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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
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700693 elfcorehdr= [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
Jiri Kosina36d95732008-10-06 02:51:09 -0400799 i8042.debug [HW] Toggle i8042 debug mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200801 i8042.dumbkbd [HW] Pretend that controller can only read data from
802 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 (Don't attempt to blink the leds)
804 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500805 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400806 i8042.noloop [HW] Disable the AUX Loopback command while probing
807 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 i8042.nomux [HW] Don't check presence of an active multiplexing
809 controller
810 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
811 controllers
812 i8042.panicblink=
813 [HW] Frequency with which keyboard LEDs should blink
814 when kernel panics (default is 0.5 sec)
815 i8042.reset [HW] Reset the controller during init and cleanup
816 i8042.unlock [HW] Unlock (ignore) the keylock
817
818 i810= [HW,DRM]
819
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700820 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
821 indicates that the driver is running on unsupported
822 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
824 does not match list of supported models.
825 i8k.power_status
826 [HW] Report power status in /proc/i8k
827 (disabled by default)
828 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
829 capability is set.
830
831 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
832 See Documentation/mca.txt.
833
834 icn= [HW,ISDN]
835 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
836
837 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200838 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100839 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100842 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843
Andi Kleenf039b752007-05-02 19:27:12 +0200844 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800845 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200846 Poll forces a polling idle loop that can slightly improves the performance
847 of waking up a idle CPU, but will use a lot of power and make the system
848 run hot. Not recommended.
849 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
850 to not use it because it doesn't save as much power as a normal idle
851 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
852 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800853 idle=halt. Halt is forced to be used for CPU idle.
854 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800855 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700856
Denis Cheng594765a2008-02-06 02:57:49 +0100857 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
858 Claim all unknown PCI IDE storage controllers.
859
Ingo Molnar792908222006-12-06 20:40:51 -0800860 ignore_loglevel [KNL]
861 Ignore loglevel setting - this will print /all/
862 kernel messages to the console. Useful for debugging.
863
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 ihash_entries= [KNL]
865 Set number of hash buckets for inode cache.
866
867 in2000= [HW,SCSI]
868 See header of drivers/scsi/in2000.c.
869
870 init= [KNL]
871 Format: <full_path>
872 Run specified binary instead of /sbin/init as init
873 process.
874
875 initcall_debug [KNL] Trace initcalls as they are executed. Useful
876 for working out where the kernel is dying during
877 startup.
878
879 initrd= [BOOT] Specify the location of the initial ramdisk
880
881 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
882 Format: <irq>
883
884 inttest= [IA64]
885
Pavel Machekb552da82008-03-19 15:58:11 +0100886 iommu= [x86]
887 off
888 force
889 noforce
890 biomerge
891 panic
892 nopanic
893 merge
894 nomerge
895 forcesac
896 soft
897
898
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700899 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
900 off
901 Disable intel iommu driver.
902 igfx_off [Default Off]
903 By default, gfx is mapped as normal device. If a gfx
904 device has a dedicated DMAR unit, the DMAR unit is
905 bypassed by not enabling DMAR with this option. In
906 this case, gfx device will use physical address for
907 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700908 forcedac [x86_64]
909 With this option iommu will not optimize to look
910 for io virtual address below 32 bit forcing dual
911 address cycle on pci bus for cards supporting greater
912 than 32 bit addressing. The default is to look
913 for translation below 32 bit and if not available
914 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800915 strict [Default Off]
916 With this option on every unmap_single operation will
917 result in a hardware IOTLB flush operation as opposed
918 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700919
Rene Hermanb02aae92008-01-30 13:30:05 +0100920 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100921 0x80
922 Standard port 0x80 based delay
923 0xed
924 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100925 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100926 Simple two microseconds delay
927 none
928 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100929
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 io7= [HW] IO7 for Marvel based alpha systems
931 See comment before marvel_specify_io7 in
932 arch/alpha/kernel/core_marvel.c.
933
934 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400935 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936
937 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700938 See comment before ip2_setup() in
939 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700940
941 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
942 See header of drivers/scsi/ips.c.
943
Simon Horman72c4a132006-09-13 19:57:18 -0700944 ports= [IP_VS_FTP] IPVS ftp helper module
945 Default is 21.
946 Up to 8 (IP_VS_APP_MAX_PORTS) ports
947 may be specified.
948 Format: <port>,<port>....
949
Alan Cox200803d2005-06-28 20:45:18 -0700950 irqfixup [HW]
951 When an interrupt is not handled search all handlers
952 for it. Intended to get systems with badly broken
953 firmware running.
954
955 irqpoll [HW]
956 When an interrupt is not handled search all handlers
957 for it. Also check all handlers each timer
958 interrupt. Intended to get systems with badly broken
959 firmware running.
960
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700962 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963
964 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800965 Format:
966 <cpu number>,...,<cpu number>
967 or
968 <cpu number>-<cpu number> (must be a positive range in ascending order)
969 or a mixture
970 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971 This option can be used to specify one or more CPUs
972 to isolate from the general SMP balancing and scheduling
973 algorithms. The only way to move a process onto or off
974 an "isolated" CPU is via the CPU affinity syscalls.
975 <cpu number> begins at 0 and the maximum value is
976 "number of CPUs in system - 1".
977
978 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700979 alternative -- manually setting the CPU mask of all
980 tasks in the system -- can cause problems and
981 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982
Randy Dunlapa9913042005-10-23 12:57:11 -0700983 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984
985 js= [HW,JOY] Analog joystick
986 See Documentation/input/joystick.txt.
987
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700988 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700989 specifies the amount of memory usable by the kernel
990 for non-movable allocations. The requested amount is
991 spread evenly throughout all nodes in the system. The
992 remaining memory in each node is used for Movable
993 pages. In the event, a node is too small to have both
994 kernelcore and Movable pages, kernelcore pages will
995 take priority and other nodes will have a larger number
996 of kernelcore pages. The Movable zone is used for the
997 allocation of pages that may be reclaimed or moved
998 by the page migration subsystem. This means that
999 HugeTLB pages may not be allocated from this zone.
1000 Note that allocations like PTEs-from-HighMem still
1001 use the HighMem zone if it exists, and the Normal
1002 zone if it does not.
1003
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001004 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -07001005 is similar to kernelcore except it specifies the
1006 amount of memory used for migratable allocations.
1007 If both kernelcore and movablecore is specified,
1008 then kernelcore will be at *least* the specified
1009 value but may be more. If movablecore on its own
1010 is specified, the administrator must be careful
1011 that the amount of memory usable for all allocations
1012 is not too small.
1013
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 keepinitrd [HW,ARM]
1015
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001016 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017 in oops dumps.
1018
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001019 kgdboc= [HW] kgdb over consoles.
1020 Requires a tty driver that supports console polling.
1021 (only serial suported for now)
1022 Format: <serial_device>[,baud]
1023
Florian Fainelli9bed90c62008-08-23 18:54:37 +02001024 kmac= [MIPS] korina ethernet MAC address.
1025 Configure the RouterBoard 532 series on-chip
1026 Ethernet adapter MAC address.
1027
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028 l2cr= [PPC]
1029
Robert Brosea78bfbf2008-03-29 07:20:23 +11001030 l3cr= [PPC]
1031
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001032 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001033 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001035 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001036 C2 power state.
1037
FD Camifcb71f62008-01-06 19:08:56 +01001038 libata.dma= [LIBATA] DMA control
1039 libata.dma=0 Disable all PATA and SATA DMA
1040 libata.dma=1 PATA and SATA Disk DMA only
1041 libata.dma=2 ATAPI (CDROM) DMA only
1042 libata.dma=4 Compact Flash DMA only
1043 Combinations also work, so libata.dma=3 enables DMA
1044 for disks and CDROMs, but not CFs.
1045
Dave Jones78e70c22007-09-27 11:50:13 -04001046 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1047 when set.
1048 Format: <int>
1049
Tejun Heo33267322008-02-13 09:15:09 +09001050 libata.force= [LIBATA] Force configurations. The format is comma
1051 separated list of "[ID:]VAL" where ID is
1052 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1053 matching port, link or device. Basically, it matches
1054 the ATA ID string printed on console by libata. If
1055 the whole ID part is omitted, the last PORT and DEVICE
1056 values are used. If ID hasn't been specified yet, the
1057 configuration applies to all ports, links and devices.
1058
1059 If only DEVICE is omitted, the parameter applies to
1060 the port and all links and devices behind it. DEVICE
1061 number of 0 either selects the first device or the
1062 first fan-out link behind PMP device. It does not
1063 select the host link. DEVICE number of 15 selects the
1064 host link and device attached to it.
1065
1066 The VAL specifies the configuration to force. As long
1067 as there's no ambiguity shortcut notation is allowed.
1068 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1069 The following configurations can be forced.
1070
1071 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1072 Any ID with matching PORT is used.
1073
1074 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1075
1076 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1077 udma[/][16,25,33,44,66,100,133] notation is also
1078 allowed.
1079
1080 * [no]ncq: Turn on or off NCQ.
1081
Tejun Heo05944bd2008-08-13 20:19:09 +09001082 * nohrst, nosrst, norst: suppress hard, soft
1083 and both resets.
1084
Tejun Heo33267322008-02-13 09:15:09 +09001085 If there are multiple matching configurations changing
1086 the same attribute, the last one is used.
1087
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 load_ramdisk= [RAM] List of ramdisks to load from floppy
1089 See Documentation/ramdisk.txt.
1090
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001091 lockd.nlm_grace_period=P [NFS] Assign grace period.
1092 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001094 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1095 Format: <integer>
1096
1097 lockd.nlm_timeout=T [NFS] Assign timeout value.
1098 Format: <integer>
1099
1100 lockd.nlm_udpport=M [NFS] Assign UDP port.
1101 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102
1103 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1104 Format: <irq>
1105
1106 loglevel= All Kernel Messages with a loglevel smaller than the
1107 console loglevel will be printed to the console. It can
1108 also be changed with klogd or other programs. The
1109 loglevels are defined as follows:
1110
1111 0 (KERN_EMERG) system is unusable
1112 1 (KERN_ALERT) action must be taken immediately
1113 2 (KERN_CRIT) critical conditions
1114 3 (KERN_ERR) error conditions
1115 4 (KERN_WARNING) warning conditions
1116 5 (KERN_NOTICE) normal but significant condition
1117 6 (KERN_INFO) informational
1118 7 (KERN_DEBUG) debug-level messages
1119
1120 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001121 Format: { n | nk | nM }
1122 n must be a power of two. The default size
1123 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001124
Randy Dunlapaccaa242007-10-16 01:29:37 -07001125 logo.nologo [FB] Disables display of the built-in Linux logo.
1126 This may be used to provide more screen space for
1127 kernel log messages and is useful when debugging
1128 kernel boot problems.
1129
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130 lp=0 [LP] Specify parallel ports to use, e.g,
1131 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1132 lp=reset first parallel port). 'lp=0' disables the
1133 lp=auto printer driver. 'lp=reset' (which can be
1134 specified in addition to the ports) causes
1135 attached printers to be reset. Using
1136 lp=port1,port2,... specifies the parallel ports
1137 to associate lp devices with, starting with
1138 lp0. A port specification may be 'none' to skip
1139 that lp device, or a parport name such as
1140 'parport0'. Specifying 'lp=auto' instead of a
1141 port specification list means that device IDs
1142 from each port should be examined, to see if
1143 an IEEE 1284-compliant printer is attached; if
1144 so, the driver will manage that printer.
1145 See also header of drivers/char/lp.c.
1146
1147 lpj=n [KNL]
1148 Sets loops_per_jiffy to given constant, thus avoiding
1149 time-consuming boot-time autodetection (up to 250 ms per
1150 CPU). 0 enables autodetection (default). To determine
1151 the correct value for your kernel, boot with normal
1152 autodetection and see what value is printed. Note that
1153 on SMP systems the preset will be applied to all CPUs,
1154 which is likely to cause problems if your CPUs need
1155 significantly divergent settings. An incorrect value
1156 will cause delays in the kernel to be wrong, leading to
1157 unpredictable I/O errors and other breakage. Although
1158 unlikely, in the extreme case this might damage your
1159 hardware.
1160
1161 ltpc= [NET]
1162 Format: <io>,<irq>,<dma>
1163
Randy Dunlapa9913042005-10-23 12:57:11 -07001164 mac5380= [HW,SCSI] Format:
1165 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166
Randy Dunlapa9913042005-10-23 12:57:11 -07001167 machvec= [IA64] Force the use of a particular machine-vector
1168 (machvec) in a generic kernel.
1169 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170
Randy Dunlapa9913042005-10-23 12:57:11 -07001171 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172 be mounted
1173 Format: <1-256>
1174
1175 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001176 should make use of. maxcpus=n : n >= 0 limits the
1177 kernel to using 'n' processors. n=0 is a special case,
1178 it is equivalent to "nosmp", which also disables
1179 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180
Bob Picco2b2c3752005-06-29 18:00:00 -07001181 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1182 equal to this physical address is ignored.
1183
Randy Dunlapa9913042005-10-23 12:57:11 -07001184 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185 Should be between 1 and 2^32-1.
1186
1187 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001188 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 Should be between 1 and 16384.
1190
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 mcatest= [IA-64]
1192
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001193 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194
Andi Kleen909dd322007-10-17 18:04:38 +02001195 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1196
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 md= [HW] RAID subsystems devices and level
1198 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001199
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 mdacon= [MDA]
1201 Format: <first>,<last>
1202 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001203
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1205 Amount of memory to be used when the kernel is not able
1206 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001207 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001208 address space collisions. Without memmap= PCI devices
1209 could be placed at addresses belonging to unused RAM.
1210
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001211 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212 memory.
1213
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001214 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 E820 memory map, as specified by the user.
1216 Such memmap=exactmap lines can be constructed based on
1217 BIOS output or other requirements. See the memmap=nn@ss
1218 option description.
1219
1220 memmap=nn[KMG]@ss[KMG]
1221 [KNL] Force usage of a specific region of memory
1222 Region of memory to be used, from ss to ss+nn.
1223
1224 memmap=nn[KMG]#ss[KMG]
1225 [KNL,ACPI] Mark specific memory as ACPI data.
1226 Region of memory to be used, from ss to ss+nn.
1227
1228 memmap=nn[KMG]$ss[KMG]
1229 [KNL,ACPI] Mark specific memory as reserved.
1230 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001231 Example: Exclude memory from 0x18690000-0x1869ffff
1232 memmap=64K$0x18690000
1233 or
1234 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001235
Jeremy Fitzhardinge9f077872008-09-07 01:51:34 -07001236 memory_corruption_check=0/1 [X86]
1237 Some BIOSes seem to corrupt the first 64k of
1238 memory when doing things like suspend/resume.
1239 Setting this option will scan the memory
1240 looking for corruption. Enabling this will
1241 both detect corruption and prevent the kernel
1242 from using the memory being corrupted.
1243 However, its intended as a diagnostic tool; if
1244 repeatable BIOS-originated corruption always
1245 affects the same memory, you can use memmap=
1246 to prevent the kernel from using that memory.
1247
1248 memory_corruption_check_size=size [X86]
1249 By default it checks for corruption in the low
1250 64k, making this memory unavailable for normal
1251 use. Use this parameter to scan for
1252 corruption in more or less memory.
1253
1254 memory_corruption_check_period=seconds [X86]
1255 By default it checks for corruption every 60
1256 seconds. Use this parameter to check at some
1257 other rate. 0 disables periodic checking.
1258
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001259 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001260 Format: <integer>
1261 range: 0,4 : pattern number
1262 default : 0 <disable>
1263
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264 meye.*= [HW] Set MotionEye Camera parameters
1265 See Documentation/video4linux/meye.txt.
1266
Andres Salomon8f368812007-10-12 23:04:06 +02001267 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1268 Multi-Function General Purpose Timers on AMD Geode
1269 platforms.
1270
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001271 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1272 the BIOS has incorrectly applied a workaround. TinyBIOS
1273 version 0.98 is known to be affected, 0.99 fixes the
1274 problem by letting the user disable the workaround.
1275
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276 mga= [HW,DRM]
1277
Mel Gorman6b74ab92008-07-23 21:26:49 -07001278 mminit_loglevel=
1279 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1280 parameter allows control of the logging verbosity for
1281 the additional memory initialisation checks. A value
1282 of 0 disables mminit logging and a level of 4 will
1283 log everything. Information is printed at KERN_DEBUG
1284 so loglevel=8 may also need to be specified.
1285
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286 mousedev.tap_time=
1287 [MOUSE] Maximum time between finger touching and
1288 leaving touchpad surface for touch to be considered
1289 a tap and be reported as a left button click (for
1290 touchpads working in absolute mode only).
1291 Format: <msecs>
1292 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1293 reporting absolute coordinates, such as tablets
1294 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1295 reporting absolute coordinates, such as tablets
1296
1297 mpu401= [HW,OSS]
1298 Format: <io>,<irq>
1299
1300 MTD_Partition= [MTD]
1301 Format: <name>,<region-number>,<size>,<offset>
1302
Randy Dunlapa9913042005-10-23 12:57:11 -07001303 MTD_Region= [MTD] Format:
1304 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305
1306 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001307 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001308
Ben Dooks9db829f2008-07-03 11:24:29 +01001309 mtdset= [ARM]
1310 ARM/S3C2412 JIVE boot control
1311
1312 See arch/arm/mach-s3c2412/mach-jive.c
1313
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001315 [HW] Make the MicroTouch USB driver use raw coordinates
1316 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317
1318 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1319
1320 NCR_D700= [HW,SCSI]
1321 See header of drivers/scsi/NCR_D700.c.
1322
1323 ncr5380= [HW,SCSI]
1324
1325 ncr53c400= [HW,SCSI]
1326
1327 ncr53c400a= [HW,SCSI]
1328
1329 ncr53c406a= [HW,SCSI]
1330
1331 ncr53c8xx= [HW,SCSI]
1332
1333 netdev= [NET] Network devices parameters
1334 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1335 Note that mem_start is often overloaded to mean
1336 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001337 This usage is only documented in each driver source
1338 file if at all.
1339
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001340 nf_conntrack.acct=
1341 [NETFILTER] Enable connection tracking flow accounting
1342 0 to disable accounting
1343 1 to enable accounting
1344 Default value depends on CONFIG_NF_CT_ACCT that is
1345 going to be removed in 2.6.29.
1346
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001348 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349
1350 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001351 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352
Trond Myklebusta72b4422006-01-03 09:55:41 +01001353 nfs.callback_tcpport=
1354 [NFS] set the TCP port on which the NFSv4 callback
1355 channel should listen.
1356
Trond Myklebust58df0952006-01-03 09:55:57 +01001357 nfs.idmap_cache_timeout=
1358 [NFS] set the maximum lifetime for idmapper cache
1359 entries.
1360
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001361 nfs.enable_ino64=
1362 [NFS] enable 64-bit inode numbers.
1363 If zero, the NFS client will fake up a 32-bit inode
1364 number for the readdir() and stat() syscalls instead
1365 of returning the full 64-bit number.
1366 The default is to return 64-bit inode numbers.
1367
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001368 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1369 when a NMI is triggered.
1370 Format: [state][,regs][,debounce][,die]
1371
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001372 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001374 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001375 emulation library even if a 387 maths coprocessor
1376 is present.
1377
Christoph Lameterc1aee212007-05-31 00:40:47 -07001378 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1379 caches in the slab allocator. Saves per-node memory,
1380 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001381
Randy Dunlapa9913042005-10-23 12:57:11 -07001382 noalign [KNL,ARM]
1383
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384 noapic [SMP,APIC] Tells the kernel to not make use of any
1385 IOAPICs that may be present in the system.
1386
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 nobats [PPC] Do not use BATs for mapping kernel lowmem
1388 on "Classic" PPC cores.
1389
1390 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001391
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001392 nodelayacct [KNL] Disable per-task delay accounting
1393
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1395
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001396 noefi [X86-32,X86-64] Disable EFI runtime services support.
1397
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 noexec [IA-64]
1399
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001400 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001401 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001403 noexec=off: disable non-executable mappings
1404
1405 noexec32 [X86-64]
1406 This affects only 32-bit executables.
1407 noexec32=on: enable non-executable mappings (default)
1408 read doesn't imply executable mappings
1409 noexec32=off: disable non-executable mappings
1410 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001412 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001413 register save and restore. The kernel will only save
1414 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415
Andi Kleen191679f2008-01-30 13:33:21 +01001416 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1417
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001419
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001420 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421 instruction doesn't work correctly and not to
1422 use it.
1423
1424 nohalt [IA-64] Tells the kernel not to use the power saving
1425 function PAL_HALT_LIGHT when idle. This increases
1426 power-consumption. On the positive side, it reduces
1427 interrupt wake-up latency, which may improve performance
1428 in certain environments such as networked servers or
1429 real-time systems.
1430
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001431 nohz= [KNL] Boottime enable/disable dynamic ticks
1432 Valid arguments: on, off
1433 Default: on
1434
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001435 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001436
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001437 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438 disable unhandled interrupt sources.
1439
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001440 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001441 broken timer IRQ sources.
1442
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 noisapnp [ISAPNP] Disables ISA PnP code.
1444
1445 noinitrd [RAM] Tells the kernel not to load any configured
1446 initial RAM disk.
1447
1448 nointroute [IA-64]
1449
Tony Luck0aa366f2007-07-20 11:22:30 -07001450 nojitter [IA64] Disables jitter checking for ITC timers.
1451
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001452 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001454 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001455
Suresh Siddha6e1cb382008-07-10 11:16:58 -07001456 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1457
Suresh Siddhaaf9d1382008-07-11 13:11:57 -07001458 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1459 default x2apic cluster mode on platforms
1460 supporting x2apic.
1461
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462 noltlbs [PPC] Do not use large page/tlb entries for kernel
1463 lowmem mapping on PPC40x.
1464
Horms312f1f02006-02-22 09:57:55 +09001465 nomca [IA-64] Disable machine check abort handling
1466
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001467 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001468
Andres Salomon83d73842007-10-12 23:04:06 +02001469 nomfgpt [X86-32] Disable Multi-Function General Purpose
1470 Timer usage (for AMD Geode machines).
1471
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001472 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001473
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001474 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001475 with UP alternatives
1476
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477 noresidual [PPC] Don't use residual data on PReP machines.
1478
Randy Dunlapa9913042005-10-23 12:57:11 -07001479 noresume [SWSUSP] Disables resume and restores original swap
1480 space.
1481
Linus Torvalds1da177e2005-04-16 15:20:36 -07001482 no-scroll [VGA] Disables scrollback.
1483 This is required for the Braillex ib80-piezo Braille
1484 reader made by F.H. Papenmeier (Germany).
1485
1486 nosbagart [IA-64]
1487
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001488 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001489
Len Brown61ec7562007-08-16 03:34:22 -04001490 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1491 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001492
Dave Jones97842212007-07-15 23:41:05 -07001493 nosoftlockup [KNL] Disable the soft-lockup detector.
1494
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 nosync [HW,M68K] Disables sync negotiation for all devices.
1496
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001497 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001498
1499 nousb [USB] Disable the USB subsystem
1500
1501 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001502
Fenghua Yua6c75b862008-03-14 13:57:08 -07001503 nptcg= [IA64] Override max number of concurrent global TLB
1504 purges which is reported from either PAL_VM_SUMMARY or
1505 SAL PALO.
1506
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001507 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1508 one of ['zone', 'node', 'default'] can be specified
1509 This can be set from sysctl after boot.
1510 See Documentation/sysctl/vm.txt for details.
1511
Dave Jonesa61c2d72006-01-07 23:18:19 +00001512 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1513
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001514 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1515 Rather than timing out after 20 ms if an EC
1516 command is not properly ACKed, override the length
1517 of the timeout. We have interrupts disabled while
1518 waiting for the ACK, so if this is set too high
1519 interrupts *may* be lost!
1520
Linus Torvalds1da177e2005-04-16 15:20:36 -07001521 opl3= [HW,OSS]
1522 Format: <io>
1523
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524 oprofile.timer= [HW]
1525 Use timer interrupt instead of performance counters
1526
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 osst= [HW,SCSI] SCSI Tape Driver
1528 Format: <buffer_size>,<write_threshold>
1529 See also Documentation/scsi/st.txt.
1530
1531 panic= [KNL] Kernel behaviour on panic
1532 Format: <timeout>
1533
1534 parkbd.port= [HW] Parallel port number the keyboard adapter is
1535 connected to, default is 0.
1536 Format: <parport#>
1537 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1538 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001539 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540
Randy Dunlapa9913042005-10-23 12:57:11 -07001541 parport= [HW,PPT] Specify parallel ports. 0 disables.
1542 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1543 Use 'auto' to force the driver to use any
1544 IRQ/DMA settings detected (the default is to
1545 ignore detected IRQ/DMA settings because of
1546 possible conflicts). You can specify the base
1547 address, IRQ, and DMA settings; IRQ and DMA
1548 should be numbers, or 'auto' (for using detected
1549 settings on that particular port), or 'nofifo'
1550 (to avoid using a FIFO even if it is detected).
1551 Parallel ports are assigned in the order they
1552 are specified on the command line, starting
1553 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554
Randy Dunlapa9913042005-10-23 12:57:11 -07001555 parport_init_mode= [HW,PPT]
1556 Configure VIA parallel port to operate in
1557 a specific mode. This is necessary on Pegasos
1558 computer where firmware has no options for setting
1559 up parallel port mode and sets it to spp.
1560 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001561 Format: [spp|ps2|epp|ecp|ecpepp]
1562
Randy Dunlapa9913042005-10-23 12:57:11 -07001563 pas2= [HW,OSS] Format:
1564 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1565
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566 pas16= [HW,SCSI]
1567 See header of drivers/scsi/pas16.c.
1568
Andrew Mortondd287792006-03-23 03:00:57 -08001569 pause_on_oops=
1570 Halt all CPUs after the first oops has been printed for
1571 the specified number of seconds. This is to be used if
1572 your oopses keep scrolling off the screen.
1573
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574 pcbit= [HW,ISDN]
1575
1576 pcd. [PARIDE]
1577 See header of drivers/block/paride/pcd.c.
1578 See also Documentation/paride.txt.
1579
Randy Dunlapa9913042005-10-23 12:57:11 -07001580 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001581 off [X86-32] don't probe for the PCI bus
1582 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001583 the hardware directly. Use this if your machine
1584 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001585 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001586 hardware access methods are allowed. Use this
1587 if you experience crashes upon bootup and you
1588 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001589 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001590 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001591 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001592 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001593 noaer [PCIE] If the PCIEAER kernel config parameter is
1594 enabled, this kernel boot option can be used to
1595 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001596 nodomains [PCI] Disable support for multiple PCI
1597 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001598 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001599 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001600 nomsi [MSI] If the PCI_MSI kernel config parameter is
1601 enabled, this kernel boot option can be used to
1602 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001603 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001604 routing table. These calls are known to be buggy
1605 on several machines and they hang the machine
1606 when used, but on other computers it's the only
1607 way to get the interrupt routing table. Try
1608 this option if the kernel is unable to allocate
1609 IRQs or discover secondary PCI buses on your
1610 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001611 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001612 Use with caution as certain devices share
1613 address decoders between ROMs and other
1614 resources.
Gary Hadebb71ad82008-05-12 13:57:46 -07001615 norom [X86-32,X86_64] Do not assign address space to
1616 expansion ROMs that do not already have
1617 BIOS assigned address ranges.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001618 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001619 assigned automatically to PCI devices. You can
1620 make the kernel exclude IRQs of your ISA cards
1621 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001622 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001623 of the PIRQ table (normally generated
1624 by the BIOS) if it is outside the
1625 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001626 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001627 useful if the kernel is unable to find your
1628 secondary buses and you want to tell it
1629 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001630 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001631 numbers ourselves, overriding
1632 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001633 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001634 in the BIOS $PIR table. This is needed on
1635 some systems with broken BIOSes, notably
1636 some HP Pavilion N5400 and Omnibook XE3
1637 notebooks. This will have no effect if ACPI
1638 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001639 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001640 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001641 use_crs [X86-32] Use _CRS for PCI resource
1642 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001643 routeirq Do IRQ routing for all PCI devices.
1644 This is normally done in pci_enable_device(),
1645 so this option is a temporary workaround
1646 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001647 skip_isa_align [X86] do not align io start addr, so can
1648 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001649 firmware [ARM] Do not re-enumerate the bus but instead
1650 just use the configuration from the
1651 bootloader. This is currently used on
1652 IXP2000 systems where the bus has to be
1653 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001654 noearly [X86] Don't do any early type 1 scanning.
1655 This might help on some broken boards which
1656 machine check when some devices' config space
1657 is read. But various workarounds are disabled
1658 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001659 bfsort Sort PCI devices into breadth-first order.
1660 This sorting is done to get a device
1661 order compatible with older (<= 2.4) kernels.
1662 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001663 cbiosize=nn[KMG] The fixed amount of bus space which is
1664 reserved for the CardBus bridge's IO window.
1665 The default value is 256 bytes.
1666 cbmemsize=nn[KMG] The fixed amount of bus space which is
1667 reserved for the CardBus bridge's memory
1668 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001669
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670 pcmv= [HW,PCMCIA] BadgePAD 4
1671
1672 pd. [PARIDE]
1673 See Documentation/paride.txt.
1674
1675 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1676 boot time.
1677 Format: { 0 | 1 }
1678 See arch/parisc/kernel/pdc_chassis.c
1679
1680 pf. [PARIDE]
1681 See Documentation/paride.txt.
1682
1683 pg. [PARIDE]
1684 See Documentation/paride.txt.
1685
1686 pirq= [SMP,APIC] Manual mp-table setup
1687 See Documentation/i386/IO-APIC.txt.
1688
1689 plip= [PPT,NET] Parallel port network link
1690 Format: { parport<nr> | timid | 0 }
1691 See also Documentation/parport.txt.
1692
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001693 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1694 Override pmtimer IOPort with a hex value.
1695 e.g. pmtmr=0x508
1696
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697 pnpacpi= [ACPI]
1698 { off }
1699
1700 pnpbios= [ISAPNP]
1701 { on | off | curr | res | no-curr | no-res }
1702
1703 pnp_reserve_irq=
1704 [ISAPNP] Exclude IRQs for the autoconfiguration
1705
1706 pnp_reserve_dma=
1707 [ISAPNP] Exclude DMAs for the autoconfiguration
1708
1709 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001710 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001711
1712 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001713 [ISAPNP] Exclude memory regions for the
1714 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001715 Ranges are in pairs (memory base and size).
1716
Jason Baron346e15b2008-08-12 16:46:19 -04001717 dynamic_printk
1718 Enables pr_debug()/dev_dbg() calls if
1719 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
1720 be switched on/off via <debugfs>/dynamic_printk/modules
1721
Ingo Molnar45807a12007-07-15 23:40:10 -07001722 print-fatal-signals=
1723 [KNL] debug: print fatal signals
1724 print-fatal-signals=1: print segfault info to
1725 the kernel console.
1726 default: off.
1727
Randy Dunlape84845c2007-07-15 23:40:25 -07001728 printk.time= Show timing data prefixed to each printk message line
1729 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1730
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001732 Format: [schedule,]<number>
1733 Param: "schedule" - profile schedule points.
1734 Param: <number> - step/bucket size as a power of 2 for
1735 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001736 Param: "sleep" - profile D-state sleeping (millisecs).
1737 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001738 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739
Randy Dunlapa9913042005-10-23 12:57:11 -07001740 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741 Limit processor to maximum C-state
1742 max_cstate=9 overrides any DMI blacklist limit.
1743
Len Brown41c0d862005-12-28 12:43:51 -05001744 processor.nocst [HW,ACPI]
1745 Ignore the _CST method to determine C-states,
1746 instead using the legacy FADT method
1747
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1749 before loading.
1750 See Documentation/ramdisk.txt.
1751
Randy Dunlapa9913042005-10-23 12:57:11 -07001752 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1753 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1755 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001756 psmouse.resetafter= [HW,MOUSE]
1757 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001758 (0 = never).
1759 psmouse.resolution=
1760 [HW,MOUSE] Set desired mouse resolution, in dpi.
1761 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001762 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763 0 = disabled, 1 = enabled (default).
1764
1765 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001766 Format:
1767 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001768
1769 pt. [PARIDE]
1770 See Documentation/paride.txt.
1771
Kay Sieversdc8c8582007-08-15 12:25:38 +02001772 pty.legacy_count=
1773 [KNL] Number of legacy pty's. Overwrites compiled-in
1774 default number.
1775
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001776 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001777
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 r128= [HW,DRM]
1779
1780 raid= [HW,RAID]
1781 See Documentation/md.txt.
1782
Randy Dunlapa9913042005-10-23 12:57:11 -07001783 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001785
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787 See Documentation/ramdisk.txt.
1788
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001789 rcupdate.blimit= [KNL,BOOT]
1790 Set maximum number of finished RCU callbacks to process
1791 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001792
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001793 rcupdate.qhimark= [KNL,BOOT]
1794 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001795 RCU callbacks over which batch limiting is disabled.
1796
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001797 rcupdate.qlowmark= [KNL,BOOT]
1798 Set threshold of queued RCU callbacks below which
1799 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001800
Olof Johanssonffdfc402005-09-06 15:17:19 -07001801 rdinit= [KNL]
1802 Format: <full_path>
1803 Run specified binary instead of /init from the ramdisk,
1804 used for early userspace startup. See initrd.
1805
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001806 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001808 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809
Paul Jackson46b6d942008-07-04 10:00:09 -07001810 relax_domain_level=
1811 [KNL, SMP] Set scheduler's default relax_domain_level.
1812 See Documentation/cpusets.txt.
1813
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1815
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001816 reservetop= [X86-32]
Zachary Amsden461a9af2006-09-25 23:32:25 -07001817 Format: nn[KMG]
1818 Reserves a hole at the top of the kernel virtual
1819 address space.
1820
Vivek Goyal7e962872006-09-27 01:50:44 -07001821 reset_devices [KNL] Force drivers to reset the underlying device
1822 during initialization.
1823
Randy Dunlapa9913042005-10-23 12:57:11 -07001824 resume= [SWSUSP]
1825 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001827 resume_offset= [SWSUSP]
1828 Specify the offset from the beginning of the partition
1829 given by "resume=" at which the swap header is located,
1830 in <PAGE_SIZE> units (needed only for swap files).
1831 See Documentation/power/swsusp-and-swap-files.txt
1832
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001833 retain_initrd [RAM] Keep initrd memory after extraction
1834
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835 rhash_entries= [KNL,NET]
1836 Set number of hash buckets for route cache
1837
1838 riscom8= [HW,SERIAL]
1839 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1840
1841 ro [KNL] Mount root device read-only on boot
1842
1843 root= [KNL] Root filesystem
1844
1845 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1846 mount the root filesystem
1847
1848 rootflags= [KNL] Set root filesystem mount option string
1849
1850 rootfstype= [KNL] Set root filesystem type
1851
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001852 rootwait [KNL] Wait (indefinitely) for root device to show up.
1853 Useful for devices that are detected asynchronously
1854 (e.g. USB and MMC devices).
1855
James Morris20510f22007-10-16 23:31:32 -07001856 root_plug.vendor_id=
1857 [ROOTPLUG] Override the default vendor ID
1858
1859 root_plug.product_id=
1860 [ROOTPLUG] Override the default product ID
1861
1862 root_plug.debug=
1863 [ROOTPLUG] Enable debugging output
1864
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865 rw [KNL] Mount root device read-write on boot
1866
1867 S [KNL] Run init in single mode
1868
1869 sa1100ir [NET]
1870 See drivers/net/irda/sa1100_ir.c.
1871
Linus Torvalds1da177e2005-04-16 15:20:36 -07001872 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001873
Linus Torvalds1da177e2005-04-16 15:20:36 -07001874 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1875 Format: <io>[,<timeout>[,<isapnp>]]
1876
1877 scsi_debug_*= [SCSI]
1878 See drivers/scsi/scsi_debug.c.
1879
1880 scsi_default_dev_flags=
1881 [SCSI] SCSI default device flags
1882 Format: <integer>
1883
1884 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1885 Format: <vendor>:<model>:<flags>
1886 (flags are integer value)
1887
Randy Dunlap6af66322007-11-14 16:52:25 -08001888 scsi_logging_level= [SCSI] a bit mask of logging levels
1889 See drivers/scsi/scsi_logging.h for bits. Also
1890 settable via sysctl at dev.scsi.logging_level
1891 (/proc/sys/dev/scsi/logging_level).
1892 There is also a nice 'scsi_logging_level' script in the
1893 S390-tools package, available for download at
1894 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001896 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1897 discovered. async scans them in kernel threads,
1898 allowing boot to proceed. none ignores them, expecting
1899 user space to do the scan.
1900
Linus Torvalds1da177e2005-04-16 15:20:36 -07001901 selinux [SELINUX] Disable or enable SELinux at boot time.
1902 Format: { "0" | "1" }
1903 See security/selinux/Kconfig help text.
1904 0 -- disable.
1905 1 -- enable.
1906 Default value is set via kernel config option.
1907 If enabled at boot time, /selinux/disable can be used
1908 later to disable prior to initial policy load.
1909
James Morris4e5ab4c2006-06-09 00:33:33 -07001910 selinux_compat_net =
1911 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001912 Format: { "0" | "1" }
1913 0 -- use new secmark-based packet controls
1914 1 -- use legacy packet controls
1915 Default value is 0 (preferred).
1916 Value can be changed at runtime via
1917 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001918
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001919 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921 shapers= [NET]
1922 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001923
Yinghai Lub05f78f2008-08-22 01:32:50 -07001924 show_msr= [x86] show boot-time MSR settings
1925 Format: { <integer> }
1926 Show boot-time (BIOS-initialized) MSR settings.
1927 The parameter means the number of CPUs to show,
1928 for example 1 means boot CPU only.
1929
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930 sim710= [SCSI,HW]
1931 See header of drivers/scsi/sim710.c.
1932
1933 simeth= [IA-64]
1934 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001935
Linus Torvalds1da177e2005-04-16 15:20:36 -07001936 slram= [HW,MTD]
1937
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001938 slub_debug[=options[,slabs]] [MM, SLUB]
1939 Enabling slub_debug allows one to determine the
1940 culprit if slab objects become corrupted. Enabling
1941 slub_debug can create guard zones around objects and
1942 may poison objects when not in use. Also tracks the
1943 last alloc / free. For more information see
1944 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001945
1946 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001947 Determines the maximum allowed order for slabs.
1948 A high setting may cause OOMs due to memory
1949 fragmentation. For more information see
1950 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001951
1952 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001953 The minimum number of objects per slab. SLUB will
1954 increase the slab order up to slub_max_order to
1955 generate a sufficiently large slab able to contain
1956 the number of objects indicated. The higher the number
1957 of objects the smaller the overhead of tracking slabs
1958 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001959 For more information see Documentation/vm/slub.txt.
1960
1961 slub_min_order= [MM, SLUB]
1962 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001963 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001964 For more information see Documentation/vm/slub.txt.
1965
1966 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001967 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001968 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001969 allocs to different slabs. Debug options disable
1970 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001971 For more information see Documentation/vm/slub.txt.
1972
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973 smart2= [HW]
1974 Format: <io1>[,<io2>[,...,<io8>]]
1975
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001976 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001977 attempt to substitute SMP alternatives once at boot.
1978
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001979 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1980 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1981 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1982 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1983 smsc-ircc2.ircc_irq= [HW] IRQ line
1984 smsc-ircc2.ircc_dma= [HW] DMA channel
1985 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1986 0: Toshiba Satellite 1800 (GP data pin select)
1987 1: Fast pin select (default)
1988 2: ATC IRMode
1989
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990 snd-ad1816a= [HW,ALSA]
1991
1992 snd-ad1848= [HW,ALSA]
1993
1994 snd-ali5451= [HW,ALSA]
1995
1996 snd-als100= [HW,ALSA]
1997
1998 snd-als4000= [HW,ALSA]
1999
2000 snd-azt2320= [HW,ALSA]
2001
2002 snd-cmi8330= [HW,ALSA]
2003
2004 snd-cmipci= [HW,ALSA]
2005
2006 snd-cs4231= [HW,ALSA]
2007
2008 snd-cs4232= [HW,ALSA]
2009
2010 snd-cs4236= [HW,ALSA]
2011
2012 snd-cs4281= [HW,ALSA]
2013
2014 snd-cs46xx= [HW,ALSA]
2015
2016 snd-dt019x= [HW,ALSA]
2017
2018 snd-dummy= [HW,ALSA]
2019
2020 snd-emu10k1= [HW,ALSA]
2021
2022 snd-ens1370= [HW,ALSA]
2023
2024 snd-ens1371= [HW,ALSA]
2025
2026 snd-es968= [HW,ALSA]
2027
2028 snd-es1688= [HW,ALSA]
2029
2030 snd-es18xx= [HW,ALSA]
2031
2032 snd-es1938= [HW,ALSA]
2033
2034 snd-es1968= [HW,ALSA]
2035
2036 snd-fm801= [HW,ALSA]
2037
2038 snd-gusclassic= [HW,ALSA]
2039
2040 snd-gusextreme= [HW,ALSA]
2041
2042 snd-gusmax= [HW,ALSA]
2043
2044 snd-hdsp= [HW,ALSA]
2045
2046 snd-ice1712= [HW,ALSA]
2047
2048 snd-intel8x0= [HW,ALSA]
2049
2050 snd-interwave= [HW,ALSA]
2051
2052 snd-interwave-stb=
2053 [HW,ALSA]
2054
2055 snd-korg1212= [HW,ALSA]
2056
2057 snd-maestro3= [HW,ALSA]
2058
2059 snd-mpu401= [HW,ALSA]
2060
2061 snd-mtpav= [HW,ALSA]
2062
2063 snd-nm256= [HW,ALSA]
2064
2065 snd-opl3sa2= [HW,ALSA]
2066
2067 snd-opti92x-ad1848=
2068 [HW,ALSA]
2069
2070 snd-opti92x-cs4231=
2071 [HW,ALSA]
2072
2073 snd-opti93x= [HW,ALSA]
2074
2075 snd-pmac= [HW,ALSA]
2076
2077 snd-rme32= [HW,ALSA]
2078
2079 snd-rme96= [HW,ALSA]
2080
2081 snd-rme9652= [HW,ALSA]
2082
2083 snd-sb8= [HW,ALSA]
2084
2085 snd-sb16= [HW,ALSA]
2086
2087 snd-sbawe= [HW,ALSA]
2088
2089 snd-serial= [HW,ALSA]
2090
2091 snd-sgalaxy= [HW,ALSA]
2092
2093 snd-sonicvibes= [HW,ALSA]
2094
2095 snd-sun-amd7930=
2096 [HW,ALSA]
2097
2098 snd-sun-cs4231= [HW,ALSA]
2099
2100 snd-trident= [HW,ALSA]
2101
2102 snd-usb-audio= [HW,ALSA,USB]
2103
2104 snd-via82xx= [HW,ALSA]
2105
2106 snd-virmidi= [HW,ALSA]
2107
2108 snd-wavefront= [HW,ALSA]
2109
2110 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002111
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002112 softlockup_panic=
2113 [KNL] Should the soft-lockup detector generate panics.
2114
Linus Torvalds1da177e2005-04-16 15:20:36 -07002115 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2116 See Documentation/sonypi.txt
2117
2118 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2119 See Documentation/specialix.txt.
2120
2121 spia_io_base= [HW,MTD]
2122 spia_fio_base=
2123 spia_pedr=
2124 spia_peddr=
2125
2126 sscape= [HW,OSS]
2127 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002128
Linus Torvalds1da177e2005-04-16 15:20:36 -07002129 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2130 See Documentation/scsi/st.txt.
2131
Linus Torvalds1da177e2005-04-16 15:20:36 -07002132 sti= [PARISC,HW]
2133 Format: <num>
2134 Set the STI (builtin display/keyboard on the HP-PARISC
2135 machines) console (graphic card) which should be used
2136 as the initial boot-console.
2137 See also comment in drivers/video/console/sticore.c.
2138
2139 sti_font= [HW]
2140 See comment in drivers/video/console/sticore.c.
2141
2142 stifb= [HW]
2143 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2144
Greg Banks42a7fc42007-03-06 01:42:23 -08002145 sunrpc.pool_mode=
2146 [NFS]
2147 Control how the NFS server code allocates CPUs to
2148 service thread pools. Depending on how many NICs
2149 you have and where their interrupts are bound, this
2150 option will affect which CPUs will do NFS serving.
2151 Note: this parameter cannot be changed while the
2152 NFS server is running.
2153
2154 auto the server chooses an appropriate mode
2155 automatically using heuristics
2156 global a single global pool contains all CPUs
2157 percpu one pool for each CPU
2158 pernode one pool for each NUMA node (equivalent
2159 to global on non-NUMA machines)
2160
Linus Torvalds1da177e2005-04-16 15:20:36 -07002161 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002162
Linus Torvalds1da177e2005-04-16 15:20:36 -07002163 switches= [HW,M68k]
2164
2165 sym53c416= [HW,SCSI]
2166 See header of drivers/scsi/sym53c416.c.
2167
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002168 sysrq_always_enabled
2169 [KNL]
2170 Ignore sysrq setting - this boot parameter will
2171 neutralize any effect of /proc/sys/kernel/sysrq.
2172 Useful for debugging.
2173
Linus Torvalds1da177e2005-04-16 15:20:36 -07002174 t128= [HW,SCSI]
2175 See header of drivers/scsi/t128.c.
2176
2177 tdfx= [HW,DRM]
2178
David Brownell77437fd2008-07-23 21:28:33 -07002179 test_suspend= [SUSPEND]
2180 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2181 standby suspend) as the system sleep state to briefly
2182 enter during system startup. The system is woken from
2183 this state using a wakeup-capable RTC alarm.
2184
Linus Torvalds1da177e2005-04-16 15:20:36 -07002185 thash_entries= [KNL,NET]
2186 Set number of hash buckets for TCP connection
2187
Len Brownf8707ec2007-08-12 00:12:54 -04002188 thermal.act= [HW,ACPI]
2189 -1: disable all active trip points in all thermal zones
2190 <degrees C>: override all lowest active trip points
2191
Len Brownc52a7412007-08-14 15:49:32 -04002192 thermal.crt= [HW,ACPI]
2193 -1: disable all critical trip points in all thermal zones
2194 <degrees C>: lower all critical trip points
2195
Len Brownf5487142007-08-12 00:12:44 -04002196 thermal.nocrt= [HW,ACPI]
2197 Set to disable actions on ACPI thermal zone
2198 critical and hot trip points.
2199
Len Brown72b33ef2007-08-12 00:12:17 -04002200 thermal.off= [HW,ACPI]
2201 1: disable ACPI thermal control
2202
Len Browna70cdc52007-08-12 00:12:35 -04002203 thermal.psv= [HW,ACPI]
2204 -1: disable all passive trip points
2205 <degrees C>: override all passive trip points to this value
2206
Len Brown730ff342007-08-12 00:12:26 -04002207 thermal.tzp= [HW,ACPI]
2208 Specify global default ACPI thermal zone polling rate
2209 <deci-seconds>: poll all this frequency
2210 0: no polling (default)
2211
Linus Torvalds1da177e2005-04-16 15:20:36 -07002212 tmscsim= [HW,SCSI]
2213 See comment before function dc390_setup() in
2214 drivers/scsi/tmscsim.c.
2215
2216 tp720= [HW,PS2]
2217
2218 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002219 Format:
2220 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2221
Randy Dunlapa9913042005-10-23 12:57:11 -07002222 turbografx.map[2|3]= [HW,JOY]
2223 TurboGraFX parallel port interface
2224 Format:
2225 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002226 See also Documentation/input/joystick-parport.txt
2227
2228 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2229 See header of drivers/scsi/u14-34f.c.
2230
2231 uart401= [HW,OSS]
2232 Format: <io>,<irq>
2233
2234 uart6850= [HW,OSS]
2235 Format: <io>,<irq>
2236
Alan Stern5f8364b2006-12-05 16:29:55 -05002237 uhci-hcd.ignore_oc=
2238 [USB] Ignore overcurrent events (default N).
2239 Some badly-designed motherboards generate lots of
2240 bogus events, for ports that aren't wired to
2241 anything. Set this parameter to avoid log spamming.
2242 Note that genuine overcurrent events won't be
2243 reported either.
2244
Simon Arlotte3a61b02008-07-19 23:32:54 +01002245 unknown_nmi_panic
2246 [X86-32,X86-64]
2247 Set unknown_nmi_panic=1 early on boot.
2248
Alan Sternb5e795f2007-02-20 15:00:53 -05002249 usbcore.autosuspend=
2250 [USB] The autosuspend time delay (in seconds) used
2251 for newly-detected USB devices (default 2). This
2252 is the time required before an idle device will be
2253 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002254 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002255
Linus Torvalds1da177e2005-04-16 15:20:36 -07002256 usbhid.mousepoll=
2257 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002258
Paul Jackson200001e2008-06-25 05:44:46 -07002259 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2260 kernel's map of available physical RAM.
2261
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002262 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002263 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002264 vdso=1: enable VDSO (default)
2265 vdso=0: disable VDSO mapping
2266
Roland McGrathaf65d642008-01-30 13:30:43 +01002267 vdso32= [X86-32,X86-64]
2268 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2269 vdso32=1: enable 32-bit VDSO (default)
2270 vdso32=0: disable 32-bit VDSO mapping
2271
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002272 vector= [IA-64,SMP]
2273 vector=percpu: enable percpu vector domain
2274
Linus Torvalds1da177e2005-04-16 15:20:36 -07002275 video= [FB] Frame buffer configuration
2276 See Documentation/fb/modedb.txt.
2277
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002278 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002279 See Documentation/i386/boot.txt and
2280 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002281 Use vga=ask for menu.
2282 This is actually a boot loader parameter; the value is
2283 passed to the kernel using a special protocol.
2284
Randy Dunlapa9913042005-10-23 12:57:11 -07002285 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002286 size of <nn>. This can be used to increase the
2287 minimum size (128MB on x86). It can also be used to
2288 decrease the size and leave more room for directly
2289 mapped kernel RAM.
2290
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002291 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2292 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002293
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002294 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2295 Format: <command>
2296
2297 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2298 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002299
Linus Torvalds1da177e2005-04-16 15:20:36 -07002300 waveartist= [HW,OSS]
2301 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002302
Linus Torvalds1da177e2005-04-16 15:20:36 -07002303 wd33c93= [HW,SCSI]
2304 See header of drivers/scsi/wd33c93.c.
2305
2306 wd7000= [HW,SCSI]
2307 See header of drivers/scsi/wd7000.c.
2308
2309 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002310 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002311
2312 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2313 xd_geo= See header of drivers/block/xd.c.
2314
2315 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002316 Format:
2317 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002318
Andi Kleena62eaf12006-02-16 23:41:58 +01002319 norandmaps Don't use address space randomization
2320 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2321
Randy Dunlapa9913042005-10-23 12:57:11 -07002322______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002323
2324TODO:
2325
2326 Add documentation for ALSA options.
2327 Add more DRM drivers.