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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)
287 amd_iommu_size= [HW,X86-64]
288 Define the size of the aperture for the AMD IOMMU
289 driver. Possible values are:
290 '32M', '64M' (default), '128M', '256M', '512M', '1G'
291
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 amijoy.map= [HW,JOY] Amiga joystick support
293 Map of devices attached to JOY0DAT and JOY1DAT
294 Format: <a>,<b>
295 See also Documentation/kernel/input/joystick.txt
296
297 analog.map= [HW,JOY] Analog joystick and gamepad support
298 Specifies type or capabilities of an analog joystick
299 connected to one of 16 gameports
300 Format: <type1>,<type2>,..<type16>
301
Randy Dunlapa9913042005-10-23 12:57:11 -0700302 apc= [HW,SPARC]
303 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 Format: noidle
305 Disable APC CPU standby support. SPARCstation-Fox does
306 not play well with APC CPU idle - disable it if you have
307 APC and your system crashes randomly.
308
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700309 apic= [APIC,i386] Advanced Programmable Interrupt Controller
310 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 Format: { quiet (default) | verbose | debug }
312 Change the amount of debugging information output
313 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700314
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700316 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
319 Format: <io>,<irq>,<nodeID>
320
321 ataflop= [HW,M68k]
322
323 atarimouse= [HW,MOUSE] Atari Mouse
324
325 atascsi= [HW,SCSI] Atari SCSI
326
327 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
328 EzKey and similar keyboards
329
330 atkbd.reset= [HW] Reset keyboard during initialization
331
Randy Dunlapa9913042005-10-23 12:57:11 -0700332 atkbd.set= [HW] Select keyboard code set
333 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334
335 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
336 keyboards
337
338 atkbd.softraw= [HW] Choose between synthetic and real raw mode
339 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700340
341 atkbd.softrepeat= [HW]
342 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343
344 autotest [IA64]
345
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 baycom_epp= [HW,AX25]
347 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700348
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
350 Format: <io>,<mode>
351 See header of drivers/net/hamradio/baycom_par.c.
352
Randy Dunlapa9913042005-10-23 12:57:11 -0700353 baycom_ser_fdx= [HW,AX25]
354 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 Format: <io>,<irq>,<mode>[,<baud>]
356 See header of drivers/net/hamradio/baycom_ser_fdx.c.
357
Randy Dunlapa9913042005-10-23 12:57:11 -0700358 baycom_ser_hdx= [HW,AX25]
359 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 Format: <io>,<irq>,<mode>
361 See header of drivers/net/hamradio/baycom_ser_hdx.c.
362
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700363 boot_delay= Milliseconds to delay each printk during boot.
364 Values larger than 10 seconds (10000) are changed to
365 no delay (0).
366 Format: integer
367
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700369 bttv.radio= Most important insmod options are available as
370 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
372 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
373
374 BusLogic= [HW,SCSI]
375 See drivers/scsi/BusLogic.c, comment before function
376 BusLogic_ParseDriverOptions().
377
378 c101= [NET] Moxa C101 synchronous serial card
379
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700380 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 Sometimes CPU hardware bugs make them report the cache
382 size incorrectly. The kernel will attempt work arounds
383 to fix known problems, but for some CPUs it is not
384 possible to determine what the correct size should be.
385 This option provides an override for these situations.
386
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200387 security= [SECURITY] Choose a security module to enable at boot.
388 If this boot parameter is not specified, only the first
389 security module asking for security registration will be
390 loaded. An invalid security module name will be treated
391 as if no module has been chosen.
392
James Morris20510f22007-10-16 23:31:32 -0700393 capability.disable=
394 [SECURITY] Disable capabilities. This would normally
395 be used only if an alternative security model is to be
396 configured. Potentially dangerous and should only be
397 used if you are entirely sure of the consequences.
398
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100399 ccw_timeout_log [S390]
400 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401
Paul Menage8bab8dd2008-04-04 14:29:57 -0700402 cgroup_disable= [KNL] Disable a particular controller
403 Format: {name of the controller(s) to disable}
404 {Currently supported controllers - "memory"}
405
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 checkreqprot [SELINUX] Set initial checkreqprot flag value.
407 Format: { "0" | "1" }
408 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700409 0 -- check protection applied by kernel (includes
410 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 1 -- check protection requested by application.
412 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700413 Value can be changed at runtime via
414 /selinux/checkreqprot.
415
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100416 cio_ignore= [S390]
417 See Documentation/s390/CommonIO for details.
418
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700419 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700420 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200421 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700422 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200423 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 Format: { pit | tsc | cyclone | pmtmr }
425
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700426 clocksource= [GENERIC_TIME] Override the default clocksource
427 Format: <string>
428 Override the default clocksource and use the clocksource
429 with the name specified.
430 Some clocksource names to choose from, depending on
431 the platform:
432 [all] jiffies (this is the base, fallback clocksource)
433 [ACPI] acpi_pm
434 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
435 pxa_timer,timer3,32k_counter,timer0_1
436 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700437 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700438 scx200_hrt on Geode; cyclone on IBM x440
439 [MIPS] MIPS
440 [PARISC] cr16
441 [S390] tod
442 [SH] SuperH
443 [SPARC64] tick
444 [X86-64] hpet,tsc
445
Andi Kleenac72e782008-01-30 13:33:21 +0100446 clearcpuid=BITNUM [X86]
447 Disable CPUID feature X for the kernel. See
448 include/asm-x86/cpufeature.h for the valid bit numbers.
449 Note the Linux specific bits are not necessarily
450 stable over kernel options, but the vendor specific
451 ones should be.
452 Also note that user programs calling CPUID directly
453 or using the feature without checking anything
454 will still see it. This just prevents it from
455 being used by the kernel or shown in /proc/cpuinfo.
456 Also note the kernel might malfunction if you disable
457 some critical bits.
458
Arjan van de Vena25bd942008-01-30 13:33:08 +0100459 code_bytes [IA32/X86_64] How many bytes of object code to print
460 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100461 Range: 0 - 8192
462 Default: 64
463
Andi Kleenf9262c12006-03-08 17:57:25 -0800464 disable_8254_timer
465 enable_8254_timer
466 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
467 over the 8254 in addition to over the IO-APIC. The
468 kernel tries to set a sensible default.
469
Thomas Gleixnerb17530b2007-10-19 20:35:02 +0200470 hpet= [X86-32,HPET] option to control HPET usage
471 Format: { enable (default) | disable | force }
472 disable: disable HPET and use PIT instead
Carlos Corbachod79a5f82007-10-19 18:51:27 +0100473 force: allow force enabled of undocumented chips (ICH4,
474 VIA, nVidia)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 com20020= [HW,NET] ARCnet - COM20020 chipset
Randy Dunlapa9913042005-10-23 12:57:11 -0700477 Format:
478 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479
480 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
481 Format: <io>[,<irq>]
482
Randy Dunlapa9913042005-10-23 12:57:11 -0700483 com90xx= [HW,NET]
484 ARCnet - COM90xx chipset (memory-mapped buffers)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 Format: <io>[,<irq>[,<memstart>]]
486
487 condev= [HW,S390] console device
488 conmode=
Randy Dunlapa9913042005-10-23 12:57:11 -0700489
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 console= [KNL] Output console device and options.
491
492 tty<n> Use the virtual console device <n>.
493
494 ttyS<n>[,options]
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800495 ttyUSB0[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 Use the specified serial port. The options are of
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800497 the form "bbbbpnf", where "bbbb" is the baud rate,
498 "p" is parity ("n", "o", or "e"), "n" is number of
499 bits, and "f" is flow control ("r" for RTS or
500 omit it). Default is "9600n8".
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501
Randy Dunlapf1a1c2d2006-03-25 03:08:17 -0800502 See Documentation/serial-console.txt for more
503 information. See
504 Documentation/networking/netconsole.txt for an
505 alternative.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700507 uart[8250],io,<addr>[,options]
508 uart[8250],mmio,<addr>[,options]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 Start an early, polled-mode console on the 8250/16550
510 UART at the specified I/O port or MMIO address,
511 switching to the matching ttyS device later. The
512 options are the same as for ttyS, above.
513
Samuel Thibaultf7511d52008-04-30 00:54:51 -0700514 If the device connected to the port is not a TTY but a braille
515 device, prepend "brl," before the device type, for instance
516 console=brl,ttyS0
517 For now, only VisioBraille is supported.
518
Yinghai Lu18a8bd92007-07-15 23:37:59 -0700519 earlycon= [KNL] Output early console device and options.
520 uart[8250],io,<addr>[,options]
521 uart[8250],mmio,<addr>[,options]
522 Start an early, polled-mode console on the 8250/16550
523 UART at the specified I/O port or MMIO address.
524 The options are the same as for ttyS, above.
525
Andres Salomon8f4ce8c2007-10-18 03:04:50 -0700526 no_console_suspend
527 [HW] Never suspend the console
528 Disable suspending of consoles during suspend and
529 hibernate operations. Once disabled, debugging
530 messages can reach various consoles while the rest
531 of the system is being put to sleep (ie, while
532 debugging driver suspend/resume hooks). This may
533 not work reliably with all consoles, but is known
534 to work with serial and VGA consoles.
535
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Randy Dunlapa9913042005-10-23 12:57:11 -0700537 Format:
538 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539
Eric W. Biedermandc009d92005-06-25 14:57:52 -0700540 crashkernel=nn[KMG]@ss[KMG]
541 [KNL] Reserve a chunk of physical memory to
542 hold a kernel to switch to with kexec on panic.
543
Bernhard Wallefb391592007-10-18 23:41:02 -0700544 crashkernel=range1:size1[,range2:size2,...][@offset]
545 [KNL] Same as above, but depends on the memory
546 in the running system. The syntax of range is
547 start-[end] where start and end are both
548 a memory unit (amount[KMG]). See also
549 Documentation/kdump/kdump.txt for a example.
550
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 cs4232= [HW,OSS]
552 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
553
554 cs89x0_dma= [HW,NET]
555 Format: <dma>
556
557 cs89x0_media= [HW,NET]
558 Format: { rj45 | aui | bnc }
Randy Dunlapa9913042005-10-23 12:57:11 -0700559
Randy Dunlapa9913042005-10-23 12:57:11 -0700560 dasd= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 See header of drivers/s390/block/dasd_devmap.c.
562
563 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
564 (one device per port)
565 Format: <port#>,<type>
566 See also Documentation/input/joystick-parport.txt
567
568 debug [KNL] Enable kernel debugging (events log level).
569
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700570 debug_locks_verbose=
571 [KNL] verbose self-tests
572 Format=<0|1>
573 Print debugging info while doing the locking API
574 self-tests.
575 We default to 0 (no extra messages), setting it to
576 1 will print _a lot_ more information - normally
577 only useful to kernel developers.
578
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700579 debug_objects [KNL] Enable object debugging
580
Thomas Gleixnerd3af01f2008-07-15 15:04:56 +0200581 debugpat [X86] Enable PAT debugging
582
Robert P. J. Day2d27a962008-02-03 15:18:45 +0200583 decnet.addr= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 Format: <area>[,<node>]
585 See also Documentation/networking/decnet.txt.
586
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000587 vt.default_blu= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700588 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
589 Change the default blue palette of the console.
590 This is a 16-member array composed of values
591 ranging from 0-255.
592
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000593 vt.default_grn= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700594 Format: <green0>,<green1>,<green2>,...,<green15>
595 Change the default green palette of the console.
596 This is a 16-member array composed of values
597 ranging from 0-255.
598
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000599 vt.default_red= [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700600 Format: <red0>,<red1>,<red2>,...,<red15>
601 Change the default red palette of the console.
602 This is a 16-member array composed of values
603 ranging from 0-255.
604
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000605 vt.default_utf8=
606 [VT]
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700607 Format=<0|1>
608 Set system-wide default UTF-8 mode for all tty's.
Samuel Thibaultecb77fa2008-01-03 16:17:54 +0000609 Default is 1, i.e. UTF-8 mode is enabled for all
610 newly opened terminals.
Antonino A. Daplas55ff9782007-05-08 00:38:53 -0700611
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 dhash_entries= [KNL]
613 Set number of hash buckets for dentry cache.
Randy Dunlapa9913042005-10-23 12:57:11 -0700614
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 digi= [HW,SERIAL]
616 IO parameters + enable/disable command.
617
618 digiepca= [HW,SERIAL]
619 See drivers/char/README.epca and
620 Documentation/digiepca.txt.
621
Yinghai Lu95ffa242008-04-29 03:52:33 -0700622 disable_mtrr_cleanup [X86]
623 enable_mtrr_cleanup [X86]
624 The kernel tries to adjust MTRR layout from continuous
625 to discrete, to make X server driver able to add WB
626 entry later. This parameter enables/disables that.
627
628 mtrr_chunk_size=nn[KMG] [X86]
629 used for mtrr cleanup. It is largest continous chunk
630 that could hold holes aka. UC entries.
631
632 mtrr_gran_size=nn[KMG] [X86]
Yinghai Lu12031a62008-05-02 02:40:22 -0700633 Used for mtrr cleanup. It is granularity of mtrr block.
634 Default is 1.
635 Large value could prevent small alignment from
636 using up MTRRs.
637
638 mtrr_spare_reg_nr=n [X86]
639 Format: <integer>
640 Range: 0,7 : spare reg number
641 Default : 1
642 Used for mtrr cleanup. It is spare mtrr entries number.
643 Set to 2 or more if your graphical card needs more.
Yinghai Lu95ffa242008-04-29 03:52:33 -0700644
Yinghai Lu093af8d2008-01-30 13:33:32 +0100645 disable_mtrr_trim [X86, Intel and AMD only]
Jesse Barnes99fc8d42008-01-30 13:33:18 +0100646 By default the kernel will trim any uncacheable
647 memory out of your available memory pool based on
648 MTRR settings. This parameter disables that behavior,
649 possibly causing your machine to run very slowly.
650
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 dmasound= [HW,OSS] Sound subsystem buffers
652
653 dscc4.setup= [NET]
654
655 dtc3181e= [HW,SCSI]
656
Robin Getz0ae53642007-10-09 17:24:49 +0800657 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 earlyprintk=vga
659 earlyprintk=serial[,ttySn[,baudrate]]
660
Randy Dunlapa9913042005-10-23 12:57:11 -0700661 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 takes over.
663
664 Only vga or serial at a time, not both.
665
666 Currently only ttyS0 and ttyS1 are supported.
667
668 Interaction with the standard serial driver is not
669 very good.
670
671 The VGA output is eventually overwritten by the real
672 console.
673
674 eata= [HW,SCSI]
675
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700677 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 eisa_irq_edge= [PARISC,HW]
680 See header of drivers/parisc/eisa.c.
681
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700682 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700684 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685
686 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800687 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700688 See Documentation/block/as-iosched.txt and
689 Documentation/block/deadline-iosched.txt for details.
690
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700691 elfcorehdr= [X86-32, X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700692 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800693 image elf header. Generally kexec loader will
694 pass this option to capture kernel.
695 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696
697 enforcing [SELINUX] Set initial enforcing status.
698 Format: {"0" | "1"}
699 See security/selinux/Kconfig help text.
700 0 -- permissive (log only, no denials).
701 1 -- enforcing (deny and log).
702 Default value is 0.
703 Value can be changed at runtime via /selinux/enforce.
704
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 es1371= [HW,OSS]
706 Format: <spdif>,[<nomix>,[<amplifier>]]
707 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700708
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 ether= [HW,NET] Ethernet cards parameters
710 This option is obsoleted by the "netdev=" option, which
711 has equivalent usage. See its documentation for details.
712
713 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
714 Format: <io>[,<irq>]
715
Akinobu Mitade1ba092006-12-08 02:39:42 -0800716 failslab=
717 fail_page_alloc=
718 fail_make_request=[KNL]
719 General fault injection mechanism.
720 Format: <interval>,<probability>,<space>,<times>
721 See also /Documentation/fault-injection/.
722
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 fd_mcs= [HW,SCSI]
724 See header of drivers/scsi/fd_mcs.c.
725
726 fdomain= [HW,SCSI]
727 See header of drivers/scsi/fdomain.c.
728
729 floppy= [HW]
730 See Documentation/floppy.txt.
731
Alex Chiangf13ae302008-05-08 14:03:23 -0600732 force_pal_cache_flush
733 [IA-64] Avoid check_sal_cache_flush which may hang on
734 buggy SAL_CACHE_FLUSH implementations. Using this
735 parameter will force ia64_sal_cache_flush to call
736 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
737
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 gamecon.map[2|3]=
739 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
740 support via parallel port (up to 5 devices per port)
741 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
742 See also Documentation/input/joystick-parport.txt
743
744 gamma= [HW,DRM]
745
Yinghai Luaaf23042008-01-30 13:33:09 +0100746 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
747 Format: off | on
748 default: on
749
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 gdth= [HW,SCSI]
751 See header of drivers/scsi/gdth.c.
752
753 gpt [EFI] Forces disk with valid GPT signature but
754 invalid Protective MBR to be treated as GPT.
755
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 gvp11= [HW,SCSI]
757
758 hashdist= [KNL,NUMA] Large hashes allocated during boot
759 are distributed across NUMA nodes. Defaults on
760 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700761 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762
763 hcl= [IA-64] SGI's Hardware Graph compatibility layer
764
765 hd= [EIDE] (E)IDE hard drive subsystem geometry
766 Format: <cyl>,<head>,<sect>
767
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
769 size of <nn>. This works even on boxes that have no
770 highmem otherwise. This also works to reduce highmem
771 size on bigger boxes.
772
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800773 highres= [KNL] Enable/disable high resolution timer mode.
774 Valid parameters: "on", "off"
775 Default: "on"
776
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 hisax= [HW,ISDN]
778 See Documentation/isdn/README.HiSax.
779
Andi Kleenb4718e62008-07-23 21:27:51 -0700780 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
781 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
Jon Tollefson0d9ea752008-07-23 21:27:56 -0700782 On x86-64 and powerpc, this option can be specified
783 multiple times interleaved with hugepages= to reserve
784 huge pages of different sizes. Valid pages sizes on
785 x86-64 are 2M (when the CPU supports "pse") and 1G
786 (when the CPU supports the "pdpe1gb" cpuinfo flag)
Andi Kleenb4718e62008-07-23 21:27:51 -0700787 Note that 1GB pages can only be allocated at boot time
788 using hugepages= and not freed afterwards.
Nick Piggine11bfbf2008-07-23 21:27:52 -0700789 default_hugepagesz=
790 [same as hugepagesz=] The size of the default
791 HugeTLB page size. This is the size represented by
792 the legacy /proc/ hugepages APIs, used for SHM, and
793 default size when mounting hugetlbfs filesystems.
794 Defaults to the default architecture's huge page size
795 if not specified.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200798 i8042.dumbkbd [HW] Pretend that controller can only read data from
799 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 (Don't attempt to blink the leds)
801 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500802 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400803 i8042.noloop [HW] Disable the AUX Loopback command while probing
804 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 i8042.nomux [HW] Don't check presence of an active multiplexing
806 controller
807 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
808 controllers
809 i8042.panicblink=
810 [HW] Frequency with which keyboard LEDs should blink
811 when kernel panics (default is 0.5 sec)
812 i8042.reset [HW] Reset the controller during init and cleanup
813 i8042.unlock [HW] Unlock (ignore) the keylock
814
815 i810= [HW,DRM]
816
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700817 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
818 indicates that the driver is running on unsupported
819 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
821 does not match list of supported models.
822 i8k.power_status
823 [HW] Report power status in /proc/i8k
824 (disabled by default)
825 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
826 capability is set.
827
828 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
829 See Documentation/mca.txt.
830
831 icn= [HW,ISDN]
832 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
833
834 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200835 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100836 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100839 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840
Andi Kleenf039b752007-05-02 19:27:12 +0200841 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800842 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200843 Poll forces a polling idle loop that can slightly improves the performance
844 of waking up a idle CPU, but will use a lot of power and make the system
845 run hot. Not recommended.
846 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
847 to not use it because it doesn't save as much power as a normal idle
848 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
849 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800850 idle=halt. Halt is forced to be used for CPU idle.
851 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800852 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700853
Denis Cheng594765a2008-02-06 02:57:49 +0100854 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
855 Claim all unknown PCI IDE storage controllers.
856
Ingo Molnar792908222006-12-06 20:40:51 -0800857 ignore_loglevel [KNL]
858 Ignore loglevel setting - this will print /all/
859 kernel messages to the console. Useful for debugging.
860
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 ihash_entries= [KNL]
862 Set number of hash buckets for inode cache.
863
864 in2000= [HW,SCSI]
865 See header of drivers/scsi/in2000.c.
866
867 init= [KNL]
868 Format: <full_path>
869 Run specified binary instead of /sbin/init as init
870 process.
871
872 initcall_debug [KNL] Trace initcalls as they are executed. Useful
873 for working out where the kernel is dying during
874 startup.
875
876 initrd= [BOOT] Specify the location of the initial ramdisk
877
878 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
879 Format: <irq>
880
881 inttest= [IA64]
882
Pavel Machekb552da82008-03-19 15:58:11 +0100883 iommu= [x86]
884 off
885 force
886 noforce
887 biomerge
888 panic
889 nopanic
890 merge
891 nomerge
892 forcesac
893 soft
894
895
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700896 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
897 off
898 Disable intel iommu driver.
899 igfx_off [Default Off]
900 By default, gfx is mapped as normal device. If a gfx
901 device has a dedicated DMAR unit, the DMAR unit is
902 bypassed by not enabling DMAR with this option. In
903 this case, gfx device will use physical address for
904 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700905 forcedac [x86_64]
906 With this option iommu will not optimize to look
907 for io virtual address below 32 bit forcing dual
908 address cycle on pci bus for cards supporting greater
909 than 32 bit addressing. The default is to look
910 for translation below 32 bit and if not available
911 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800912 strict [Default Off]
913 With this option on every unmap_single operation will
914 result in a hardware IOTLB flush operation as opposed
915 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700916
Rene Hermanb02aae92008-01-30 13:30:05 +0100917 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100918 0x80
919 Standard port 0x80 based delay
920 0xed
921 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100922 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100923 Simple two microseconds delay
924 none
925 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100926
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 io7= [HW] IO7 for Marvel based alpha systems
928 See comment before marvel_specify_io7 in
929 arch/alpha/kernel/core_marvel.c.
930
931 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400932 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933
934 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700935 See comment before ip2_setup() in
936 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937
938 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
939 See header of drivers/scsi/ips.c.
940
Simon Horman72c4a132006-09-13 19:57:18 -0700941 ports= [IP_VS_FTP] IPVS ftp helper module
942 Default is 21.
943 Up to 8 (IP_VS_APP_MAX_PORTS) ports
944 may be specified.
945 Format: <port>,<port>....
946
Alan Cox200803d2005-06-28 20:45:18 -0700947 irqfixup [HW]
948 When an interrupt is not handled search all handlers
949 for it. Intended to get systems with badly broken
950 firmware running.
951
952 irqpoll [HW]
953 When an interrupt is not handled search all handlers
954 for it. Also check all handlers each timer
955 interrupt. Intended to get systems with badly broken
956 firmware running.
957
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700959 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960
961 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800962 Format:
963 <cpu number>,...,<cpu number>
964 or
965 <cpu number>-<cpu number> (must be a positive range in ascending order)
966 or a mixture
967 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 This option can be used to specify one or more CPUs
969 to isolate from the general SMP balancing and scheduling
970 algorithms. The only way to move a process onto or off
971 an "isolated" CPU is via the CPU affinity syscalls.
972 <cpu number> begins at 0 and the maximum value is
973 "number of CPUs in system - 1".
974
975 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700976 alternative -- manually setting the CPU mask of all
977 tasks in the system -- can cause problems and
978 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979
Randy Dunlapa9913042005-10-23 12:57:11 -0700980 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981
982 js= [HW,JOY] Analog joystick
983 See Documentation/input/joystick.txt.
984
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700985 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700986 specifies the amount of memory usable by the kernel
987 for non-movable allocations. The requested amount is
988 spread evenly throughout all nodes in the system. The
989 remaining memory in each node is used for Movable
990 pages. In the event, a node is too small to have both
991 kernelcore and Movable pages, kernelcore pages will
992 take priority and other nodes will have a larger number
993 of kernelcore pages. The Movable zone is used for the
994 allocation of pages that may be reclaimed or moved
995 by the page migration subsystem. This means that
996 HugeTLB pages may not be allocated from this zone.
997 Note that allocations like PTEs-from-HighMem still
998 use the HighMem zone if it exists, and the Normal
999 zone if it does not.
1000
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001001 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -07001002 is similar to kernelcore except it specifies the
1003 amount of memory used for migratable allocations.
1004 If both kernelcore and movablecore is specified,
1005 then kernelcore will be at *least* the specified
1006 value but may be more. If movablecore on its own
1007 is specified, the administrator must be careful
1008 that the amount of memory usable for all allocations
1009 is not too small.
1010
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 keepinitrd [HW,ARM]
1012
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001013 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 in oops dumps.
1015
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001016 kgdboc= [HW] kgdb over consoles.
1017 Requires a tty driver that supports console polling.
1018 (only serial suported for now)
1019 Format: <serial_device>[,baud]
1020
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 l2cr= [PPC]
1022
Robert Brosea78bfbf2008-03-29 07:20:23 +11001023 l3cr= [PPC]
1024
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001025 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001026 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001028 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001029 C2 power state.
1030
FD Camifcb71f62008-01-06 19:08:56 +01001031 libata.dma= [LIBATA] DMA control
1032 libata.dma=0 Disable all PATA and SATA DMA
1033 libata.dma=1 PATA and SATA Disk DMA only
1034 libata.dma=2 ATAPI (CDROM) DMA only
1035 libata.dma=4 Compact Flash DMA only
1036 Combinations also work, so libata.dma=3 enables DMA
1037 for disks and CDROMs, but not CFs.
1038
Dave Jones78e70c22007-09-27 11:50:13 -04001039 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1040 when set.
1041 Format: <int>
1042
Tejun Heo33267322008-02-13 09:15:09 +09001043 libata.force= [LIBATA] Force configurations. The format is comma
1044 separated list of "[ID:]VAL" where ID is
1045 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1046 matching port, link or device. Basically, it matches
1047 the ATA ID string printed on console by libata. If
1048 the whole ID part is omitted, the last PORT and DEVICE
1049 values are used. If ID hasn't been specified yet, the
1050 configuration applies to all ports, links and devices.
1051
1052 If only DEVICE is omitted, the parameter applies to
1053 the port and all links and devices behind it. DEVICE
1054 number of 0 either selects the first device or the
1055 first fan-out link behind PMP device. It does not
1056 select the host link. DEVICE number of 15 selects the
1057 host link and device attached to it.
1058
1059 The VAL specifies the configuration to force. As long
1060 as there's no ambiguity shortcut notation is allowed.
1061 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1062 The following configurations can be forced.
1063
1064 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1065 Any ID with matching PORT is used.
1066
1067 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1068
1069 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1070 udma[/][16,25,33,44,66,100,133] notation is also
1071 allowed.
1072
1073 * [no]ncq: Turn on or off NCQ.
1074
1075 If there are multiple matching configurations changing
1076 the same attribute, the last one is used.
1077
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078 load_ramdisk= [RAM] List of ramdisks to load from floppy
1079 See Documentation/ramdisk.txt.
1080
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001081 lockd.nlm_grace_period=P [NFS] Assign grace period.
1082 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001084 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1085 Format: <integer>
1086
1087 lockd.nlm_timeout=T [NFS] Assign timeout value.
1088 Format: <integer>
1089
1090 lockd.nlm_udpport=M [NFS] Assign UDP port.
1091 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092
1093 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1094 Format: <irq>
1095
1096 loglevel= All Kernel Messages with a loglevel smaller than the
1097 console loglevel will be printed to the console. It can
1098 also be changed with klogd or other programs. The
1099 loglevels are defined as follows:
1100
1101 0 (KERN_EMERG) system is unusable
1102 1 (KERN_ALERT) action must be taken immediately
1103 2 (KERN_CRIT) critical conditions
1104 3 (KERN_ERR) error conditions
1105 4 (KERN_WARNING) warning conditions
1106 5 (KERN_NOTICE) normal but significant condition
1107 6 (KERN_INFO) informational
1108 7 (KERN_DEBUG) debug-level messages
1109
1110 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001111 Format: { n | nk | nM }
1112 n must be a power of two. The default size
1113 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001114
Randy Dunlapaccaa242007-10-16 01:29:37 -07001115 logo.nologo [FB] Disables display of the built-in Linux logo.
1116 This may be used to provide more screen space for
1117 kernel log messages and is useful when debugging
1118 kernel boot problems.
1119
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120 lp=0 [LP] Specify parallel ports to use, e.g,
1121 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1122 lp=reset first parallel port). 'lp=0' disables the
1123 lp=auto printer driver. 'lp=reset' (which can be
1124 specified in addition to the ports) causes
1125 attached printers to be reset. Using
1126 lp=port1,port2,... specifies the parallel ports
1127 to associate lp devices with, starting with
1128 lp0. A port specification may be 'none' to skip
1129 that lp device, or a parport name such as
1130 'parport0'. Specifying 'lp=auto' instead of a
1131 port specification list means that device IDs
1132 from each port should be examined, to see if
1133 an IEEE 1284-compliant printer is attached; if
1134 so, the driver will manage that printer.
1135 See also header of drivers/char/lp.c.
1136
1137 lpj=n [KNL]
1138 Sets loops_per_jiffy to given constant, thus avoiding
1139 time-consuming boot-time autodetection (up to 250 ms per
1140 CPU). 0 enables autodetection (default). To determine
1141 the correct value for your kernel, boot with normal
1142 autodetection and see what value is printed. Note that
1143 on SMP systems the preset will be applied to all CPUs,
1144 which is likely to cause problems if your CPUs need
1145 significantly divergent settings. An incorrect value
1146 will cause delays in the kernel to be wrong, leading to
1147 unpredictable I/O errors and other breakage. Although
1148 unlikely, in the extreme case this might damage your
1149 hardware.
1150
1151 ltpc= [NET]
1152 Format: <io>,<irq>,<dma>
1153
Randy Dunlapa9913042005-10-23 12:57:11 -07001154 mac5380= [HW,SCSI] Format:
1155 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156
Randy Dunlapa9913042005-10-23 12:57:11 -07001157 machvec= [IA64] Force the use of a particular machine-vector
1158 (machvec) in a generic kernel.
1159 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160
Randy Dunlapa9913042005-10-23 12:57:11 -07001161 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 be mounted
1163 Format: <1-256>
1164
1165 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001166 should make use of. maxcpus=n : n >= 0 limits the
1167 kernel to using 'n' processors. n=0 is a special case,
1168 it is equivalent to "nosmp", which also disables
1169 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170
Bob Picco2b2c3752005-06-29 18:00:00 -07001171 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1172 equal to this physical address is ignored.
1173
Randy Dunlapa9913042005-10-23 12:57:11 -07001174 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175 Should be between 1 and 2^32-1.
1176
1177 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001178 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179 Should be between 1 and 16384.
1180
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181 mcatest= [IA-64]
1182
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001183 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184
Andi Kleen909dd322007-10-17 18:04:38 +02001185 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1186
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 md= [HW] RAID subsystems devices and level
1188 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001189
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 mdacon= [MDA]
1191 Format: <first>,<last>
1192 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001193
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1195 Amount of memory to be used when the kernel is not able
1196 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001197 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198 address space collisions. Without memmap= PCI devices
1199 could be placed at addresses belonging to unused RAM.
1200
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001201 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 memory.
1203
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001204 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 E820 memory map, as specified by the user.
1206 Such memmap=exactmap lines can be constructed based on
1207 BIOS output or other requirements. See the memmap=nn@ss
1208 option description.
1209
1210 memmap=nn[KMG]@ss[KMG]
1211 [KNL] Force usage of a specific region of memory
1212 Region of memory to be used, from ss to ss+nn.
1213
1214 memmap=nn[KMG]#ss[KMG]
1215 [KNL,ACPI] Mark specific memory as ACPI data.
1216 Region of memory to be used, from ss to ss+nn.
1217
1218 memmap=nn[KMG]$ss[KMG]
1219 [KNL,ACPI] Mark specific memory as reserved.
1220 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001221 Example: Exclude memory from 0x18690000-0x1869ffff
1222 memmap=64K$0x18690000
1223 or
1224 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001226 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001227 Format: <integer>
1228 range: 0,4 : pattern number
1229 default : 0 <disable>
1230
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231 meye.*= [HW] Set MotionEye Camera parameters
1232 See Documentation/video4linux/meye.txt.
1233
Andres Salomon8f368812007-10-12 23:04:06 +02001234 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1235 Multi-Function General Purpose Timers on AMD Geode
1236 platforms.
1237
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001238 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1239 the BIOS has incorrectly applied a workaround. TinyBIOS
1240 version 0.98 is known to be affected, 0.99 fixes the
1241 problem by letting the user disable the workaround.
1242
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 mga= [HW,DRM]
1244
Mel Gorman6b74ab92008-07-23 21:26:49 -07001245 mminit_loglevel=
1246 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1247 parameter allows control of the logging verbosity for
1248 the additional memory initialisation checks. A value
1249 of 0 disables mminit logging and a level of 4 will
1250 log everything. Information is printed at KERN_DEBUG
1251 so loglevel=8 may also need to be specified.
1252
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 mousedev.tap_time=
1254 [MOUSE] Maximum time between finger touching and
1255 leaving touchpad surface for touch to be considered
1256 a tap and be reported as a left button click (for
1257 touchpads working in absolute mode only).
1258 Format: <msecs>
1259 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1260 reporting absolute coordinates, such as tablets
1261 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1262 reporting absolute coordinates, such as tablets
1263
1264 mpu401= [HW,OSS]
1265 Format: <io>,<irq>
1266
1267 MTD_Partition= [MTD]
1268 Format: <name>,<region-number>,<size>,<offset>
1269
Randy Dunlapa9913042005-10-23 12:57:11 -07001270 MTD_Region= [MTD] Format:
1271 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272
1273 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001274 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275
Ben Dooks9db829f2008-07-03 11:24:29 +01001276 mtdset= [ARM]
1277 ARM/S3C2412 JIVE boot control
1278
1279 See arch/arm/mach-s3c2412/mach-jive.c
1280
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001282 [HW] Make the MicroTouch USB driver use raw coordinates
1283 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284
1285 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1286
1287 NCR_D700= [HW,SCSI]
1288 See header of drivers/scsi/NCR_D700.c.
1289
1290 ncr5380= [HW,SCSI]
1291
1292 ncr53c400= [HW,SCSI]
1293
1294 ncr53c400a= [HW,SCSI]
1295
1296 ncr53c406a= [HW,SCSI]
1297
1298 ncr53c8xx= [HW,SCSI]
1299
1300 netdev= [NET] Network devices parameters
1301 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1302 Note that mem_start is often overloaded to mean
1303 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001304 This usage is only documented in each driver source
1305 file if at all.
1306
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001307 nf_conntrack.acct=
1308 [NETFILTER] Enable connection tracking flow accounting
1309 0 to disable accounting
1310 1 to enable accounting
1311 Default value depends on CONFIG_NF_CT_ACCT that is
1312 going to be removed in 2.6.29.
1313
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001315 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316
1317 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001318 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319
Trond Myklebusta72b4422006-01-03 09:55:41 +01001320 nfs.callback_tcpport=
1321 [NFS] set the TCP port on which the NFSv4 callback
1322 channel should listen.
1323
Trond Myklebust58df0952006-01-03 09:55:57 +01001324 nfs.idmap_cache_timeout=
1325 [NFS] set the maximum lifetime for idmapper cache
1326 entries.
1327
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001328 nfs.enable_ino64=
1329 [NFS] enable 64-bit inode numbers.
1330 If zero, the NFS client will fake up a 32-bit inode
1331 number for the readdir() and stat() syscalls instead
1332 of returning the full 64-bit number.
1333 The default is to return 64-bit inode numbers.
1334
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001335 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1336 when a NMI is triggered.
1337 Format: [state][,regs][,debounce][,die]
1338
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001339 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001341 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342 emulation library even if a 387 maths coprocessor
1343 is present.
1344
Christoph Lameterc1aee212007-05-31 00:40:47 -07001345 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1346 caches in the slab allocator. Saves per-node memory,
1347 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001348
Randy Dunlapa9913042005-10-23 12:57:11 -07001349 noalign [KNL,ARM]
1350
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 noapic [SMP,APIC] Tells the kernel to not make use of any
1352 IOAPICs that may be present in the system.
1353
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354 nobats [PPC] Do not use BATs for mapping kernel lowmem
1355 on "Classic" PPC cores.
1356
1357 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001358
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001359 nodelayacct [KNL] Disable per-task delay accounting
1360
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1362
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001363 noefi [X86-32,X86-64] Disable EFI runtime services support.
1364
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365 noexec [IA-64]
1366
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001367 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001368 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001370 noexec=off: disable non-executable mappings
1371
1372 noexec32 [X86-64]
1373 This affects only 32-bit executables.
1374 noexec32=on: enable non-executable mappings (default)
1375 read doesn't imply executable mappings
1376 noexec32=off: disable non-executable mappings
1377 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001379 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001380 register save and restore. The kernel will only save
1381 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382
Andi Kleen191679f2008-01-30 13:33:21 +01001383 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1384
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001386
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001387 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388 instruction doesn't work correctly and not to
1389 use it.
1390
1391 nohalt [IA-64] Tells the kernel not to use the power saving
1392 function PAL_HALT_LIGHT when idle. This increases
1393 power-consumption. On the positive side, it reduces
1394 interrupt wake-up latency, which may improve performance
1395 in certain environments such as networked servers or
1396 real-time systems.
1397
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001398 nohz= [KNL] Boottime enable/disable dynamic ticks
1399 Valid arguments: on, off
1400 Default: on
1401
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001402 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001403
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001404 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405 disable unhandled interrupt sources.
1406
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001407 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001408 broken timer IRQ sources.
1409
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410 noisapnp [ISAPNP] Disables ISA PnP code.
1411
1412 noinitrd [RAM] Tells the kernel not to load any configured
1413 initial RAM disk.
1414
1415 nointroute [IA-64]
1416
Tony Luck0aa366f2007-07-20 11:22:30 -07001417 nojitter [IA64] Disables jitter checking for ITC timers.
1418
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001419 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001421 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001422
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423 noltlbs [PPC] Do not use large page/tlb entries for kernel
1424 lowmem mapping on PPC40x.
1425
Horms312f1f02006-02-22 09:57:55 +09001426 nomca [IA-64] Disable machine check abort handling
1427
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001428 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001429
Andres Salomon83d73842007-10-12 23:04:06 +02001430 nomfgpt [X86-32] Disable Multi-Function General Purpose
1431 Timer usage (for AMD Geode machines).
1432
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001433 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001434
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001435 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001436 with UP alternatives
1437
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438 noresidual [PPC] Don't use residual data on PReP machines.
1439
Randy Dunlapa9913042005-10-23 12:57:11 -07001440 noresume [SWSUSP] Disables resume and restores original swap
1441 space.
1442
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 no-scroll [VGA] Disables scrollback.
1444 This is required for the Braillex ib80-piezo Braille
1445 reader made by F.H. Papenmeier (Germany).
1446
1447 nosbagart [IA-64]
1448
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001449 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001450
Len Brown61ec7562007-08-16 03:34:22 -04001451 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1452 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453
Dave Jones97842212007-07-15 23:41:05 -07001454 nosoftlockup [KNL] Disable the soft-lockup detector.
1455
Linus Torvalds1da177e2005-04-16 15:20:36 -07001456 nosync [HW,M68K] Disables sync negotiation for all devices.
1457
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001458 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459
1460 nousb [USB] Disable the USB subsystem
1461
1462 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001463
Fenghua Yua6c75b862008-03-14 13:57:08 -07001464 nptcg= [IA64] Override max number of concurrent global TLB
1465 purges which is reported from either PAL_VM_SUMMARY or
1466 SAL PALO.
1467
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001468 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1469 one of ['zone', 'node', 'default'] can be specified
1470 This can be set from sysctl after boot.
1471 See Documentation/sysctl/vm.txt for details.
1472
Dave Jonesa61c2d72006-01-07 23:18:19 +00001473 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1474
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001475 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1476 Rather than timing out after 20 ms if an EC
1477 command is not properly ACKed, override the length
1478 of the timeout. We have interrupts disabled while
1479 waiting for the ACK, so if this is set too high
1480 interrupts *may* be lost!
1481
Linus Torvalds1da177e2005-04-16 15:20:36 -07001482 opl3= [HW,OSS]
1483 Format: <io>
1484
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 oprofile.timer= [HW]
1486 Use timer interrupt instead of performance counters
1487
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 osst= [HW,SCSI] SCSI Tape Driver
1489 Format: <buffer_size>,<write_threshold>
1490 See also Documentation/scsi/st.txt.
1491
1492 panic= [KNL] Kernel behaviour on panic
1493 Format: <timeout>
1494
1495 parkbd.port= [HW] Parallel port number the keyboard adapter is
1496 connected to, default is 0.
1497 Format: <parport#>
1498 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1499 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001500 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001501
Randy Dunlapa9913042005-10-23 12:57:11 -07001502 parport= [HW,PPT] Specify parallel ports. 0 disables.
1503 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1504 Use 'auto' to force the driver to use any
1505 IRQ/DMA settings detected (the default is to
1506 ignore detected IRQ/DMA settings because of
1507 possible conflicts). You can specify the base
1508 address, IRQ, and DMA settings; IRQ and DMA
1509 should be numbers, or 'auto' (for using detected
1510 settings on that particular port), or 'nofifo'
1511 (to avoid using a FIFO even if it is detected).
1512 Parallel ports are assigned in the order they
1513 are specified on the command line, starting
1514 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001515
Randy Dunlapa9913042005-10-23 12:57:11 -07001516 parport_init_mode= [HW,PPT]
1517 Configure VIA parallel port to operate in
1518 a specific mode. This is necessary on Pegasos
1519 computer where firmware has no options for setting
1520 up parallel port mode and sets it to spp.
1521 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001522 Format: [spp|ps2|epp|ecp|ecpepp]
1523
Randy Dunlapa9913042005-10-23 12:57:11 -07001524 pas2= [HW,OSS] Format:
1525 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1526
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 pas16= [HW,SCSI]
1528 See header of drivers/scsi/pas16.c.
1529
Andrew Mortondd287792006-03-23 03:00:57 -08001530 pause_on_oops=
1531 Halt all CPUs after the first oops has been printed for
1532 the specified number of seconds. This is to be used if
1533 your oopses keep scrolling off the screen.
1534
Linus Torvalds1da177e2005-04-16 15:20:36 -07001535 pcbit= [HW,ISDN]
1536
1537 pcd. [PARIDE]
1538 See header of drivers/block/paride/pcd.c.
1539 See also Documentation/paride.txt.
1540
Randy Dunlapa9913042005-10-23 12:57:11 -07001541 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001542 off [X86-32] don't probe for the PCI bus
1543 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001544 the hardware directly. Use this if your machine
1545 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001546 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001547 hardware access methods are allowed. Use this
1548 if you experience crashes upon bootup and you
1549 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001550 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001551 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001552 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001553 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001554 noaer [PCIE] If the PCIEAER kernel config parameter is
1555 enabled, this kernel boot option can be used to
1556 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001557 nodomains [PCI] Disable support for multiple PCI
1558 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001559 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001560 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001561 nomsi [MSI] If the PCI_MSI kernel config parameter is
1562 enabled, this kernel boot option can be used to
1563 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001564 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001565 routing table. These calls are known to be buggy
1566 on several machines and they hang the machine
1567 when used, but on other computers it's the only
1568 way to get the interrupt routing table. Try
1569 this option if the kernel is unable to allocate
1570 IRQs or discover secondary PCI buses on your
1571 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001572 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001573 Use with caution as certain devices share
1574 address decoders between ROMs and other
1575 resources.
Gary Hadebb71ad82008-05-12 13:57:46 -07001576 norom [X86-32,X86_64] Do not assign address space to
1577 expansion ROMs that do not already have
1578 BIOS assigned address ranges.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001579 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001580 assigned automatically to PCI devices. You can
1581 make the kernel exclude IRQs of your ISA cards
1582 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001583 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001584 of the PIRQ table (normally generated
1585 by the BIOS) if it is outside the
1586 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001587 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001588 useful if the kernel is unable to find your
1589 secondary buses and you want to tell it
1590 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001591 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001592 numbers ourselves, overriding
1593 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001594 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001595 in the BIOS $PIR table. This is needed on
1596 some systems with broken BIOSes, notably
1597 some HP Pavilion N5400 and Omnibook XE3
1598 notebooks. This will have no effect if ACPI
1599 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001600 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001601 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001602 use_crs [X86-32] Use _CRS for PCI resource
1603 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001604 routeirq Do IRQ routing for all PCI devices.
1605 This is normally done in pci_enable_device(),
1606 so this option is a temporary workaround
1607 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001608 skip_isa_align [X86] do not align io start addr, so can
1609 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001610 firmware [ARM] Do not re-enumerate the bus but instead
1611 just use the configuration from the
1612 bootloader. This is currently used on
1613 IXP2000 systems where the bus has to be
1614 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001615 noearly [X86] Don't do any early type 1 scanning.
1616 This might help on some broken boards which
1617 machine check when some devices' config space
1618 is read. But various workarounds are disabled
1619 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001620 bfsort Sort PCI devices into breadth-first order.
1621 This sorting is done to get a device
1622 order compatible with older (<= 2.4) kernels.
1623 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001624 cbiosize=nn[KMG] The fixed amount of bus space which is
1625 reserved for the CardBus bridge's IO window.
1626 The default value is 256 bytes.
1627 cbmemsize=nn[KMG] The fixed amount of bus space which is
1628 reserved for the CardBus bridge's memory
1629 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001630
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 pcmv= [HW,PCMCIA] BadgePAD 4
1632
1633 pd. [PARIDE]
1634 See Documentation/paride.txt.
1635
1636 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1637 boot time.
1638 Format: { 0 | 1 }
1639 See arch/parisc/kernel/pdc_chassis.c
1640
1641 pf. [PARIDE]
1642 See Documentation/paride.txt.
1643
1644 pg. [PARIDE]
1645 See Documentation/paride.txt.
1646
1647 pirq= [SMP,APIC] Manual mp-table setup
1648 See Documentation/i386/IO-APIC.txt.
1649
1650 plip= [PPT,NET] Parallel port network link
1651 Format: { parport<nr> | timid | 0 }
1652 See also Documentation/parport.txt.
1653
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001654 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1655 Override pmtimer IOPort with a hex value.
1656 e.g. pmtmr=0x508
1657
Linus Torvalds1da177e2005-04-16 15:20:36 -07001658 pnpacpi= [ACPI]
1659 { off }
1660
1661 pnpbios= [ISAPNP]
1662 { on | off | curr | res | no-curr | no-res }
1663
1664 pnp_reserve_irq=
1665 [ISAPNP] Exclude IRQs for the autoconfiguration
1666
1667 pnp_reserve_dma=
1668 [ISAPNP] Exclude DMAs for the autoconfiguration
1669
1670 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001671 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001672
1673 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001674 [ISAPNP] Exclude memory regions for the
1675 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001676 Ranges are in pairs (memory base and size).
1677
Ingo Molnar45807a12007-07-15 23:40:10 -07001678 print-fatal-signals=
1679 [KNL] debug: print fatal signals
1680 print-fatal-signals=1: print segfault info to
1681 the kernel console.
1682 default: off.
1683
Randy Dunlape84845c2007-07-15 23:40:25 -07001684 printk.time= Show timing data prefixed to each printk message line
1685 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1686
Linus Torvalds1da177e2005-04-16 15:20:36 -07001687 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001688 Format: [schedule,]<number>
1689 Param: "schedule" - profile schedule points.
1690 Param: <number> - step/bucket size as a power of 2 for
1691 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001692 Param: "sleep" - profile D-state sleeping (millisecs).
1693 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001694 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001695
Randy Dunlapa9913042005-10-23 12:57:11 -07001696 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697 Limit processor to maximum C-state
1698 max_cstate=9 overrides any DMI blacklist limit.
1699
Len Brown41c0d862005-12-28 12:43:51 -05001700 processor.nocst [HW,ACPI]
1701 Ignore the _CST method to determine C-states,
1702 instead using the legacy FADT method
1703
Linus Torvalds1da177e2005-04-16 15:20:36 -07001704 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1705 before loading.
1706 See Documentation/ramdisk.txt.
1707
Randy Dunlapa9913042005-10-23 12:57:11 -07001708 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1709 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1711 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001712 psmouse.resetafter= [HW,MOUSE]
1713 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714 (0 = never).
1715 psmouse.resolution=
1716 [HW,MOUSE] Set desired mouse resolution, in dpi.
1717 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001718 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719 0 = disabled, 1 = enabled (default).
1720
1721 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001722 Format:
1723 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001724
1725 pt. [PARIDE]
1726 See Documentation/paride.txt.
1727
Kay Sieversdc8c8582007-08-15 12:25:38 +02001728 pty.legacy_count=
1729 [KNL] Number of legacy pty's. Overwrites compiled-in
1730 default number.
1731
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001732 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001733
Linus Torvalds1da177e2005-04-16 15:20:36 -07001734 r128= [HW,DRM]
1735
1736 raid= [HW,RAID]
1737 See Documentation/md.txt.
1738
Randy Dunlapa9913042005-10-23 12:57:11 -07001739 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001741
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743 See Documentation/ramdisk.txt.
1744
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001745 rcupdate.blimit= [KNL,BOOT]
1746 Set maximum number of finished RCU callbacks to process
1747 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001748
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001749 rcupdate.qhimark= [KNL,BOOT]
1750 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001751 RCU callbacks over which batch limiting is disabled.
1752
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001753 rcupdate.qlowmark= [KNL,BOOT]
1754 Set threshold of queued RCU callbacks below which
1755 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001756
Olof Johanssonffdfc402005-09-06 15:17:19 -07001757 rdinit= [KNL]
1758 Format: <full_path>
1759 Run specified binary instead of /init from the ramdisk,
1760 used for early userspace startup. See initrd.
1761
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001762 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001764 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001765
Paul Jackson46b6d942008-07-04 10:00:09 -07001766 relax_domain_level=
1767 [KNL, SMP] Set scheduler's default relax_domain_level.
1768 See Documentation/cpusets.txt.
1769
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1771
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001772 reservetop= [X86-32]
Zachary Amsden461a9af2006-09-25 23:32:25 -07001773 Format: nn[KMG]
1774 Reserves a hole at the top of the kernel virtual
1775 address space.
1776
Vivek Goyal7e962872006-09-27 01:50:44 -07001777 reset_devices [KNL] Force drivers to reset the underlying device
1778 during initialization.
1779
Randy Dunlapa9913042005-10-23 12:57:11 -07001780 resume= [SWSUSP]
1781 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001783 resume_offset= [SWSUSP]
1784 Specify the offset from the beginning of the partition
1785 given by "resume=" at which the swap header is located,
1786 in <PAGE_SIZE> units (needed only for swap files).
1787 See Documentation/power/swsusp-and-swap-files.txt
1788
Michael Neuling0a7b35c2007-02-10 01:44:33 -08001789 retain_initrd [RAM] Keep initrd memory after extraction
1790
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 rhash_entries= [KNL,NET]
1792 Set number of hash buckets for route cache
1793
1794 riscom8= [HW,SERIAL]
1795 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1796
1797 ro [KNL] Mount root device read-only on boot
1798
1799 root= [KNL] Root filesystem
1800
1801 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1802 mount the root filesystem
1803
1804 rootflags= [KNL] Set root filesystem mount option string
1805
1806 rootfstype= [KNL] Set root filesystem type
1807
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001808 rootwait [KNL] Wait (indefinitely) for root device to show up.
1809 Useful for devices that are detected asynchronously
1810 (e.g. USB and MMC devices).
1811
James Morris20510f22007-10-16 23:31:32 -07001812 root_plug.vendor_id=
1813 [ROOTPLUG] Override the default vendor ID
1814
1815 root_plug.product_id=
1816 [ROOTPLUG] Override the default product ID
1817
1818 root_plug.debug=
1819 [ROOTPLUG] Enable debugging output
1820
Linus Torvalds1da177e2005-04-16 15:20:36 -07001821 rw [KNL] Mount root device read-write on boot
1822
1823 S [KNL] Run init in single mode
1824
1825 sa1100ir [NET]
1826 See drivers/net/irda/sa1100_ir.c.
1827
Linus Torvalds1da177e2005-04-16 15:20:36 -07001828 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001829
Linus Torvalds1da177e2005-04-16 15:20:36 -07001830 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1831 Format: <io>[,<timeout>[,<isapnp>]]
1832
1833 scsi_debug_*= [SCSI]
1834 See drivers/scsi/scsi_debug.c.
1835
1836 scsi_default_dev_flags=
1837 [SCSI] SCSI default device flags
1838 Format: <integer>
1839
1840 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1841 Format: <vendor>:<model>:<flags>
1842 (flags are integer value)
1843
Randy Dunlap6af66322007-11-14 16:52:25 -08001844 scsi_logging_level= [SCSI] a bit mask of logging levels
1845 See drivers/scsi/scsi_logging.h for bits. Also
1846 settable via sysctl at dev.scsi.logging_level
1847 (/proc/sys/dev/scsi/logging_level).
1848 There is also a nice 'scsi_logging_level' script in the
1849 S390-tools package, available for download at
1850 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001852 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1853 discovered. async scans them in kernel threads,
1854 allowing boot to proceed. none ignores them, expecting
1855 user space to do the scan.
1856
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 selinux [SELINUX] Disable or enable SELinux at boot time.
1858 Format: { "0" | "1" }
1859 See security/selinux/Kconfig help text.
1860 0 -- disable.
1861 1 -- enable.
1862 Default value is set via kernel config option.
1863 If enabled at boot time, /selinux/disable can be used
1864 later to disable prior to initial policy load.
1865
James Morris4e5ab4c2006-06-09 00:33:33 -07001866 selinux_compat_net =
1867 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001868 Format: { "0" | "1" }
1869 0 -- use new secmark-based packet controls
1870 1 -- use legacy packet controls
1871 Default value is 0 (preferred).
1872 Value can be changed at runtime via
1873 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001874
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001875 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001876
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877 shapers= [NET]
1878 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001879
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880 sim710= [SCSI,HW]
1881 See header of drivers/scsi/sim710.c.
1882
1883 simeth= [IA-64]
1884 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001885
Linus Torvalds1da177e2005-04-16 15:20:36 -07001886 slram= [HW,MTD]
1887
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001888 slub_debug[=options[,slabs]] [MM, SLUB]
1889 Enabling slub_debug allows one to determine the
1890 culprit if slab objects become corrupted. Enabling
1891 slub_debug can create guard zones around objects and
1892 may poison objects when not in use. Also tracks the
1893 last alloc / free. For more information see
1894 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001895
1896 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001897 Determines the maximum allowed order for slabs.
1898 A high setting may cause OOMs due to memory
1899 fragmentation. For more information see
1900 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001901
1902 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001903 The minimum number of objects per slab. SLUB will
1904 increase the slab order up to slub_max_order to
1905 generate a sufficiently large slab able to contain
1906 the number of objects indicated. The higher the number
1907 of objects the smaller the overhead of tracking slabs
1908 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001909 For more information see Documentation/vm/slub.txt.
1910
1911 slub_min_order= [MM, SLUB]
1912 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001913 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001914 For more information see Documentation/vm/slub.txt.
1915
1916 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001917 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001918 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001919 allocs to different slabs. Debug options disable
1920 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001921 For more information see Documentation/vm/slub.txt.
1922
Linus Torvalds1da177e2005-04-16 15:20:36 -07001923 smart2= [HW]
1924 Format: <io1>[,<io2>[,...,<io8>]]
1925
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001926 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001927 attempt to substitute SMP alternatives once at boot.
1928
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001929 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1930 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1931 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1932 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1933 smsc-ircc2.ircc_irq= [HW] IRQ line
1934 smsc-ircc2.ircc_dma= [HW] DMA channel
1935 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1936 0: Toshiba Satellite 1800 (GP data pin select)
1937 1: Fast pin select (default)
1938 2: ATC IRMode
1939
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940 snd-ad1816a= [HW,ALSA]
1941
1942 snd-ad1848= [HW,ALSA]
1943
1944 snd-ali5451= [HW,ALSA]
1945
1946 snd-als100= [HW,ALSA]
1947
1948 snd-als4000= [HW,ALSA]
1949
1950 snd-azt2320= [HW,ALSA]
1951
1952 snd-cmi8330= [HW,ALSA]
1953
1954 snd-cmipci= [HW,ALSA]
1955
1956 snd-cs4231= [HW,ALSA]
1957
1958 snd-cs4232= [HW,ALSA]
1959
1960 snd-cs4236= [HW,ALSA]
1961
1962 snd-cs4281= [HW,ALSA]
1963
1964 snd-cs46xx= [HW,ALSA]
1965
1966 snd-dt019x= [HW,ALSA]
1967
1968 snd-dummy= [HW,ALSA]
1969
1970 snd-emu10k1= [HW,ALSA]
1971
1972 snd-ens1370= [HW,ALSA]
1973
1974 snd-ens1371= [HW,ALSA]
1975
1976 snd-es968= [HW,ALSA]
1977
1978 snd-es1688= [HW,ALSA]
1979
1980 snd-es18xx= [HW,ALSA]
1981
1982 snd-es1938= [HW,ALSA]
1983
1984 snd-es1968= [HW,ALSA]
1985
1986 snd-fm801= [HW,ALSA]
1987
1988 snd-gusclassic= [HW,ALSA]
1989
1990 snd-gusextreme= [HW,ALSA]
1991
1992 snd-gusmax= [HW,ALSA]
1993
1994 snd-hdsp= [HW,ALSA]
1995
1996 snd-ice1712= [HW,ALSA]
1997
1998 snd-intel8x0= [HW,ALSA]
1999
2000 snd-interwave= [HW,ALSA]
2001
2002 snd-interwave-stb=
2003 [HW,ALSA]
2004
2005 snd-korg1212= [HW,ALSA]
2006
2007 snd-maestro3= [HW,ALSA]
2008
2009 snd-mpu401= [HW,ALSA]
2010
2011 snd-mtpav= [HW,ALSA]
2012
2013 snd-nm256= [HW,ALSA]
2014
2015 snd-opl3sa2= [HW,ALSA]
2016
2017 snd-opti92x-ad1848=
2018 [HW,ALSA]
2019
2020 snd-opti92x-cs4231=
2021 [HW,ALSA]
2022
2023 snd-opti93x= [HW,ALSA]
2024
2025 snd-pmac= [HW,ALSA]
2026
2027 snd-rme32= [HW,ALSA]
2028
2029 snd-rme96= [HW,ALSA]
2030
2031 snd-rme9652= [HW,ALSA]
2032
2033 snd-sb8= [HW,ALSA]
2034
2035 snd-sb16= [HW,ALSA]
2036
2037 snd-sbawe= [HW,ALSA]
2038
2039 snd-serial= [HW,ALSA]
2040
2041 snd-sgalaxy= [HW,ALSA]
2042
2043 snd-sonicvibes= [HW,ALSA]
2044
2045 snd-sun-amd7930=
2046 [HW,ALSA]
2047
2048 snd-sun-cs4231= [HW,ALSA]
2049
2050 snd-trident= [HW,ALSA]
2051
2052 snd-usb-audio= [HW,ALSA,USB]
2053
2054 snd-via82xx= [HW,ALSA]
2055
2056 snd-virmidi= [HW,ALSA]
2057
2058 snd-wavefront= [HW,ALSA]
2059
2060 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002061
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002062 softlockup_panic=
2063 [KNL] Should the soft-lockup detector generate panics.
2064
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2066 See Documentation/sonypi.txt
2067
2068 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2069 See Documentation/specialix.txt.
2070
2071 spia_io_base= [HW,MTD]
2072 spia_fio_base=
2073 spia_pedr=
2074 spia_peddr=
2075
2076 sscape= [HW,OSS]
2077 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002078
Linus Torvalds1da177e2005-04-16 15:20:36 -07002079 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2080 See Documentation/scsi/st.txt.
2081
Linus Torvalds1da177e2005-04-16 15:20:36 -07002082 sti= [PARISC,HW]
2083 Format: <num>
2084 Set the STI (builtin display/keyboard on the HP-PARISC
2085 machines) console (graphic card) which should be used
2086 as the initial boot-console.
2087 See also comment in drivers/video/console/sticore.c.
2088
2089 sti_font= [HW]
2090 See comment in drivers/video/console/sticore.c.
2091
2092 stifb= [HW]
2093 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2094
Greg Banks42a7fc42007-03-06 01:42:23 -08002095 sunrpc.pool_mode=
2096 [NFS]
2097 Control how the NFS server code allocates CPUs to
2098 service thread pools. Depending on how many NICs
2099 you have and where their interrupts are bound, this
2100 option will affect which CPUs will do NFS serving.
2101 Note: this parameter cannot be changed while the
2102 NFS server is running.
2103
2104 auto the server chooses an appropriate mode
2105 automatically using heuristics
2106 global a single global pool contains all CPUs
2107 percpu one pool for each CPU
2108 pernode one pool for each NUMA node (equivalent
2109 to global on non-NUMA machines)
2110
Linus Torvalds1da177e2005-04-16 15:20:36 -07002111 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002112
Linus Torvalds1da177e2005-04-16 15:20:36 -07002113 switches= [HW,M68k]
2114
2115 sym53c416= [HW,SCSI]
2116 See header of drivers/scsi/sym53c416.c.
2117
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002118 sysrq_always_enabled
2119 [KNL]
2120 Ignore sysrq setting - this boot parameter will
2121 neutralize any effect of /proc/sys/kernel/sysrq.
2122 Useful for debugging.
2123
Linus Torvalds1da177e2005-04-16 15:20:36 -07002124 t128= [HW,SCSI]
2125 See header of drivers/scsi/t128.c.
2126
2127 tdfx= [HW,DRM]
2128
David Brownell77437fd2008-07-23 21:28:33 -07002129 test_suspend= [SUSPEND]
2130 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2131 standby suspend) as the system sleep state to briefly
2132 enter during system startup. The system is woken from
2133 this state using a wakeup-capable RTC alarm.
2134
Linus Torvalds1da177e2005-04-16 15:20:36 -07002135 thash_entries= [KNL,NET]
2136 Set number of hash buckets for TCP connection
2137
Len Brownf8707ec2007-08-12 00:12:54 -04002138 thermal.act= [HW,ACPI]
2139 -1: disable all active trip points in all thermal zones
2140 <degrees C>: override all lowest active trip points
2141
Len Brownc52a7412007-08-14 15:49:32 -04002142 thermal.crt= [HW,ACPI]
2143 -1: disable all critical trip points in all thermal zones
2144 <degrees C>: lower all critical trip points
2145
Len Brownf5487142007-08-12 00:12:44 -04002146 thermal.nocrt= [HW,ACPI]
2147 Set to disable actions on ACPI thermal zone
2148 critical and hot trip points.
2149
Len Brown72b33ef2007-08-12 00:12:17 -04002150 thermal.off= [HW,ACPI]
2151 1: disable ACPI thermal control
2152
Len Browna70cdc52007-08-12 00:12:35 -04002153 thermal.psv= [HW,ACPI]
2154 -1: disable all passive trip points
2155 <degrees C>: override all passive trip points to this value
2156
Len Brown730ff342007-08-12 00:12:26 -04002157 thermal.tzp= [HW,ACPI]
2158 Specify global default ACPI thermal zone polling rate
2159 <deci-seconds>: poll all this frequency
2160 0: no polling (default)
2161
Linus Torvalds1da177e2005-04-16 15:20:36 -07002162 tmscsim= [HW,SCSI]
2163 See comment before function dc390_setup() in
2164 drivers/scsi/tmscsim.c.
2165
2166 tp720= [HW,PS2]
2167
2168 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002169 Format:
2170 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2171
Randy Dunlapa9913042005-10-23 12:57:11 -07002172 turbografx.map[2|3]= [HW,JOY]
2173 TurboGraFX parallel port interface
2174 Format:
2175 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002176 See also Documentation/input/joystick-parport.txt
2177
2178 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2179 See header of drivers/scsi/u14-34f.c.
2180
2181 uart401= [HW,OSS]
2182 Format: <io>,<irq>
2183
2184 uart6850= [HW,OSS]
2185 Format: <io>,<irq>
2186
Alan Stern5f8364b2006-12-05 16:29:55 -05002187 uhci-hcd.ignore_oc=
2188 [USB] Ignore overcurrent events (default N).
2189 Some badly-designed motherboards generate lots of
2190 bogus events, for ports that aren't wired to
2191 anything. Set this parameter to avoid log spamming.
2192 Note that genuine overcurrent events won't be
2193 reported either.
2194
Simon Arlotte3a61b02008-07-19 23:32:54 +01002195 unknown_nmi_panic
2196 [X86-32,X86-64]
2197 Set unknown_nmi_panic=1 early on boot.
2198
Alan Sternb5e795f2007-02-20 15:00:53 -05002199 usbcore.autosuspend=
2200 [USB] The autosuspend time delay (in seconds) used
2201 for newly-detected USB devices (default 2). This
2202 is the time required before an idle device will be
2203 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002204 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002205
Linus Torvalds1da177e2005-04-16 15:20:36 -07002206 usbhid.mousepoll=
2207 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002208
Paul Jackson200001e2008-06-25 05:44:46 -07002209 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2210 kernel's map of available physical RAM.
2211
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002212 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf5272007-05-02 19:27:12 +02002213 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002214 vdso=1: enable VDSO (default)
2215 vdso=0: disable VDSO mapping
2216
Roland McGrathaf65d642008-01-30 13:30:43 +01002217 vdso32= [X86-32,X86-64]
2218 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2219 vdso32=1: enable 32-bit VDSO (default)
2220 vdso32=0: disable 32-bit VDSO mapping
2221
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002222 vector= [IA-64,SMP]
2223 vector=percpu: enable percpu vector domain
2224
Linus Torvalds1da177e2005-04-16 15:20:36 -07002225 video= [FB] Frame buffer configuration
2226 See Documentation/fb/modedb.txt.
2227
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002228 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002229 See Documentation/i386/boot.txt and
2230 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231 Use vga=ask for menu.
2232 This is actually a boot loader parameter; the value is
2233 passed to the kernel using a special protocol.
2234
Randy Dunlapa9913042005-10-23 12:57:11 -07002235 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002236 size of <nn>. This can be used to increase the
2237 minimum size (128MB on x86). It can also be used to
2238 decrease the size and leave more room for directly
2239 mapped kernel RAM.
2240
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002241 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2242 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002243
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002244 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2245 Format: <command>
2246
2247 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2248 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002249
Linus Torvalds1da177e2005-04-16 15:20:36 -07002250 waveartist= [HW,OSS]
2251 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002252
Linus Torvalds1da177e2005-04-16 15:20:36 -07002253 wd33c93= [HW,SCSI]
2254 See header of drivers/scsi/wd33c93.c.
2255
2256 wd7000= [HW,SCSI]
2257 See header of drivers/scsi/wd7000.c.
2258
2259 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002260 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002261
2262 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2263 xd_geo= See header of drivers/block/xd.c.
2264
2265 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002266 Format:
2267 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002268
Andi Kleena62eaf12006-02-16 23:41:58 +01002269 norandmaps Don't use address space randomization
2270 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2271
Randy Dunlapa9913042005-10-23 12:57:11 -07002272______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002273
2274TODO:
2275
2276 Add documentation for ALSA options.
2277 Add more DRM drivers.