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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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200800 i8042.dumbkbd [HW] Pretend that controller can only read data from
801 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 (Don't attempt to blink the leds)
803 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500804 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400805 i8042.noloop [HW] Disable the AUX Loopback command while probing
806 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 i8042.nomux [HW] Don't check presence of an active multiplexing
808 controller
809 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
810 controllers
811 i8042.panicblink=
812 [HW] Frequency with which keyboard LEDs should blink
813 when kernel panics (default is 0.5 sec)
814 i8042.reset [HW] Reset the controller during init and cleanup
815 i8042.unlock [HW] Unlock (ignore) the keylock
816
817 i810= [HW,DRM]
818
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700819 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
820 indicates that the driver is running on unsupported
821 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
823 does not match list of supported models.
824 i8k.power_status
825 [HW] Report power status in /proc/i8k
826 (disabled by default)
827 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
828 capability is set.
829
830 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
831 See Documentation/mca.txt.
832
833 icn= [HW,ISDN]
834 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
835
836 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200837 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100838 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100841 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842
Andi Kleenf039b752007-05-02 19:27:12 +0200843 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800844 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200845 Poll forces a polling idle loop that can slightly improves the performance
846 of waking up a idle CPU, but will use a lot of power and make the system
847 run hot. Not recommended.
848 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
849 to not use it because it doesn't save as much power as a normal idle
850 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
851 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800852 idle=halt. Halt is forced to be used for CPU idle.
853 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800854 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700855
Denis Cheng594765a2008-02-06 02:57:49 +0100856 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
857 Claim all unknown PCI IDE storage controllers.
858
Ingo Molnar792908222006-12-06 20:40:51 -0800859 ignore_loglevel [KNL]
860 Ignore loglevel setting - this will print /all/
861 kernel messages to the console. Useful for debugging.
862
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 ihash_entries= [KNL]
864 Set number of hash buckets for inode cache.
865
866 in2000= [HW,SCSI]
867 See header of drivers/scsi/in2000.c.
868
869 init= [KNL]
870 Format: <full_path>
871 Run specified binary instead of /sbin/init as init
872 process.
873
874 initcall_debug [KNL] Trace initcalls as they are executed. Useful
875 for working out where the kernel is dying during
876 startup.
877
878 initrd= [BOOT] Specify the location of the initial ramdisk
879
880 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
881 Format: <irq>
882
883 inttest= [IA64]
884
Pavel Machekb552da82008-03-19 15:58:11 +0100885 iommu= [x86]
886 off
887 force
888 noforce
889 biomerge
890 panic
891 nopanic
892 merge
893 nomerge
894 forcesac
895 soft
896
897
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700898 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
899 off
900 Disable intel iommu driver.
901 igfx_off [Default Off]
902 By default, gfx is mapped as normal device. If a gfx
903 device has a dedicated DMAR unit, the DMAR unit is
904 bypassed by not enabling DMAR with this option. In
905 this case, gfx device will use physical address for
906 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700907 forcedac [x86_64]
908 With this option iommu will not optimize to look
909 for io virtual address below 32 bit forcing dual
910 address cycle on pci bus for cards supporting greater
911 than 32 bit addressing. The default is to look
912 for translation below 32 bit and if not available
913 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800914 strict [Default Off]
915 With this option on every unmap_single operation will
916 result in a hardware IOTLB flush operation as opposed
917 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700918
Rene Hermanb02aae92008-01-30 13:30:05 +0100919 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100920 0x80
921 Standard port 0x80 based delay
922 0xed
923 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100924 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100925 Simple two microseconds delay
926 none
927 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100928
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 io7= [HW] IO7 for Marvel based alpha systems
930 See comment before marvel_specify_io7 in
931 arch/alpha/kernel/core_marvel.c.
932
933 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400934 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935
936 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700937 See comment before ip2_setup() in
938 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939
940 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
941 See header of drivers/scsi/ips.c.
942
Simon Horman72c4a132006-09-13 19:57:18 -0700943 ports= [IP_VS_FTP] IPVS ftp helper module
944 Default is 21.
945 Up to 8 (IP_VS_APP_MAX_PORTS) ports
946 may be specified.
947 Format: <port>,<port>....
948
Alan Cox200803d2005-06-28 20:45:18 -0700949 irqfixup [HW]
950 When an interrupt is not handled search all handlers
951 for it. Intended to get systems with badly broken
952 firmware running.
953
954 irqpoll [HW]
955 When an interrupt is not handled search all handlers
956 for it. Also check all handlers each timer
957 interrupt. Intended to get systems with badly broken
958 firmware running.
959
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700961 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962
963 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800964 Format:
965 <cpu number>,...,<cpu number>
966 or
967 <cpu number>-<cpu number> (must be a positive range in ascending order)
968 or a mixture
969 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970 This option can be used to specify one or more CPUs
971 to isolate from the general SMP balancing and scheduling
972 algorithms. The only way to move a process onto or off
973 an "isolated" CPU is via the CPU affinity syscalls.
974 <cpu number> begins at 0 and the maximum value is
975 "number of CPUs in system - 1".
976
977 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700978 alternative -- manually setting the CPU mask of all
979 tasks in the system -- can cause problems and
980 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981
Randy Dunlapa9913042005-10-23 12:57:11 -0700982 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983
984 js= [HW,JOY] Analog joystick
985 See Documentation/input/joystick.txt.
986
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700987 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700988 specifies the amount of memory usable by the kernel
989 for non-movable allocations. The requested amount is
990 spread evenly throughout all nodes in the system. The
991 remaining memory in each node is used for Movable
992 pages. In the event, a node is too small to have both
993 kernelcore and Movable pages, kernelcore pages will
994 take priority and other nodes will have a larger number
995 of kernelcore pages. The Movable zone is used for the
996 allocation of pages that may be reclaimed or moved
997 by the page migration subsystem. This means that
998 HugeTLB pages may not be allocated from this zone.
999 Note that allocations like PTEs-from-HighMem still
1000 use the HighMem zone if it exists, and the Normal
1001 zone if it does not.
1002
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001003 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -07001004 is similar to kernelcore except it specifies the
1005 amount of memory used for migratable allocations.
1006 If both kernelcore and movablecore is specified,
1007 then kernelcore will be at *least* the specified
1008 value but may be more. If movablecore on its own
1009 is specified, the administrator must be careful
1010 that the amount of memory usable for all allocations
1011 is not too small.
1012
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 keepinitrd [HW,ARM]
1014
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001015 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 in oops dumps.
1017
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001018 kgdboc= [HW] kgdb over consoles.
1019 Requires a tty driver that supports console polling.
1020 (only serial suported for now)
1021 Format: <serial_device>[,baud]
1022
Florian Fainelli9bed90c62008-08-23 18:54:37 +02001023 kmac= [MIPS] korina ethernet MAC address.
1024 Configure the RouterBoard 532 series on-chip
1025 Ethernet adapter MAC address.
1026
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027 l2cr= [PPC]
1028
Robert Brosea78bfbf2008-03-29 07:20:23 +11001029 l3cr= [PPC]
1030
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001031 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001032 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001034 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001035 C2 power state.
1036
FD Camifcb71f62008-01-06 19:08:56 +01001037 libata.dma= [LIBATA] DMA control
1038 libata.dma=0 Disable all PATA and SATA DMA
1039 libata.dma=1 PATA and SATA Disk DMA only
1040 libata.dma=2 ATAPI (CDROM) DMA only
1041 libata.dma=4 Compact Flash DMA only
1042 Combinations also work, so libata.dma=3 enables DMA
1043 for disks and CDROMs, but not CFs.
1044
Dave Jones78e70c22007-09-27 11:50:13 -04001045 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1046 when set.
1047 Format: <int>
1048
Tejun Heo33267322008-02-13 09:15:09 +09001049 libata.force= [LIBATA] Force configurations. The format is comma
1050 separated list of "[ID:]VAL" where ID is
1051 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1052 matching port, link or device. Basically, it matches
1053 the ATA ID string printed on console by libata. If
1054 the whole ID part is omitted, the last PORT and DEVICE
1055 values are used. If ID hasn't been specified yet, the
1056 configuration applies to all ports, links and devices.
1057
1058 If only DEVICE is omitted, the parameter applies to
1059 the port and all links and devices behind it. DEVICE
1060 number of 0 either selects the first device or the
1061 first fan-out link behind PMP device. It does not
1062 select the host link. DEVICE number of 15 selects the
1063 host link and device attached to it.
1064
1065 The VAL specifies the configuration to force. As long
1066 as there's no ambiguity shortcut notation is allowed.
1067 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1068 The following configurations can be forced.
1069
1070 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1071 Any ID with matching PORT is used.
1072
1073 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1074
1075 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1076 udma[/][16,25,33,44,66,100,133] notation is also
1077 allowed.
1078
1079 * [no]ncq: Turn on or off NCQ.
1080
Tejun Heo05944bd2008-08-13 20:19:09 +09001081 * nohrst, nosrst, norst: suppress hard, soft
1082 and both resets.
1083
Tejun Heo33267322008-02-13 09:15:09 +09001084 If there are multiple matching configurations changing
1085 the same attribute, the last one is used.
1086
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 load_ramdisk= [RAM] List of ramdisks to load from floppy
1088 See Documentation/ramdisk.txt.
1089
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001090 lockd.nlm_grace_period=P [NFS] Assign grace period.
1091 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001093 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1094 Format: <integer>
1095
1096 lockd.nlm_timeout=T [NFS] Assign timeout value.
1097 Format: <integer>
1098
1099 lockd.nlm_udpport=M [NFS] Assign UDP port.
1100 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101
1102 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1103 Format: <irq>
1104
1105 loglevel= All Kernel Messages with a loglevel smaller than the
1106 console loglevel will be printed to the console. It can
1107 also be changed with klogd or other programs. The
1108 loglevels are defined as follows:
1109
1110 0 (KERN_EMERG) system is unusable
1111 1 (KERN_ALERT) action must be taken immediately
1112 2 (KERN_CRIT) critical conditions
1113 3 (KERN_ERR) error conditions
1114 4 (KERN_WARNING) warning conditions
1115 5 (KERN_NOTICE) normal but significant condition
1116 6 (KERN_INFO) informational
1117 7 (KERN_DEBUG) debug-level messages
1118
1119 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001120 Format: { n | nk | nM }
1121 n must be a power of two. The default size
1122 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123
Randy Dunlapaccaa242007-10-16 01:29:37 -07001124 logo.nologo [FB] Disables display of the built-in Linux logo.
1125 This may be used to provide more screen space for
1126 kernel log messages and is useful when debugging
1127 kernel boot problems.
1128
Linus Torvalds1da177e2005-04-16 15:20:36 -07001129 lp=0 [LP] Specify parallel ports to use, e.g,
1130 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1131 lp=reset first parallel port). 'lp=0' disables the
1132 lp=auto printer driver. 'lp=reset' (which can be
1133 specified in addition to the ports) causes
1134 attached printers to be reset. Using
1135 lp=port1,port2,... specifies the parallel ports
1136 to associate lp devices with, starting with
1137 lp0. A port specification may be 'none' to skip
1138 that lp device, or a parport name such as
1139 'parport0'. Specifying 'lp=auto' instead of a
1140 port specification list means that device IDs
1141 from each port should be examined, to see if
1142 an IEEE 1284-compliant printer is attached; if
1143 so, the driver will manage that printer.
1144 See also header of drivers/char/lp.c.
1145
1146 lpj=n [KNL]
1147 Sets loops_per_jiffy to given constant, thus avoiding
1148 time-consuming boot-time autodetection (up to 250 ms per
1149 CPU). 0 enables autodetection (default). To determine
1150 the correct value for your kernel, boot with normal
1151 autodetection and see what value is printed. Note that
1152 on SMP systems the preset will be applied to all CPUs,
1153 which is likely to cause problems if your CPUs need
1154 significantly divergent settings. An incorrect value
1155 will cause delays in the kernel to be wrong, leading to
1156 unpredictable I/O errors and other breakage. Although
1157 unlikely, in the extreme case this might damage your
1158 hardware.
1159
1160 ltpc= [NET]
1161 Format: <io>,<irq>,<dma>
1162
Randy Dunlapa9913042005-10-23 12:57:11 -07001163 mac5380= [HW,SCSI] Format:
1164 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165
Randy Dunlapa9913042005-10-23 12:57:11 -07001166 machvec= [IA64] Force the use of a particular machine-vector
1167 (machvec) in a generic kernel.
1168 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169
Randy Dunlapa9913042005-10-23 12:57:11 -07001170 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171 be mounted
1172 Format: <1-256>
1173
1174 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001175 should make use of. maxcpus=n : n >= 0 limits the
1176 kernel to using 'n' processors. n=0 is a special case,
1177 it is equivalent to "nosmp", which also disables
1178 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179
Bob Picco2b2c3752005-06-29 18:00:00 -07001180 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1181 equal to this physical address is ignored.
1182
Randy Dunlapa9913042005-10-23 12:57:11 -07001183 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184 Should be between 1 and 2^32-1.
1185
1186 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001187 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188 Should be between 1 and 16384.
1189
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 mcatest= [IA-64]
1191
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001192 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193
Andi Kleen909dd322007-10-17 18:04:38 +02001194 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1195
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196 md= [HW] RAID subsystems devices and level
1197 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001198
Linus Torvalds1da177e2005-04-16 15:20:36 -07001199 mdacon= [MDA]
1200 Format: <first>,<last>
1201 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001202
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1204 Amount of memory to be used when the kernel is not able
1205 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001206 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 address space collisions. Without memmap= PCI devices
1208 could be placed at addresses belonging to unused RAM.
1209
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001210 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211 memory.
1212
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001213 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214 E820 memory map, as specified by the user.
1215 Such memmap=exactmap lines can be constructed based on
1216 BIOS output or other requirements. See the memmap=nn@ss
1217 option description.
1218
1219 memmap=nn[KMG]@ss[KMG]
1220 [KNL] Force usage of a specific region of memory
1221 Region of memory to be used, from ss to ss+nn.
1222
1223 memmap=nn[KMG]#ss[KMG]
1224 [KNL,ACPI] Mark specific memory as ACPI data.
1225 Region of memory to be used, from ss to ss+nn.
1226
1227 memmap=nn[KMG]$ss[KMG]
1228 [KNL,ACPI] Mark specific memory as reserved.
1229 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001230 Example: Exclude memory from 0x18690000-0x1869ffff
1231 memmap=64K$0x18690000
1232 or
1233 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234
Jeremy Fitzhardinge9f077872008-09-07 01:51:34 -07001235 memory_corruption_check=0/1 [X86]
1236 Some BIOSes seem to corrupt the first 64k of
1237 memory when doing things like suspend/resume.
1238 Setting this option will scan the memory
1239 looking for corruption. Enabling this will
1240 both detect corruption and prevent the kernel
1241 from using the memory being corrupted.
1242 However, its intended as a diagnostic tool; if
1243 repeatable BIOS-originated corruption always
1244 affects the same memory, you can use memmap=
1245 to prevent the kernel from using that memory.
1246
1247 memory_corruption_check_size=size [X86]
1248 By default it checks for corruption in the low
1249 64k, making this memory unavailable for normal
1250 use. Use this parameter to scan for
1251 corruption in more or less memory.
1252
1253 memory_corruption_check_period=seconds [X86]
1254 By default it checks for corruption every 60
1255 seconds. Use this parameter to check at some
1256 other rate. 0 disables periodic checking.
1257
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001258 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001259 Format: <integer>
1260 range: 0,4 : pattern number
1261 default : 0 <disable>
1262
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 meye.*= [HW] Set MotionEye Camera parameters
1264 See Documentation/video4linux/meye.txt.
1265
Andres Salomon8f368812007-10-12 23:04:06 +02001266 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1267 Multi-Function General Purpose Timers on AMD Geode
1268 platforms.
1269
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001270 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1271 the BIOS has incorrectly applied a workaround. TinyBIOS
1272 version 0.98 is known to be affected, 0.99 fixes the
1273 problem by letting the user disable the workaround.
1274
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 mga= [HW,DRM]
1276
Mel Gorman6b74ab92008-07-23 21:26:49 -07001277 mminit_loglevel=
1278 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1279 parameter allows control of the logging verbosity for
1280 the additional memory initialisation checks. A value
1281 of 0 disables mminit logging and a level of 4 will
1282 log everything. Information is printed at KERN_DEBUG
1283 so loglevel=8 may also need to be specified.
1284
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285 mousedev.tap_time=
1286 [MOUSE] Maximum time between finger touching and
1287 leaving touchpad surface for touch to be considered
1288 a tap and be reported as a left button click (for
1289 touchpads working in absolute mode only).
1290 Format: <msecs>
1291 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1292 reporting absolute coordinates, such as tablets
1293 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1294 reporting absolute coordinates, such as tablets
1295
1296 mpu401= [HW,OSS]
1297 Format: <io>,<irq>
1298
1299 MTD_Partition= [MTD]
1300 Format: <name>,<region-number>,<size>,<offset>
1301
Randy Dunlapa9913042005-10-23 12:57:11 -07001302 MTD_Region= [MTD] Format:
1303 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304
1305 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001306 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001307
Ben Dooks9db829f2008-07-03 11:24:29 +01001308 mtdset= [ARM]
1309 ARM/S3C2412 JIVE boot control
1310
1311 See arch/arm/mach-s3c2412/mach-jive.c
1312
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001314 [HW] Make the MicroTouch USB driver use raw coordinates
1315 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316
1317 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1318
1319 NCR_D700= [HW,SCSI]
1320 See header of drivers/scsi/NCR_D700.c.
1321
1322 ncr5380= [HW,SCSI]
1323
1324 ncr53c400= [HW,SCSI]
1325
1326 ncr53c400a= [HW,SCSI]
1327
1328 ncr53c406a= [HW,SCSI]
1329
1330 ncr53c8xx= [HW,SCSI]
1331
1332 netdev= [NET] Network devices parameters
1333 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1334 Note that mem_start is often overloaded to mean
1335 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001336 This usage is only documented in each driver source
1337 file if at all.
1338
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001339 nf_conntrack.acct=
1340 [NETFILTER] Enable connection tracking flow accounting
1341 0 to disable accounting
1342 1 to enable accounting
1343 Default value depends on CONFIG_NF_CT_ACCT that is
1344 going to be removed in 2.6.29.
1345
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001347 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348
1349 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001350 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351
Trond Myklebusta72b4422006-01-03 09:55:41 +01001352 nfs.callback_tcpport=
1353 [NFS] set the TCP port on which the NFSv4 callback
1354 channel should listen.
1355
Trond Myklebust58df0952006-01-03 09:55:57 +01001356 nfs.idmap_cache_timeout=
1357 [NFS] set the maximum lifetime for idmapper cache
1358 entries.
1359
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001360 nfs.enable_ino64=
1361 [NFS] enable 64-bit inode numbers.
1362 If zero, the NFS client will fake up a 32-bit inode
1363 number for the readdir() and stat() syscalls instead
1364 of returning the full 64-bit number.
1365 The default is to return 64-bit inode numbers.
1366
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001367 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1368 when a NMI is triggered.
1369 Format: [state][,regs][,debounce][,die]
1370
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001371 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001373 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001374 emulation library even if a 387 maths coprocessor
1375 is present.
1376
Christoph Lameterc1aee212007-05-31 00:40:47 -07001377 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1378 caches in the slab allocator. Saves per-node memory,
1379 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001380
Randy Dunlapa9913042005-10-23 12:57:11 -07001381 noalign [KNL,ARM]
1382
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383 noapic [SMP,APIC] Tells the kernel to not make use of any
1384 IOAPICs that may be present in the system.
1385
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386 nobats [PPC] Do not use BATs for mapping kernel lowmem
1387 on "Classic" PPC cores.
1388
1389 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001390
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001391 nodelayacct [KNL] Disable per-task delay accounting
1392
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1394
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001395 noefi [X86-32,X86-64] Disable EFI runtime services support.
1396
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 noexec [IA-64]
1398
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001399 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001400 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001402 noexec=off: disable non-executable mappings
1403
1404 noexec32 [X86-64]
1405 This affects only 32-bit executables.
1406 noexec32=on: enable non-executable mappings (default)
1407 read doesn't imply executable mappings
1408 noexec32=off: disable non-executable mappings
1409 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001411 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001412 register save and restore. The kernel will only save
1413 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414
Andi Kleen191679f2008-01-30 13:33:21 +01001415 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1416
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001418
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001419 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420 instruction doesn't work correctly and not to
1421 use it.
1422
1423 nohalt [IA-64] Tells the kernel not to use the power saving
1424 function PAL_HALT_LIGHT when idle. This increases
1425 power-consumption. On the positive side, it reduces
1426 interrupt wake-up latency, which may improve performance
1427 in certain environments such as networked servers or
1428 real-time systems.
1429
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001430 nohz= [KNL] Boottime enable/disable dynamic ticks
1431 Valid arguments: on, off
1432 Default: on
1433
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001434 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001435
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001436 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437 disable unhandled interrupt sources.
1438
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001439 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001440 broken timer IRQ sources.
1441
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442 noisapnp [ISAPNP] Disables ISA PnP code.
1443
1444 noinitrd [RAM] Tells the kernel not to load any configured
1445 initial RAM disk.
1446
1447 nointroute [IA-64]
1448
Tony Luck0aa366f2007-07-20 11:22:30 -07001449 nojitter [IA64] Disables jitter checking for ITC timers.
1450
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001451 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001452
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001453 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001454
Suresh Siddha6e1cb382008-07-10 11:16:58 -07001455 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1456
Suresh Siddhaaf9d1382008-07-11 13:11:57 -07001457 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1458 default x2apic cluster mode on platforms
1459 supporting x2apic.
1460
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461 noltlbs [PPC] Do not use large page/tlb entries for kernel
1462 lowmem mapping on PPC40x.
1463
Horms312f1f02006-02-22 09:57:55 +09001464 nomca [IA-64] Disable machine check abort handling
1465
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001466 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001467
Andres Salomon83d73842007-10-12 23:04:06 +02001468 nomfgpt [X86-32] Disable Multi-Function General Purpose
1469 Timer usage (for AMD Geode machines).
1470
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001471 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001472
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001473 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001474 with UP alternatives
1475
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476 noresidual [PPC] Don't use residual data on PReP machines.
1477
Randy Dunlapa9913042005-10-23 12:57:11 -07001478 noresume [SWSUSP] Disables resume and restores original swap
1479 space.
1480
Linus Torvalds1da177e2005-04-16 15:20:36 -07001481 no-scroll [VGA] Disables scrollback.
1482 This is required for the Braillex ib80-piezo Braille
1483 reader made by F.H. Papenmeier (Germany).
1484
1485 nosbagart [IA-64]
1486
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001487 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001488
Len Brown61ec7562007-08-16 03:34:22 -04001489 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1490 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491
Dave Jones97842212007-07-15 23:41:05 -07001492 nosoftlockup [KNL] Disable the soft-lockup detector.
1493
Linus Torvalds1da177e2005-04-16 15:20:36 -07001494 nosync [HW,M68K] Disables sync negotiation for all devices.
1495
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001496 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497
1498 nousb [USB] Disable the USB subsystem
1499
1500 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001501
Fenghua Yua6c75b862008-03-14 13:57:08 -07001502 nptcg= [IA64] Override max number of concurrent global TLB
1503 purges which is reported from either PAL_VM_SUMMARY or
1504 SAL PALO.
1505
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001506 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1507 one of ['zone', 'node', 'default'] can be specified
1508 This can be set from sysctl after boot.
1509 See Documentation/sysctl/vm.txt for details.
1510
Dave Jonesa61c2d72006-01-07 23:18:19 +00001511 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1512
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001513 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1514 Rather than timing out after 20 ms if an EC
1515 command is not properly ACKed, override the length
1516 of the timeout. We have interrupts disabled while
1517 waiting for the ACK, so if this is set too high
1518 interrupts *may* be lost!
1519
Linus Torvalds1da177e2005-04-16 15:20:36 -07001520 opl3= [HW,OSS]
1521 Format: <io>
1522
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 oprofile.timer= [HW]
1524 Use timer interrupt instead of performance counters
1525
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526 osst= [HW,SCSI] SCSI Tape Driver
1527 Format: <buffer_size>,<write_threshold>
1528 See also Documentation/scsi/st.txt.
1529
1530 panic= [KNL] Kernel behaviour on panic
1531 Format: <timeout>
1532
1533 parkbd.port= [HW] Parallel port number the keyboard adapter is
1534 connected to, default is 0.
1535 Format: <parport#>
1536 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1537 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001538 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539
Randy Dunlapa9913042005-10-23 12:57:11 -07001540 parport= [HW,PPT] Specify parallel ports. 0 disables.
1541 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1542 Use 'auto' to force the driver to use any
1543 IRQ/DMA settings detected (the default is to
1544 ignore detected IRQ/DMA settings because of
1545 possible conflicts). You can specify the base
1546 address, IRQ, and DMA settings; IRQ and DMA
1547 should be numbers, or 'auto' (for using detected
1548 settings on that particular port), or 'nofifo'
1549 (to avoid using a FIFO even if it is detected).
1550 Parallel ports are assigned in the order they
1551 are specified on the command line, starting
1552 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553
Randy Dunlapa9913042005-10-23 12:57:11 -07001554 parport_init_mode= [HW,PPT]
1555 Configure VIA parallel port to operate in
1556 a specific mode. This is necessary on Pegasos
1557 computer where firmware has no options for setting
1558 up parallel port mode and sets it to spp.
1559 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001560 Format: [spp|ps2|epp|ecp|ecpepp]
1561
Randy Dunlapa9913042005-10-23 12:57:11 -07001562 pas2= [HW,OSS] Format:
1563 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1564
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565 pas16= [HW,SCSI]
1566 See header of drivers/scsi/pas16.c.
1567
Andrew Mortondd287792006-03-23 03:00:57 -08001568 pause_on_oops=
1569 Halt all CPUs after the first oops has been printed for
1570 the specified number of seconds. This is to be used if
1571 your oopses keep scrolling off the screen.
1572
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573 pcbit= [HW,ISDN]
1574
1575 pcd. [PARIDE]
1576 See header of drivers/block/paride/pcd.c.
1577 See also Documentation/paride.txt.
1578
Randy Dunlapa9913042005-10-23 12:57:11 -07001579 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001580 off [X86-32] don't probe for the PCI bus
1581 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001582 the hardware directly. Use this if your machine
1583 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001584 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001585 hardware access methods are allowed. Use this
1586 if you experience crashes upon bootup and you
1587 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001588 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001589 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001590 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001591 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001592 noaer [PCIE] If the PCIEAER kernel config parameter is
1593 enabled, this kernel boot option can be used to
1594 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001595 nodomains [PCI] Disable support for multiple PCI
1596 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001597 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001598 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001599 nomsi [MSI] If the PCI_MSI kernel config parameter is
1600 enabled, this kernel boot option can be used to
1601 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001602 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001603 routing table. These calls are known to be buggy
1604 on several machines and they hang the machine
1605 when used, but on other computers it's the only
1606 way to get the interrupt routing table. Try
1607 this option if the kernel is unable to allocate
1608 IRQs or discover secondary PCI buses on your
1609 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001610 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001611 Use with caution as certain devices share
1612 address decoders between ROMs and other
1613 resources.
Gary Hadebb71ad82008-05-12 13:57:46 -07001614 norom [X86-32,X86_64] Do not assign address space to
1615 expansion ROMs that do not already have
1616 BIOS assigned address ranges.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001617 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001618 assigned automatically to PCI devices. You can
1619 make the kernel exclude IRQs of your ISA cards
1620 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001621 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001622 of the PIRQ table (normally generated
1623 by the BIOS) if it is outside the
1624 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001625 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001626 useful if the kernel is unable to find your
1627 secondary buses and you want to tell it
1628 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001629 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001630 numbers ourselves, overriding
1631 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001632 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001633 in the BIOS $PIR table. This is needed on
1634 some systems with broken BIOSes, notably
1635 some HP Pavilion N5400 and Omnibook XE3
1636 notebooks. This will have no effect if ACPI
1637 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001638 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001639 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001640 use_crs [X86-32] Use _CRS for PCI resource
1641 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001642 routeirq Do IRQ routing for all PCI devices.
1643 This is normally done in pci_enable_device(),
1644 so this option is a temporary workaround
1645 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001646 skip_isa_align [X86] do not align io start addr, so can
1647 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001648 firmware [ARM] Do not re-enumerate the bus but instead
1649 just use the configuration from the
1650 bootloader. This is currently used on
1651 IXP2000 systems where the bus has to be
1652 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001653 noearly [X86] Don't do any early type 1 scanning.
1654 This might help on some broken boards which
1655 machine check when some devices' config space
1656 is read. But various workarounds are disabled
1657 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001658 bfsort Sort PCI devices into breadth-first order.
1659 This sorting is done to get a device
1660 order compatible with older (<= 2.4) kernels.
1661 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001662 cbiosize=nn[KMG] The fixed amount of bus space which is
1663 reserved for the CardBus bridge's IO window.
1664 The default value is 256 bytes.
1665 cbmemsize=nn[KMG] The fixed amount of bus space which is
1666 reserved for the CardBus bridge's memory
1667 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001668
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669 pcmv= [HW,PCMCIA] BadgePAD 4
1670
1671 pd. [PARIDE]
1672 See Documentation/paride.txt.
1673
1674 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1675 boot time.
1676 Format: { 0 | 1 }
1677 See arch/parisc/kernel/pdc_chassis.c
1678
1679 pf. [PARIDE]
1680 See Documentation/paride.txt.
1681
1682 pg. [PARIDE]
1683 See Documentation/paride.txt.
1684
1685 pirq= [SMP,APIC] Manual mp-table setup
1686 See Documentation/i386/IO-APIC.txt.
1687
1688 plip= [PPT,NET] Parallel port network link
1689 Format: { parport<nr> | timid | 0 }
1690 See also Documentation/parport.txt.
1691
Thomas Gleixnerde32a2432008-07-12 05:33:30 +02001692 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1693 Override pmtimer IOPort with a hex value.
1694 e.g. pmtmr=0x508
1695
Linus Torvalds1da177e2005-04-16 15:20:36 -07001696 pnpacpi= [ACPI]
1697 { off }
1698
1699 pnpbios= [ISAPNP]
1700 { on | off | curr | res | no-curr | no-res }
1701
1702 pnp_reserve_irq=
1703 [ISAPNP] Exclude IRQs for the autoconfiguration
1704
1705 pnp_reserve_dma=
1706 [ISAPNP] Exclude DMAs for the autoconfiguration
1707
1708 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001709 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710
1711 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001712 [ISAPNP] Exclude memory regions for the
1713 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714 Ranges are in pairs (memory base and size).
1715
Ingo Molnar45807a12007-07-15 23:40:10 -07001716 print-fatal-signals=
1717 [KNL] debug: print fatal signals
1718 print-fatal-signals=1: print segfault info to
1719 the kernel console.
1720 default: off.
1721
Randy Dunlape84845c2007-07-15 23:40:25 -07001722 printk.time= Show timing data prefixed to each printk message line
1723 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1724
Linus Torvalds1da177e2005-04-16 15:20:36 -07001725 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001726 Format: [schedule,]<number>
1727 Param: "schedule" - profile schedule points.
1728 Param: <number> - step/bucket size as a power of 2 for
1729 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001730 Param: "sleep" - profile D-state sleeping (millisecs).
1731 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001732 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733
Randy Dunlapa9913042005-10-23 12:57:11 -07001734 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735 Limit processor to maximum C-state
1736 max_cstate=9 overrides any DMI blacklist limit.
1737
Len Brown41c0d862005-12-28 12:43:51 -05001738 processor.nocst [HW,ACPI]
1739 Ignore the _CST method to determine C-states,
1740 instead using the legacy FADT method
1741
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1743 before loading.
1744 See Documentation/ramdisk.txt.
1745
Randy Dunlapa9913042005-10-23 12:57:11 -07001746 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1747 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1749 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001750 psmouse.resetafter= [HW,MOUSE]
1751 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752 (0 = never).
1753 psmouse.resolution=
1754 [HW,MOUSE] Set desired mouse resolution, in dpi.
1755 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001756 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757 0 = disabled, 1 = enabled (default).
1758
1759 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001760 Format:
1761 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001762
1763 pt. [PARIDE]
1764 See Documentation/paride.txt.
1765
Kay Sieversdc8c8582007-08-15 12:25:38 +02001766 pty.legacy_count=
1767 [KNL] Number of legacy pty's. Overwrites compiled-in
1768 default number.
1769
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001770 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001771
Linus Torvalds1da177e2005-04-16 15:20:36 -07001772 r128= [HW,DRM]
1773
1774 raid= [HW,RAID]
1775 See Documentation/md.txt.
1776
Randy Dunlapa9913042005-10-23 12:57:11 -07001777 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001779
Linus Torvalds1da177e2005-04-16 15:20:36 -07001780 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781 See Documentation/ramdisk.txt.
1782
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001783 rcupdate.blimit= [KNL,BOOT]
1784 Set maximum number of finished RCU callbacks to process
1785 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001786
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001787 rcupdate.qhimark= [KNL,BOOT]
1788 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001789 RCU callbacks over which batch limiting is disabled.
1790
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001791 rcupdate.qlowmark= [KNL,BOOT]
1792 Set threshold of queued RCU callbacks below which
1793 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001794
Olof Johanssonffdfc402005-09-06 15:17:19 -07001795 rdinit= [KNL]
1796 Format: <full_path>
1797 Run specified binary instead of /init from the ramdisk,
1798 used for early userspace startup. See initrd.
1799
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001800 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001801 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001802 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001803
Paul Jackson46b6d942008-07-04 10:00:09 -07001804 relax_domain_level=
1805 [KNL, SMP] Set scheduler's default relax_domain_level.
1806 See Documentation/cpusets.txt.
1807
Linus Torvalds1da177e2005-04-16 15:20:36 -07001808 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1809
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001810 reservetop= [X86-32]
Zachary Amsden461a9aff2006-09-25 23:32:25 -07001811 Format: nn[KMG]
1812 Reserves a hole at the top of the kernel virtual
1813 address space.
1814
Vivek Goyal7e962872006-09-27 01:50:44 -07001815 reset_devices [KNL] Force drivers to reset the underlying device
1816 during initialization.
1817
Randy Dunlapa9913042005-10-23 12:57:11 -07001818 resume= [SWSUSP]
1819 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001821 resume_offset= [SWSUSP]
1822 Specify the offset from the beginning of the partition
1823 given by "resume=" at which the swap header is located,
1824 in <PAGE_SIZE> units (needed only for swap files).
1825 See Documentation/power/swsusp-and-swap-files.txt
1826
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001827 retain_initrd [RAM] Keep initrd memory after extraction
1828
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 rhash_entries= [KNL,NET]
1830 Set number of hash buckets for route cache
1831
1832 riscom8= [HW,SERIAL]
1833 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1834
1835 ro [KNL] Mount root device read-only on boot
1836
1837 root= [KNL] Root filesystem
1838
1839 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1840 mount the root filesystem
1841
1842 rootflags= [KNL] Set root filesystem mount option string
1843
1844 rootfstype= [KNL] Set root filesystem type
1845
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001846 rootwait [KNL] Wait (indefinitely) for root device to show up.
1847 Useful for devices that are detected asynchronously
1848 (e.g. USB and MMC devices).
1849
James Morris20510f22007-10-16 23:31:32 -07001850 root_plug.vendor_id=
1851 [ROOTPLUG] Override the default vendor ID
1852
1853 root_plug.product_id=
1854 [ROOTPLUG] Override the default product ID
1855
1856 root_plug.debug=
1857 [ROOTPLUG] Enable debugging output
1858
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859 rw [KNL] Mount root device read-write on boot
1860
1861 S [KNL] Run init in single mode
1862
1863 sa1100ir [NET]
1864 See drivers/net/irda/sa1100_ir.c.
1865
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001867
Linus Torvalds1da177e2005-04-16 15:20:36 -07001868 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1869 Format: <io>[,<timeout>[,<isapnp>]]
1870
1871 scsi_debug_*= [SCSI]
1872 See drivers/scsi/scsi_debug.c.
1873
1874 scsi_default_dev_flags=
1875 [SCSI] SCSI default device flags
1876 Format: <integer>
1877
1878 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1879 Format: <vendor>:<model>:<flags>
1880 (flags are integer value)
1881
Randy Dunlap6af66322007-11-14 16:52:25 -08001882 scsi_logging_level= [SCSI] a bit mask of logging levels
1883 See drivers/scsi/scsi_logging.h for bits. Also
1884 settable via sysctl at dev.scsi.logging_level
1885 (/proc/sys/dev/scsi/logging_level).
1886 There is also a nice 'scsi_logging_level' script in the
1887 S390-tools package, available for download at
1888 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001889
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001890 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1891 discovered. async scans them in kernel threads,
1892 allowing boot to proceed. none ignores them, expecting
1893 user space to do the scan.
1894
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895 selinux [SELINUX] Disable or enable SELinux at boot time.
1896 Format: { "0" | "1" }
1897 See security/selinux/Kconfig help text.
1898 0 -- disable.
1899 1 -- enable.
1900 Default value is set via kernel config option.
1901 If enabled at boot time, /selinux/disable can be used
1902 later to disable prior to initial policy load.
1903
James Morris4e5ab4c2006-06-09 00:33:33 -07001904 selinux_compat_net =
1905 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001906 Format: { "0" | "1" }
1907 0 -- use new secmark-based packet controls
1908 1 -- use legacy packet controls
1909 Default value is 0 (preferred).
1910 Value can be changed at runtime via
1911 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001912
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001913 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914
Linus Torvalds1da177e2005-04-16 15:20:36 -07001915 shapers= [NET]
1916 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001917
Yinghai Lub05f78f2008-08-22 01:32:50 -07001918 show_msr= [x86] show boot-time MSR settings
1919 Format: { <integer> }
1920 Show boot-time (BIOS-initialized) MSR settings.
1921 The parameter means the number of CPUs to show,
1922 for example 1 means boot CPU only.
1923
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924 sim710= [SCSI,HW]
1925 See header of drivers/scsi/sim710.c.
1926
1927 simeth= [IA-64]
1928 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001929
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930 slram= [HW,MTD]
1931
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001932 slub_debug[=options[,slabs]] [MM, SLUB]
1933 Enabling slub_debug allows one to determine the
1934 culprit if slab objects become corrupted. Enabling
1935 slub_debug can create guard zones around objects and
1936 may poison objects when not in use. Also tracks the
1937 last alloc / free. For more information see
1938 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001939
1940 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001941 Determines the maximum allowed order for slabs.
1942 A high setting may cause OOMs due to memory
1943 fragmentation. For more information see
1944 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001945
1946 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001947 The minimum number of objects per slab. SLUB will
1948 increase the slab order up to slub_max_order to
1949 generate a sufficiently large slab able to contain
1950 the number of objects indicated. The higher the number
1951 of objects the smaller the overhead of tracking slabs
1952 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001953 For more information see Documentation/vm/slub.txt.
1954
1955 slub_min_order= [MM, SLUB]
1956 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001957 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001958 For more information see Documentation/vm/slub.txt.
1959
1960 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001961 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001962 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001963 allocs to different slabs. Debug options disable
1964 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001965 For more information see Documentation/vm/slub.txt.
1966
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967 smart2= [HW]
1968 Format: <io1>[,<io2>[,...,<io8>]]
1969
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001970 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001971 attempt to substitute SMP alternatives once at boot.
1972
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001973 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1974 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1975 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1976 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1977 smsc-ircc2.ircc_irq= [HW] IRQ line
1978 smsc-ircc2.ircc_dma= [HW] DMA channel
1979 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1980 0: Toshiba Satellite 1800 (GP data pin select)
1981 1: Fast pin select (default)
1982 2: ATC IRMode
1983
Linus Torvalds1da177e2005-04-16 15:20:36 -07001984 snd-ad1816a= [HW,ALSA]
1985
1986 snd-ad1848= [HW,ALSA]
1987
1988 snd-ali5451= [HW,ALSA]
1989
1990 snd-als100= [HW,ALSA]
1991
1992 snd-als4000= [HW,ALSA]
1993
1994 snd-azt2320= [HW,ALSA]
1995
1996 snd-cmi8330= [HW,ALSA]
1997
1998 snd-cmipci= [HW,ALSA]
1999
2000 snd-cs4231= [HW,ALSA]
2001
2002 snd-cs4232= [HW,ALSA]
2003
2004 snd-cs4236= [HW,ALSA]
2005
2006 snd-cs4281= [HW,ALSA]
2007
2008 snd-cs46xx= [HW,ALSA]
2009
2010 snd-dt019x= [HW,ALSA]
2011
2012 snd-dummy= [HW,ALSA]
2013
2014 snd-emu10k1= [HW,ALSA]
2015
2016 snd-ens1370= [HW,ALSA]
2017
2018 snd-ens1371= [HW,ALSA]
2019
2020 snd-es968= [HW,ALSA]
2021
2022 snd-es1688= [HW,ALSA]
2023
2024 snd-es18xx= [HW,ALSA]
2025
2026 snd-es1938= [HW,ALSA]
2027
2028 snd-es1968= [HW,ALSA]
2029
2030 snd-fm801= [HW,ALSA]
2031
2032 snd-gusclassic= [HW,ALSA]
2033
2034 snd-gusextreme= [HW,ALSA]
2035
2036 snd-gusmax= [HW,ALSA]
2037
2038 snd-hdsp= [HW,ALSA]
2039
2040 snd-ice1712= [HW,ALSA]
2041
2042 snd-intel8x0= [HW,ALSA]
2043
2044 snd-interwave= [HW,ALSA]
2045
2046 snd-interwave-stb=
2047 [HW,ALSA]
2048
2049 snd-korg1212= [HW,ALSA]
2050
2051 snd-maestro3= [HW,ALSA]
2052
2053 snd-mpu401= [HW,ALSA]
2054
2055 snd-mtpav= [HW,ALSA]
2056
2057 snd-nm256= [HW,ALSA]
2058
2059 snd-opl3sa2= [HW,ALSA]
2060
2061 snd-opti92x-ad1848=
2062 [HW,ALSA]
2063
2064 snd-opti92x-cs4231=
2065 [HW,ALSA]
2066
2067 snd-opti93x= [HW,ALSA]
2068
2069 snd-pmac= [HW,ALSA]
2070
2071 snd-rme32= [HW,ALSA]
2072
2073 snd-rme96= [HW,ALSA]
2074
2075 snd-rme9652= [HW,ALSA]
2076
2077 snd-sb8= [HW,ALSA]
2078
2079 snd-sb16= [HW,ALSA]
2080
2081 snd-sbawe= [HW,ALSA]
2082
2083 snd-serial= [HW,ALSA]
2084
2085 snd-sgalaxy= [HW,ALSA]
2086
2087 snd-sonicvibes= [HW,ALSA]
2088
2089 snd-sun-amd7930=
2090 [HW,ALSA]
2091
2092 snd-sun-cs4231= [HW,ALSA]
2093
2094 snd-trident= [HW,ALSA]
2095
2096 snd-usb-audio= [HW,ALSA,USB]
2097
2098 snd-via82xx= [HW,ALSA]
2099
2100 snd-virmidi= [HW,ALSA]
2101
2102 snd-wavefront= [HW,ALSA]
2103
2104 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002105
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002106 softlockup_panic=
2107 [KNL] Should the soft-lockup detector generate panics.
2108
Linus Torvalds1da177e2005-04-16 15:20:36 -07002109 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2110 See Documentation/sonypi.txt
2111
2112 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2113 See Documentation/specialix.txt.
2114
2115 spia_io_base= [HW,MTD]
2116 spia_fio_base=
2117 spia_pedr=
2118 spia_peddr=
2119
2120 sscape= [HW,OSS]
2121 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002122
Linus Torvalds1da177e2005-04-16 15:20:36 -07002123 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2124 See Documentation/scsi/st.txt.
2125
Linus Torvalds1da177e2005-04-16 15:20:36 -07002126 sti= [PARISC,HW]
2127 Format: <num>
2128 Set the STI (builtin display/keyboard on the HP-PARISC
2129 machines) console (graphic card) which should be used
2130 as the initial boot-console.
2131 See also comment in drivers/video/console/sticore.c.
2132
2133 sti_font= [HW]
2134 See comment in drivers/video/console/sticore.c.
2135
2136 stifb= [HW]
2137 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2138
Greg Banks42a7fc42007-03-06 01:42:23 -08002139 sunrpc.pool_mode=
2140 [NFS]
2141 Control how the NFS server code allocates CPUs to
2142 service thread pools. Depending on how many NICs
2143 you have and where their interrupts are bound, this
2144 option will affect which CPUs will do NFS serving.
2145 Note: this parameter cannot be changed while the
2146 NFS server is running.
2147
2148 auto the server chooses an appropriate mode
2149 automatically using heuristics
2150 global a single global pool contains all CPUs
2151 percpu one pool for each CPU
2152 pernode one pool for each NUMA node (equivalent
2153 to global on non-NUMA machines)
2154
Linus Torvalds1da177e2005-04-16 15:20:36 -07002155 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002156
Linus Torvalds1da177e2005-04-16 15:20:36 -07002157 switches= [HW,M68k]
2158
2159 sym53c416= [HW,SCSI]
2160 See header of drivers/scsi/sym53c416.c.
2161
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002162 sysrq_always_enabled
2163 [KNL]
2164 Ignore sysrq setting - this boot parameter will
2165 neutralize any effect of /proc/sys/kernel/sysrq.
2166 Useful for debugging.
2167
Linus Torvalds1da177e2005-04-16 15:20:36 -07002168 t128= [HW,SCSI]
2169 See header of drivers/scsi/t128.c.
2170
2171 tdfx= [HW,DRM]
2172
David Brownell77437fd2008-07-23 21:28:33 -07002173 test_suspend= [SUSPEND]
2174 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2175 standby suspend) as the system sleep state to briefly
2176 enter during system startup. The system is woken from
2177 this state using a wakeup-capable RTC alarm.
2178
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179 thash_entries= [KNL,NET]
2180 Set number of hash buckets for TCP connection
2181
Len Brownf8707ec2007-08-12 00:12:54 -04002182 thermal.act= [HW,ACPI]
2183 -1: disable all active trip points in all thermal zones
2184 <degrees C>: override all lowest active trip points
2185
Len Brownc52a7412007-08-14 15:49:32 -04002186 thermal.crt= [HW,ACPI]
2187 -1: disable all critical trip points in all thermal zones
2188 <degrees C>: lower all critical trip points
2189
Len Brownf5487142007-08-12 00:12:44 -04002190 thermal.nocrt= [HW,ACPI]
2191 Set to disable actions on ACPI thermal zone
2192 critical and hot trip points.
2193
Len Brown72b33ef2007-08-12 00:12:17 -04002194 thermal.off= [HW,ACPI]
2195 1: disable ACPI thermal control
2196
Len Browna70cdc52007-08-12 00:12:35 -04002197 thermal.psv= [HW,ACPI]
2198 -1: disable all passive trip points
2199 <degrees C>: override all passive trip points to this value
2200
Len Brown730ff342007-08-12 00:12:26 -04002201 thermal.tzp= [HW,ACPI]
2202 Specify global default ACPI thermal zone polling rate
2203 <deci-seconds>: poll all this frequency
2204 0: no polling (default)
2205
Linus Torvalds1da177e2005-04-16 15:20:36 -07002206 tmscsim= [HW,SCSI]
2207 See comment before function dc390_setup() in
2208 drivers/scsi/tmscsim.c.
2209
2210 tp720= [HW,PS2]
2211
2212 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002213 Format:
2214 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2215
Randy Dunlapa9913042005-10-23 12:57:11 -07002216 turbografx.map[2|3]= [HW,JOY]
2217 TurboGraFX parallel port interface
2218 Format:
2219 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002220 See also Documentation/input/joystick-parport.txt
2221
2222 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2223 See header of drivers/scsi/u14-34f.c.
2224
2225 uart401= [HW,OSS]
2226 Format: <io>,<irq>
2227
2228 uart6850= [HW,OSS]
2229 Format: <io>,<irq>
2230
Alan Stern5f8364b2006-12-05 16:29:55 -05002231 uhci-hcd.ignore_oc=
2232 [USB] Ignore overcurrent events (default N).
2233 Some badly-designed motherboards generate lots of
2234 bogus events, for ports that aren't wired to
2235 anything. Set this parameter to avoid log spamming.
2236 Note that genuine overcurrent events won't be
2237 reported either.
2238
Simon Arlotte3a61b02008-07-19 23:32:54 +01002239 unknown_nmi_panic
2240 [X86-32,X86-64]
2241 Set unknown_nmi_panic=1 early on boot.
2242
Alan Sternb5e795f2007-02-20 15:00:53 -05002243 usbcore.autosuspend=
2244 [USB] The autosuspend time delay (in seconds) used
2245 for newly-detected USB devices (default 2). This
2246 is the time required before an idle device will be
2247 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002248 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002249
Linus Torvalds1da177e2005-04-16 15:20:36 -07002250 usbhid.mousepoll=
2251 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002252
Paul Jackson200001e2008-06-25 05:44:46 -07002253 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2254 kernel's map of available physical RAM.
2255
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002256 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002257 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002258 vdso=1: enable VDSO (default)
2259 vdso=0: disable VDSO mapping
2260
Roland McGrathaf65d642008-01-30 13:30:43 +01002261 vdso32= [X86-32,X86-64]
2262 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2263 vdso32=1: enable 32-bit VDSO (default)
2264 vdso32=0: disable 32-bit VDSO mapping
2265
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002266 vector= [IA-64,SMP]
2267 vector=percpu: enable percpu vector domain
2268
Linus Torvalds1da177e2005-04-16 15:20:36 -07002269 video= [FB] Frame buffer configuration
2270 See Documentation/fb/modedb.txt.
2271
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002272 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002273 See Documentation/i386/boot.txt and
2274 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002275 Use vga=ask for menu.
2276 This is actually a boot loader parameter; the value is
2277 passed to the kernel using a special protocol.
2278
Randy Dunlapa9913042005-10-23 12:57:11 -07002279 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002280 size of <nn>. This can be used to increase the
2281 minimum size (128MB on x86). It can also be used to
2282 decrease the size and leave more room for directly
2283 mapped kernel RAM.
2284
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002285 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2286 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002287
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002288 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2289 Format: <command>
2290
2291 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2292 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002293
Linus Torvalds1da177e2005-04-16 15:20:36 -07002294 waveartist= [HW,OSS]
2295 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002296
Linus Torvalds1da177e2005-04-16 15:20:36 -07002297 wd33c93= [HW,SCSI]
2298 See header of drivers/scsi/wd33c93.c.
2299
2300 wd7000= [HW,SCSI]
2301 See header of drivers/scsi/wd7000.c.
2302
2303 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002304 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002305
2306 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2307 xd_geo= See header of drivers/block/xd.c.
2308
2309 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002310 Format:
2311 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002312
Andi Kleena62eaf12006-02-16 23:41:58 +01002313 norandmaps Don't use address space randomization
2314 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2315
Randy Dunlapa9913042005-10-23 12:57:11 -07002316______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002317
2318TODO:
2319
2320 Add documentation for ALSA options.
2321 Add more DRM drivers.