-03-29 07:20:23 +11001032 l3cr= [PPC]
1033
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001034 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001035 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001037 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001038 C2 power state.
1039
FD Camifcb71f62008-01-06 19:08:56 +01001040 libata.dma= [LIBATA] DMA control
1041 libata.dma=0 Disable all PATA and SATA DMA
1042 libata.dma=1 PATA and SATA Disk DMA only
1043 libata.dma=2 ATAPI (CDROM) DMA only
1044 libata.dma=4 Compact Flash DMA only
1045 Combinations also work, so libata.dma=3 enables DMA
1046 for disks and CDROMs, but not CFs.
1047
Dave Jones78e70c22007-09-27 11:50:13 -04001048 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1049 when set.
1050 Format: <int>
1051
Tejun Heo33267322008-02-13 09:15:09 +09001052 libata.force= [LIBATA] Force configurations. The format is comma
1053 separated list of "[ID:]VAL" where ID is
1054 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1055 matching port, link or device. Basically, it matches
1056 the ATA ID string printed on console by libata. If
1057 the whole ID part is omitted, the last PORT and DEVICE
1058 values are used. If ID hasn't been specified yet, the
1059 configuration applies to all ports, links and devices.
1060
1061 If only DEVICE is omitted, the parameter applies to
1062 the port and all links and devices behind it. DEVICE
1063 number of 0 either selects the first device or the
1064 first fan-out link behind PMP device. It does not
1065 select the host link. DEVICE number of 15 selects the
1066 host link and device attached to it.
1067
1068 The VAL specifies the configuration to force. As long
1069 as there's no ambiguity shortcut notation is allowed.
1070 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1071 The following configurations can be forced.
1072
1073 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1074 Any ID with matching PORT is used.
1075
1076 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1077
1078 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1079 udma[/][16,25,33,44,66,100,133] notation is also
1080 allowed.
1081
1082 * [no]ncq: Turn on or off NCQ.
1083
Tejun Heo05944bd2008-08-13 20:19:09 +09001084 * nohrst, nosrst, norst: suppress hard, soft
1085 and both resets.
1086
Tejun Heo33267322008-02-13 09:15:09 +09001087 If there are multiple matching configurations changing
1088 the same attribute, the last one is used.
1089
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 load_ramdisk= [RAM] List of ramdisks to load from floppy
1091 See Documentation/ramdisk.txt.
1092
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001093 lockd.nlm_grace_period=P [NFS] Assign grace period.
1094 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001096 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1097 Format: <integer>
1098
1099 lockd.nlm_timeout=T [NFS] Assign timeout value.
1100 Format: <integer>
1101
1102 lockd.nlm_udpport=M [NFS] Assign UDP port.
1103 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001104
1105 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1106 Format: <irq>
1107
1108 loglevel= All Kernel Messages with a loglevel smaller than the
1109 console loglevel will be printed to the console. It can
1110 also be changed with klogd or other programs. The
1111 loglevels are defined as follows:
1112
1113 0 (KERN_EMERG) system is unusable
1114 1 (KERN_ALERT) action must be taken immediately
1115 2 (KERN_CRIT) critical conditions
1116 3 (KERN_ERR) error conditions
1117 4 (KERN_WARNING) warning conditions
1118 5 (KERN_NOTICE) normal but significant condition
1119 6 (KERN_INFO) informational
1120 7 (KERN_DEBUG) debug-level messages
1121
1122 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001123 Format: { n | nk | nM }
1124 n must be a power of two. The default size
1125 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001126
Randy Dunlapaccaa242007-10-16 01:29:37 -07001127 logo.nologo [FB] Disables display of the built-in Linux logo.
1128 This may be used to provide more screen space for
1129 kernel log messages and is useful when debugging
1130 kernel boot problems.
1131
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132 lp=0 [LP] Specify parallel ports to use, e.g,
1133 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1134 lp=reset first parallel port). 'lp=0' disables the
1135 lp=auto printer driver. 'lp=reset' (which can be
1136 specified in addition to the ports) causes
1137 attached printers to be reset. Using
1138 lp=port1,port2,... specifies the parallel ports
1139 to associate lp devices with, starting with
1140 lp0. A port specification may be 'none' to skip
1141 that lp device, or a parport name such as
1142 'parport0'. Specifying 'lp=auto' instead of a
1143 port specification list means that device IDs
1144 from each port should be examined, to see if
1145 an IEEE 1284-compliant printer is attached; if
1146 so, the driver will manage that printer.
1147 See also header of drivers/char/lp.c.
1148
1149 lpj=n [KNL]
1150 Sets loops_per_jiffy to given constant, thus avoiding
1151 time-consuming boot-time autodetection (up to 250 ms per
1152 CPU). 0 enables autodetection (default). To determine
1153 the correct value for your kernel, boot with normal
1154 autodetection and see what value is printed. Note that
1155 on SMP systems the preset will be applied to all CPUs,
1156 which is likely to cause problems if your CPUs need
1157 significantly divergent settings. An incorrect value
1158 will cause delays in the kernel to be wrong, leading to
1159 unpredictable I/O errors and other breakage. Although
1160 unlikely, in the extreme case this might damage your
1161 hardware.
1162
1163 ltpc= [NET]
1164 Format: <io>,<irq>,<dma>
1165
Randy Dunlapa9913042005-10-23 12:57:11 -07001166 mac5380= [HW,SCSI] Format:
1167 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168
Randy Dunlapa9913042005-10-23 12:57:11 -07001169 machvec= [IA64] Force the use of a particular machine-vector
1170 (machvec) in a generic kernel.
1171 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172
Randy Dunlapa9913042005-10-23 12:57:11 -07001173 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 be mounted
1175 Format: <1-256>
1176
1177 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001178 should make use of. maxcpus=n : n >= 0 limits the
1179 kernel to using 'n' processors. n=0 is a special case,
1180 it is equivalent to "nosmp", which also disables
1181 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182
Bob Picco2b2c3752005-06-29 18:00:00 -07001183 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1184 equal to this physical address is ignored.
1185
Randy Dunlapa9913042005-10-23 12:57:11 -07001186 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 Should be between 1 and 2^32-1.
1188
1189 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001190 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 Should be between 1 and 16384.
1192
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193 mcatest= [IA-64]
1194
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001195 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196
Andi Kleen909dd322007-10-17 18:04:38 +02001197 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1198
Linus Torvalds1da177e2005-04-16 15:20:36 -07001199 md= [HW] RAID subsystems devices and level
1200 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001201
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 mdacon= [MDA]
1203 Format: <first>,<last>
1204 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001205
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1207 Amount of memory to be used when the kernel is not able
1208 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001209 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210 address space collisions. Without memmap= PCI devices
1211 could be placed at addresses belonging to unused RAM.
1212
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001213 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214 memory.
1215
Paul Mundt6902aa82008-09-21 17:14:42 +09001216 memchunk=nn[KMG]
1217 [KNL,SH] Allow user to override the default size for
1218 per-device physically contiguous DMA buffers.
1219
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001220 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 E820 memory map, as specified by the user.
1222 Such memmap=exactmap lines can be constructed based on
1223 BIOS output or other requirements. See the memmap=nn@ss
1224 option description.
1225
1226 memmap=nn[KMG]@ss[KMG]
1227 [KNL] Force usage of a specific region of memory
1228 Region of memory to be used, from ss to ss+nn.
1229
1230 memmap=nn[KMG]#ss[KMG]
1231 [KNL,ACPI] Mark specific memory as ACPI data.
1232 Region of memory to be used, from ss to ss+nn.
1233
1234 memmap=nn[KMG]$ss[KMG]
1235 [KNL,ACPI] Mark specific memory as reserved.
1236 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001237 Example: Exclude memory from 0x18690000-0x1869ffff
1238 memmap=64K$0x18690000
1239 or
1240 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241
Jeremy Fitzhardinge9f077872008-09-07 01:51:34 -07001242 memory_corruption_check=0/1 [X86]
1243 Some BIOSes seem to corrupt the first 64k of
1244 memory when doing things like suspend/resume.
1245 Setting this option will scan the memory
1246 looking for corruption. Enabling this will
1247 both detect corruption and prevent the kernel
1248 from using the memory being corrupted.
1249 However, its intended as a diagnostic tool; if
1250 repeatable BIOS-originated corruption always
1251 affects the same memory, you can use memmap=
1252 to prevent the kernel from using that memory.
1253
1254 memory_corruption_check_size=size [X86]
1255 By default it checks for corruption in the low
1256 64k, making this memory unavailable for normal
1257 use. Use this parameter to scan for
1258 corruption in more or less memory.
1259
1260 memory_corruption_check_period=seconds [X86]
1261 By default it checks for corruption every 60
1262 seconds. Use this parameter to check at some
1263 other rate. 0 disables periodic checking.
1264
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001265 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001266 Format: <integer>
1267 range: 0,4 : pattern number
1268 default : 0 <disable>
1269
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 meye.*= [HW] Set MotionEye Camera parameters
1271 See Documentation/video4linux/meye.txt.
1272
Andres Salomon8f368812007-10-12 23:04:06 +02001273 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1274 Multi-Function General Purpose Timers on AMD Geode
1275 platforms.
1276
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001277 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1278 the BIOS has incorrectly applied a workaround. TinyBIOS
1279 version 0.98 is known to be affected, 0.99 fixes the
1280 problem by letting the user disable the workaround.
1281
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 mga= [HW,DRM]
1283
Mel Gorman6b74ab92008-07-23 21:26:49 -07001284 mminit_loglevel=
1285 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1286 parameter allows control of the logging verbosity for
1287 the additional memory initialisation checks. A value
1288 of 0 disables mminit logging and a level of 4 will
1289 log everything. Information is printed at KERN_DEBUG
1290 so loglevel=8 may also need to be specified.
1291
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 mousedev.tap_time=
1293 [MOUSE] Maximum time between finger touching and
1294 leaving touchpad surface for touch to be considered
1295 a tap and be reported as a left button click (for
1296 touchpads working in absolute mode only).
1297 Format: <msecs>
1298 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1299 reporting absolute coordinates, such as tablets
1300 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1301 reporting absolute coordinates, such as tablets
1302
1303 mpu401= [HW,OSS]
1304 Format: <io>,<irq>
1305
1306 MTD_Partition= [MTD]
1307 Format: <name>,<region-number>,<size>,<offset>
1308
Randy Dunlapa9913042005-10-23 12:57:11 -07001309 MTD_Region= [MTD] Format:
1310 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311
1312 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001313 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314
Ben Dooks9db829f2008-07-03 11:24:29 +01001315 mtdset= [ARM]
1316 ARM/S3C2412 JIVE boot control
1317
1318 See arch/arm/mach-s3c2412/mach-jive.c
1319
Linus Torvalds1da177e2005-04-16 15:20:36 -07001320 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001321 [HW] Make the MicroTouch USB driver use raw coordinates
1322 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001323
1324 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1325
1326 NCR_D700= [HW,SCSI]
1327 See header of drivers/scsi/NCR_D700.c.
1328
1329 ncr5380= [HW,SCSI]
1330
1331 ncr53c400= [HW,SCSI]
1332
1333 ncr53c400a= [HW,SCSI]
1334
1335 ncr53c406a= [HW,SCSI]
1336
1337 ncr53c8xx= [HW,SCSI]
1338
1339 netdev= [NET] Network devices parameters
1340 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1341 Note that mem_start is often overloaded to mean
1342 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001343 This usage is only documented in each driver source
1344 file if at all.
1345
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001346 nf_conntrack.acct=
1347 [NETFILTER] Enable connection tracking flow accounting
1348 0 to disable accounting
1349 1 to enable accounting
1350 Default value depends on CONFIG_NF_CT_ACCT that is
1351 going to be removed in 2.6.29.
1352
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001354 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355
1356 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001357 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358
Trond Myklebusta72b4422006-01-03 09:55:41 +01001359 nfs.callback_tcpport=
1360 [NFS] set the TCP port on which the NFSv4 callback
1361 channel should listen.
1362
Trond Myklebust58df0952006-01-03 09:55:57 +01001363 nfs.idmap_cache_timeout=
1364 [NFS] set the maximum lifetime for idmapper cache
1365 entries.
1366
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001367 nfs.enable_ino64=
1368 [NFS] enable 64-bit inode numbers.
1369 If zero, the NFS client will fake up a 32-bit inode
1370 number for the readdir() and stat() syscalls instead
1371 of returning the full 64-bit number.
1372 The default is to return 64-bit inode numbers.
1373
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001374 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1375 when a NMI is triggered.
1376 Format: [state][,regs][,debounce][,die]
1377
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001378 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001380 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381 emulation library even if a 387 maths coprocessor
1382 is present.
1383
Christoph Lameterc1aee212007-05-31 00:40:47 -07001384 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1385 caches in the slab allocator. Saves per-node memory,
1386 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001387
Randy Dunlapa9913042005-10-23 12:57:11 -07001388 noalign [KNL,ARM]
1389
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390 noapic [SMP,APIC] Tells the kernel to not make use of any
1391 IOAPICs that may be present in the system.
1392
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393 nobats [PPC] Do not use BATs for mapping kernel lowmem
1394 on "Classic" PPC cores.
1395
1396 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001397
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001398 nodelayacct [KNL] Disable per-task delay accounting
1399
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1401
Paul Mundt6902aa82008-09-21 17:14:42 +09001402 nodsp [SH] Disable hardware DSP at boot time.
1403
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001404 noefi [X86-32,X86-64] Disable EFI runtime services support.
1405
Linus Torvalds1da177e2005-04-16 15:20:36 -07001406 noexec [IA-64]
1407
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001408 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001409 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001411 noexec=off: disable non-executable mappings
1412
1413 noexec32 [X86-64]
1414 This affects only 32-bit executables.
1415 noexec32=on: enable non-executable mappings (default)
1416 read doesn't imply executable mappings
1417 noexec32=off: disable non-executable mappings
1418 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419
Paul Mundt6902aa82008-09-21 17:14:42 +09001420 nofpu [SH] Disable hardware FPU at boot time.
1421
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001422 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001423 register save and restore. The kernel will only save
1424 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001425
Andi Kleen191679f2008-01-30 13:33:21 +01001426 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1427
Paul Mundt6902aa82008-09-21 17:14:42 +09001428 nohlt [BUGS=ARM,SH]
Randy Dunlapa9913042005-10-23 12:57:11 -07001429
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001430 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 instruction doesn't work correctly and not to
1432 use it.
1433
1434 nohalt [IA-64] Tells the kernel not to use the power saving
1435 function PAL_HALT_LIGHT when idle. This increases
1436 power-consumption. On the positive side, it reduces
1437 interrupt wake-up latency, which may improve performance
1438 in certain environments such as networked servers or
1439 real-time systems.
1440
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001441 nohz= [KNL] Boottime enable/disable dynamic ticks
1442 Valid arguments: on, off
1443 Default: on
1444
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001445 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001446
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001447 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001448 disable unhandled interrupt sources.
1449
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001450 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001451 broken timer IRQ sources.
1452
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453 noisapnp [ISAPNP] Disables ISA PnP code.
1454
1455 noinitrd [RAM] Tells the kernel not to load any configured
1456 initial RAM disk.
1457
1458 nointroute [IA-64]
1459
Tony Luck0aa366f2007-07-20 11:22:30 -07001460 nojitter [IA64] Disables jitter checking for ITC timers.
1461
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001462 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001463
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001464 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001465
Suresh Siddha6e1cb382008-07-10 11:16:58 -07001466 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1467
Suresh Siddhaaf9d1382008-07-11 13:11:57 -07001468 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1469 default x2apic cluster mode on platforms
1470 supporting x2apic.
1471
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 noltlbs [PPC] Do not use large page/tlb entries for kernel
1473 lowmem mapping on PPC40x.
1474
Horms312f1f02006-02-22 09:57:55 +09001475 nomca [IA-64] Disable machine check abort handling
1476
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001477 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001478
Andres Salomon83d73842007-10-12 23:04:06 +02001479 nomfgpt [X86-32] Disable Multi-Function General Purpose
1480 Timer usage (for AMD Geode machines).
1481
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001482 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001483
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001484 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001485 with UP alternatives
1486
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 noresidual [PPC] Don't use residual data on PReP machines.
1488
Randy Dunlapa9913042005-10-23 12:57:11 -07001489 noresume [SWSUSP] Disables resume and restores original swap
1490 space.
1491
Linus Torvalds1da177e2005-04-16 15:20:36 -07001492 no-scroll [VGA] Disables scrollback.
1493 This is required for the Braillex ib80-piezo Braille
1494 reader made by F.H. Papenmeier (Germany).
1495
1496 nosbagart [IA-64]
1497
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001498 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001499
Len Brown61ec7562007-08-16 03:34:22 -04001500 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1501 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502
Dave Jones97842212007-07-15 23:41:05 -07001503 nosoftlockup [KNL] Disable the soft-lockup detector.
1504
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505 nosync [HW,M68K] Disables sync negotiation for all devices.
1506
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001507 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508
1509 nousb [USB] Disable the USB subsystem
1510
1511 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001512
Fenghua Yua6c75b862008-03-14 13:57:08 -07001513 nptcg= [IA64] Override max number of concurrent global TLB
1514 purges which is reported from either PAL_VM_SUMMARY or
1515 SAL PALO.
1516
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001517 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1518 one of ['zone', 'node', 'default'] can be specified
1519 This can be set from sysctl after boot.
1520 See Documentation/sysctl/vm.txt for details.
1521
Dave Jonesa61c2d72006-01-07 23:18:19 +00001522 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1523
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001524 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1525 Rather than timing out after 20 ms if an EC
1526 command is not properly ACKed, override the length
1527 of the timeout. We have interrupts disabled while
1528 waiting for the ACK, so if this is set too high
1529 interrupts *may* be lost!
1530
Linus Torvalds1da177e2005-04-16 15:20:36 -07001531 opl3= [HW,OSS]
1532 Format: <io>
1533
Linus Torvalds1da177e2005-04-16 15:20:36 -07001534 oprofile.timer= [HW]
1535 Use timer interrupt instead of performance counters
1536
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537 osst= [HW,SCSI] SCSI Tape Driver
1538 Format: <buffer_size>,<write_threshold>
1539 See also Documentation/scsi/st.txt.
1540
1541 panic= [KNL] Kernel behaviour on panic
1542 Format: <timeout>
1543
1544 parkbd.port= [HW] Parallel port number the keyboard adapter is
1545 connected to, default is 0.
1546 Format: <parport#>
1547 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1548 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001549 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001550
Randy Dunlapa9913042005-10-23 12:57:11 -07001551 parport= [HW,PPT] Specify parallel ports. 0 disables.
1552 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1553 Use 'auto' to force the driver to use any
1554 IRQ/DMA settings detected (the default is to
1555 ignore detected IRQ/DMA settings because of
1556 possible conflicts). You can specify the base
1557 address, IRQ, and DMA settings; IRQ and DMA
1558 should be numbers, or 'auto' (for using detected
1559 settings on that particular port), or 'nofifo'
1560 (to avoid using a FIFO even if it is detected).
1561 Parallel ports are assigned in the order they
1562 are specified on the command line, starting
1563 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001564
Randy Dunlapa9913042005-10-23 12:57:11 -07001565 parport_init_mode= [HW,PPT]
1566 Configure VIA parallel port to operate in
1567 a specific mode. This is necessary on Pegasos
1568 computer where firmware has no options for setting
1569 up parallel port mode and sets it to spp.
1570 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571 Format: [spp|ps2|epp|ecp|ecpepp]
1572
Randy Dunlapa9913042005-10-23 12:57:11 -07001573 pas2= [HW,OSS] Format:
1574 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1575
Linus Torvalds1da177e2005-04-16 15:20:36 -07001576 pas16= [HW,SCSI]
1577 See header of drivers/scsi/pas16.c.
1578
Andrew Mortondd287792006-03-23 03:00:57 -08001579 pause_on_oops=
1580 Halt all CPUs after the first oops has been printed for
1581 the specified number of seconds. This is to be used if
1582 your oopses keep scrolling off the screen.
1583
Linus Torvalds1da177e2005-04-16 15:20:36 -07001584 pcbit= [HW,ISDN]
1585
1586 pcd. [PARIDE]
1587 See header of drivers/block/paride/pcd.c.
1588 See also Documentation/paride.txt.
1589
Randy Dunlapa9913042005-10-23 12:57:11 -07001590 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001591 off [X86-32] don't probe for the PCI bus
1592 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001593 the hardware directly. Use this if your machine
1594 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001595 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001596 hardware access methods are allowed. Use this
1597 if you experience crashes upon bootup and you
1598 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001599 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001600 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001601 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001602 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001603 noaer [PCIE] If the PCIEAER kernel config parameter is
1604 enabled, this kernel boot option can be used to
1605 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001606 nodomains [PCI] Disable support for multiple PCI
1607 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001608 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001609 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001610 nomsi [MSI] If the PCI_MSI kernel config parameter is
1611 enabled, this kernel boot option can be used to
1612 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001613 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001614 routing table. These calls are known to be buggy
1615 on several machines and they hang the machine
1616 when used, but on other computers it's the only
1617 way to get the interrupt routing table. Try
1618 this option if the kernel is unable to allocate
1619 IRQs or discover secondary PCI buses on your
1620 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001621 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001622 Use with caution as certain devices share
1623 address decoders between ROMs and other
1624 resources.
Gary Hadebb71ad82008-05-12 13:57:46 -07001625 norom [X86-32,X86_64] Do not assign address space to
1626 expansion ROMs that do not already have
1627 BIOS assigned address ranges.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001628 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001629 assigned automatically to PCI devices. You can
1630 make the kernel exclude IRQs of your ISA cards
1631 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001632 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001633 of the PIRQ table (normally generated
1634 by the BIOS) if it is outside the
1635 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001636 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001637 useful if the kernel is unable to find your
1638 secondary buses and you want to tell it
1639 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001640 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001641 numbers ourselves, overriding
1642 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001643 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001644 in the BIOS $PIR table. This is needed on
1645 some systems with broken BIOSes, notably
1646 some HP Pavilion N5400 and Omnibook XE3
1647 notebooks. This will have no effect if ACPI
1648 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001649 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001650 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001651 use_crs [X86-32] Use _CRS for PCI resource
1652 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001653 routeirq Do IRQ routing for all PCI devices.
1654 This is normally done in pci_enable_device(),
1655 so this option is a temporary workaround
1656 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001657 skip_isa_align [X86] do not align io start addr, so can
1658 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001659 firmware [ARM] Do not re-enumerate the bus but instead
1660 just use the configuration from the
1661 bootloader. This is currently used on
1662 IXP2000 systems where the bus has to be
1663 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001664 noearly [X86] Don't do any early type 1 scanning.
1665 This might help on some broken boards which
1666 machine check when some devices' config space
1667 is read. But various workarounds are disabled
1668 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001669 bfsort Sort PCI devices into breadth-first order.
1670 This sorting is done to get a device
1671 order compatible with older (<= 2.4) kernels.
1672 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001673 cbiosize=nn[KMG] The fixed amount of bus space which is
1674 reserved for the CardBus bridge's IO window.
1675 The default value is 256 bytes.
1676 cbmemsize=nn[KMG] The fixed amount of bus space which is
1677 reserved for the CardBus bridge's memory
1678 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001679
Linus Torvalds1da177e2005-04-16 15:20:36 -07001680 pcmv= [HW,PCMCIA] BadgePAD 4
1681
1682 pd. [PARIDE]
1683 See Documentation/paride.txt.
1684
1685 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1686 boot time.
1687 Format: { 0 | 1 }
1688 See arch/parisc/kernel/pdc_chassis.c
1689
1690 pf. [PARIDE]
1691 See Documentation/paride.txt.
1692
1693 pg. [PARIDE]
1694 See Documentation/paride.txt.
1695
1696 pirq= [SMP,APIC] Manual mp-table setup
1697 See Documentation/i386/IO-APIC.txt.
1698
1699 plip= [PPT,NET] Parallel port network link
1700 Format: { parport<nr> | timid | 0 }
1701 See also Documentation/parport.txt.
1702
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001703 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1704 Override pmtimer IOPort with a hex value.
1705 e.g. pmtmr=0x508
1706
Linus Torvalds1da177e2005-04-16 15:20:36 -07001707 pnpacpi= [ACPI]
1708 { off }
1709
1710 pnpbios= [ISAPNP]
1711 { on | off | curr | res | no-curr | no-res }
1712
1713 pnp_reserve_irq=
1714 [ISAPNP] Exclude IRQs for the autoconfiguration
1715
1716 pnp_reserve_dma=
1717 [ISAPNP] Exclude DMAs for the autoconfiguration
1718
1719 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001720 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001721
1722 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001723 [ISAPNP] Exclude memory regions for the
1724 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001725 Ranges are in pairs (memory base and size).
1726
Jason Baron346e15b2008-08-12 16:46:19 -04001727 dynamic_printk
1728 Enables pr_debug()/dev_dbg() calls if
1729 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
1730 be switched on/off via <debugfs>/dynamic_printk/modules
1731
Ingo Molnar45807a12007-07-15 23:40:10 -07001732 print-fatal-signals=
1733 [KNL] debug: print fatal signals
1734 print-fatal-signals=1: print segfault info to
1735 the kernel console.
1736 default: off.
1737
Randy Dunlape84845c2007-07-15 23:40:25 -07001738 printk.time= Show timing data prefixed to each printk message line
1739 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1740
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001742 Format: [schedule,]<number>
1743 Param: "schedule" - profile schedule points.
1744 Param: <number> - step/bucket size as a power of 2 for
1745 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001746 Param: "sleep" - profile D-state sleeping (millisecs).
1747 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001748 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749
Randy Dunlapa9913042005-10-23 12:57:11 -07001750 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001751 Limit processor to maximum C-state
1752 max_cstate=9 overrides any DMI blacklist limit.
1753
Len Brown41c0d862005-12-28 12:43:51 -05001754 processor.nocst [HW,ACPI]
1755 Ignore the _CST method to determine C-states,
1756 instead using the legacy FADT method
1757
Linus Torvalds1da177e2005-04-16 15:20:36 -07001758 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1759 before loading.
1760 See Documentation/ramdisk.txt.
1761
Randy Dunlapa9913042005-10-23 12:57:11 -07001762 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1763 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001764 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1765 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001766 psmouse.resetafter= [HW,MOUSE]
1767 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001768 (0 = never).
1769 psmouse.resolution=
1770 [HW,MOUSE] Set desired mouse resolution, in dpi.
1771 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001772 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 0 = disabled, 1 = enabled (default).
1774
1775 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001776 Format:
1777 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778
1779 pt. [PARIDE]
1780 See Documentation/paride.txt.
1781
Kay Sieversdc8c8582007-08-15 12:25:38 +02001782 pty.legacy_count=
1783 [KNL] Number of legacy pty's. Overwrites compiled-in
1784 default number.
1785
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001786 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001787
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788 r128= [HW,DRM]
1789
1790 raid= [HW,RAID]
1791 See Documentation/md.txt.
1792
Randy Dunlapa9913042005-10-23 12:57:11 -07001793 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001794 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001795
Linus Torvalds1da177e2005-04-16 15:20:36 -07001796 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001797 See Documentation/ramdisk.txt.
1798
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001799 rcupdate.blimit= [KNL,BOOT]
1800 Set maximum number of finished RCU callbacks to process
1801 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001802
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001803 rcupdate.qhimark= [KNL,BOOT]
1804 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001805 RCU callbacks over which batch limiting is disabled.
1806
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001807 rcupdate.qlowmark= [KNL,BOOT]
1808 Set threshold of queued RCU callbacks below which
1809 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001810
Olof Johanssonffdfc402005-09-06 15:17:19 -07001811 rdinit= [KNL]
1812 Format: <full_path>
1813 Run specified binary instead of /init from the ramdisk,
1814 used for early userspace startup. See initrd.
1815
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001816 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001818 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819
Paul Jackson46b6d942008-07-04 10:00:09 -07001820 relax_domain_level=
1821 [KNL, SMP] Set scheduler's default relax_domain_level.
1822 See Documentation/cpusets.txt.
1823
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1825
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001826 reservetop= [X86-32]
Zachary Amsden461a9af2006-09-25 23:32:25 -07001827 Format: nn[KMG]
1828 Reserves a hole at the top of the kernel virtual
1829 address space.
1830
Vivek Goyal7e962872006-09-27 01:50:44 -07001831 reset_devices [KNL] Force drivers to reset the underlying device
1832 during initialization.
1833
Randy Dunlapa9913042005-10-23 12:57:11 -07001834 resume= [SWSUSP]
1835 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001837 resume_offset= [SWSUSP]
1838 Specify the offset from the beginning of the partition
1839 given by "resume=" at which the swap header is located,
1840 in <PAGE_SIZE> units (needed only for swap files).
1841 See Documentation/power/swsusp-and-swap-files.txt
1842
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001843 retain_initrd [RAM] Keep initrd memory after extraction
1844
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845 rhash_entries= [KNL,NET]
1846 Set number of hash buckets for route cache
1847
1848 riscom8= [HW,SERIAL]
1849 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1850
1851 ro [KNL] Mount root device read-only on boot
1852
1853 root= [KNL] Root filesystem
1854
1855 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1856 mount the root filesystem
1857
1858 rootflags= [KNL] Set root filesystem mount option string
1859
1860 rootfstype= [KNL] Set root filesystem type
1861
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001862 rootwait [KNL] Wait (indefinitely) for root device to show up.
1863 Useful for devices that are detected asynchronously
1864 (e.g. USB and MMC devices).
1865
James Morris20510f22007-10-16 23:31:32 -07001866 root_plug.vendor_id=
1867 [ROOTPLUG] Override the default vendor ID
1868
1869 root_plug.product_id=
1870 [ROOTPLUG] Override the default product ID
1871
1872 root_plug.debug=
1873 [ROOTPLUG] Enable debugging output
1874
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875 rw [KNL] Mount root device read-write on boot
1876
1877 S [KNL] Run init in single mode
1878
1879 sa1100ir [NET]
1880 See drivers/net/irda/sa1100_ir.c.
1881
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001883
Linus Torvalds1da177e2005-04-16 15:20:36 -07001884 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1885 Format: <io>[,<timeout>[,<isapnp>]]
1886
1887 scsi_debug_*= [SCSI]
1888 See drivers/scsi/scsi_debug.c.
1889
1890 scsi_default_dev_flags=
1891 [SCSI] SCSI default device flags
1892 Format: <integer>
1893
1894 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1895 Format: <vendor>:<model>:<flags>
1896 (flags are integer value)
1897
Randy Dunlap6af66322007-11-14 16:52:25 -08001898 scsi_logging_level= [SCSI] a bit mask of logging levels
1899 See drivers/scsi/scsi_logging.h for bits. Also
1900 settable via sysctl at dev.scsi.logging_level
1901 (/proc/sys/dev/scsi/logging_level).
1902 There is also a nice 'scsi_logging_level' script in the
1903 S390-tools package, available for download at
1904 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001905
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001906 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1907 discovered. async scans them in kernel threads,
1908 allowing boot to proceed. none ignores them, expecting
1909 user space to do the scan.
1910
Linus Torvalds1da177e2005-04-16 15:20:36 -07001911 selinux [SELINUX] Disable or enable SELinux at boot time.
1912 Format: { "0" | "1" }
1913 See security/selinux/Kconfig help text.
1914 0 -- disable.
1915 1 -- enable.
1916 Default value is set via kernel config option.
1917 If enabled at boot time, /selinux/disable can be used
1918 later to disable prior to initial policy load.
1919
James Morris4e5ab4c2006-06-09 00:33:33 -07001920 selinux_compat_net =
1921 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001922 Format: { "0" | "1" }
1923 0 -- use new secmark-based packet controls
1924 1 -- use legacy packet controls
1925 Default value is 0 (preferred).
1926 Value can be changed at runtime via
1927 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001928
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001929 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930
Linus Torvalds1da177e2005-04-16 15:20:36 -07001931 shapers= [NET]
1932 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001933
Yinghai Lub05f78f2008-08-22 01:32:50 -07001934 show_msr= [x86] show boot-time MSR settings
1935 Format: { <integer> }
1936 Show boot-time (BIOS-initialized) MSR settings.
1937 The parameter means the number of CPUs to show,
1938 for example 1 means boot CPU only.
1939
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940 sim710= [SCSI,HW]
1941 See header of drivers/scsi/sim710.c.
1942
1943 simeth= [IA-64]
1944 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001945
Linus Torvalds1da177e2005-04-16 15:20:36 -07001946 slram= [HW,MTD]
1947
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001948 slub_debug[=options[,slabs]] [MM, SLUB]
1949 Enabling slub_debug allows one to determine the
1950 culprit if slab objects become corrupted. Enabling
1951 slub_debug can create guard zones around objects and
1952 may poison objects when not in use. Also tracks the
1953 last alloc / free. For more information see
1954 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001955
1956 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001957 Determines the maximum allowed order for slabs.
1958 A high setting may cause OOMs due to memory
1959 fragmentation. For more information see
1960 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001961
1962 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001963 The minimum number of objects per slab. SLUB will
1964 increase the slab order up to slub_max_order to
1965 generate a sufficiently large slab able to contain
1966 the number of objects indicated. The higher the number
1967 of objects the smaller the overhead of tracking slabs
1968 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001969 For more information see Documentation/vm/slub.txt.
1970
1971 slub_min_order= [MM, SLUB]
1972 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001973 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001974 For more information see Documentation/vm/slub.txt.
1975
1976 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001977 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001978 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001979 allocs to different slabs. Debug options disable
1980 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001981 For more information see Documentation/vm/slub.txt.
1982
Linus Torvalds1da177e2005-04-16 15:20:36 -07001983 smart2= [HW]
1984 Format: <io1>[,<io2>[,...,<io8>]]
1985
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001986 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001987 attempt to substitute SMP alternatives once at boot.
1988
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001989 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1990 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1991 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1992 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1993 smsc-ircc2.ircc_irq= [HW] IRQ line
1994 smsc-ircc2.ircc_dma= [HW] DMA channel
1995 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1996 0: Toshiba Satellite 1800 (GP data pin select)
1997 1: Fast pin select (default)
1998 2: ATC IRMode
1999
Linus Torvalds1da177e2005-04-16 15:20:36 -07002000 snd-ad1816a= [HW,ALSA]
2001
2002 snd-ad1848= [HW,ALSA]
2003
2004 snd-ali5451= [HW,ALSA]
2005
2006 snd-als100= [HW,ALSA]
2007
2008 snd-als4000= [HW,ALSA]
2009
2010 snd-azt2320= [HW,ALSA]
2011
2012 snd-cmi8330= [HW,ALSA]
2013
2014 snd-cmipci= [HW,ALSA]
2015
2016 snd-cs4231= [HW,ALSA]
2017
2018 snd-cs4232= [HW,ALSA]
2019
2020 snd-cs4236= [HW,ALSA]
2021
2022 snd-cs4281= [HW,ALSA]
2023
2024 snd-cs46xx= [HW,ALSA]
2025
2026 snd-dt019x= [HW,ALSA]
2027
2028 snd-dummy= [HW,ALSA]
2029
2030 snd-emu10k1= [HW,ALSA]
2031
2032 snd-ens1370= [HW,ALSA]
2033
2034 snd-ens1371= [HW,ALSA]
2035
2036 snd-es968= [HW,ALSA]
2037
2038 snd-es1688= [HW,ALSA]
2039
2040 snd-es18xx= [HW,ALSA]
2041
2042 snd-es1938= [HW,ALSA]
2043
2044 snd-es1968= [HW,ALSA]
2045
2046 snd-fm801= [HW,ALSA]
2047
2048 snd-gusclassic= [HW,ALSA]
2049
2050 snd-gusextreme= [HW,ALSA]
2051
2052 snd-gusmax= [HW,ALSA]
2053
2054 snd-hdsp= [HW,ALSA]
2055
2056 snd-ice1712= [HW,ALSA]
2057
2058 snd-intel8x0= [HW,ALSA]
2059
2060 snd-interwave= [HW,ALSA]
2061
2062 snd-interwave-stb=
2063 [HW,ALSA]
2064
2065 snd-korg1212= [HW,ALSA]
2066
2067 snd-maestro3= [HW,ALSA]
2068
2069 snd-mpu401= [HW,ALSA]
2070
2071 snd-mtpav= [HW,ALSA]
2072
2073 snd-nm256= [HW,ALSA]
2074
2075 snd-opl3sa2= [HW,ALSA]
2076
2077 snd-opti92x-ad1848=
2078 [HW,ALSA]
2079
2080 snd-opti92x-cs4231=
2081 [HW,ALSA]
2082
2083 snd-opti93x= [HW,ALSA]
2084
2085 snd-pmac= [HW,ALSA]
2086
2087 snd-rme32= [HW,ALSA]
2088
2089 snd-rme96= [HW,ALSA]
2090
2091 snd-rme9652= [HW,ALSA]
2092
2093 snd-sb8= [HW,ALSA]
2094
2095 snd-sb16= [HW,ALSA]
2096
2097 snd-sbawe= [HW,ALSA]
2098
2099 snd-serial= [HW,ALSA]
2100
2101 snd-sgalaxy= [HW,ALSA]
2102
2103 snd-sonicvibes= [HW,ALSA]
2104
2105 snd-sun-amd7930=
2106 [HW,ALSA]
2107
2108 snd-sun-cs4231= [HW,ALSA]
2109
2110 snd-trident= [HW,ALSA]
2111
2112 snd-usb-audio= [HW,ALSA,USB]
2113
2114 snd-via82xx= [HW,ALSA]
2115
2116 snd-virmidi= [HW,ALSA]
2117
2118 snd-wavefront= [HW,ALSA]
2119
2120 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002121
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002122 softlockup_panic=
2123 [KNL] Should the soft-lockup detector generate panics.
2124
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2126 See Documentation/sonypi.txt
2127
2128 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2129 See Documentation/specialix.txt.
2130
2131 spia_io_base= [HW,MTD]
2132 spia_fio_base=
2133 spia_pedr=
2134 spia_peddr=
2135
2136 sscape= [HW,OSS]
2137 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002138
Linus Torvalds1da177e2005-04-16 15:20:36 -07002139 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2140 See Documentation/scsi/st.txt.
2141
Linus Torvalds1da177e2005-04-16 15:20:36 -07002142 sti= [PARISC,HW]
2143 Format: <num>
2144 Set the STI (builtin display/keyboard on the HP-PARISC
2145 machines) console (graphic card) which should be used
2146 as the initial boot-console.
2147 See also comment in drivers/video/console/sticore.c.
2148
2149 sti_font= [HW]
2150 See comment in drivers/video/console/sticore.c.
2151
2152 stifb= [HW]
2153 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2154
Greg Banks42a7fc42007-03-06 01:42:23 -08002155 sunrpc.pool_mode=
2156 [NFS]
2157 Control how the NFS server code allocates CPUs to
2158 service thread pools. Depending on how many NICs
2159 you have and where their interrupts are bound, this
2160 option will affect which CPUs will do NFS serving.
2161 Note: this parameter cannot be changed while the
2162 NFS server is running.
2163
2164 auto the server chooses an appropriate mode
2165 automatically using heuristics
2166 global a single global pool contains all CPUs
2167 percpu one pool for each CPU
2168 pernode one pool for each NUMA node (equivalent
2169 to global on non-NUMA machines)
2170
Linus Torvalds1da177e2005-04-16 15:20:36 -07002171 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002172
Linus Torvalds1da177e2005-04-16 15:20:36 -07002173 switches= [HW,M68k]
2174
2175 sym53c416= [HW,SCSI]
2176 See header of drivers/scsi/sym53c416.c.
2177
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002178 sysrq_always_enabled
2179 [KNL]
2180 Ignore sysrq setting - this boot parameter will
2181 neutralize any effect of /proc/sys/kernel/sysrq.
2182 Useful for debugging.
2183
Linus Torvalds1da177e2005-04-16 15:20:36 -07002184 t128= [HW,SCSI]
2185 See header of drivers/scsi/t128.c.
2186
2187 tdfx= [HW,DRM]
2188
David Brownell77437fd2008-07-23 21:28:33 -07002189 test_suspend= [SUSPEND]
2190 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2191 standby suspend) as the system sleep state to briefly
2192 enter during system startup. The system is woken from
2193 this state using a wakeup-capable RTC alarm.
2194
Linus Torvalds1da177e2005-04-16 15:20:36 -07002195 thash_entries= [KNL,NET]
2196 Set number of hash buckets for TCP connection
2197
Len Brownf8707ec2007-08-12 00:12:54 -04002198 thermal.act= [HW,ACPI]
2199 -1: disable all active trip points in all thermal zones
2200 <degrees C>: override all lowest active trip points
2201
Len Brownc52a7412007-08-14 15:49:32 -04002202 thermal.crt= [HW,ACPI]
2203 -1: disable all critical trip points in all thermal zones
2204 <degrees C>: lower all critical trip points
2205
Len Brownf5487142007-08-12 00:12:44 -04002206 thermal.nocrt= [HW,ACPI]
2207 Set to disable actions on ACPI thermal zone
2208 critical and hot trip points.
2209
Len Brown72b33ef2007-08-12 00:12:17 -04002210 thermal.off= [HW,ACPI]
2211 1: disable ACPI thermal control
2212
Len Browna70cdc52007-08-12 00:12:35 -04002213 thermal.psv= [HW,ACPI]
2214 -1: disable all passive trip points
2215 <degrees C>: override all passive trip points to this value
2216
Len Brown730ff342007-08-12 00:12:26 -04002217 thermal.tzp= [HW,ACPI]
2218 Specify global default ACPI thermal zone polling rate
2219 <deci-seconds>: poll all this frequency
2220 0: no polling (default)
2221
Linus Torvalds1da177e2005-04-16 15:20:36 -07002222 tmscsim= [HW,SCSI]
2223 See comment before function dc390_setup() in
2224 drivers/scsi/tmscsim.c.
2225
2226 tp720= [HW,PS2]
2227
2228 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002229 Format:
2230 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2231
Randy Dunlapa9913042005-10-23 12:57:11 -07002232 turbografx.map[2|3]= [HW,JOY]
2233 TurboGraFX parallel port interface
2234 Format:
2235 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002236 See also Documentation/input/joystick-parport.txt
2237
2238 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2239 See header of drivers/scsi/u14-34f.c.
2240
2241 uart401= [HW,OSS]
2242 Format: <io>,<irq>
2243
2244 uart6850= [HW,OSS]
2245 Format: <io>,<irq>
2246
Alan Stern5f8364b2006-12-05 16:29:55 -05002247 uhci-hcd.ignore_oc=
2248 [USB] Ignore overcurrent events (default N).
2249 Some badly-designed motherboards generate lots of
2250 bogus events, for ports that aren't wired to
2251 anything. Set this parameter to avoid log spamming.
2252 Note that genuine overcurrent events won't be
2253 reported either.
2254
Simon Arlotte3a61b02008-07-19 23:32:54 +01002255 unknown_nmi_panic
2256 [X86-32,X86-64]
2257 Set unknown_nmi_panic=1 early on boot.
2258
Alan Sternb5e795f2007-02-20 15:00:53 -05002259 usbcore.autosuspend=
2260 [USB] The autosuspend time delay (in seconds) used
2261 for newly-detected USB devices (default 2). This
2262 is the time required before an idle device will be
2263 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002264 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002265
Jaroslav Kyselafd7c5192008-10-10 16:24:45 +02002266 usbcore.usbfs_snoop=
2267 [USB] Set to log all usbfs traffic (default 0 = off).
2268
2269 usbcore.blinkenlights=
2270 [USB] Set to cycle leds on hubs (default 0 = off).
2271
2272 usbcore.old_scheme_first=
2273 [USB] Start with the old device initialization
2274 scheme (default 0 = off).
2275
2276 usbcore.use_both_schemes=
2277 [USB] Try the other device initialization scheme
2278 if the first one fails (default 1 = enabled).
2279
2280 usbcore.initial_descriptor_timeout=
2281 [USB] Specifies timeout for the initial 64-byte
2282 USB_REQ_GET_DESCRIPTOR request in milliseconds
2283 (default 5000 = 5.0 seconds).
2284
Linus Torvalds1da177e2005-04-16 15:20:36 -07002285 usbhid.mousepoll=
2286 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002287
Paul Jackson200001e2008-06-25 05:44:46 -07002288 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2289 kernel's map of available physical RAM.
2290
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002291 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002292 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002293 vdso=1: enable VDSO (default)
2294 vdso=0: disable VDSO mapping
2295
Roland McGrathaf65d642008-01-30 13:30:43 +01002296 vdso32= [X86-32,X86-64]
2297 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2298 vdso32=1: enable 32-bit VDSO (default)
2299 vdso32=0: disable 32-bit VDSO mapping
2300
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002301 vector= [IA-64,SMP]
2302 vector=percpu: enable percpu vector domain
2303
Linus Torvalds1da177e2005-04-16 15:20:36 -07002304 video= [FB] Frame buffer configuration
2305 See Documentation/fb/modedb.txt.
2306
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002307 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002308 See Documentation/i386/boot.txt and
2309 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002310 Use vga=ask for menu.
2311 This is actually a boot loader parameter; the value is
2312 passed to the kernel using a special protocol.
2313
Randy Dunlapa9913042005-10-23 12:57:11 -07002314 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002315 size of <nn>. This can be used to increase the
2316 minimum size (128MB on x86). It can also be used to
2317 decrease the size and leave more room for directly
2318 mapped kernel RAM.
2319
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002320 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2321 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002322
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002323 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2324 Format: <command>
2325
2326 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2327 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002328
Linus Torvalds1da177e2005-04-16 15:20:36 -07002329 waveartist= [HW,OSS]
2330 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002331
Linus Torvalds1da177e2005-04-16 15:20:36 -07002332 wd33c93= [HW,SCSI]
2333 See header of drivers/scsi/wd33c93.c.
2334
2335 wd7000= [HW,SCSI]
2336 See header of drivers/scsi/wd7000.c.
2337
2338 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002339 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002340
2341 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2342 xd_geo= See header of drivers/block/xd.c.
2343
2344 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002345 Format:
2346 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002347
Andi Kleena62eaf12006-02-16 23:41:58 +01002348 norandmaps Don't use address space randomization
2349 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2350
Randy Dunlapa9913042005-10-23 12:57:11 -07002351______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002352
2353TODO:
2354
2355 Add documentation for ALSA options.
2356 Add more DRM drivers.