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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]]
Yinghai Lu5c059172008-07-24 17:29:40 -0700660 earlyprintk=dbgp
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661
Randy Dunlapa9913042005-10-23 12:57:11 -0700662 Append ",keep" to not disable it when the real console
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 takes over.
664
Yinghai Lu5c059172008-07-24 17:29:40 -0700665 Only vga or serial or usb debug port at a time.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666
667 Currently only ttyS0 and ttyS1 are supported.
668
669 Interaction with the standard serial driver is not
670 very good.
671
672 The VGA output is eventually overwritten by the real
673 console.
674
675 eata= [HW,SCSI]
676
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 edd= [EDD]
Tim Gardner8c4dd602008-04-29 01:02:45 -0700678 Format: {"off" | "on" | "skip[mbr]"}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 eisa_irq_edge= [PARISC,HW]
681 See header of drivers/parisc/eisa.c.
682
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700683 elanfreq= [X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 See comment before function elanfreq_setup() in
Pavel Machek71f77052008-07-04 09:59:43 -0700685 arch/x86/kernel/cpu/cpufreq/elanfreq.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686
687 elevator= [IOSCHED]
Randy Dunlap16ab3ad2006-01-14 13:21:20 -0800688 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
Randy Dunlapa9913042005-10-23 12:57:11 -0700689 See Documentation/block/as-iosched.txt and
690 Documentation/block/deadline-iosched.txt for details.
691
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700692 elfcorehdr= [X86-32, X86_64]
Randy Dunlapa9913042005-10-23 12:57:11 -0700693 Specifies physical address of start of kernel core
Vivek Goyalaac04b32006-01-09 20:51:47 -0800694 image elf header. Generally kexec loader will
695 pass this option to capture kernel.
696 See Documentation/kdump/kdump.txt for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697
698 enforcing [SELINUX] Set initial enforcing status.
699 Format: {"0" | "1"}
700 See security/selinux/Kconfig help text.
701 0 -- permissive (log only, no denials).
702 1 -- enforcing (deny and log).
703 Default value is 0.
704 Value can be changed at runtime via /selinux/enforce.
705
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 es1371= [HW,OSS]
707 Format: <spdif>,[<nomix>,[<amplifier>]]
708 See also header of sound/oss/es1371.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700709
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 ether= [HW,NET] Ethernet cards parameters
711 This option is obsoleted by the "netdev=" option, which
712 has equivalent usage. See its documentation for details.
713
714 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
715 Format: <io>[,<irq>]
716
Akinobu Mitade1ba092006-12-08 02:39:42 -0800717 failslab=
718 fail_page_alloc=
719 fail_make_request=[KNL]
720 General fault injection mechanism.
721 Format: <interval>,<probability>,<space>,<times>
722 See also /Documentation/fault-injection/.
723
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 fd_mcs= [HW,SCSI]
725 See header of drivers/scsi/fd_mcs.c.
726
727 fdomain= [HW,SCSI]
728 See header of drivers/scsi/fdomain.c.
729
730 floppy= [HW]
731 See Documentation/floppy.txt.
732
Alex Chiangf13ae302008-05-08 14:03:23 -0600733 force_pal_cache_flush
734 [IA-64] Avoid check_sal_cache_flush which may hang on
735 buggy SAL_CACHE_FLUSH implementations. Using this
736 parameter will force ia64_sal_cache_flush to call
737 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
738
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 gamecon.map[2|3]=
740 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
741 support via parallel port (up to 5 devices per port)
742 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
743 See also Documentation/input/joystick-parport.txt
744
745 gamma= [HW,DRM]
746
Yinghai Luaaf23042008-01-30 13:33:09 +0100747 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
748 Format: off | on
749 default: on
750
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 gdth= [HW,SCSI]
752 See header of drivers/scsi/gdth.c.
753
754 gpt [EFI] Forces disk with valid GPT signature but
755 invalid Protective MBR to be treated as GPT.
756
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 gvp11= [HW,SCSI]
758
759 hashdist= [KNL,NUMA] Large hashes allocated during boot
760 are distributed across NUMA nodes. Defaults on
761 for IA-64, off otherwise.
Randy Dunlapa9913042005-10-23 12:57:11 -0700762 Format: 0 | 1 (for off | on)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763
764 hcl= [IA-64] SGI's Hardware Graph compatibility layer
765
766 hd= [EIDE] (E)IDE hard drive subsystem geometry
767 Format: <cyl>,<head>,<sect>
768
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
770 size of <nn>. This works even on boxes that have no
771 highmem otherwise. This also works to reduce highmem
772 size on bigger boxes.
773
Thomas Gleixner54cdfdb2007-02-16 01:28:11 -0800774 highres= [KNL] Enable/disable high resolution timer mode.
775 Valid parameters: "on", "off"
776 Default: "on"
777
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 hisax= [HW,ISDN]
779 See Documentation/isdn/README.HiSax.
780
Andi Kleenb4718e62008-07-23 21:27:51 -0700781 hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot.
782 hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages.
Jon Tollefson0d9ea752008-07-23 21:27:56 -0700783 On x86-64 and powerpc, this option can be specified
784 multiple times interleaved with hugepages= to reserve
785 huge pages of different sizes. Valid pages sizes on
786 x86-64 are 2M (when the CPU supports "pse") and 1G
787 (when the CPU supports the "pdpe1gb" cpuinfo flag)
Andi Kleenb4718e62008-07-23 21:27:51 -0700788 Note that 1GB pages can only be allocated at boot time
789 using hugepages= and not freed afterwards.
Nick Piggine11bfbf2008-07-23 21:27:52 -0700790 default_hugepagesz=
791 [same as hugepagesz=] The size of the default
792 HugeTLB page size. This is the size represented by
793 the legacy /proc/ hugepages APIs, used for SHM, and
794 default size when mounting hugetlbfs filesystems.
795 Defaults to the default architecture's huge page size
796 if not specified.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200799 i8042.dumbkbd [HW] Pretend that controller can only read data from
800 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 (Don't attempt to blink the leds)
802 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500803 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400804 i8042.noloop [HW] Disable the AUX Loopback command while probing
805 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 i8042.nomux [HW] Don't check presence of an active multiplexing
807 controller
808 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
809 controllers
810 i8042.panicblink=
811 [HW] Frequency with which keyboard LEDs should blink
812 when kernel panics (default is 0.5 sec)
813 i8042.reset [HW] Reset the controller during init and cleanup
814 i8042.unlock [HW] Unlock (ignore) the keylock
815
816 i810= [HW,DRM]
817
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700818 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
819 indicates that the driver is running on unsupported
820 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
822 does not match list of supported models.
823 i8k.power_status
824 [HW] Report power status in /proc/i8k
825 (disabled by default)
826 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
827 capability is set.
828
829 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
830 See Documentation/mca.txt.
831
832 icn= [HW,ISDN]
833 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
834
835 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200836 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100837 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100840 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841
Andi Kleenf039b752007-05-02 19:27:12 +0200842 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800843 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200844 Poll forces a polling idle loop that can slightly improves the performance
845 of waking up a idle CPU, but will use a lot of power and make the system
846 run hot. Not recommended.
847 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
848 to not use it because it doesn't save as much power as a normal idle
849 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
850 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800851 idle=halt. Halt is forced to be used for CPU idle.
852 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800853 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700854
Denis Cheng594765a2008-02-06 02:57:49 +0100855 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
856 Claim all unknown PCI IDE storage controllers.
857
Ingo Molnar792908222006-12-06 20:40:51 -0800858 ignore_loglevel [KNL]
859 Ignore loglevel setting - this will print /all/
860 kernel messages to the console. Useful for debugging.
861
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 ihash_entries= [KNL]
863 Set number of hash buckets for inode cache.
864
865 in2000= [HW,SCSI]
866 See header of drivers/scsi/in2000.c.
867
868 init= [KNL]
869 Format: <full_path>
870 Run specified binary instead of /sbin/init as init
871 process.
872
873 initcall_debug [KNL] Trace initcalls as they are executed. Useful
874 for working out where the kernel is dying during
875 startup.
876
877 initrd= [BOOT] Specify the location of the initial ramdisk
878
879 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
880 Format: <irq>
881
882 inttest= [IA64]
883
Pavel Machekb552da82008-03-19 15:58:11 +0100884 iommu= [x86]
885 off
886 force
887 noforce
888 biomerge
889 panic
890 nopanic
891 merge
892 nomerge
893 forcesac
894 soft
895
896
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700897 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
898 off
899 Disable intel iommu driver.
900 igfx_off [Default Off]
901 By default, gfx is mapped as normal device. If a gfx
902 device has a dedicated DMAR unit, the DMAR unit is
903 bypassed by not enabling DMAR with this option. In
904 this case, gfx device will use physical address for
905 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700906 forcedac [x86_64]
907 With this option iommu will not optimize to look
908 for io virtual address below 32 bit forcing dual
909 address cycle on pci bus for cards supporting greater
910 than 32 bit addressing. The default is to look
911 for translation below 32 bit and if not available
912 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800913 strict [Default Off]
914 With this option on every unmap_single operation will
915 result in a hardware IOTLB flush operation as opposed
916 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700917
Rene Hermanb02aae92008-01-30 13:30:05 +0100918 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100919 0x80
920 Standard port 0x80 based delay
921 0xed
922 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100923 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100924 Simple two microseconds delay
925 none
926 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100927
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928 io7= [HW] IO7 for Marvel based alpha systems
929 See comment before marvel_specify_io7 in
930 arch/alpha/kernel/core_marvel.c.
931
932 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400933 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934
935 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700936 See comment before ip2_setup() in
937 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938
939 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
940 See header of drivers/scsi/ips.c.
941
Simon Horman72c4a132006-09-13 19:57:18 -0700942 ports= [IP_VS_FTP] IPVS ftp helper module
943 Default is 21.
944 Up to 8 (IP_VS_APP_MAX_PORTS) ports
945 may be specified.
946 Format: <port>,<port>....
947
Alan Cox200803d2005-06-28 20:45:18 -0700948 irqfixup [HW]
949 When an interrupt is not handled search all handlers
950 for it. Intended to get systems with badly broken
951 firmware running.
952
953 irqpoll [HW]
954 When an interrupt is not handled search all handlers
955 for it. Also check all handlers each timer
956 interrupt. Intended to get systems with badly broken
957 firmware running.
958
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700960 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961
962 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800963 Format:
964 <cpu number>,...,<cpu number>
965 or
966 <cpu number>-<cpu number> (must be a positive range in ascending order)
967 or a mixture
968 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969 This option can be used to specify one or more CPUs
970 to isolate from the general SMP balancing and scheduling
971 algorithms. The only way to move a process onto or off
972 an "isolated" CPU is via the CPU affinity syscalls.
973 <cpu number> begins at 0 and the maximum value is
974 "number of CPUs in system - 1".
975
976 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700977 alternative -- manually setting the CPU mask of all
978 tasks in the system -- can cause problems and
979 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980
Randy Dunlapa9913042005-10-23 12:57:11 -0700981 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982
983 js= [HW,JOY] Analog joystick
984 See Documentation/input/joystick.txt.
985
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700986 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700987 specifies the amount of memory usable by the kernel
988 for non-movable allocations. The requested amount is
989 spread evenly throughout all nodes in the system. The
990 remaining memory in each node is used for Movable
991 pages. In the event, a node is too small to have both
992 kernelcore and Movable pages, kernelcore pages will
993 take priority and other nodes will have a larger number
994 of kernelcore pages. The Movable zone is used for the
995 allocation of pages that may be reclaimed or moved
996 by the page migration subsystem. This means that
997 HugeTLB pages may not be allocated from this zone.
998 Note that allocations like PTEs-from-HighMem still
999 use the HighMem zone if it exists, and the Normal
1000 zone if it does not.
1001
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001002 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -07001003 is similar to kernelcore except it specifies the
1004 amount of memory used for migratable allocations.
1005 If both kernelcore and movablecore is specified,
1006 then kernelcore will be at *least* the specified
1007 value but may be more. If movablecore on its own
1008 is specified, the administrator must be careful
1009 that the amount of memory usable for all allocations
1010 is not too small.
1011
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 keepinitrd [HW,ARM]
1013
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001014 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015 in oops dumps.
1016
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001017 kgdboc= [HW] kgdb over consoles.
1018 Requires a tty driver that supports console polling.
1019 (only serial suported for now)
1020 Format: <serial_device>[,baud]
1021
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022 l2cr= [PPC]
1023
Robert Brosea78bfbf2008-03-29 07:20:23 +11001024 l3cr= [PPC]
1025
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001026 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001027 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001029 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001030 C2 power state.
1031
FD Camifcb71f62008-01-06 19:08:56 +01001032 libata.dma= [LIBATA] DMA control
1033 libata.dma=0 Disable all PATA and SATA DMA
1034 libata.dma=1 PATA and SATA Disk DMA only
1035 libata.dma=2 ATAPI (CDROM) DMA only
1036 libata.dma=4 Compact Flash DMA only
1037 Combinations also work, so libata.dma=3 enables DMA
1038 for disks and CDROMs, but not CFs.
1039
Dave Jones78e70c22007-09-27 11:50:13 -04001040 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1041 when set.
1042 Format: <int>
1043
Tejun Heo33267322008-02-13 09:15:09 +09001044 libata.force= [LIBATA] Force configurations. The format is comma
1045 separated list of "[ID:]VAL" where ID is
1046 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1047 matching port, link or device. Basically, it matches
1048 the ATA ID string printed on console by libata. If
1049 the whole ID part is omitted, the last PORT and DEVICE
1050 values are used. If ID hasn't been specified yet, the
1051 configuration applies to all ports, links and devices.
1052
1053 If only DEVICE is omitted, the parameter applies to
1054 the port and all links and devices behind it. DEVICE
1055 number of 0 either selects the first device or the
1056 first fan-out link behind PMP device. It does not
1057 select the host link. DEVICE number of 15 selects the
1058 host link and device attached to it.
1059
1060 The VAL specifies the configuration to force. As long
1061 as there's no ambiguity shortcut notation is allowed.
1062 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1063 The following configurations can be forced.
1064
1065 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1066 Any ID with matching PORT is used.
1067
1068 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1069
1070 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1071 udma[/][16,25,33,44,66,100,133] notation is also
1072 allowed.
1073
1074 * [no]ncq: Turn on or off NCQ.
1075
1076 If there are multiple matching configurations changing
1077 the same attribute, the last one is used.
1078
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079 load_ramdisk= [RAM] List of ramdisks to load from floppy
1080 See Documentation/ramdisk.txt.
1081
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001082 lockd.nlm_grace_period=P [NFS] Assign grace period.
1083 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001085 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1086 Format: <integer>
1087
1088 lockd.nlm_timeout=T [NFS] Assign timeout value.
1089 Format: <integer>
1090
1091 lockd.nlm_udpport=M [NFS] Assign UDP port.
1092 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093
1094 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1095 Format: <irq>
1096
1097 loglevel= All Kernel Messages with a loglevel smaller than the
1098 console loglevel will be printed to the console. It can
1099 also be changed with klogd or other programs. The
1100 loglevels are defined as follows:
1101
1102 0 (KERN_EMERG) system is unusable
1103 1 (KERN_ALERT) action must be taken immediately
1104 2 (KERN_CRIT) critical conditions
1105 3 (KERN_ERR) error conditions
1106 4 (KERN_WARNING) warning conditions
1107 5 (KERN_NOTICE) normal but significant condition
1108 6 (KERN_INFO) informational
1109 7 (KERN_DEBUG) debug-level messages
1110
1111 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001112 Format: { n | nk | nM }
1113 n must be a power of two. The default size
1114 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115
Randy Dunlapaccaa242007-10-16 01:29:37 -07001116 logo.nologo [FB] Disables display of the built-in Linux logo.
1117 This may be used to provide more screen space for
1118 kernel log messages and is useful when debugging
1119 kernel boot problems.
1120
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121 lp=0 [LP] Specify parallel ports to use, e.g,
1122 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1123 lp=reset first parallel port). 'lp=0' disables the
1124 lp=auto printer driver. 'lp=reset' (which can be
1125 specified in addition to the ports) causes
1126 attached printers to be reset. Using
1127 lp=port1,port2,... specifies the parallel ports
1128 to associate lp devices with, starting with
1129 lp0. A port specification may be 'none' to skip
1130 that lp device, or a parport name such as
1131 'parport0'. Specifying 'lp=auto' instead of a
1132 port specification list means that device IDs
1133 from each port should be examined, to see if
1134 an IEEE 1284-compliant printer is attached; if
1135 so, the driver will manage that printer.
1136 See also header of drivers/char/lp.c.
1137
1138 lpj=n [KNL]
1139 Sets loops_per_jiffy to given constant, thus avoiding
1140 time-consuming boot-time autodetection (up to 250 ms per
1141 CPU). 0 enables autodetection (default). To determine
1142 the correct value for your kernel, boot with normal
1143 autodetection and see what value is printed. Note that
1144 on SMP systems the preset will be applied to all CPUs,
1145 which is likely to cause problems if your CPUs need
1146 significantly divergent settings. An incorrect value
1147 will cause delays in the kernel to be wrong, leading to
1148 unpredictable I/O errors and other breakage. Although
1149 unlikely, in the extreme case this might damage your
1150 hardware.
1151
1152 ltpc= [NET]
1153 Format: <io>,<irq>,<dma>
1154
Randy Dunlapa9913042005-10-23 12:57:11 -07001155 mac5380= [HW,SCSI] Format:
1156 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157
Randy Dunlapa9913042005-10-23 12:57:11 -07001158 machvec= [IA64] Force the use of a particular machine-vector
1159 (machvec) in a generic kernel.
1160 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161
Randy Dunlapa9913042005-10-23 12:57:11 -07001162 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 be mounted
1164 Format: <1-256>
1165
1166 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001167 should make use of. maxcpus=n : n >= 0 limits the
1168 kernel to using 'n' processors. n=0 is a special case,
1169 it is equivalent to "nosmp", which also disables
1170 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171
Bob Picco2b2c3752005-06-29 18:00:00 -07001172 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1173 equal to this physical address is ignored.
1174
Randy Dunlapa9913042005-10-23 12:57:11 -07001175 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176 Should be between 1 and 2^32-1.
1177
1178 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001179 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180 Should be between 1 and 16384.
1181
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 mcatest= [IA-64]
1183
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001184 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185
Andi Kleen909dd322007-10-17 18:04:38 +02001186 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1187
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188 md= [HW] RAID subsystems devices and level
1189 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001190
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 mdacon= [MDA]
1192 Format: <first>,<last>
1193 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001194
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1196 Amount of memory to be used when the kernel is not able
1197 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001198 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001199 address space collisions. Without memmap= PCI devices
1200 could be placed at addresses belonging to unused RAM.
1201
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001202 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 memory.
1204
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001205 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 E820 memory map, as specified by the user.
1207 Such memmap=exactmap lines can be constructed based on
1208 BIOS output or other requirements. See the memmap=nn@ss
1209 option description.
1210
1211 memmap=nn[KMG]@ss[KMG]
1212 [KNL] Force usage of a specific region of memory
1213 Region of memory to be used, from ss to ss+nn.
1214
1215 memmap=nn[KMG]#ss[KMG]
1216 [KNL,ACPI] Mark specific memory as ACPI data.
1217 Region of memory to be used, from ss to ss+nn.
1218
1219 memmap=nn[KMG]$ss[KMG]
1220 [KNL,ACPI] Mark specific memory as reserved.
1221 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001222 Example: Exclude memory from 0x18690000-0x1869ffff
1223 memmap=64K$0x18690000
1224 or
1225 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001227 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001228 Format: <integer>
1229 range: 0,4 : pattern number
1230 default : 0 <disable>
1231
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232 meye.*= [HW] Set MotionEye Camera parameters
1233 See Documentation/video4linux/meye.txt.
1234
Andres Salomon8f368812007-10-12 23:04:06 +02001235 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1236 Multi-Function General Purpose Timers on AMD Geode
1237 platforms.
1238
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001239 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1240 the BIOS has incorrectly applied a workaround. TinyBIOS
1241 version 0.98 is known to be affected, 0.99 fixes the
1242 problem by letting the user disable the workaround.
1243
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244 mga= [HW,DRM]
1245
Mel Gorman6b74ab92008-07-23 21:26:49 -07001246 mminit_loglevel=
1247 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1248 parameter allows control of the logging verbosity for
1249 the additional memory initialisation checks. A value
1250 of 0 disables mminit logging and a level of 4 will
1251 log everything. Information is printed at KERN_DEBUG
1252 so loglevel=8 may also need to be specified.
1253
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 mousedev.tap_time=
1255 [MOUSE] Maximum time between finger touching and
1256 leaving touchpad surface for touch to be considered
1257 a tap and be reported as a left button click (for
1258 touchpads working in absolute mode only).
1259 Format: <msecs>
1260 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1261 reporting absolute coordinates, such as tablets
1262 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1263 reporting absolute coordinates, such as tablets
1264
1265 mpu401= [HW,OSS]
1266 Format: <io>,<irq>
1267
1268 MTD_Partition= [MTD]
1269 Format: <name>,<region-number>,<size>,<offset>
1270
Randy Dunlapa9913042005-10-23 12:57:11 -07001271 MTD_Region= [MTD] Format:
1272 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273
1274 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001275 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276
Ben Dooks9db829f2008-07-03 11:24:29 +01001277 mtdset= [ARM]
1278 ARM/S3C2412 JIVE boot control
1279
1280 See arch/arm/mach-s3c2412/mach-jive.c
1281
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001283 [HW] Make the MicroTouch USB driver use raw coordinates
1284 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285
1286 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1287
1288 NCR_D700= [HW,SCSI]
1289 See header of drivers/scsi/NCR_D700.c.
1290
1291 ncr5380= [HW,SCSI]
1292
1293 ncr53c400= [HW,SCSI]
1294
1295 ncr53c400a= [HW,SCSI]
1296
1297 ncr53c406a= [HW,SCSI]
1298
1299 ncr53c8xx= [HW,SCSI]
1300
1301 netdev= [NET] Network devices parameters
1302 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1303 Note that mem_start is often overloaded to mean
1304 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001305 This usage is only documented in each driver source
1306 file if at all.
1307
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001308 nf_conntrack.acct=
1309 [NETFILTER] Enable connection tracking flow accounting
1310 0 to disable accounting
1311 1 to enable accounting
1312 Default value depends on CONFIG_NF_CT_ACCT that is
1313 going to be removed in 2.6.29.
1314
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001316 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317
1318 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001319 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001320
Trond Myklebusta72b4422006-01-03 09:55:41 +01001321 nfs.callback_tcpport=
1322 [NFS] set the TCP port on which the NFSv4 callback
1323 channel should listen.
1324
Trond Myklebust58df0952006-01-03 09:55:57 +01001325 nfs.idmap_cache_timeout=
1326 [NFS] set the maximum lifetime for idmapper cache
1327 entries.
1328
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001329 nfs.enable_ino64=
1330 [NFS] enable 64-bit inode numbers.
1331 If zero, the NFS client will fake up a 32-bit inode
1332 number for the readdir() and stat() syscalls instead
1333 of returning the full 64-bit number.
1334 The default is to return 64-bit inode numbers.
1335
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001336 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1337 when a NMI is triggered.
1338 Format: [state][,regs][,debounce][,die]
1339
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001340 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001342 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343 emulation library even if a 387 maths coprocessor
1344 is present.
1345
Christoph Lameterc1aee212007-05-31 00:40:47 -07001346 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1347 caches in the slab allocator. Saves per-node memory,
1348 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001349
Randy Dunlapa9913042005-10-23 12:57:11 -07001350 noalign [KNL,ARM]
1351
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352 noapic [SMP,APIC] Tells the kernel to not make use of any
1353 IOAPICs that may be present in the system.
1354
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355 nobats [PPC] Do not use BATs for mapping kernel lowmem
1356 on "Classic" PPC cores.
1357
1358 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001359
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001360 nodelayacct [KNL] Disable per-task delay accounting
1361
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1363
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001364 noefi [X86-32,X86-64] Disable EFI runtime services support.
1365
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366 noexec [IA-64]
1367
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001368 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001369 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001371 noexec=off: disable non-executable mappings
1372
1373 noexec32 [X86-64]
1374 This affects only 32-bit executables.
1375 noexec32=on: enable non-executable mappings (default)
1376 read doesn't imply executable mappings
1377 noexec32=off: disable non-executable mappings
1378 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001380 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001381 register save and restore. The kernel will only save
1382 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383
Andi Kleen191679f2008-01-30 13:33:21 +01001384 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1385
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386 nohlt [BUGS=ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001387
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001388 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389 instruction doesn't work correctly and not to
1390 use it.
1391
1392 nohalt [IA-64] Tells the kernel not to use the power saving
1393 function PAL_HALT_LIGHT when idle. This increases
1394 power-consumption. On the positive side, it reduces
1395 interrupt wake-up latency, which may improve performance
1396 in certain environments such as networked servers or
1397 real-time systems.
1398
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001399 nohz= [KNL] Boottime enable/disable dynamic ticks
1400 Valid arguments: on, off
1401 Default: on
1402
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001403 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001404
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001405 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001406 disable unhandled interrupt sources.
1407
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001408 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001409 broken timer IRQ sources.
1410
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411 noisapnp [ISAPNP] Disables ISA PnP code.
1412
1413 noinitrd [RAM] Tells the kernel not to load any configured
1414 initial RAM disk.
1415
1416 nointroute [IA-64]
1417
Tony Luck0aa366f2007-07-20 11:22:30 -07001418 nojitter [IA64] Disables jitter checking for ITC timers.
1419
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001420 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001422 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001423
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424 noltlbs [PPC] Do not use large page/tlb entries for kernel
1425 lowmem mapping on PPC40x.
1426
Horms312f1f02006-02-22 09:57:55 +09001427 nomca [IA-64] Disable machine check abort handling
1428
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001429 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001430
Andres Salomon83d73842007-10-12 23:04:06 +02001431 nomfgpt [X86-32] Disable Multi-Function General Purpose
1432 Timer usage (for AMD Geode machines).
1433
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001434 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001435
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001436 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001437 with UP alternatives
1438
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439 noresidual [PPC] Don't use residual data on PReP machines.
1440
Randy Dunlapa9913042005-10-23 12:57:11 -07001441 noresume [SWSUSP] Disables resume and restores original swap
1442 space.
1443
Linus Torvalds1da177e2005-04-16 15:20:36 -07001444 no-scroll [VGA] Disables scrollback.
1445 This is required for the Braillex ib80-piezo Braille
1446 reader made by F.H. Papenmeier (Germany).
1447
1448 nosbagart [IA-64]
1449
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001450 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001451
Len Brown61ec7562007-08-16 03:34:22 -04001452 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1453 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001454
Dave Jones97842212007-07-15 23:41:05 -07001455 nosoftlockup [KNL] Disable the soft-lockup detector.
1456
Linus Torvalds1da177e2005-04-16 15:20:36 -07001457 nosync [HW,M68K] Disables sync negotiation for all devices.
1458
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001459 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460
1461 nousb [USB] Disable the USB subsystem
1462
1463 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001464
Fenghua Yua6c75b862008-03-14 13:57:08 -07001465 nptcg= [IA64] Override max number of concurrent global TLB
1466 purges which is reported from either PAL_VM_SUMMARY or
1467 SAL PALO.
1468
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001469 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1470 one of ['zone', 'node', 'default'] can be specified
1471 This can be set from sysctl after boot.
1472 See Documentation/sysctl/vm.txt for details.
1473
Dave Jonesa61c2d72006-01-07 23:18:19 +00001474 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1475
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001476 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1477 Rather than timing out after 20 ms if an EC
1478 command is not properly ACKed, override the length
1479 of the timeout. We have interrupts disabled while
1480 waiting for the ACK, so if this is set too high
1481 interrupts *may* be lost!
1482
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483 opl3= [HW,OSS]
1484 Format: <io>
1485
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486 oprofile.timer= [HW]
1487 Use timer interrupt instead of performance counters
1488
Linus Torvalds1da177e2005-04-16 15:20:36 -07001489 osst= [HW,SCSI] SCSI Tape Driver
1490 Format: <buffer_size>,<write_threshold>
1491 See also Documentation/scsi/st.txt.
1492
1493 panic= [KNL] Kernel behaviour on panic
1494 Format: <timeout>
1495
1496 parkbd.port= [HW] Parallel port number the keyboard adapter is
1497 connected to, default is 0.
1498 Format: <parport#>
1499 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1500 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001501 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001502
Randy Dunlapa9913042005-10-23 12:57:11 -07001503 parport= [HW,PPT] Specify parallel ports. 0 disables.
1504 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1505 Use 'auto' to force the driver to use any
1506 IRQ/DMA settings detected (the default is to
1507 ignore detected IRQ/DMA settings because of
1508 possible conflicts). You can specify the base
1509 address, IRQ, and DMA settings; IRQ and DMA
1510 should be numbers, or 'auto' (for using detected
1511 settings on that particular port), or 'nofifo'
1512 (to avoid using a FIFO even if it is detected).
1513 Parallel ports are assigned in the order they
1514 are specified on the command line, starting
1515 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001516
Randy Dunlapa9913042005-10-23 12:57:11 -07001517 parport_init_mode= [HW,PPT]
1518 Configure VIA parallel port to operate in
1519 a specific mode. This is necessary on Pegasos
1520 computer where firmware has no options for setting
1521 up parallel port mode and sets it to spp.
1522 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 Format: [spp|ps2|epp|ecp|ecpepp]
1524
Randy Dunlapa9913042005-10-23 12:57:11 -07001525 pas2= [HW,OSS] Format:
1526 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1527
Linus Torvalds1da177e2005-04-16 15:20:36 -07001528 pas16= [HW,SCSI]
1529 See header of drivers/scsi/pas16.c.
1530
Andrew Mortondd287792006-03-23 03:00:57 -08001531 pause_on_oops=
1532 Halt all CPUs after the first oops has been printed for
1533 the specified number of seconds. This is to be used if
1534 your oopses keep scrolling off the screen.
1535
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 pcbit= [HW,ISDN]
1537
1538 pcd. [PARIDE]
1539 See header of drivers/block/paride/pcd.c.
1540 See also Documentation/paride.txt.
1541
Randy Dunlapa9913042005-10-23 12:57:11 -07001542 pci=option[,option...] [PCI] various PCI subsystem options:
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001543 off [X86-32] don't probe for the PCI bus
1544 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001545 the hardware directly. Use this if your machine
1546 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001547 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001548 hardware access methods are allowed. Use this
1549 if you experience crashes upon bootup and you
1550 suspect they are caused by the BIOS.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001551 conf1 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001552 Mechanism 1.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001553 conf2 [X86-32] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001554 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001555 noaer [PCIE] If the PCIEAER kernel config parameter is
1556 enabled, this kernel boot option can be used to
1557 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001558 nodomains [PCI] Disable support for multiple PCI
1559 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001560 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001561 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001562 nomsi [MSI] If the PCI_MSI kernel config parameter is
1563 enabled, this kernel boot option can be used to
1564 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001565 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001566 routing table. These calls are known to be buggy
1567 on several machines and they hang the machine
1568 when used, but on other computers it's the only
1569 way to get the interrupt routing table. Try
1570 this option if the kernel is unable to allocate
1571 IRQs or discover secondary PCI buses on your
1572 motherboard.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001573 rom [X86-32] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001574 Use with caution as certain devices share
1575 address decoders between ROMs and other
1576 resources.
Gary Hadebb71ad82008-05-12 13:57:46 -07001577 norom [X86-32,X86_64] Do not assign address space to
1578 expansion ROMs that do not already have
1579 BIOS assigned address ranges.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001580 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001581 assigned automatically to PCI devices. You can
1582 make the kernel exclude IRQs of your ISA cards
1583 this way.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001584 pirqaddr=0xAAAAA [X86-32] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001585 of the PIRQ table (normally generated
1586 by the BIOS) if it is outside the
1587 F0000h-100000h range.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001588 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001589 useful if the kernel is unable to find your
1590 secondary buses and you want to tell it
1591 explicitly which ones they are.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001592 assign-busses [X86-32] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001593 numbers ourselves, overriding
1594 whatever the firmware may have done.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001595 usepirqmask [X86-32] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001596 in the BIOS $PIR table. This is needed on
1597 some systems with broken BIOSes, notably
1598 some HP Pavilion N5400 and Omnibook XE3
1599 notebooks. This will have no effect if ACPI
1600 IRQ routing is enabled.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001601 noacpi [X86-32] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001602 or for PCI scanning.
Gary Hade62f420f2007-10-03 15:56:51 -07001603 use_crs [X86-32] Use _CRS for PCI resource
1604 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001605 routeirq Do IRQ routing for all PCI devices.
1606 This is normally done in pci_enable_device(),
1607 so this option is a temporary workaround
1608 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001609 skip_isa_align [X86] do not align io start addr, so can
1610 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001611 firmware [ARM] Do not re-enumerate the bus but instead
1612 just use the configuration from the
1613 bootloader. This is currently used on
1614 IXP2000 systems where the bus has to be
1615 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001616 noearly [X86] Don't do any early type 1 scanning.
1617 This might help on some broken boards which
1618 machine check when some devices' config space
1619 is read. But various workarounds are disabled
1620 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001621 bfsort Sort PCI devices into breadth-first order.
1622 This sorting is done to get a device
1623 order compatible with older (<= 2.4) kernels.
1624 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001625 cbiosize=nn[KMG] The fixed amount of bus space which is
1626 reserved for the CardBus bridge's IO window.
1627 The default value is 256 bytes.
1628 cbmemsize=nn[KMG] The fixed amount of bus space which is
1629 reserved for the CardBus bridge's memory
1630 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001631
Linus Torvalds1da177e2005-04-16 15:20:36 -07001632 pcmv= [HW,PCMCIA] BadgePAD 4
1633
1634 pd. [PARIDE]
1635 See Documentation/paride.txt.
1636
1637 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1638 boot time.
1639 Format: { 0 | 1 }
1640 See arch/parisc/kernel/pdc_chassis.c
1641
1642 pf. [PARIDE]
1643 See Documentation/paride.txt.
1644
1645 pg. [PARIDE]
1646 See Documentation/paride.txt.
1647
1648 pirq= [SMP,APIC] Manual mp-table setup
1649 See Documentation/i386/IO-APIC.txt.
1650
1651 plip= [PPT,NET] Parallel port network link
1652 Format: { parport<nr> | timid | 0 }
1653 See also Documentation/parport.txt.
1654
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001655 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1656 Override pmtimer IOPort with a hex value.
1657 e.g. pmtmr=0x508
1658
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659 pnpacpi= [ACPI]
1660 { off }
1661
1662 pnpbios= [ISAPNP]
1663 { on | off | curr | res | no-curr | no-res }
1664
1665 pnp_reserve_irq=
1666 [ISAPNP] Exclude IRQs for the autoconfiguration
1667
1668 pnp_reserve_dma=
1669 [ISAPNP] Exclude DMAs for the autoconfiguration
1670
1671 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001672 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673
1674 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001675 [ISAPNP] Exclude memory regions for the
1676 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677 Ranges are in pairs (memory base and size).
1678
Ingo Molnar45807a12007-07-15 23:40:10 -07001679 print-fatal-signals=
1680 [KNL] debug: print fatal signals
1681 print-fatal-signals=1: print segfault info to
1682 the kernel console.
1683 default: off.
1684
Randy Dunlape84845c2007-07-15 23:40:25 -07001685 printk.time= Show timing data prefixed to each printk message line
1686 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1687
Linus Torvalds1da177e2005-04-16 15:20:36 -07001688 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001689 Format: [schedule,]<number>
1690 Param: "schedule" - profile schedule points.
1691 Param: <number> - step/bucket size as a power of 2 for
1692 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001693 Param: "sleep" - profile D-state sleeping (millisecs).
1694 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001695 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001696
Randy Dunlapa9913042005-10-23 12:57:11 -07001697 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001698 Limit processor to maximum C-state
1699 max_cstate=9 overrides any DMI blacklist limit.
1700
Len Brown41c0d862005-12-28 12:43:51 -05001701 processor.nocst [HW,ACPI]
1702 Ignore the _CST method to determine C-states,
1703 instead using the legacy FADT method
1704
Linus Torvalds1da177e2005-04-16 15:20:36 -07001705 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1706 before loading.
1707 See Documentation/ramdisk.txt.
1708
Randy Dunlapa9913042005-10-23 12:57:11 -07001709 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1710 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001711 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1712 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001713 psmouse.resetafter= [HW,MOUSE]
1714 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001715 (0 = never).
1716 psmouse.resolution=
1717 [HW,MOUSE] Set desired mouse resolution, in dpi.
1718 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001719 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001720 0 = disabled, 1 = enabled (default).
1721
1722 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001723 Format:
1724 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001725
1726 pt. [PARIDE]
1727 See Documentation/paride.txt.
1728
Kay Sieversdc8c8582007-08-15 12:25:38 +02001729 pty.legacy_count=
1730 [KNL] Number of legacy pty's. Overwrites compiled-in
1731 default number.
1732
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001733 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001734
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735 r128= [HW,DRM]
1736
1737 raid= [HW,RAID]
1738 See Documentation/md.txt.
1739
Randy Dunlapa9913042005-10-23 12:57:11 -07001740 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001742
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001744 See Documentation/ramdisk.txt.
1745
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001746 rcupdate.blimit= [KNL,BOOT]
1747 Set maximum number of finished RCU callbacks to process
1748 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001749
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001750 rcupdate.qhimark= [KNL,BOOT]
1751 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001752 RCU callbacks over which batch limiting is disabled.
1753
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001754 rcupdate.qlowmark= [KNL,BOOT]
1755 Set threshold of queued RCU callbacks below which
1756 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001757
Olof Johanssonffdfc402005-09-06 15:17:19 -07001758 rdinit= [KNL]
1759 Format: <full_path>
1760 Run specified binary instead of /init from the ramdisk,
1761 used for early userspace startup. See initrd.
1762
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001763 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001764 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001765 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001766
Paul Jackson46b6d942008-07-04 10:00:09 -07001767 relax_domain_level=
1768 [KNL, SMP] Set scheduler's default relax_domain_level.
1769 See Documentation/cpusets.txt.
1770
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1772
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001773 reservetop= [X86-32]
Zachary Amsden461a9af2006-09-25 23:32:25 -07001774 Format: nn[KMG]
1775 Reserves a hole at the top of the kernel virtual
1776 address space.
1777
Vivek Goyal7e962872006-09-27 01:50:44 -07001778 reset_devices [KNL] Force drivers to reset the underlying device
1779 during initialization.
1780
Randy Dunlapa9913042005-10-23 12:57:11 -07001781 resume= [SWSUSP]
1782 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001784 resume_offset= [SWSUSP]
1785 Specify the offset from the beginning of the partition
1786 given by "resume=" at which the swap header is located,
1787 in <PAGE_SIZE> units (needed only for swap files).
1788 See Documentation/power/swsusp-and-swap-files.txt
1789
Michael Neuling0a7b35c2007-02-10 01:44:33 -08001790 retain_initrd [RAM] Keep initrd memory after extraction
1791
Linus Torvalds1da177e2005-04-16 15:20:36 -07001792 rhash_entries= [KNL,NET]
1793 Set number of hash buckets for route cache
1794
1795 riscom8= [HW,SERIAL]
1796 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1797
1798 ro [KNL] Mount root device read-only on boot
1799
1800 root= [KNL] Root filesystem
1801
1802 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1803 mount the root filesystem
1804
1805 rootflags= [KNL] Set root filesystem mount option string
1806
1807 rootfstype= [KNL] Set root filesystem type
1808
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001809 rootwait [KNL] Wait (indefinitely) for root device to show up.
1810 Useful for devices that are detected asynchronously
1811 (e.g. USB and MMC devices).
1812
James Morris20510f22007-10-16 23:31:32 -07001813 root_plug.vendor_id=
1814 [ROOTPLUG] Override the default vendor ID
1815
1816 root_plug.product_id=
1817 [ROOTPLUG] Override the default product ID
1818
1819 root_plug.debug=
1820 [ROOTPLUG] Enable debugging output
1821
Linus Torvalds1da177e2005-04-16 15:20:36 -07001822 rw [KNL] Mount root device read-write on boot
1823
1824 S [KNL] Run init in single mode
1825
1826 sa1100ir [NET]
1827 See drivers/net/irda/sa1100_ir.c.
1828
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001830
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1832 Format: <io>[,<timeout>[,<isapnp>]]
1833
1834 scsi_debug_*= [SCSI]
1835 See drivers/scsi/scsi_debug.c.
1836
1837 scsi_default_dev_flags=
1838 [SCSI] SCSI default device flags
1839 Format: <integer>
1840
1841 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1842 Format: <vendor>:<model>:<flags>
1843 (flags are integer value)
1844
Randy Dunlap6af66322007-11-14 16:52:25 -08001845 scsi_logging_level= [SCSI] a bit mask of logging levels
1846 See drivers/scsi/scsi_logging.h for bits. Also
1847 settable via sysctl at dev.scsi.logging_level
1848 (/proc/sys/dev/scsi/logging_level).
1849 There is also a nice 'scsi_logging_level' script in the
1850 S390-tools package, available for download at
1851 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001852
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001853 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1854 discovered. async scans them in kernel threads,
1855 allowing boot to proceed. none ignores them, expecting
1856 user space to do the scan.
1857
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858 selinux [SELINUX] Disable or enable SELinux at boot time.
1859 Format: { "0" | "1" }
1860 See security/selinux/Kconfig help text.
1861 0 -- disable.
1862 1 -- enable.
1863 Default value is set via kernel config option.
1864 If enabled at boot time, /selinux/disable can be used
1865 later to disable prior to initial policy load.
1866
James Morris4e5ab4c2006-06-09 00:33:33 -07001867 selinux_compat_net =
1868 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001869 Format: { "0" | "1" }
1870 0 -- use new secmark-based packet controls
1871 1 -- use legacy packet controls
1872 Default value is 0 (preferred).
1873 Value can be changed at runtime via
1874 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001875
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001876 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878 shapers= [NET]
1879 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001880
Linus Torvalds1da177e2005-04-16 15:20:36 -07001881 sim710= [SCSI,HW]
1882 See header of drivers/scsi/sim710.c.
1883
1884 simeth= [IA-64]
1885 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001886
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887 slram= [HW,MTD]
1888
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001889 slub_debug[=options[,slabs]] [MM, SLUB]
1890 Enabling slub_debug allows one to determine the
1891 culprit if slab objects become corrupted. Enabling
1892 slub_debug can create guard zones around objects and
1893 may poison objects when not in use. Also tracks the
1894 last alloc / free. For more information see
1895 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001896
1897 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001898 Determines the maximum allowed order for slabs.
1899 A high setting may cause OOMs due to memory
1900 fragmentation. For more information see
1901 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001902
1903 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001904 The minimum number of objects per slab. SLUB will
1905 increase the slab order up to slub_max_order to
1906 generate a sufficiently large slab able to contain
1907 the number of objects indicated. The higher the number
1908 of objects the smaller the overhead of tracking slabs
1909 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001910 For more information see Documentation/vm/slub.txt.
1911
1912 slub_min_order= [MM, SLUB]
1913 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001914 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001915 For more information see Documentation/vm/slub.txt.
1916
1917 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001918 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001919 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001920 allocs to different slabs. Debug options disable
1921 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001922 For more information see Documentation/vm/slub.txt.
1923
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924 smart2= [HW]
1925 Format: <io1>[,<io2>[,...,<io8>]]
1926
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001927 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001928 attempt to substitute SMP alternatives once at boot.
1929
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001930 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1931 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1932 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1933 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1934 smsc-ircc2.ircc_irq= [HW] IRQ line
1935 smsc-ircc2.ircc_dma= [HW] DMA channel
1936 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1937 0: Toshiba Satellite 1800 (GP data pin select)
1938 1: Fast pin select (default)
1939 2: ATC IRMode
1940
Linus Torvalds1da177e2005-04-16 15:20:36 -07001941 snd-ad1816a= [HW,ALSA]
1942
1943 snd-ad1848= [HW,ALSA]
1944
1945 snd-ali5451= [HW,ALSA]
1946
1947 snd-als100= [HW,ALSA]
1948
1949 snd-als4000= [HW,ALSA]
1950
1951 snd-azt2320= [HW,ALSA]
1952
1953 snd-cmi8330= [HW,ALSA]
1954
1955 snd-cmipci= [HW,ALSA]
1956
1957 snd-cs4231= [HW,ALSA]
1958
1959 snd-cs4232= [HW,ALSA]
1960
1961 snd-cs4236= [HW,ALSA]
1962
1963 snd-cs4281= [HW,ALSA]
1964
1965 snd-cs46xx= [HW,ALSA]
1966
1967 snd-dt019x= [HW,ALSA]
1968
1969 snd-dummy= [HW,ALSA]
1970
1971 snd-emu10k1= [HW,ALSA]
1972
1973 snd-ens1370= [HW,ALSA]
1974
1975 snd-ens1371= [HW,ALSA]
1976
1977 snd-es968= [HW,ALSA]
1978
1979 snd-es1688= [HW,ALSA]
1980
1981 snd-es18xx= [HW,ALSA]
1982
1983 snd-es1938= [HW,ALSA]
1984
1985 snd-es1968= [HW,ALSA]
1986
1987 snd-fm801= [HW,ALSA]
1988
1989 snd-gusclassic= [HW,ALSA]
1990
1991 snd-gusextreme= [HW,ALSA]
1992
1993 snd-gusmax= [HW,ALSA]
1994
1995 snd-hdsp= [HW,ALSA]
1996
1997 snd-ice1712= [HW,ALSA]
1998
1999 snd-intel8x0= [HW,ALSA]
2000
2001 snd-interwave= [HW,ALSA]
2002
2003 snd-interwave-stb=
2004 [HW,ALSA]
2005
2006 snd-korg1212= [HW,ALSA]
2007
2008 snd-maestro3= [HW,ALSA]
2009
2010 snd-mpu401= [HW,ALSA]
2011
2012 snd-mtpav= [HW,ALSA]
2013
2014 snd-nm256= [HW,ALSA]
2015
2016 snd-opl3sa2= [HW,ALSA]
2017
2018 snd-opti92x-ad1848=
2019 [HW,ALSA]
2020
2021 snd-opti92x-cs4231=
2022 [HW,ALSA]
2023
2024 snd-opti93x= [HW,ALSA]
2025
2026 snd-pmac= [HW,ALSA]
2027
2028 snd-rme32= [HW,ALSA]
2029
2030 snd-rme96= [HW,ALSA]
2031
2032 snd-rme9652= [HW,ALSA]
2033
2034 snd-sb8= [HW,ALSA]
2035
2036 snd-sb16= [HW,ALSA]
2037
2038 snd-sbawe= [HW,ALSA]
2039
2040 snd-serial= [HW,ALSA]
2041
2042 snd-sgalaxy= [HW,ALSA]
2043
2044 snd-sonicvibes= [HW,ALSA]
2045
2046 snd-sun-amd7930=
2047 [HW,ALSA]
2048
2049 snd-sun-cs4231= [HW,ALSA]
2050
2051 snd-trident= [HW,ALSA]
2052
2053 snd-usb-audio= [HW,ALSA,USB]
2054
2055 snd-via82xx= [HW,ALSA]
2056
2057 snd-virmidi= [HW,ALSA]
2058
2059 snd-wavefront= [HW,ALSA]
2060
2061 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002062
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002063 softlockup_panic=
2064 [KNL] Should the soft-lockup detector generate panics.
2065
Linus Torvalds1da177e2005-04-16 15:20:36 -07002066 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2067 See Documentation/sonypi.txt
2068
2069 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2070 See Documentation/specialix.txt.
2071
2072 spia_io_base= [HW,MTD]
2073 spia_fio_base=
2074 spia_pedr=
2075 spia_peddr=
2076
2077 sscape= [HW,OSS]
2078 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002079
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2081 See Documentation/scsi/st.txt.
2082
Linus Torvalds1da177e2005-04-16 15:20:36 -07002083 sti= [PARISC,HW]
2084 Format: <num>
2085 Set the STI (builtin display/keyboard on the HP-PARISC
2086 machines) console (graphic card) which should be used
2087 as the initial boot-console.
2088 See also comment in drivers/video/console/sticore.c.
2089
2090 sti_font= [HW]
2091 See comment in drivers/video/console/sticore.c.
2092
2093 stifb= [HW]
2094 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2095
Greg Banks42a7fc42007-03-06 01:42:23 -08002096 sunrpc.pool_mode=
2097 [NFS]
2098 Control how the NFS server code allocates CPUs to
2099 service thread pools. Depending on how many NICs
2100 you have and where their interrupts are bound, this
2101 option will affect which CPUs will do NFS serving.
2102 Note: this parameter cannot be changed while the
2103 NFS server is running.
2104
2105 auto the server chooses an appropriate mode
2106 automatically using heuristics
2107 global a single global pool contains all CPUs
2108 percpu one pool for each CPU
2109 pernode one pool for each NUMA node (equivalent
2110 to global on non-NUMA machines)
2111
Linus Torvalds1da177e2005-04-16 15:20:36 -07002112 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002113
Linus Torvalds1da177e2005-04-16 15:20:36 -07002114 switches= [HW,M68k]
2115
2116 sym53c416= [HW,SCSI]
2117 See header of drivers/scsi/sym53c416.c.
2118
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002119 sysrq_always_enabled
2120 [KNL]
2121 Ignore sysrq setting - this boot parameter will
2122 neutralize any effect of /proc/sys/kernel/sysrq.
2123 Useful for debugging.
2124
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125 t128= [HW,SCSI]
2126 See header of drivers/scsi/t128.c.
2127
2128 tdfx= [HW,DRM]
2129
David Brownell77437fd2008-07-23 21:28:33 -07002130 test_suspend= [SUSPEND]
2131 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2132 standby suspend) as the system sleep state to briefly
2133 enter during system startup. The system is woken from
2134 this state using a wakeup-capable RTC alarm.
2135
Linus Torvalds1da177e2005-04-16 15:20:36 -07002136 thash_entries= [KNL,NET]
2137 Set number of hash buckets for TCP connection
2138
Len Brownf8707ec2007-08-12 00:12:54 -04002139 thermal.act= [HW,ACPI]
2140 -1: disable all active trip points in all thermal zones
2141 <degrees C>: override all lowest active trip points
2142
Len Brownc52a7412007-08-14 15:49:32 -04002143 thermal.crt= [HW,ACPI]
2144 -1: disable all critical trip points in all thermal zones
2145 <degrees C>: lower all critical trip points
2146
Len Brownf5487142007-08-12 00:12:44 -04002147 thermal.nocrt= [HW,ACPI]
2148 Set to disable actions on ACPI thermal zone
2149 critical and hot trip points.
2150
Len Brown72b33ef2007-08-12 00:12:17 -04002151 thermal.off= [HW,ACPI]
2152 1: disable ACPI thermal control
2153
Len Browna70cdc52007-08-12 00:12:35 -04002154 thermal.psv= [HW,ACPI]
2155 -1: disable all passive trip points
2156 <degrees C>: override all passive trip points to this value
2157
Len Brown730ff342007-08-12 00:12:26 -04002158 thermal.tzp= [HW,ACPI]
2159 Specify global default ACPI thermal zone polling rate
2160 <deci-seconds>: poll all this frequency
2161 0: no polling (default)
2162
Linus Torvalds1da177e2005-04-16 15:20:36 -07002163 tmscsim= [HW,SCSI]
2164 See comment before function dc390_setup() in
2165 drivers/scsi/tmscsim.c.
2166
2167 tp720= [HW,PS2]
2168
2169 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002170 Format:
2171 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2172
Randy Dunlapa9913042005-10-23 12:57:11 -07002173 turbografx.map[2|3]= [HW,JOY]
2174 TurboGraFX parallel port interface
2175 Format:
2176 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002177 See also Documentation/input/joystick-parport.txt
2178
2179 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2180 See header of drivers/scsi/u14-34f.c.
2181
2182 uart401= [HW,OSS]
2183 Format: <io>,<irq>
2184
2185 uart6850= [HW,OSS]
2186 Format: <io>,<irq>
2187
Alan Stern5f8364b2006-12-05 16:29:55 -05002188 uhci-hcd.ignore_oc=
2189 [USB] Ignore overcurrent events (default N).
2190 Some badly-designed motherboards generate lots of
2191 bogus events, for ports that aren't wired to
2192 anything. Set this parameter to avoid log spamming.
2193 Note that genuine overcurrent events won't be
2194 reported either.
2195
Simon Arlotte3a61b02008-07-19 23:32:54 +01002196 unknown_nmi_panic
2197 [X86-32,X86-64]
2198 Set unknown_nmi_panic=1 early on boot.
2199
Alan Sternb5e795f2007-02-20 15:00:53 -05002200 usbcore.autosuspend=
2201 [USB] The autosuspend time delay (in seconds) used
2202 for newly-detected USB devices (default 2). This
2203 is the time required before an idle device will be
2204 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002205 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002206
Linus Torvalds1da177e2005-04-16 15:20:36 -07002207 usbhid.mousepoll=
2208 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002209
Paul Jackson200001e2008-06-25 05:44:46 -07002210 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2211 kernel's map of available physical RAM.
2212
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002213 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002214 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002215 vdso=1: enable VDSO (default)
2216 vdso=0: disable VDSO mapping
2217
Roland McGrathaf65d642008-01-30 13:30:43 +01002218 vdso32= [X86-32,X86-64]
2219 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2220 vdso32=1: enable 32-bit VDSO (default)
2221 vdso32=0: disable 32-bit VDSO mapping
2222
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002223 vector= [IA-64,SMP]
2224 vector=percpu: enable percpu vector domain
2225
Linus Torvalds1da177e2005-04-16 15:20:36 -07002226 video= [FB] Frame buffer configuration
2227 See Documentation/fb/modedb.txt.
2228
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002229 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002230 See Documentation/i386/boot.txt and
2231 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002232 Use vga=ask for menu.
2233 This is actually a boot loader parameter; the value is
2234 passed to the kernel using a special protocol.
2235
Randy Dunlapa9913042005-10-23 12:57:11 -07002236 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002237 size of <nn>. This can be used to increase the
2238 minimum size (128MB on x86). It can also be used to
2239 decrease the size and leave more room for directly
2240 mapped kernel RAM.
2241
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002242 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2243 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002244
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002245 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2246 Format: <command>
2247
2248 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2249 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002250
Linus Torvalds1da177e2005-04-16 15:20:36 -07002251 waveartist= [HW,OSS]
2252 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002253
Linus Torvalds1da177e2005-04-16 15:20:36 -07002254 wd33c93= [HW,SCSI]
2255 See header of drivers/scsi/wd33c93.c.
2256
2257 wd7000= [HW,SCSI]
2258 See header of drivers/scsi/wd7000.c.
2259
2260 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002261 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002262
2263 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2264 xd_geo= See header of drivers/block/xd.c.
2265
2266 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002267 Format:
2268 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002269
Andi Kleena62eaf12006-02-16 23:41:58 +01002270 norandmaps Don't use address space randomization
2271 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2272
Randy Dunlapa9913042005-10-23 12:57:11 -07002273______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002274
2275TODO:
2276
2277 Add documentation for ALSA options.
2278 Add more DRM drivers.