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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 .
Andi Kleenc0115602008-08-22 09:53:39 +0200104 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105
106In addition, the following text indicates that the option:
107
108 BUGS= Relates to possible processor bugs on the said processor.
109 KNL Is a kernel start-up parameter.
110 BOOT Is a boot loader parameter.
111
112Parameters denoted with BOOT are actually interpreted by the boot
113loader, and have no meaning to the kernel directly.
114Do not modify the syntax of boot loader parameters without extreme
115need or coordination with <Documentation/i386/boot.txt>.
116
Karsten Weiss55588702007-02-13 13:26:21 +0100117There are also arch-specific kernel-parameters not documented here.
118See for example <Documentation/x86_64/boot-options.txt>.
119
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
121a trailing = on the name of any parameter states that that parameter will
122be entered as an environment variable, whereas its absence indicates that
123it will appear as a kernel argument readable via /proc/cmdline by programs
124running once the system is up.
125
jens m. noedler9c4751f2006-09-29 02:00:27 -0700126The number of kernel parameters is not limited, but the length of the
127complete command line (parameters including spaces etc.) is limited to
128a fixed number of characters. This limit depends on the architecture
129and is between 256 and 4096 characters. It is defined in the file
130./include/asm/setup.h as COMMAND_LINE_SIZE.
131
132
Bernhard Walle03d926f2007-03-06 02:29:44 -0800133 acpi= [HW,ACPI,X86-64,i386]
134 Advanced Configuration and Power Interface
Randy Dunlapa9913042005-10-23 12:57:11 -0700135 Format: { force | off | ht | strict | noirq }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 force -- enable ACPI if default was off
137 off -- disable ACPI if default was on
138 noirq -- do not use ACPI for IRQ routing
139 ht -- run only enough ACPI to enable Hyper Threading
Randy Dunlapa9913042005-10-23 12:57:11 -0700140 strict -- Be less tolerant of platforms that are not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 strictly ACPI specification compliant.
142
Randy Dunlap53471122008-03-12 18:10:51 -0400143 See also Documentation/power/pm.txt, pci=noacpi
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
Len Browna1fdcc02007-03-11 03:26:14 -0400145 acpi_apic_instance= [ACPI, IOAPIC]
146 Format: <int>
147 2: use 2nd APIC table, if available
148 1,0: use 1st APIC table
Len Brown4e381a42007-03-30 14:16:10 -0400149 default: 0
Len Browna1fdcc02007-03-11 03:26:14 -0400150
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 acpi_sleep= [HW,ACPI] Sleep options
Shaohua Libdfe6b72008-07-23 21:28:41 -0700152 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
Pavel Machek23b168d2008-02-05 19:27:12 +0100153 See Documentation/power/video.txt for s3_bios and s3_mode.
154 s3_beep is for debugging; it makes the PC's speaker beep
155 as soon as the kernel's real-mode entry point is called.
Shaohua Libdfe6b72008-07-23 21:28:41 -0700156 s4_nohwsig prevents ACPI hardware signature from being
157 used during resume from hibernation.
Rafael J. Wysockid8f3de02008-06-12 23:24:06 +0200158 old_ordering causes the ACPI 1.0 ordering of the _PTS
159 control method, wrt putting devices into low power
160 states, to be enforced (the ACPI 2.0 ordering of _PTS is
161 used by default).
Randy Dunlapa9913042005-10-23 12:57:11 -0700162
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Randy Dunlapa9913042005-10-23 12:57:11 -0700164 Format: { level | edge | high | low }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
Randy Dunlapa9913042005-10-23 12:57:11 -0700166 acpi_irq_balance [HW,ACPI]
167 ACPI will balance active IRQs
168 default in APIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169
Randy Dunlapa9913042005-10-23 12:57:11 -0700170 acpi_irq_nobalance [HW,ACPI]
171 ACPI will not move active IRQs (default)
172 default in PIC mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173
Randy Dunlapa9913042005-10-23 12:57:11 -0700174 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
175 use by PCI
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 Format: <irq>,<irq>...
177
Randy Dunlapa9913042005-10-23 12:57:11 -0700178 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 Format: <irq>,<irq>...
180
Len Brown67effe82007-07-26 00:50:06 -0400181 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
182
Len Browna1f9e652006-01-25 23:47:36 -0500183 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
184 Format: To spoof as Windows 98: ="Microsoft Windows"
185
Len Brownae00d812007-05-29 18:43:33 -0400186 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
187 acpi_osi="string1" # add string1 -- only one string
188 acpi_osi="!string2" # remove built-in string2
189 acpi_osi= # disable all strings
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190
191 acpi_serialize [HW,ACPI] force serialization of AML methods
192
193 acpi_skip_timer_override [HW,ACPI]
194 Recognize and ignore IRQ0/pin2 Interrupt Override.
195 For broken nForce2 BIOS resulting in XT-PIC timer.
Andi Kleenfa18f472006-11-14 16:57:46 +0100196 acpi_use_timer_override [HW,ACPI}
197 Use timer override. For some broken Nvidia NF5 boards
198 that require a timer override, but don't have
199 HPET
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700201 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
202 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 Format: <int>
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700204 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
205 debug output. Bits in debug_layer correspond to a
206 _COMPONENT in an ACPI source file, e.g.,
207 #define _COMPONENT ACPI_PCI_COMPONENT
208 Bits in debug_level correspond to a level in
209 ACPI_DEBUG_PRINT statements, e.g.,
210 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
211 See Documentation/acpi/debug.txt for more information
212 about debug layers and levels.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700214 Enable AML "Debug" output, i.e., stores to the Debug
215 object while interpreting AML:
216 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
217 Enable PCI/PCI interrupt routing info messages:
218 acpi.debug_layer=0x400000 acpi.debug_level=0x4
219 Enable all messages related to ACPI hardware:
220 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
Thomas Renninger36eec5e2008-08-11 15:03:20 +0200221
Bjorn Helgaasa0d84a92008-11-07 16:58:05 -0700222 Some values produce so much output that the system is
223 unusable. The "log_buf_len" parameter may be useful
224 if you need to capture more output.
Zhang Ruif9891062007-04-24 13:53:22 +0800225
Zhao Yakuif5adfaa2008-08-11 14:57:50 +0800226 acpi.power_nocheck= [HW,ACPI]
227 Format: 1/0 enable/disable the check of power state.
228 On some bogus BIOS the _PSC object/_STA object of
229 power resource can't return the correct device power
230 state. In such case it is unneccessary to check its
231 power state again in power transition.
232 1 : disable the power state check
233
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700234 acpi_pm_good [X86-32,X86-64]
john stultz5d0cf412006-06-26 00:25:12 -0700235 Override the pmtimer bug detection: force the kernel
236 to assume that this machine's pmtimer latches its value
237 and always returns good values.
238
Chuck Ebbertc99c1082007-07-27 10:46:20 +1000239 agp= [AGP]
240 { off | try_unsupported }
241 off: disable AGP support
242 try_unsupported: try to drive unsupported chipsets
243 (may crash computer or cause data corruption)
244
Chuck Ebbert66759a02005-09-12 18:49:25 +0200245 enable_timer_pin_1 [i386,x86-64]
246 Enable PIN 1 of APIC timer
Randy Dunlapa9913042005-10-23 12:57:11 -0700247 Can be useful to work around chipset bugs
248 (in particular on some ATI chipsets).
Chuck Ebbert66759a02005-09-12 18:49:25 +0200249 The kernel tries to set a reasonable default.
250
251 disable_timer_pin_1 [i386,x86-64]
252 Disable PIN 1 of APIC timer
253 Can be useful to work around chipset bugs.
254
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 ad1848= [HW,OSS]
256 Format: <io>,<irq>,<dma>,<dma2>,<type>
257
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 advansys= [HW,SCSI]
259 See header of drivers/scsi/advansys.c.
260
261 advwdt= [HW,WDT] Advantech WDT
262 Format: <iostart>,<iostop>
263
264 aedsp16= [HW,OSS] Audio Excel DSP 16
265 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
266 See also header of sound/oss/aedsp16.c.
Randy Dunlapa9913042005-10-23 12:57:11 -0700267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 aha152x= [HW,SCSI]
269 See Documentation/scsi/aha152x.txt.
270
271 aha1542= [HW,SCSI]
272 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
273
274 aic7xxx= [HW,SCSI]
275 See Documentation/scsi/aic7xxx.txt.
276
277 aic79xx= [HW,SCSI]
278 See Documentation/scsi/aic79xx.txt.
279
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200280 amd_iommu= [HW,X86-84]
281 Pass parameters to the AMD IOMMU driver in the system.
282 Possible values are:
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200283 isolate - enable device isolation (each device, as far
284 as possible, will get its own protection
285 domain)
FUJITA Tomonoriafa9fdc2008-09-20 01:23:30 +0900286 fullflush - enable flushing of IO/TLB entries when
287 they are unmapped. Otherwise they are
288 flushed before they will be reused, which
289 is a lot of faster
290
Joerg Roedel54b4cbd2008-06-26 21:28:10 +0200291 amd_iommu_size= [HW,X86-64]
292 Define the size of the aperture for the AMD IOMMU
293 driver. Possible values are:
294 '32M', '64M' (default), '128M', '256M', '512M', '1G'
295
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 amijoy.map= [HW,JOY] Amiga joystick support
297 Map of devices attached to JOY0DAT and JOY1DAT
298 Format: <a>,<b>
299 See also Documentation/kernel/input/joystick.txt
300
301 analog.map= [HW,JOY] Analog joystick and gamepad support
302 Specifies type or capabilities of an analog joystick
303 connected to one of 16 gameports
304 Format: <type1>,<type2>,..<type16>
305
Randy Dunlapa9913042005-10-23 12:57:11 -0700306 apc= [HW,SPARC]
307 Power management functions (SPARCstation-4/5 + deriv.)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 Format: noidle
309 Disable APC CPU standby support. SPARCstation-Fox does
310 not play well with APC CPU idle - disable it if you have
311 APC and your system crashes randomly.
312
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700313 apic= [APIC,i386] Advanced Programmable Interrupt Controller
314 Change the output verbosity whilst booting
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 Format: { quiet (default) | verbose | debug }
316 Change the amount of debugging information output
317 when initialising the APIC and IO-APIC components.
Randy Dunlapa9913042005-10-23 12:57:11 -0700318
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 apm= [APM] Advanced Power Management
Pavel Machek71f77052008-07-04 09:59:43 -0700320 See header of arch/x86/kernel/apm_32.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
323 Format: <io>,<irq>,<nodeID>
324
325 ataflop= [HW,M68k]
326
327 atarimouse= [HW,MOUSE] Atari Mouse
328
329 atascsi= [HW,SCSI] Atari SCSI
330
331 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
332 EzKey and similar keyboards
333
334 atkbd.reset= [HW] Reset keyboard during initialization
335
Randy Dunlapa9913042005-10-23 12:57:11 -0700336 atkbd.set= [HW] Select keyboard code set
337 Format: <int> (2 = AT (default), 3 = PS/2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
339 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
340 keyboards
341
342 atkbd.softraw= [HW] Choose between synthetic and real raw mode
343 Format: <bool> (0 = real, 1 = synthetic (default))
Randy Dunlapa9913042005-10-23 12:57:11 -0700344
345 atkbd.softrepeat= [HW]
346 Use software keyboard repeat
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347
348 autotest [IA64]
349
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 baycom_epp= [HW,AX25]
351 Format: <io>,<mode>
Randy Dunlapa9913042005-10-23 12:57:11 -0700352
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
354 Format: <io>,<mode>
355 See header of drivers/net/hamradio/baycom_par.c.
356
Randy Dunlapa9913042005-10-23 12:57:11 -0700357 baycom_ser_fdx= [HW,AX25]
358 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 Format: <io>,<irq>,<mode>[,<baud>]
360 See header of drivers/net/hamradio/baycom_ser_fdx.c.
361
Randy Dunlapa9913042005-10-23 12:57:11 -0700362 baycom_ser_hdx= [HW,AX25]
363 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 Format: <io>,<irq>,<mode>
365 See header of drivers/net/hamradio/baycom_ser_hdx.c.
366
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700367 boot_delay= Milliseconds to delay each printk during boot.
368 Values larger than 10 seconds (10000) are changed to
369 no delay (0).
370 Format: integer
371
Andreas Herrmann35fc9082008-08-20 14:08:58 -0700372 bootmem_debug [KNL] Enable bootmem allocator debug messages.
373
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
Randy Dunlapa9913042005-10-23 12:57:11 -0700375 bttv.radio= Most important insmod options are available as
376 kernel args too.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
378 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
379
380 BusLogic= [HW,SCSI]
381 See drivers/scsi/BusLogic.c, comment before function
382 BusLogic_ParseDriverOptions().
383
384 c101= [NET] Moxa C101 synchronous serial card
385
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700386 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 Sometimes CPU hardware bugs make them report the cache
388 size incorrectly. The kernel will attempt work arounds
389 to fix known problems, but for some CPUs it is not
390 possible to determine what the correct size should be.
391 This option provides an override for these situations.
392
Ahmed S. Darwish076c54c2008-03-06 18:09:10 +0200393 security= [SECURITY] Choose a security module to enable at boot.
394 If this boot parameter is not specified, only the first
395 security module asking for security registration will be
396 loaded. An invalid security module name will be treated
397 as if no module has been chosen.
398
James Morris20510f22007-10-16 23:31:32 -0700399 capability.disable=
400 [SECURITY] Disable capabilities. This would normally
401 be used only if an alternative security model is to be
402 configured. Potentially dangerous and should only be
403 used if you are entirely sure of the consequences.
404
Sebastian Ott14ff56b2008-01-26 14:10:37 +0100405 ccw_timeout_log [S390]
406 See Documentation/s390/CommonIO for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407
Paul Menage8bab8dd2008-04-04 14:29:57 -0700408 cgroup_disable= [KNL] Disable a particular controller
409 Format: {name of the controller(s) to disable}
410 {Currently supported controllers - "memory"}
411
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 checkreqprot [SELINUX] Set initial checkreqprot flag value.
413 Format: { "0" | "1" }
414 See security/selinux/Kconfig help text.
Randy Dunlapa9913042005-10-23 12:57:11 -0700415 0 -- check protection applied by kernel (includes
416 any implied execute protection).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 1 -- check protection requested by application.
418 Default value is set via a kernel config option.
Randy Dunlapa9913042005-10-23 12:57:11 -0700419 Value can be changed at runtime via
420 /selinux/checkreqprot.
421
Sebastian Ott661ca0d2008-01-26 14:10:36 +0100422 cio_ignore= [S390]
423 See Documentation/s390/CommonIO for details.
424
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700425 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
john stultz734efb42006-06-26 00:25:05 -0700426 [Deprecated]
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200427 Forces specified clocksource (if available) to be used
john stultz734efb42006-06-26 00:25:05 -0700428 when calculating gettimeofday(). If specified
Matt LaPlante3f6dee92006-10-03 22:45:33 +0200429 clocksource is not available, it defaults to PIT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 Format: { pit | tsc | cyclone | pmtmr }
431
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700432 clocksource= [GENERIC_TIME] Override the default clocksource
433 Format: <string>
434 Override the default clocksource and use the clocksource
435 with the name specified.
436 Some clocksource names to choose from, depending on
437 the platform:
438 [all] jiffies (this is the base, fallback clocksource)
439 [ACPI] acpi_pm
440 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
441 pxa_timer,timer3,32k_counter,timer0_1
442 [AVR32] avr32
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700443 [X86-32] pit,hpet,tsc,vmi-timer;
Randy Dunlap3d6ac982007-05-23 13:58:16 -0700444 scx200_hrt on Geode; cyclone on IBM x440
445 [MIPS] MIPS
446 [PARISC] cr16
447 [S390] tod
448 [SH] SuperH
449 [SPARC64] tick
450 [X86-64] hpet,tsc
451
Andi Kleenac72e782008-01-30 13:33:21 +0100452 clearcpuid=BITNUM [X86]
453 Disable CPUID feature X for the kernel. See
454 include/asm-x86/cpufeature.h for the valid bit numbers.
455 Note the Linux specific bits are not necessarily
456 stable over kernel options, but the vendor specific
457 ones should be.
458 Also note that user programs calling CPUID directly
459 or using the feature without checking anything
460 will still see it. This just prevents it from
461 being used by the kernel or shown in /proc/cpuinfo.
462 Also note the kernel might malfunction if you disable
463 some critical bits.
464
Arjan van de Vena25bd942008-01-30 13:33:08 +0100465 code_bytes [IA32/X86_64] How many bytes of object code to print
466 in an oops report.
Chuck Ebbert86c41832007-02-13 13:26:25 +0100467 Range: 0 - 8192
468 Default: 64
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
Simon Hormane515a0d2008-10-18 20:28:27 -0700692 elfcorehdr= [IA64,PPC,SH,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
Paul Mundt6902aa82008-09-21 17:14:42 +0900798 hlt [BUGS=ARM,SH]
799
Jiri Kosina36d95732008-10-06 02:51:09 -0400800 i8042.debug [HW] Toggle i8042 debug mode
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 i8042.direct [HW] Put keyboard port into non-translated mode
Matt LaPlante84eb8d02006-10-03 22:53:09 +0200802 i8042.dumbkbd [HW] Pretend that controller can only read data from
803 keyboard and cannot control its state
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 (Don't attempt to blink the leds)
805 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
Dmitry Torokhov945ef0d2005-09-04 01:42:00 -0500806 i8042.nokbd [HW] Don't check/create keyboard port
Jiri Kosina75d08c72008-03-13 16:13:59 -0400807 i8042.noloop [HW] Disable the AUX Loopback command while probing
808 for the AUX port
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 i8042.nomux [HW] Don't check presence of an active multiplexing
810 controller
811 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
812 controllers
813 i8042.panicblink=
814 [HW] Frequency with which keyboard LEDs should blink
815 when kernel panics (default is 0.5 sec)
816 i8042.reset [HW] Reset the controller during init and cleanup
817 i8042.unlock [HW] Unlock (ignore) the keylock
818
819 i810= [HW,DRM]
820
Dmitry Torokhove70c9d52005-06-25 14:54:25 -0700821 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
822 indicates that the driver is running on unsupported
823 hardware.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
825 does not match list of supported models.
826 i8k.power_status
827 [HW] Report power status in /proc/i8k
828 (disabled by default)
829 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
830 capability is set.
831
832 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
833 See Documentation/mca.txt.
834
835 icn= [HW,ISDN]
836 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
837
838 ide= [HW] (E)IDE subsystem
Greg Kroah-Hartmana594eeb2008-04-18 00:46:20 +0200839 Format: ide=nodma or ide=doubler
Randy Dunlap1c10e932008-03-07 21:53:50 +0100840 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
Randy Dunlap1c10e932008-03-07 21:53:50 +0100843 See Documentation/ide/ide.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844
Andi Kleenf039b752007-05-02 19:27:12 +0200845 idle= [X86]
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800846 Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Andi Kleenf039b752007-05-02 19:27:12 +0200847 Poll forces a polling idle loop that can slightly improves the performance
848 of waking up a idle CPU, but will use a lot of power and make the system
849 run hot. Not recommended.
850 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
851 to not use it because it doesn't save as much power as a normal idle
852 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
853 as idle=poll.
Zhao Yakuic1e3b372008-06-24 17:58:53 +0800854 idle=halt. Halt is forced to be used for CPU idle.
855 In such case C2/C3 won't be used again.
Zhao Yakuida5e09a2008-06-24 18:01:09 +0800856 idle=nomwait. Disable mwait for CPU C-states
Randy Dunlapa9913042005-10-23 12:57:11 -0700857
Denis Cheng594765a2008-02-06 02:57:49 +0100858 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
859 Claim all unknown PCI IDE storage controllers.
860
Ingo Molnar792908222006-12-06 20:40:51 -0800861 ignore_loglevel [KNL]
862 Ignore loglevel setting - this will print /all/
863 kernel messages to the console. Useful for debugging.
864
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 ihash_entries= [KNL]
866 Set number of hash buckets for inode cache.
867
868 in2000= [HW,SCSI]
869 See header of drivers/scsi/in2000.c.
870
871 init= [KNL]
872 Format: <full_path>
873 Run specified binary instead of /sbin/init as init
874 process.
875
876 initcall_debug [KNL] Trace initcalls as they are executed. Useful
877 for working out where the kernel is dying during
878 startup.
879
880 initrd= [BOOT] Specify the location of the initial ramdisk
881
882 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
883 Format: <irq>
884
885 inttest= [IA64]
886
Pavel Machekb552da82008-03-19 15:58:11 +0100887 iommu= [x86]
888 off
889 force
890 noforce
891 biomerge
892 panic
893 nopanic
894 merge
895 nomerge
896 forcesac
897 soft
898
899
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700900 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
901 off
902 Disable intel iommu driver.
903 igfx_off [Default Off]
904 By default, gfx is mapped as normal device. If a gfx
905 device has a dedicated DMAR unit, the DMAR unit is
906 bypassed by not enabling DMAR with this option. In
907 this case, gfx device will use physical address for
908 DMA.
Keshavamurthy, Anil S7d3b03c2007-10-21 16:41:53 -0700909 forcedac [x86_64]
910 With this option iommu will not optimize to look
911 for io virtual address below 32 bit forcing dual
912 address cycle on pci bus for cards supporting greater
913 than 32 bit addressing. The default is to look
914 for translation below 32 bit and if not available
915 then look in the higher range.
mark gross5e0d2a62008-03-04 15:22:08 -0800916 strict [Default Off]
917 With this option on every unmap_single operation will
918 result in a hardware IOTLB flush operation as opposed
919 to batching them for performance.
Keshavamurthy, Anil Sba395922007-10-21 16:41:49 -0700920
Rene Hermanb02aae92008-01-30 13:30:05 +0100921 io_delay= [X86-32,X86-64] I/O delay method
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100922 0x80
923 Standard port 0x80 based delay
924 0xed
925 Alternate port 0xed based delay (needed on some systems)
Rene Hermanb02aae92008-01-30 13:30:05 +0100926 udelay
Ingo Molnar6e7c4022008-01-30 13:30:05 +0100927 Simple two microseconds delay
928 none
929 No delay
Rene Hermanb02aae92008-01-30 13:30:05 +0100930
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 io7= [HW] IO7 for Marvel based alpha systems
932 See comment before marvel_specify_io7 in
933 arch/alpha/kernel/core_marvel.c.
934
935 ip= [IP_PNP]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -0400936 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937
938 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
Randy Dunlapc8facbb2007-07-31 00:37:40 -0700939 See comment before ip2_setup() in
940 drivers/char/ip2/ip2base.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941
942 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
943 See header of drivers/scsi/ips.c.
944
Simon Horman72c4a132006-09-13 19:57:18 -0700945 ports= [IP_VS_FTP] IPVS ftp helper module
946 Default is 21.
947 Up to 8 (IP_VS_APP_MAX_PORTS) ports
948 may be specified.
949 Format: <port>,<port>....
950
Alan Cox200803d2005-06-28 20:45:18 -0700951 irqfixup [HW]
952 When an interrupt is not handled search all handlers
953 for it. Intended to get systems with badly broken
954 firmware running.
955
956 irqpoll [HW]
957 When an interrupt is not handled search all handlers
958 for it. Also check all handlers each timer
959 interrupt. Intended to get systems with badly broken
960 firmware running.
961
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 isapnp= [ISAPNP]
Randy Dunlapa9913042005-10-23 12:57:11 -0700963 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964
965 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
Derek Fults22f2e282006-12-06 20:37:11 -0800966 Format:
967 <cpu number>,...,<cpu number>
968 or
969 <cpu number>-<cpu number> (must be a positive range in ascending order)
970 or a mixture
971 <cpu number>,...,<cpu number>-<cpu number>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 This option can be used to specify one or more CPUs
973 to isolate from the general SMP balancing and scheduling
974 algorithms. The only way to move a process onto or off
975 an "isolated" CPU is via the CPU affinity syscalls.
976 <cpu number> begins at 0 and the maximum value is
977 "number of CPUs in system - 1".
978
979 This option is the preferred way to isolate CPUs. The
Randy Dunlapa9913042005-10-23 12:57:11 -0700980 alternative -- manually setting the CPU mask of all
981 tasks in the system -- can cause problems and
982 suboptimal load balancer performance.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983
Randy Dunlapa9913042005-10-23 12:57:11 -0700984 iucv= [HW,NET]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985
986 js= [HW,JOY] Analog joystick
987 See Documentation/input/joystick.txt.
988
Alan Coxcd4f0ef2007-07-31 00:37:59 -0700989 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gormaned7ed362007-07-17 04:03:14 -0700990 specifies the amount of memory usable by the kernel
991 for non-movable allocations. The requested amount is
992 spread evenly throughout all nodes in the system. The
993 remaining memory in each node is used for Movable
994 pages. In the event, a node is too small to have both
995 kernelcore and Movable pages, kernelcore pages will
996 take priority and other nodes will have a larger number
997 of kernelcore pages. The Movable zone is used for the
998 allocation of pages that may be reclaimed or moved
999 by the page migration subsystem. This means that
1000 HugeTLB pages may not be allocated from this zone.
1001 Note that allocations like PTEs-from-HighMem still
1002 use the HighMem zone if it exists, and the Normal
1003 zone if it does not.
1004
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001005 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
Mel Gorman7e63efe2007-07-17 04:03:15 -07001006 is similar to kernelcore except it specifies the
1007 amount of memory used for migratable allocations.
1008 If both kernelcore and movablecore is specified,
1009 then kernelcore will be at *least* the specified
1010 value but may be more. If movablecore on its own
1011 is specified, the administrator must be careful
1012 that the amount of memory usable for all allocations
1013 is not too small.
1014
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015 keepinitrd [HW,ARM]
1016
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001017 kstack=N [X86-32,X86-64] Print N words from the kernel stack
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 in oops dumps.
1019
Jason Wessel6cdf6e02008-04-17 20:05:38 +02001020 kgdboc= [HW] kgdb over consoles.
1021 Requires a tty driver that supports console polling.
1022 (only serial suported for now)
1023 Format: <serial_device>[,baud]
1024
Florian Fainelli9bed90c62008-08-23 18:54:37 +02001025 kmac= [MIPS] korina ethernet MAC address.
1026 Configure the RouterBoard 532 series on-chip
1027 Ethernet adapter MAC address.
1028
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029 l2cr= [PPC]
1030
Robert Brosea78bfbf2008-03-29 07:20:23 +11001031 l3cr= [PPC]
1032
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001033 lapic [X86-32,APIC] Enable the local APIC even if BIOS
Randy Dunlapa9913042005-10-23 12:57:11 -07001034 disabled it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001036 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
Thomas Gleixnere585bef2007-03-23 16:08:01 +01001037 C2 power state.
1038
FD Camifcb71f62008-01-06 19:08:56 +01001039 libata.dma= [LIBATA] DMA control
1040 libata.dma=0 Disable all PATA and SATA DMA
1041 libata.dma=1 PATA and SATA Disk DMA only
1042 libata.dma=2 ATAPI (CDROM) DMA only
1043 libata.dma=4 Compact Flash DMA only
1044 Combinations also work, so libata.dma=3 enables DMA
1045 for disks and CDROMs, but not CFs.
1046
Dave Jones78e70c22007-09-27 11:50:13 -04001047 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1048 when set.
1049 Format: <int>
1050
Tejun Heo33267322008-02-13 09:15:09 +09001051 libata.force= [LIBATA] Force configurations. The format is comma
1052 separated list of "[ID:]VAL" where ID is
1053 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
1054 matching port, link or device. Basically, it matches
1055 the ATA ID string printed on console by libata. If
1056 the whole ID part is omitted, the last PORT and DEVICE
1057 values are used. If ID hasn't been specified yet, the
1058 configuration applies to all ports, links and devices.
1059
1060 If only DEVICE is omitted, the parameter applies to
1061 the port and all links and devices behind it. DEVICE
1062 number of 0 either selects the first device or the
1063 first fan-out link behind PMP device. It does not
1064 select the host link. DEVICE number of 15 selects the
1065 host link and device attached to it.
1066
1067 The VAL specifies the configuration to force. As long
1068 as there's no ambiguity shortcut notation is allowed.
1069 For example, both 1.5 and 1.5G would work for 1.5Gbps.
1070 The following configurations can be forced.
1071
1072 * Cable type: 40c, 80c, short40c, unk, ign or sata.
1073 Any ID with matching PORT is used.
1074
1075 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
1076
1077 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
1078 udma[/][16,25,33,44,66,100,133] notation is also
1079 allowed.
1080
1081 * [no]ncq: Turn on or off NCQ.
1082
Tejun Heo05944bd2008-08-13 20:19:09 +09001083 * nohrst, nosrst, norst: suppress hard, soft
1084 and both resets.
1085
Tejun Heo33267322008-02-13 09:15:09 +09001086 If there are multiple matching configurations changing
1087 the same attribute, the last one is used.
1088
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 load_ramdisk= [RAM] List of ramdisks to load from floppy
1090 See Documentation/ramdisk.txt.
1091
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001092 lockd.nlm_grace_period=P [NFS] Assign grace period.
1093 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094
Randy Dunlapa6b25b62006-01-14 13:21:19 -08001095 lockd.nlm_tcpport=N [NFS] Assign TCP port.
1096 Format: <integer>
1097
1098 lockd.nlm_timeout=T [NFS] Assign timeout value.
1099 Format: <integer>
1100
1101 lockd.nlm_udpport=M [NFS] Assign UDP port.
1102 Format: <integer>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103
1104 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1105 Format: <irq>
1106
1107 loglevel= All Kernel Messages with a loglevel smaller than the
1108 console loglevel will be printed to the console. It can
1109 also be changed with klogd or other programs. The
1110 loglevels are defined as follows:
1111
1112 0 (KERN_EMERG) system is unusable
1113 1 (KERN_ALERT) action must be taken immediately
1114 2 (KERN_CRIT) critical conditions
1115 3 (KERN_ERR) error conditions
1116 4 (KERN_WARNING) warning conditions
1117 5 (KERN_NOTICE) normal but significant condition
1118 6 (KERN_INFO) informational
1119 7 (KERN_DEBUG) debug-level messages
1120
1121 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
Randy Dunlapa9913042005-10-23 12:57:11 -07001122 Format: { n | nk | nM }
1123 n must be a power of two. The default size
1124 is set in the kernel config file.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001125
Randy Dunlapaccaa242007-10-16 01:29:37 -07001126 logo.nologo [FB] Disables display of the built-in Linux logo.
1127 This may be used to provide more screen space for
1128 kernel log messages and is useful when debugging
1129 kernel boot problems.
1130
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 lp=0 [LP] Specify parallel ports to use, e.g,
1132 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1133 lp=reset first parallel port). 'lp=0' disables the
1134 lp=auto printer driver. 'lp=reset' (which can be
1135 specified in addition to the ports) causes
1136 attached printers to be reset. Using
1137 lp=port1,port2,... specifies the parallel ports
1138 to associate lp devices with, starting with
1139 lp0. A port specification may be 'none' to skip
1140 that lp device, or a parport name such as
1141 'parport0'. Specifying 'lp=auto' instead of a
1142 port specification list means that device IDs
1143 from each port should be examined, to see if
1144 an IEEE 1284-compliant printer is attached; if
1145 so, the driver will manage that printer.
1146 See also header of drivers/char/lp.c.
1147
1148 lpj=n [KNL]
1149 Sets loops_per_jiffy to given constant, thus avoiding
1150 time-consuming boot-time autodetection (up to 250 ms per
1151 CPU). 0 enables autodetection (default). To determine
1152 the correct value for your kernel, boot with normal
1153 autodetection and see what value is printed. Note that
1154 on SMP systems the preset will be applied to all CPUs,
1155 which is likely to cause problems if your CPUs need
1156 significantly divergent settings. An incorrect value
1157 will cause delays in the kernel to be wrong, leading to
1158 unpredictable I/O errors and other breakage. Although
1159 unlikely, in the extreme case this might damage your
1160 hardware.
1161
1162 ltpc= [NET]
1163 Format: <io>,<irq>,<dma>
1164
Randy Dunlapa9913042005-10-23 12:57:11 -07001165 mac5380= [HW,SCSI] Format:
1166 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167
Randy Dunlapa9913042005-10-23 12:57:11 -07001168 machvec= [IA64] Force the use of a particular machine-vector
1169 (machvec) in a generic kernel.
1170 Example: machvec=hpzx1_swiotlb
Linus Torvalds1da177e2005-04-16 15:20:36 -07001171
Randy Dunlapa9913042005-10-23 12:57:11 -07001172 max_loop= [LOOP] Maximum number of loopback devices that can
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 be mounted
1174 Format: <1-256>
1175
1176 maxcpus= [SMP] Maximum number of processors that an SMP kernel
Len Brown61ec7562007-08-16 03:34:22 -04001177 should make use of. maxcpus=n : n >= 0 limits the
1178 kernel to using 'n' processors. n=0 is a special case,
1179 it is equivalent to "nosmp", which also disables
1180 the IO APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181
Bob Picco2b2c3752005-06-29 18:00:00 -07001182 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1183 equal to this physical address is ignored.
1184
Randy Dunlapa9913042005-10-23 12:57:11 -07001185 max_luns= [SCSI] Maximum number of LUNs to probe.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001186 Should be between 1 and 2^32-1.
1187
1188 max_report_luns=
Randy Dunlapa9913042005-10-23 12:57:11 -07001189 [SCSI] Maximum number of LUNs received.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 Should be between 1 and 16384.
1191
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192 mcatest= [IA-64]
1193
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001194 mce [X86-32] Machine Check Exception
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195
Andi Kleen909dd322007-10-17 18:04:38 +02001196 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1197
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198 md= [HW] RAID subsystems devices and level
1199 See Documentation/md.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001200
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 mdacon= [MDA]
1202 Format: <first>,<last>
1203 Specifies range of consoles to be captured by the MDA.
Randy Dunlapa9913042005-10-23 12:57:11 -07001204
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1206 Amount of memory to be used when the kernel is not able
1207 to see the whole system memory or for test.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001208 [X86-32] Use together with memmap= to avoid physical
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 address space collisions. Without memmap= PCI devices
1210 could be placed at addresses belonging to unused RAM.
1211
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001212 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 memory.
1214
Paul Mundt6902aa82008-09-21 17:14:42 +09001215 memchunk=nn[KMG]
1216 [KNL,SH] Allow user to override the default size for
1217 per-device physically contiguous DMA buffers.
1218
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001219 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220 E820 memory map, as specified by the user.
1221 Such memmap=exactmap lines can be constructed based on
1222 BIOS output or other requirements. See the memmap=nn@ss
1223 option description.
1224
1225 memmap=nn[KMG]@ss[KMG]
1226 [KNL] Force usage of a specific region of memory
1227 Region of memory to be used, from ss to ss+nn.
1228
1229 memmap=nn[KMG]#ss[KMG]
1230 [KNL,ACPI] Mark specific memory as ACPI data.
1231 Region of memory to be used, from ss to ss+nn.
1232
1233 memmap=nn[KMG]$ss[KMG]
1234 [KNL,ACPI] Mark specific memory as reserved.
1235 Region of memory to be used, from ss to ss+nn.
Pavel Machek13128482008-03-24 12:29:43 -07001236 Example: Exclude memory from 0x18690000-0x1869ffff
1237 memmap=64K$0x18690000
1238 or
1239 memmap=0x10000$0x18690000
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240
Jeremy Fitzhardinge9f077872008-09-07 01:51:34 -07001241 memory_corruption_check=0/1 [X86]
1242 Some BIOSes seem to corrupt the first 64k of
1243 memory when doing things like suspend/resume.
1244 Setting this option will scan the memory
1245 looking for corruption. Enabling this will
1246 both detect corruption and prevent the kernel
1247 from using the memory being corrupted.
1248 However, its intended as a diagnostic tool; if
1249 repeatable BIOS-originated corruption always
1250 affects the same memory, you can use memmap=
1251 to prevent the kernel from using that memory.
1252
1253 memory_corruption_check_size=size [X86]
1254 By default it checks for corruption in the low
1255 64k, making this memory unavailable for normal
1256 use. Use this parameter to scan for
1257 corruption in more or less memory.
1258
1259 memory_corruption_check_period=seconds [X86]
1260 By default it checks for corruption every 60
1261 seconds. Use this parameter to check at some
1262 other rate. 0 disables periodic checking.
1263
Yinghai Lucaadbdc2008-07-15 00:03:44 -07001264 memtest= [KNL,X86] Enable memtest
Yinghai Luc64df702008-03-21 18:56:19 -07001265 Format: <integer>
1266 range: 0,4 : pattern number
1267 default : 0 <disable>
1268
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 meye.*= [HW] Set MotionEye Camera parameters
1270 See Documentation/video4linux/meye.txt.
1271
Andres Salomon8f368812007-10-12 23:04:06 +02001272 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1273 Multi-Function General Purpose Timers on AMD Geode
1274 platforms.
1275
Willy Tarreaue6c4dc62008-01-30 13:33:33 +01001276 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1277 the BIOS has incorrectly applied a workaround. TinyBIOS
1278 version 0.98 is known to be affected, 0.99 fixes the
1279 problem by letting the user disable the workaround.
1280
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 mga= [HW,DRM]
1282
Mel Gorman6b74ab92008-07-23 21:26:49 -07001283 mminit_loglevel=
1284 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1285 parameter allows control of the logging verbosity for
1286 the additional memory initialisation checks. A value
1287 of 0 disables mminit logging and a level of 4 will
1288 log everything. Information is printed at KERN_DEBUG
1289 so loglevel=8 may also need to be specified.
1290
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291 mousedev.tap_time=
1292 [MOUSE] Maximum time between finger touching and
1293 leaving touchpad surface for touch to be considered
1294 a tap and be reported as a left button click (for
1295 touchpads working in absolute mode only).
1296 Format: <msecs>
1297 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1298 reporting absolute coordinates, such as tablets
1299 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1300 reporting absolute coordinates, such as tablets
1301
1302 mpu401= [HW,OSS]
1303 Format: <io>,<irq>
1304
1305 MTD_Partition= [MTD]
1306 Format: <name>,<region-number>,<size>,<offset>
1307
Randy Dunlapa9913042005-10-23 12:57:11 -07001308 MTD_Region= [MTD] Format:
1309 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001310
1311 mtdparts= [MTD]
Randy Dunlapc8facbb2007-07-31 00:37:40 -07001312 See drivers/mtd/cmdlinepart.c.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313
Ben Dooks9db829f2008-07-03 11:24:29 +01001314 mtdset= [ARM]
1315 ARM/S3C2412 JIVE boot control
1316
1317 See arch/arm/mach-s3c2412/mach-jive.c
1318
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 mtouchusb.raw_coordinates=
Randy Dunlapa9913042005-10-23 12:57:11 -07001320 [HW] Make the MicroTouch USB driver use raw coordinates
1321 ('y', default) or cooked coordinates ('n')
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322
1323 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1324
1325 NCR_D700= [HW,SCSI]
1326 See header of drivers/scsi/NCR_D700.c.
1327
1328 ncr5380= [HW,SCSI]
1329
1330 ncr53c400= [HW,SCSI]
1331
1332 ncr53c400a= [HW,SCSI]
1333
1334 ncr53c406a= [HW,SCSI]
1335
1336 ncr53c8xx= [HW,SCSI]
1337
1338 netdev= [NET] Network devices parameters
1339 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1340 Note that mem_start is often overloaded to mean
1341 something different and driver-specific.
Randy Dunlapa9913042005-10-23 12:57:11 -07001342 This usage is only documented in each driver source
1343 file if at all.
1344
Krzysztof Piotr Oledzki58401572008-07-21 10:01:34 -07001345 nf_conntrack.acct=
1346 [NETFILTER] Enable connection tracking flow accounting
1347 0 to disable accounting
1348 1 to enable accounting
1349 Default value depends on CONFIG_NF_CT_ACCT that is
1350 going to be removed in 2.6.29.
1351
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352 nfsaddrs= [NFS]
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001353 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354
1355 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
J. Bruce Fields6ded55d2008-04-07 15:59:03 -04001356 See Documentation/filesystems/nfsroot.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001357
Trond Myklebusta72b4422006-01-03 09:55:41 +01001358 nfs.callback_tcpport=
1359 [NFS] set the TCP port on which the NFSv4 callback
1360 channel should listen.
1361
Trond Myklebust58df0952006-01-03 09:55:57 +01001362 nfs.idmap_cache_timeout=
1363 [NFS] set the maximum lifetime for idmapper cache
1364 entries.
1365
Trond Myklebustf43bf0b2007-10-09 12:01:04 -04001366 nfs.enable_ino64=
1367 [NFS] enable 64-bit inode numbers.
1368 If zero, the NFS client will fake up a 32-bit inode
1369 number for the readdir() and stat() syscalls instead
1370 of returning the full 64-bit number.
1371 The default is to return 64-bit inode numbers.
1372
Haavard Skinnemoene7ba1762007-10-10 14:58:29 +02001373 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1374 when a NMI is triggered.
1375 Format: [state][,regs][,debounce][,die]
1376
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001377 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001379 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
Linus Torvalds1da177e2005-04-16 15:20:36 -07001380 emulation library even if a 387 maths coprocessor
1381 is present.
1382
Christoph Lameterc1aee212007-05-31 00:40:47 -07001383 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1384 caches in the slab allocator. Saves per-node memory,
1385 but will impact performance.
Paul Menage3395ee02006-12-06 20:32:16 -08001386
Randy Dunlapa9913042005-10-23 12:57:11 -07001387 noalign [KNL,ARM]
1388
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389 noapic [SMP,APIC] Tells the kernel to not make use of any
1390 IOAPICs that may be present in the system.
1391
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392 nobats [PPC] Do not use BATs for mapping kernel lowmem
1393 on "Classic" PPC cores.
1394
1395 nocache [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001396
Shailabh Nagar163ecdf2006-07-30 03:03:11 -07001397 nodelayacct [KNL] Disable per-task delay accounting
1398
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1400
Paul Mundt6902aa82008-09-21 17:14:42 +09001401 nodsp [SH] Disable hardware DSP at boot time.
1402
Huang, Ying8b2cb7a2008-01-30 13:32:11 +01001403 noefi [X86-32,X86-64] Disable EFI runtime services support.
1404
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405 noexec [IA-64]
1406
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001407 noexec [X86-32,X86-64]
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001408 On X86-32 available only on PAE configured kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001409 noexec=on: enable non-executable mappings (default)
Jiri Slabyf5a1b192008-04-12 10:28:25 +02001410 noexec=off: disable non-executable mappings
1411
1412 noexec32 [X86-64]
1413 This affects only 32-bit executables.
1414 noexec32=on: enable non-executable mappings (default)
1415 read doesn't imply executable mappings
1416 noexec32=off: disable non-executable mappings
1417 read implies executable mappings
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418
Paul Mundt6902aa82008-09-21 17:14:42 +09001419 nofpu [SH] Disable hardware FPU at boot time.
1420
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001421 nofxsr [BUGS=X86-32] Disables x86 floating point extended
Chuck Ebbert4f886512006-03-23 02:59:34 -08001422 register save and restore. The kernel will only save
1423 legacy floating-point registers on task switch.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424
Andi Kleen191679f2008-01-30 13:33:21 +01001425 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1426
Paul Mundt6902aa82008-09-21 17:14:42 +09001427 nohlt [BUGS=ARM,SH]
Randy Dunlapa9913042005-10-23 12:57:11 -07001428
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001429 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 instruction doesn't work correctly and not to
1431 use it.
1432
1433 nohalt [IA-64] Tells the kernel not to use the power saving
1434 function PAL_HALT_LIGHT when idle. This increases
1435 power-consumption. On the positive side, it reduces
1436 interrupt wake-up latency, which may improve performance
1437 in certain environments such as networked servers or
1438 real-time systems.
1439
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -08001440 nohz= [KNL] Boottime enable/disable dynamic ticks
1441 Valid arguments: on, off
1442 Default: on
1443
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001444 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
Zachary Amsden8542b202006-12-07 02:14:09 +01001445
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001446 noirqdebug [X86-32] Disables the code which attempts to detect and
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447 disable unhandled interrupt sources.
1448
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001449 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
Zachary Amsden8542b202006-12-07 02:14:09 +01001450 broken timer IRQ sources.
1451
Linus Torvalds1da177e2005-04-16 15:20:36 -07001452 noisapnp [ISAPNP] Disables ISA PnP code.
1453
1454 noinitrd [RAM] Tells the kernel not to load any configured
1455 initial RAM disk.
1456
1457 nointroute [IA-64]
1458
Tony Luck0aa366f2007-07-20 11:22:30 -07001459 nojitter [IA64] Disables jitter checking for ITC timers.
1460
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001461 nolapic [X86-32,APIC] Do not enable or use the local APIC.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001463 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
Thomas Gleixnerad62ca22007-03-22 00:11:21 -08001464
Suresh Siddha6e1cb382008-07-10 11:16:58 -07001465 nox2apic [X86-64,APIC] Do not enable x2APIC mode.
1466
Suresh Siddhaaf9d1382008-07-11 13:11:57 -07001467 x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of
1468 default x2apic cluster mode on platforms
1469 supporting x2apic.
1470
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471 noltlbs [PPC] Do not use large page/tlb entries for kernel
1472 lowmem mapping on PPC40x.
1473
Horms312f1f02006-02-22 09:57:55 +09001474 nomca [IA-64] Disable machine check abort handling
1475
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001476 nomce [X86-32] Machine Check Exception
Hormsabe37e52006-04-01 01:36:09 +02001477
Andres Salomon83d73842007-10-12 23:04:06 +02001478 nomfgpt [X86-32] Disable Multi-Function General Purpose
1479 Timer usage (for AMD Geode machines).
1480
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001481 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
Jeremy Fitzhardinge959b4fd2007-05-02 19:27:16 +02001482
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001483 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001484 with UP alternatives
1485
Linus Torvalds1da177e2005-04-16 15:20:36 -07001486 noresidual [PPC] Don't use residual data on PReP machines.
1487
Randy Dunlapa9913042005-10-23 12:57:11 -07001488 noresume [SWSUSP] Disables resume and restores original swap
1489 space.
1490
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 no-scroll [VGA] Disables scrollback.
1492 This is required for the Braillex ib80-piezo Braille
1493 reader made by F.H. Papenmeier (Germany).
1494
1495 nosbagart [IA-64]
1496
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001497 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
Chuck Ebbert4f886512006-03-23 02:59:34 -08001498
Len Brown61ec7562007-08-16 03:34:22 -04001499 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1500 and disable the IO APIC. legacy for "maxcpus=0".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001501
Dave Jones97842212007-07-15 23:41:05 -07001502 nosoftlockup [KNL] Disable the soft-lockup detector.
1503
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504 nosync [HW,M68K] Disables sync negotiation for all devices.
1505
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001506 notsc [BUGS=X86-32] Disable Time Stamp Counter
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507
1508 nousb [USB] Disable the USB subsystem
1509
1510 nowb [ARM]
Randy Dunlapa9913042005-10-23 12:57:11 -07001511
Fenghua Yua6c75b862008-03-14 13:57:08 -07001512 nptcg= [IA64] Override max number of concurrent global TLB
1513 purges which is reported from either PAL_VM_SUMMARY or
1514 SAL PALO.
1515
KAMEZAWA Hiroyukif0c0b2b2007-07-15 23:38:01 -07001516 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1517 one of ['zone', 'node', 'default'] can be specified
1518 This can be set from sysctl after boot.
1519 See Documentation/sysctl/vm.txt for details.
1520
Dave Jonesa61c2d72006-01-07 23:18:19 +00001521 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1522
Andres Salomon3ef0e1f2008-04-29 00:59:53 -07001523 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
1524 Rather than timing out after 20 ms if an EC
1525 command is not properly ACKed, override the length
1526 of the timeout. We have interrupts disabled while
1527 waiting for the ACK, so if this is set too high
1528 interrupts *may* be lost!
1529
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530 opl3= [HW,OSS]
1531 Format: <io>
1532
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 oprofile.timer= [HW]
1534 Use timer interrupt instead of performance counters
1535
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 osst= [HW,SCSI] SCSI Tape Driver
1537 Format: <buffer_size>,<write_threshold>
1538 See also Documentation/scsi/st.txt.
1539
1540 panic= [KNL] Kernel behaviour on panic
1541 Format: <timeout>
1542
1543 parkbd.port= [HW] Parallel port number the keyboard adapter is
1544 connected to, default is 0.
1545 Format: <parport#>
1546 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1547 0 for XT, 1 for AT (default is AT).
Randy Dunlapa9913042005-10-23 12:57:11 -07001548 Format: <mode>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001549
Randy Dunlapa9913042005-10-23 12:57:11 -07001550 parport= [HW,PPT] Specify parallel ports. 0 disables.
1551 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1552 Use 'auto' to force the driver to use any
1553 IRQ/DMA settings detected (the default is to
1554 ignore detected IRQ/DMA settings because of
1555 possible conflicts). You can specify the base
1556 address, IRQ, and DMA settings; IRQ and DMA
1557 should be numbers, or 'auto' (for using detected
1558 settings on that particular port), or 'nofifo'
1559 (to avoid using a FIFO even if it is detected).
1560 Parallel ports are assigned in the order they
1561 are specified on the command line, starting
1562 with parport0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001563
Randy Dunlapa9913042005-10-23 12:57:11 -07001564 parport_init_mode= [HW,PPT]
1565 Configure VIA parallel port to operate in
1566 a specific mode. This is necessary on Pegasos
1567 computer where firmware has no options for setting
1568 up parallel port mode and sets it to spp.
1569 Currently this function knows 686a and 8231 chips.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570 Format: [spp|ps2|epp|ecp|ecpepp]
1571
Randy Dunlapa9913042005-10-23 12:57:11 -07001572 pas2= [HW,OSS] Format:
1573 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1574
Linus Torvalds1da177e2005-04-16 15:20:36 -07001575 pas16= [HW,SCSI]
1576 See header of drivers/scsi/pas16.c.
1577
Andrew Mortondd287792006-03-23 03:00:57 -08001578 pause_on_oops=
1579 Halt all CPUs after the first oops has been printed for
1580 the specified number of seconds. This is to be used if
1581 your oopses keep scrolling off the screen.
1582
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583 pcbit= [HW,ISDN]
1584
1585 pcd. [PARIDE]
1586 See header of drivers/block/paride/pcd.c.
1587 See also Documentation/paride.txt.
1588
Randy Dunlapa9913042005-10-23 12:57:11 -07001589 pci=option[,option...] [PCI] various PCI subsystem options:
Andi Kleenc0115602008-08-22 09:53:39 +02001590 off [X86] don't probe for the PCI bus
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001591 bios [X86-32] force use of PCI BIOS, don't access
Randy Dunlapa9913042005-10-23 12:57:11 -07001592 the hardware directly. Use this if your machine
1593 has a non-standard PCI host bridge.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001594 nobios [X86-32] disallow use of PCI BIOS, only direct
Randy Dunlapa9913042005-10-23 12:57:11 -07001595 hardware access methods are allowed. Use this
1596 if you experience crashes upon bootup and you
1597 suspect they are caused by the BIOS.
Andi Kleenc0115602008-08-22 09:53:39 +02001598 conf1 [X86] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001599 Mechanism 1.
Andi Kleenc0115602008-08-22 09:53:39 +02001600 conf2 [X86] Force use of PCI Configuration
Randy Dunlapa9913042005-10-23 12:57:11 -07001601 Mechanism 2.
Randy Dunlap7f785762007-10-05 13:17:58 -07001602 noaer [PCIE] If the PCIEAER kernel config parameter is
1603 enabled, this kernel boot option can be used to
1604 disable the use of PCIE advanced error reporting.
Jeff Garzik32a2eea2007-10-11 16:57:27 -04001605 nodomains [PCI] Disable support for multiple PCI
1606 root domains (aka PCI segments, in ACPI-speak).
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001607 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
Bjorn Helgaas61be6d62006-02-15 15:17:43 -08001608 Configuration
Matthew Wilcox309e57d2006-03-05 22:33:34 -07001609 nomsi [MSI] If the PCI_MSI kernel config parameter is
1610 enabled, this kernel boot option can be used to
1611 disable the use of MSI interrupts system-wide.
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001612 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
Randy Dunlapa9913042005-10-23 12:57:11 -07001613 routing table. These calls are known to be buggy
1614 on several machines and they hang the machine
1615 when used, but on other computers it's the only
1616 way to get the interrupt routing table. Try
1617 this option if the kernel is unable to allocate
1618 IRQs or discover secondary PCI buses on your
1619 motherboard.
Andi Kleenc0115602008-08-22 09:53:39 +02001620 rom [X86] Assign address space to expansion ROMs.
Randy Dunlapa9913042005-10-23 12:57:11 -07001621 Use with caution as certain devices share
1622 address decoders between ROMs and other
1623 resources.
Andi Kleenc0115602008-08-22 09:53:39 +02001624 norom [X86] Do not assign address space to
Gary Hadebb71ad82008-05-12 13:57:46 -07001625 expansion ROMs that do not already have
1626 BIOS assigned address ranges.
Andi Kleenc0115602008-08-22 09:53:39 +02001627 irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be
Randy Dunlapa9913042005-10-23 12:57:11 -07001628 assigned automatically to PCI devices. You can
1629 make the kernel exclude IRQs of your ISA cards
1630 this way.
Andi Kleenc0115602008-08-22 09:53:39 +02001631 pirqaddr=0xAAAAA [X86] Specify the physical address
Randy Dunlapa9913042005-10-23 12:57:11 -07001632 of the PIRQ table (normally generated
1633 by the BIOS) if it is outside the
1634 F0000h-100000h range.
Andi Kleenc0115602008-08-22 09:53:39 +02001635 lastbus=N [X86] Scan all buses thru bus #N. Can be
Randy Dunlapa9913042005-10-23 12:57:11 -07001636 useful if the kernel is unable to find your
1637 secondary buses and you want to tell it
1638 explicitly which ones they are.
Andi Kleenc0115602008-08-22 09:53:39 +02001639 assign-busses [X86] Always assign all PCI bus
Randy Dunlapa9913042005-10-23 12:57:11 -07001640 numbers ourselves, overriding
1641 whatever the firmware may have done.
Andi Kleenc0115602008-08-22 09:53:39 +02001642 usepirqmask [X86] Honor the possible IRQ mask stored
Randy Dunlapa9913042005-10-23 12:57:11 -07001643 in the BIOS $PIR table. This is needed on
1644 some systems with broken BIOSes, notably
1645 some HP Pavilion N5400 and Omnibook XE3
1646 notebooks. This will have no effect if ACPI
1647 IRQ routing is enabled.
Andi Kleenc0115602008-08-22 09:53:39 +02001648 noacpi [X86] Do not use ACPI for IRQ routing
Randy Dunlapa9913042005-10-23 12:57:11 -07001649 or for PCI scanning.
Andi Kleenc0115602008-08-22 09:53:39 +02001650 use_crs [X86] Use _CRS for PCI resource
Gary Hade62f420f2007-10-03 15:56:51 -07001651 allocation.
Randy Dunlapa9913042005-10-23 12:57:11 -07001652 routeirq Do IRQ routing for all PCI devices.
1653 This is normally done in pci_enable_device(),
1654 so this option is a temporary workaround
1655 for broken drivers that don't call it.
Yinghai Lu13a6ddb2008-03-27 01:31:18 -07001656 skip_isa_align [X86] do not align io start addr, so can
1657 handle more pci cards
Randy Dunlapa9913042005-10-23 12:57:11 -07001658 firmware [ARM] Do not re-enumerate the bus but instead
1659 just use the configuration from the
1660 bootloader. This is currently used on
1661 IXP2000 systems where the bus has to be
1662 configured a certain way for adjunct CPUs.
Andi Kleen0637a702006-09-26 10:52:41 +02001663 noearly [X86] Don't do any early type 1 scanning.
1664 This might help on some broken boards which
1665 machine check when some devices' config space
1666 is read. But various workarounds are disabled
1667 and some IOMMU drivers will not work.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001668 bfsort Sort PCI devices into breadth-first order.
1669 This sorting is done to get a device
1670 order compatible with older (<= 2.4) kernels.
1671 nobfsort Don't sort PCI devices into breadth-first order.
Atsushi Nemoto4516a612007-02-05 16:36:06 -08001672 cbiosize=nn[KMG] The fixed amount of bus space which is
1673 reserved for the CardBus bridge's IO window.
1674 The default value is 256 bytes.
1675 cbmemsize=nn[KMG] The fixed amount of bus space which is
1676 reserved for the CardBus bridge's memory
1677 window. The default value is 64 megabytes.
Matt Domsch6b4b78f2006-09-29 15:23:23 -05001678
Chuck Ebberte5665a42008-09-24 20:40:34 -04001679 pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
1680 Management.
1681 off Disable ASPM.
1682 force Enable ASPM even on devices that claim not to support it.
1683 WARNING: Forcing ASPM on may cause system lockups.
1684
Linus Torvalds1da177e2005-04-16 15:20:36 -07001685 pcmv= [HW,PCMCIA] BadgePAD 4
1686
1687 pd. [PARIDE]
1688 See Documentation/paride.txt.
1689
1690 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1691 boot time.
1692 Format: { 0 | 1 }
1693 See arch/parisc/kernel/pdc_chassis.c
1694
1695 pf. [PARIDE]
1696 See Documentation/paride.txt.
1697
1698 pg. [PARIDE]
1699 See Documentation/paride.txt.
1700
1701 pirq= [SMP,APIC] Manual mp-table setup
1702 See Documentation/i386/IO-APIC.txt.
1703
1704 plip= [PPT,NET] Parallel port network link
1705 Format: { parport<nr> | timid | 0 }
1706 See also Documentation/parport.txt.
1707
Thomas Gleixnerde32a242008-07-12 05:33:30 +02001708 pmtmr= [X86] Manual setup of pmtmr I/O Port.
1709 Override pmtimer IOPort with a hex value.
1710 e.g. pmtmr=0x508
1711
Bjorn Helgaas97ef0622008-08-19 16:53:41 -06001712 pnp.debug [PNP]
1713 Enable PNP debug messages. This depends on the
1714 CONFIG_PNP_DEBUG_MESSAGES option.
1715
Linus Torvalds1da177e2005-04-16 15:20:36 -07001716 pnpacpi= [ACPI]
1717 { off }
1718
1719 pnpbios= [ISAPNP]
1720 { on | off | curr | res | no-curr | no-res }
1721
1722 pnp_reserve_irq=
1723 [ISAPNP] Exclude IRQs for the autoconfiguration
1724
1725 pnp_reserve_dma=
1726 [ISAPNP] Exclude DMAs for the autoconfiguration
1727
1728 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
Randy Dunlapa9913042005-10-23 12:57:11 -07001729 Ranges are in pairs (I/O port base and size).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001730
1731 pnp_reserve_mem=
Randy Dunlapa9913042005-10-23 12:57:11 -07001732 [ISAPNP] Exclude memory regions for the
1733 autoconfiguration.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001734 Ranges are in pairs (memory base and size).
1735
Jason Baron346e15b2008-08-12 16:46:19 -04001736 dynamic_printk
1737 Enables pr_debug()/dev_dbg() calls if
1738 CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
1739 be switched on/off via <debugfs>/dynamic_printk/modules
1740
Ingo Molnar45807a12007-07-15 23:40:10 -07001741 print-fatal-signals=
1742 [KNL] debug: print fatal signals
1743 print-fatal-signals=1: print segfault info to
1744 the kernel console.
1745 default: off.
1746
Randy Dunlape84845c2007-07-15 23:40:25 -07001747 printk.time= Show timing data prefixed to each printk message line
1748 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1749
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750 profile= [KNL] Enable kernel profiling via /proc/profile
Randy Dunlapa9913042005-10-23 12:57:11 -07001751 Format: [schedule,]<number>
1752 Param: "schedule" - profile schedule points.
1753 Param: <number> - step/bucket size as a power of 2 for
1754 statistical time based profiling.
Mel Gormanb3da2a72007-10-24 18:23:50 +02001755 Param: "sleep" - profile D-state sleeping (millisecs).
1756 Requires CONFIG_SCHEDSTATS
Dave Jonesc0fe2e62007-10-20 03:08:22 +02001757 Param: "kvm" - profile VM exits.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001758
Randy Dunlapa9913042005-10-23 12:57:11 -07001759 processor.max_cstate= [HW,ACPI]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760 Limit processor to maximum C-state
1761 max_cstate=9 overrides any DMI blacklist limit.
1762
Len Brown41c0d862005-12-28 12:43:51 -05001763 processor.nocst [HW,ACPI]
1764 Ignore the _CST method to determine C-states,
1765 instead using the legacy FADT method
1766
Linus Torvalds1da177e2005-04-16 15:20:36 -07001767 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1768 before loading.
1769 See Documentation/ramdisk.txt.
1770
Randy Dunlapa9913042005-10-23 12:57:11 -07001771 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1772 probe for; one of (bare|imps|exps|lifebook|any).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1774 per second.
Randy Dunlapa9913042005-10-23 12:57:11 -07001775 psmouse.resetafter= [HW,MOUSE]
1776 Try to reset the device after so many bad packets
Linus Torvalds1da177e2005-04-16 15:20:36 -07001777 (0 = never).
1778 psmouse.resolution=
1779 [HW,MOUSE] Set desired mouse resolution, in dpi.
1780 psmouse.smartscroll=
Randy Dunlapa9913042005-10-23 12:57:11 -07001781 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782 0 = disabled, 1 = enabled (default).
1783
1784 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
Randy Dunlapa9913042005-10-23 12:57:11 -07001785 Format:
1786 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787
1788 pt. [PARIDE]
1789 See Documentation/paride.txt.
1790
Kay Sieversdc8c8582007-08-15 12:25:38 +02001791 pty.legacy_count=
1792 [KNL] Number of legacy pty's. Overwrites compiled-in
1793 default number.
1794
Randy Dunlap7d2c5022006-09-29 02:01:02 -07001795 quiet [KNL] Disable most log messages
Randy Dunlapa9913042005-10-23 12:57:11 -07001796
Linus Torvalds1da177e2005-04-16 15:20:36 -07001797 r128= [HW,DRM]
1798
1799 raid= [HW,RAID]
1800 See Documentation/md.txt.
1801
Randy Dunlapa9913042005-10-23 12:57:11 -07001802 ramdisk_blocksize= [RAM]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001803 See Documentation/ramdisk.txt.
Randy Dunlapa9913042005-10-23 12:57:11 -07001804
Linus Torvalds1da177e2005-04-16 15:20:36 -07001805 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
Linus Torvalds1da177e2005-04-16 15:20:36 -07001806 See Documentation/ramdisk.txt.
1807
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001808 rcupdate.blimit= [KNL,BOOT]
1809 Set maximum number of finished RCU callbacks to process
1810 in one batch.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001811
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001812 rcupdate.qhimark= [KNL,BOOT]
1813 Set threshold of queued
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001814 RCU callbacks over which batch limiting is disabled.
1815
Robert P. J. Day24aaef82008-02-03 15:20:26 +02001816 rcupdate.qlowmark= [KNL,BOOT]
1817 Set threshold of queued RCU callbacks below which
1818 batch limiting is re-enabled.
Dipankar Sarma21a1ea92006-03-07 21:55:33 -08001819
Olof Johanssonffdfc402005-09-06 15:17:19 -07001820 rdinit= [KNL]
1821 Format: <full_path>
1822 Run specified binary instead of /init from the ramdisk,
1823 used for early userspace startup. See initrd.
1824
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001825 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001826 Format: <reboot_mode>[,<reboot_mode2>[,...]]
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001827 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07001828
Paul Jackson46b6d942008-07-04 10:00:09 -07001829 relax_domain_level=
1830 [KNL, SMP] Set scheduler's default relax_domain_level.
1831 See Documentation/cpusets.txt.
1832
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1834
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001835 reservetop= [X86-32]
Zachary Amsden461a9af2006-09-25 23:32:25 -07001836 Format: nn[KMG]
1837 Reserves a hole at the top of the kernel virtual
1838 address space.
1839
Vivek Goyal7e962872006-09-27 01:50:44 -07001840 reset_devices [KNL] Force drivers to reset the underlying device
1841 during initialization.
1842
Randy Dunlapa9913042005-10-23 12:57:11 -07001843 resume= [SWSUSP]
1844 Specify the partition device for software suspend
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845
Rafael J. Wysockiecbd0da2006-12-06 20:34:13 -08001846 resume_offset= [SWSUSP]
1847 Specify the offset from the beginning of the partition
1848 given by "resume=" at which the swap header is located,
1849 in <PAGE_SIZE> units (needed only for swap files).
1850 See Documentation/power/swsusp-and-swap-files.txt
1851
Michael Neuling0a7b35cb2007-02-10 01:44:33 -08001852 retain_initrd [RAM] Keep initrd memory after extraction
1853
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854 rhash_entries= [KNL,NET]
1855 Set number of hash buckets for route cache
1856
1857 riscom8= [HW,SERIAL]
1858 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1859
1860 ro [KNL] Mount root device read-only on boot
1861
1862 root= [KNL] Root filesystem
1863
1864 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1865 mount the root filesystem
1866
1867 rootflags= [KNL] Set root filesystem mount option string
1868
1869 rootfstype= [KNL] Set root filesystem type
1870
Pierre Ossmancc1ed752007-07-15 23:40:35 -07001871 rootwait [KNL] Wait (indefinitely) for root device to show up.
1872 Useful for devices that are detected asynchronously
1873 (e.g. USB and MMC devices).
1874
James Morris20510f22007-10-16 23:31:32 -07001875 root_plug.vendor_id=
1876 [ROOTPLUG] Override the default vendor ID
1877
1878 root_plug.product_id=
1879 [ROOTPLUG] Override the default product ID
1880
1881 root_plug.debug=
1882 [ROOTPLUG] Enable debugging output
1883
Linus Torvalds1da177e2005-04-16 15:20:36 -07001884 rw [KNL] Mount root device read-write on boot
1885
1886 S [KNL] Run init in single mode
1887
1888 sa1100ir [NET]
1889 See drivers/net/irda/sa1100_ir.c.
1890
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 sbni= [NET] Granch SBNI12 leased line adapter
Randy Dunlapa9913042005-10-23 12:57:11 -07001892
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1894 Format: <io>[,<timeout>[,<isapnp>]]
1895
1896 scsi_debug_*= [SCSI]
1897 See drivers/scsi/scsi_debug.c.
1898
1899 scsi_default_dev_flags=
1900 [SCSI] SCSI default device flags
1901 Format: <integer>
1902
1903 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1904 Format: <vendor>:<model>:<flags>
1905 (flags are integer value)
1906
Randy Dunlap6af66322007-11-14 16:52:25 -08001907 scsi_logging_level= [SCSI] a bit mask of logging levels
1908 See drivers/scsi/scsi_logging.h for bits. Also
1909 settable via sysctl at dev.scsi.logging_level
1910 (/proc/sys/dev/scsi/logging_level).
1911 There is also a nice 'scsi_logging_level' script in the
1912 S390-tools package, available for download at
1913 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914
Matthew Wilcox3e082a92006-09-28 15:19:20 -06001915 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1916 discovered. async scans them in kernel threads,
1917 allowing boot to proceed. none ignores them, expecting
1918 user space to do the scan.
1919
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920 selinux [SELINUX] Disable or enable SELinux at boot time.
1921 Format: { "0" | "1" }
1922 See security/selinux/Kconfig help text.
1923 0 -- disable.
1924 1 -- enable.
1925 Default value is set via kernel config option.
1926 If enabled at boot time, /selinux/disable can be used
1927 later to disable prior to initial policy load.
1928
James Morris4e5ab4c2006-06-09 00:33:33 -07001929 selinux_compat_net =
1930 [SELINUX] Set initial selinux_compat_net flag value.
Mauro Carvalho Chehabe53dd082007-09-15 07:38:47 -03001931 Format: { "0" | "1" }
1932 0 -- use new secmark-based packet controls
1933 1 -- use legacy packet controls
1934 Default value is 0 (preferred).
1935 Value can be changed at runtime via
1936 /selinux/compat_net.
James Morris4e5ab4c2006-06-09 00:33:33 -07001937
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001938 serialnumber [BUGS=X86-32]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001939
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940 shapers= [NET]
1941 Maximal number of shapers.
Randy Dunlapa9913042005-10-23 12:57:11 -07001942
Yinghai Lub05f78f2008-08-22 01:32:50 -07001943 show_msr= [x86] show boot-time MSR settings
1944 Format: { <integer> }
1945 Show boot-time (BIOS-initialized) MSR settings.
1946 The parameter means the number of CPUs to show,
1947 for example 1 means boot CPU only.
1948
Linus Torvalds1da177e2005-04-16 15:20:36 -07001949 sim710= [SCSI,HW]
1950 See header of drivers/scsi/sim710.c.
1951
1952 simeth= [IA-64]
1953 simscsi=
Randy Dunlapa9913042005-10-23 12:57:11 -07001954
Linus Torvalds1da177e2005-04-16 15:20:36 -07001955 slram= [HW,MTD]
1956
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001957 slub_debug[=options[,slabs]] [MM, SLUB]
1958 Enabling slub_debug allows one to determine the
1959 culprit if slab objects become corrupted. Enabling
1960 slub_debug can create guard zones around objects and
1961 may poison objects when not in use. Also tracks the
1962 last alloc / free. For more information see
1963 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001964
1965 slub_max_order= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001966 Determines the maximum allowed order for slabs.
1967 A high setting may cause OOMs due to memory
1968 fragmentation. For more information see
1969 Documentation/vm/slub.txt.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001970
1971 slub_min_objects= [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001972 The minimum number of objects per slab. SLUB will
1973 increase the slab order up to slub_max_order to
1974 generate a sufficiently large slab able to contain
1975 the number of objects indicated. The higher the number
1976 of objects the smaller the overhead of tracking slabs
1977 and the less frequently locks need to be acquired.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001978 For more information see Documentation/vm/slub.txt.
1979
1980 slub_min_order= [MM, SLUB]
1981 Determines the mininum page order for slabs. Must be
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001982 lower than slub_max_order.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001983 For more information see Documentation/vm/slub.txt.
1984
1985 slub_nomerge [MM, SLUB]
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001986 Disable merging of slabs with similar size. May be
Christoph Lameterc1aee212007-05-31 00:40:47 -07001987 necessary if there is some reason to distinguish
Christoph Lameterf0630ff2007-07-15 23:38:14 -07001988 allocs to different slabs. Debug options disable
1989 merging on their own.
Christoph Lameterc1aee212007-05-31 00:40:47 -07001990 For more information see Documentation/vm/slub.txt.
1991
Linus Torvalds1da177e2005-04-16 15:20:36 -07001992 smart2= [HW]
1993 Format: <io1>[,<io2>[,...,<io8>]]
1994
Alan Coxcd4f0ef2007-07-31 00:37:59 -07001995 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
Jeremy Fitzhardingeb7fb4af2007-05-02 19:27:13 +02001996 attempt to substitute SMP alternatives once at boot.
1997
Bjorn Helgaasd0d4f692007-05-08 00:36:05 -07001998 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1999 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
2000 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
2001 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
2002 smsc-ircc2.ircc_irq= [HW] IRQ line
2003 smsc-ircc2.ircc_dma= [HW] DMA channel
2004 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
2005 0: Toshiba Satellite 1800 (GP data pin select)
2006 1: Fast pin select (default)
2007 2: ATC IRMode
2008
Linus Torvalds1da177e2005-04-16 15:20:36 -07002009 snd-ad1816a= [HW,ALSA]
2010
2011 snd-ad1848= [HW,ALSA]
2012
2013 snd-ali5451= [HW,ALSA]
2014
2015 snd-als100= [HW,ALSA]
2016
2017 snd-als4000= [HW,ALSA]
2018
2019 snd-azt2320= [HW,ALSA]
2020
2021 snd-cmi8330= [HW,ALSA]
2022
2023 snd-cmipci= [HW,ALSA]
2024
2025 snd-cs4231= [HW,ALSA]
2026
2027 snd-cs4232= [HW,ALSA]
2028
2029 snd-cs4236= [HW,ALSA]
2030
2031 snd-cs4281= [HW,ALSA]
2032
2033 snd-cs46xx= [HW,ALSA]
2034
2035 snd-dt019x= [HW,ALSA]
2036
2037 snd-dummy= [HW,ALSA]
2038
2039 snd-emu10k1= [HW,ALSA]
2040
2041 snd-ens1370= [HW,ALSA]
2042
2043 snd-ens1371= [HW,ALSA]
2044
2045 snd-es968= [HW,ALSA]
2046
2047 snd-es1688= [HW,ALSA]
2048
2049 snd-es18xx= [HW,ALSA]
2050
2051 snd-es1938= [HW,ALSA]
2052
2053 snd-es1968= [HW,ALSA]
2054
2055 snd-fm801= [HW,ALSA]
2056
2057 snd-gusclassic= [HW,ALSA]
2058
2059 snd-gusextreme= [HW,ALSA]
2060
2061 snd-gusmax= [HW,ALSA]
2062
2063 snd-hdsp= [HW,ALSA]
2064
2065 snd-ice1712= [HW,ALSA]
2066
2067 snd-intel8x0= [HW,ALSA]
2068
2069 snd-interwave= [HW,ALSA]
2070
2071 snd-interwave-stb=
2072 [HW,ALSA]
2073
2074 snd-korg1212= [HW,ALSA]
2075
2076 snd-maestro3= [HW,ALSA]
2077
2078 snd-mpu401= [HW,ALSA]
2079
2080 snd-mtpav= [HW,ALSA]
2081
2082 snd-nm256= [HW,ALSA]
2083
2084 snd-opl3sa2= [HW,ALSA]
2085
2086 snd-opti92x-ad1848=
2087 [HW,ALSA]
2088
2089 snd-opti92x-cs4231=
2090 [HW,ALSA]
2091
2092 snd-opti93x= [HW,ALSA]
2093
2094 snd-pmac= [HW,ALSA]
2095
2096 snd-rme32= [HW,ALSA]
2097
2098 snd-rme96= [HW,ALSA]
2099
2100 snd-rme9652= [HW,ALSA]
2101
2102 snd-sb8= [HW,ALSA]
2103
2104 snd-sb16= [HW,ALSA]
2105
2106 snd-sbawe= [HW,ALSA]
2107
2108 snd-serial= [HW,ALSA]
2109
2110 snd-sgalaxy= [HW,ALSA]
2111
2112 snd-sonicvibes= [HW,ALSA]
2113
2114 snd-sun-amd7930=
2115 [HW,ALSA]
2116
2117 snd-sun-cs4231= [HW,ALSA]
2118
2119 snd-trident= [HW,ALSA]
2120
2121 snd-usb-audio= [HW,ALSA,USB]
2122
2123 snd-via82xx= [HW,ALSA]
2124
2125 snd-virmidi= [HW,ALSA]
2126
2127 snd-wavefront= [HW,ALSA]
2128
2129 snd-ymfpci= [HW,ALSA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002130
Ingo Molnar9c44bc02008-05-12 21:21:04 +02002131 softlockup_panic=
2132 [KNL] Should the soft-lockup detector generate panics.
2133
Linus Torvalds1da177e2005-04-16 15:20:36 -07002134 sonypi.*= [HW] Sony Programmable I/O Control Device driver
2135 See Documentation/sonypi.txt
2136
2137 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2138 See Documentation/specialix.txt.
2139
2140 spia_io_base= [HW,MTD]
2141 spia_fio_base=
2142 spia_pedr=
2143 spia_peddr=
2144
2145 sscape= [HW,OSS]
2146 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
Randy Dunlapa9913042005-10-23 12:57:11 -07002147
Linus Torvalds1da177e2005-04-16 15:20:36 -07002148 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
2149 See Documentation/scsi/st.txt.
2150
Linus Torvalds1da177e2005-04-16 15:20:36 -07002151 sti= [PARISC,HW]
2152 Format: <num>
2153 Set the STI (builtin display/keyboard on the HP-PARISC
2154 machines) console (graphic card) which should be used
2155 as the initial boot-console.
2156 See also comment in drivers/video/console/sticore.c.
2157
2158 sti_font= [HW]
2159 See comment in drivers/video/console/sticore.c.
2160
2161 stifb= [HW]
2162 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
2163
Greg Banks42a7fc42007-03-06 01:42:23 -08002164 sunrpc.pool_mode=
2165 [NFS]
2166 Control how the NFS server code allocates CPUs to
2167 service thread pools. Depending on how many NICs
2168 you have and where their interrupts are bound, this
2169 option will affect which CPUs will do NFS serving.
2170 Note: this parameter cannot be changed while the
2171 NFS server is running.
2172
2173 auto the server chooses an appropriate mode
2174 automatically using heuristics
2175 global a single global pool contains all CPUs
2176 percpu one pool for each CPU
2177 pernode one pool for each NUMA node (equivalent
2178 to global on non-NUMA machines)
2179
Linus Torvalds1da177e2005-04-16 15:20:36 -07002180 swiotlb= [IA-64] Number of I/O TLB slabs
Randy Dunlapa9913042005-10-23 12:57:11 -07002181
Linus Torvalds1da177e2005-04-16 15:20:36 -07002182 switches= [HW,M68k]
2183
2184 sym53c416= [HW,SCSI]
2185 See header of drivers/scsi/sym53c416.c.
2186
Ingo Molnar5d6f6472006-12-13 00:34:36 -08002187 sysrq_always_enabled
2188 [KNL]
2189 Ignore sysrq setting - this boot parameter will
2190 neutralize any effect of /proc/sys/kernel/sysrq.
2191 Useful for debugging.
2192
Linus Torvalds1da177e2005-04-16 15:20:36 -07002193 t128= [HW,SCSI]
2194 See header of drivers/scsi/t128.c.
2195
2196 tdfx= [HW,DRM]
2197
David Brownell77437fd2008-07-23 21:28:33 -07002198 test_suspend= [SUSPEND]
2199 Specify "mem" (for Suspend-to-RAM) or "standby" (for
2200 standby suspend) as the system sleep state to briefly
2201 enter during system startup. The system is woken from
2202 this state using a wakeup-capable RTC alarm.
2203
Linus Torvalds1da177e2005-04-16 15:20:36 -07002204 thash_entries= [KNL,NET]
2205 Set number of hash buckets for TCP connection
2206
Len Brownf8707ec2007-08-12 00:12:54 -04002207 thermal.act= [HW,ACPI]
2208 -1: disable all active trip points in all thermal zones
2209 <degrees C>: override all lowest active trip points
2210
Len Brownc52a7412007-08-14 15:49:32 -04002211 thermal.crt= [HW,ACPI]
2212 -1: disable all critical trip points in all thermal zones
Zhang Rui22a94d72008-10-17 02:41:20 -04002213 <degrees C>: override all critical trip points
Len Brownc52a7412007-08-14 15:49:32 -04002214
Len Brownf5487142007-08-12 00:12:44 -04002215 thermal.nocrt= [HW,ACPI]
2216 Set to disable actions on ACPI thermal zone
2217 critical and hot trip points.
2218
Len Brown72b33ef2007-08-12 00:12:17 -04002219 thermal.off= [HW,ACPI]
2220 1: disable ACPI thermal control
2221
Len Browna70cdc52007-08-12 00:12:35 -04002222 thermal.psv= [HW,ACPI]
2223 -1: disable all passive trip points
2224 <degrees C>: override all passive trip points to this value
2225
Len Brown730ff342007-08-12 00:12:26 -04002226 thermal.tzp= [HW,ACPI]
2227 Specify global default ACPI thermal zone polling rate
2228 <deci-seconds>: poll all this frequency
2229 0: no polling (default)
2230
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231 tmscsim= [HW,SCSI]
2232 See comment before function dc390_setup() in
2233 drivers/scsi/tmscsim.c.
2234
2235 tp720= [HW,PS2]
2236
2237 trix= [HW,OSS] MediaTrix AudioTrix Pro
Randy Dunlapa9913042005-10-23 12:57:11 -07002238 Format:
2239 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2240
Randy Dunlapa9913042005-10-23 12:57:11 -07002241 turbografx.map[2|3]= [HW,JOY]
2242 TurboGraFX parallel port interface
2243 Format:
2244 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002245 See also Documentation/input/joystick-parport.txt
2246
2247 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2248 See header of drivers/scsi/u14-34f.c.
2249
2250 uart401= [HW,OSS]
2251 Format: <io>,<irq>
2252
2253 uart6850= [HW,OSS]
2254 Format: <io>,<irq>
2255
Alan Stern5f8364b2006-12-05 16:29:55 -05002256 uhci-hcd.ignore_oc=
2257 [USB] Ignore overcurrent events (default N).
2258 Some badly-designed motherboards generate lots of
2259 bogus events, for ports that aren't wired to
2260 anything. Set this parameter to avoid log spamming.
2261 Note that genuine overcurrent events won't be
2262 reported either.
2263
Simon Arlotte3a61b02008-07-19 23:32:54 +01002264 unknown_nmi_panic
2265 [X86-32,X86-64]
2266 Set unknown_nmi_panic=1 early on boot.
2267
Alan Sternb5e795f2007-02-20 15:00:53 -05002268 usbcore.autosuspend=
2269 [USB] The autosuspend time delay (in seconds) used
2270 for newly-detected USB devices (default 2). This
2271 is the time required before an idle device will be
2272 autosuspended. Devices for which the delay is set
Alan Sterneaafbc32007-03-13 16:39:15 -04002273 to a negative value won't be autosuspended at all.
Alan Sternb5e795f2007-02-20 15:00:53 -05002274
Jaroslav Kyselafd7c5192008-10-10 16:24:45 +02002275 usbcore.usbfs_snoop=
2276 [USB] Set to log all usbfs traffic (default 0 = off).
2277
2278 usbcore.blinkenlights=
2279 [USB] Set to cycle leds on hubs (default 0 = off).
2280
2281 usbcore.old_scheme_first=
2282 [USB] Start with the old device initialization
2283 scheme (default 0 = off).
2284
2285 usbcore.use_both_schemes=
2286 [USB] Try the other device initialization scheme
2287 if the first one fails (default 1 = enabled).
2288
2289 usbcore.initial_descriptor_timeout=
2290 [USB] Specifies timeout for the initial 64-byte
2291 USB_REQ_GET_DESCRIPTOR request in milliseconds
2292 (default 5000 = 5.0 seconds).
2293
Linus Torvalds1da177e2005-04-16 15:20:36 -07002294 usbhid.mousepoll=
2295 [USBHID] The interval which mice are to be polled at.
Randy Dunlapa9913042005-10-23 12:57:11 -07002296
Paul Jackson200001e2008-06-25 05:44:46 -07002297 add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
2298 kernel's map of available physical RAM.
2299
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002300 vdso= [X86-32,SH,x86-64]
Jeremy Fitzhardinge1dbf527c2007-05-02 19:27:12 +02002301 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
Ingo Molnare6e54942006-06-27 02:53:50 -07002302 vdso=1: enable VDSO (default)
2303 vdso=0: disable VDSO mapping
2304
Roland McGrathaf65d642008-01-30 13:30:43 +01002305 vdso32= [X86-32,X86-64]
2306 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2307 vdso32=1: enable 32-bit VDSO (default)
2308 vdso32=0: disable 32-bit VDSO mapping
2309
Yasuaki Ishimatsud080d392007-07-17 21:22:55 +09002310 vector= [IA-64,SMP]
2311 vector=percpu: enable percpu vector domain
2312
Linus Torvalds1da177e2005-04-16 15:20:36 -07002313 video= [FB] Frame buffer configuration
2314 See Documentation/fb/modedb.txt.
2315
Alan Coxcd4f0ef2007-07-31 00:37:59 -07002316 vga= [BOOT,X86-32] Select a particular video mode
Randy Dunlapa9913042005-10-23 12:57:11 -07002317 See Documentation/i386/boot.txt and
2318 Documentation/svga.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002319 Use vga=ask for menu.
2320 This is actually a boot loader parameter; the value is
2321 passed to the kernel using a special protocol.
2322
Randy Dunlapa9913042005-10-23 12:57:11 -07002323 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
Linus Torvalds1da177e2005-04-16 15:20:36 -07002324 size of <nn>. This can be used to increase the
2325 minimum size (128MB on x86). It can also be used to
2326 decrease the size and leave more room for directly
2327 mapped kernel RAM.
2328
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002329 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2330 Format: <command>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002331
Peter Oberparleiter585c3042006-06-29 15:08:25 +02002332 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2333 Format: <command>
2334
2335 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2336 Format: <command>
Randy Dunlapa9913042005-10-23 12:57:11 -07002337
Linus Torvalds1da177e2005-04-16 15:20:36 -07002338 waveartist= [HW,OSS]
2339 Format: <io>,<irq>,<dma>,<dma2>
Randy Dunlapa9913042005-10-23 12:57:11 -07002340
Linus Torvalds1da177e2005-04-16 15:20:36 -07002341 wd33c93= [HW,SCSI]
2342 See header of drivers/scsi/wd33c93.c.
2343
2344 wd7000= [HW,SCSI]
2345 See header of drivers/scsi/wd7000.c.
2346
2347 wdt= [WDT] Watchdog
Gabriel C8dfe9c22007-08-10 13:01:00 -07002348 See Documentation/watchdog/wdt.txt.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002349
2350 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2351 xd_geo= See header of drivers/block/xd.c.
2352
2353 xirc2ps_cs= [NET,PCMCIA]
Randy Dunlapa9913042005-10-23 12:57:11 -07002354 Format:
2355 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
Linus Torvalds1da177e2005-04-16 15:20:36 -07002356
Andi Kleena62eaf12006-02-16 23:41:58 +01002357 norandmaps Don't use address space randomization
2358 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2359
Randy Dunlapa9913042005-10-23 12:57:11 -07002360______________________________________________________________________
Linus Torvalds1da177e2005-04-16 15:20:36 -07002361
2362TODO:
2363
2364 Add documentation for ALSA options.
2365 Add more DRM drivers.