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[GitHub/mt8127/android_kernel_alcatel_ttab.git] / Documentation / kernel-parameters.txt
1 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
3
4 The 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
7 case insensitive manner), and with descriptions where known.
8
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
11
12 modprobe usbcore blinkenlights=1
13
14 Module parameters for modules that are built into the kernel image
15 are 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
20 This document may not be entirely up to date and comprehensive. The command
21 "modinfo -p ${modulename}" shows a current list of all parameters of a loadable
22 module. Loadable modules, after being loaded into the running kernel, also
23 reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
24 parameters may be changed at runtime by the command
25 "echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
26
27 The parameters listed below are only valid if certain kernel build options were
28 enabled and if respective hardware is present. The text in square brackets at
29 the beginning of each description states the restrictions within which a
30 parameter is applicable:
31
32 ACPI ACPI support is enabled.
33 AGP AGP (Accelerated Graphics Port) is enabled.
34 ALSA ALSA sound support is enabled.
35 APIC APIC support is enabled.
36 APM Advanced Power Management support is enabled.
37 AVR32 AVR32 architecture is enabled.
38 AX25 Appropriate AX.25 support is enabled.
39 BLACKFIN Blackfin architecture is enabled.
40 DRM Direct Rendering Management support is enabled.
41 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.
46 IA-64 IA-64 architecture is enabled.
47 IOSCHED More than one I/O scheduler is enabled.
48 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
49 ISAPNP ISA PnP code is enabled.
50 ISDN Appropriate ISDN support is enabled.
51 JOY Appropriate joystick support is enabled.
52 LIBATA Libata driver is enabled
53 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.
61 MSI Message Signaled Interrupts (PCI).
62 MTD MTD (Memory Technology Device) support is enabled.
63 NET Appropriate network support is enabled.
64 NUMA NUMA support is enabled.
65 GENERIC_TIME The generic timeofday code is enabled.
66 NFS Appropriate NFS support is enabled.
67 OSS OSS sound support is enabled.
68 PV_OPS A paravirtualized kernel is enabled.
69 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
70 PARISC The PA-RISC architecture is enabled.
71 PCI PCI bus support is enabled.
72 PCIE PCI Express support is enabled.
73 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.
79 ROOTPLUG The example Root Plug LSM is enabled.
80 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/.
84 SECURITY Different security models are enabled.
85 SELINUX SELinux support is enabled.
86 SERIAL Serial support is enabled.
87 SH SuperH architecture is enabled.
88 SMP The kernel is an SMP kernel.
89 SPARC Sparc architecture is enabled.
90 SWSUSP Software suspend is enabled.
91 TS Appropriate touchscreen support is enabled.
92 USB USB support is enabled.
93 USBHID USB Human Interface Device support is enabled.
94 V4L Video For Linux support is enabled.
95 VGA The VGA console has been enabled.
96 VT Virtual terminal support is enabled.
97 WDT Watchdog support is enabled.
98 XT IBM PC/XT MFM hard disk support is enabled.
99 X86-32 X86-32, aka i386 architecture is enabled.
100 X86-64 X86-64 architecture is enabled.
101 More X86-64 boot options can be found in
102 Documentation/x86_64/boot-options.txt .
103
104 In addition, the following text indicates that the option:
105
106 BUGS= Relates to possible processor bugs on the said processor.
107 KNL Is a kernel start-up parameter.
108 BOOT Is a boot loader parameter.
109
110 Parameters denoted with BOOT are actually interpreted by the boot
111 loader, and have no meaning to the kernel directly.
112 Do not modify the syntax of boot loader parameters without extreme
113 need or coordination with <Documentation/i386/boot.txt>.
114
115 There are also arch-specific kernel-parameters not documented here.
116 See for example <Documentation/x86_64/boot-options.txt>.
117
118 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
119 a trailing = on the name of any parameter states that that parameter will
120 be entered as an environment variable, whereas its absence indicates that
121 it will appear as a kernel argument readable via /proc/cmdline by programs
122 running once the system is up.
123
124 The number of kernel parameters is not limited, but the length of the
125 complete command line (parameters including spaces etc.) is limited to
126 a fixed number of characters. This limit depends on the architecture
127 and is between 256 and 4096 characters. It is defined in the file
128 ./include/asm/setup.h as COMMAND_LINE_SIZE.
129
130
131 acpi= [HW,ACPI,X86-64,i386]
132 Advanced Configuration and Power Interface
133 Format: { force | off | ht | strict | noirq }
134 force -- enable ACPI if default was off
135 off -- disable ACPI if default was on
136 noirq -- do not use ACPI for IRQ routing
137 ht -- run only enough ACPI to enable Hyper Threading
138 strict -- Be less tolerant of platforms that are not
139 strictly ACPI specification compliant.
140
141 See also Documentation/power/pm.txt, pci=noacpi
142
143 acpi_apic_instance= [ACPI, IOAPIC]
144 Format: <int>
145 2: use 2nd APIC table, if available
146 1,0: use 1st APIC table
147 default: 0
148
149 acpi_sleep= [HW,ACPI] Sleep options
150 Format: { s3_bios, s3_mode, s3_beep }
151 See Documentation/power/video.txt for s3_bios and s3_mode.
152 s3_beep is for debugging; it makes the PC's speaker beep
153 as soon as the kernel's real-mode entry point is called.
154
155 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
156 Format: { level | edge | high | low }
157
158 acpi_irq_balance [HW,ACPI]
159 ACPI will balance active IRQs
160 default in APIC mode
161
162 acpi_irq_nobalance [HW,ACPI]
163 ACPI will not move active IRQs (default)
164 default in PIC mode
165
166 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
167 use by PCI
168 Format: <irq>,<irq>...
169
170 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
171 Format: <irq>,<irq>...
172
173 acpi_new_pts_ordering [HW,ACPI]
174 Enforce the ACPI 2.0 ordering of the _PTS control
175 method wrt putting devices into low power states
176 default: pre ACPI 2.0 ordering of _PTS
177
178 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
179
180 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
181 Format: To spoof as Windows 98: ="Microsoft Windows"
182
183 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
184 acpi_osi="string1" # add string1 -- only one string
185 acpi_osi="!string2" # remove built-in string2
186 acpi_osi= # disable all strings
187
188 acpi_serialize [HW,ACPI] force serialization of AML methods
189
190 acpi_skip_timer_override [HW,ACPI]
191 Recognize and ignore IRQ0/pin2 Interrupt Override.
192 For broken nForce2 BIOS resulting in XT-PIC timer.
193 acpi_use_timer_override [HW,ACPI}
194 Use timer override. For some broken Nvidia NF5 boards
195 that require a timer override, but don't have
196 HPET
197
198 acpi.debug_layer= [HW,ACPI]
199 Format: <int>
200 Each bit of the <int> indicates an ACPI debug layer,
201 1: enable, 0: disable. It is useful for boot time
202 debugging. After system has booted up, it can be set
203 via /sys/module/acpi/parameters/debug_layer.
204 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
205 Available bits (add the numbers together) to enable debug output
206 for specific parts of the ACPI subsystem:
207 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
208 0x10 namespace 0x20 parser 0x40 dispatcher
209 0x80 executer 0x100 resources 0x200 acpica debugger
210 0x400 os services 0x800 acpica disassembler.
211 The number can be in decimal or prefixed with 0x in hex.
212 Warning: Many of these options can produce a lot of
213 output and make your system unusable. Be very careful.
214
215 acpi.debug_level= [HW,ACPI]
216 Format: <int>
217 Each bit of the <int> indicates an ACPI debug level,
218 1: enable, 0: disable. It is useful for boot time
219 debugging. After system has booted up, it can be set
220 via /sys/module/acpi/parameters/debug_level.
221 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
222 Available bits (add the numbers together) to enable different
223 debug output levels of the ACPI subsystem:
224 0x01 error 0x02 warn 0x04 init 0x08 debug object
225 0x10 info 0x20 init names 0x40 parse 0x80 load
226 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
227 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
228 0x10000 resources 0x20000 user requests 0x40000 package.
229 The number can be in decimal or prefixed with 0x in hex.
230 Warning: Many of these options can produce a lot of
231 output and make your system unusable. Be very careful.
232
233 acpi_pm_good [X86-32,X86-64]
234 Override the pmtimer bug detection: force the kernel
235 to assume that this machine's pmtimer latches its value
236 and always returns good values.
237
238 agp= [AGP]
239 { off | try_unsupported }
240 off: disable AGP support
241 try_unsupported: try to drive unsupported chipsets
242 (may crash computer or cause data corruption)
243
244 enable_timer_pin_1 [i386,x86-64]
245 Enable PIN 1 of APIC timer
246 Can be useful to work around chipset bugs
247 (in particular on some ATI chipsets).
248 The kernel tries to set a reasonable default.
249
250 disable_timer_pin_1 [i386,x86-64]
251 Disable PIN 1 of APIC timer
252 Can be useful to work around chipset bugs.
253
254 ad1848= [HW,OSS]
255 Format: <io>,<irq>,<dma>,<dma2>,<type>
256
257 advansys= [HW,SCSI]
258 See header of drivers/scsi/advansys.c.
259
260 advwdt= [HW,WDT] Advantech WDT
261 Format: <iostart>,<iostop>
262
263 aedsp16= [HW,OSS] Audio Excel DSP 16
264 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
265 See also header of sound/oss/aedsp16.c.
266
267 aha152x= [HW,SCSI]
268 See Documentation/scsi/aha152x.txt.
269
270 aha1542= [HW,SCSI]
271 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
272
273 aic7xxx= [HW,SCSI]
274 See Documentation/scsi/aic7xxx.txt.
275
276 aic79xx= [HW,SCSI]
277 See Documentation/scsi/aic79xx.txt.
278
279 amijoy.map= [HW,JOY] Amiga joystick support
280 Map of devices attached to JOY0DAT and JOY1DAT
281 Format: <a>,<b>
282 See also Documentation/kernel/input/joystick.txt
283
284 analog.map= [HW,JOY] Analog joystick and gamepad support
285 Specifies type or capabilities of an analog joystick
286 connected to one of 16 gameports
287 Format: <type1>,<type2>,..<type16>
288
289 apc= [HW,SPARC]
290 Power management functions (SPARCstation-4/5 + deriv.)
291 Format: noidle
292 Disable APC CPU standby support. SPARCstation-Fox does
293 not play well with APC CPU idle - disable it if you have
294 APC and your system crashes randomly.
295
296 apic= [APIC,i386] Advanced Programmable Interrupt Controller
297 Change the output verbosity whilst booting
298 Format: { quiet (default) | verbose | debug }
299 Change the amount of debugging information output
300 when initialising the APIC and IO-APIC components.
301
302 apm= [APM] Advanced Power Management
303 See header of arch/i386/kernel/apm.c.
304
305 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
306 Format: <io>,<irq>,<nodeID>
307
308 ataflop= [HW,M68k]
309
310 atarimouse= [HW,MOUSE] Atari Mouse
311
312 atascsi= [HW,SCSI] Atari SCSI
313
314 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
315 EzKey and similar keyboards
316
317 atkbd.reset= [HW] Reset keyboard during initialization
318
319 atkbd.set= [HW] Select keyboard code set
320 Format: <int> (2 = AT (default), 3 = PS/2)
321
322 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
323 keyboards
324
325 atkbd.softraw= [HW] Choose between synthetic and real raw mode
326 Format: <bool> (0 = real, 1 = synthetic (default))
327
328 atkbd.softrepeat= [HW]
329 Use software keyboard repeat
330
331 autotest [IA64]
332
333 baycom_epp= [HW,AX25]
334 Format: <io>,<mode>
335
336 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
337 Format: <io>,<mode>
338 See header of drivers/net/hamradio/baycom_par.c.
339
340 baycom_ser_fdx= [HW,AX25]
341 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
342 Format: <io>,<irq>,<mode>[,<baud>]
343 See header of drivers/net/hamradio/baycom_ser_fdx.c.
344
345 baycom_ser_hdx= [HW,AX25]
346 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
347 Format: <io>,<irq>,<mode>
348 See header of drivers/net/hamradio/baycom_ser_hdx.c.
349
350 boot_delay= Milliseconds to delay each printk during boot.
351 Values larger than 10 seconds (10000) are changed to
352 no delay (0).
353 Format: integer
354
355 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
356 bttv.radio= Most important insmod options are available as
357 kernel args too.
358 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
359 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
360
361 BusLogic= [HW,SCSI]
362 See drivers/scsi/BusLogic.c, comment before function
363 BusLogic_ParseDriverOptions().
364
365 c101= [NET] Moxa C101 synchronous serial card
366
367 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
368 Sometimes CPU hardware bugs make them report the cache
369 size incorrectly. The kernel will attempt work arounds
370 to fix known problems, but for some CPUs it is not
371 possible to determine what the correct size should be.
372 This option provides an override for these situations.
373
374 capability.disable=
375 [SECURITY] Disable capabilities. This would normally
376 be used only if an alternative security model is to be
377 configured. Potentially dangerous and should only be
378 used if you are entirely sure of the consequences.
379
380 ccw_timeout_log [S390]
381 See Documentation/s390/CommonIO for details.
382
383 checkreqprot [SELINUX] Set initial checkreqprot flag value.
384 Format: { "0" | "1" }
385 See security/selinux/Kconfig help text.
386 0 -- check protection applied by kernel (includes
387 any implied execute protection).
388 1 -- check protection requested by application.
389 Default value is set via a kernel config option.
390 Value can be changed at runtime via
391 /selinux/checkreqprot.
392
393 cio_ignore= [S390]
394 See Documentation/s390/CommonIO for details.
395
396 cio_msg= [S390]
397 See Documentation/s390/CommonIO for details.
398
399 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
400 [Deprecated]
401 Forces specified clocksource (if available) to be used
402 when calculating gettimeofday(). If specified
403 clocksource is not available, it defaults to PIT.
404 Format: { pit | tsc | cyclone | pmtmr }
405
406 clocksource= [GENERIC_TIME] Override the default clocksource
407 Format: <string>
408 Override the default clocksource and use the clocksource
409 with the name specified.
410 Some clocksource names to choose from, depending on
411 the platform:
412 [all] jiffies (this is the base, fallback clocksource)
413 [ACPI] acpi_pm
414 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
415 pxa_timer,timer3,32k_counter,timer0_1
416 [AVR32] avr32
417 [X86-32] pit,hpet,tsc,vmi-timer;
418 scx200_hrt on Geode; cyclone on IBM x440
419 [MIPS] MIPS
420 [PARISC] cr16
421 [S390] tod
422 [SH] SuperH
423 [SPARC64] tick
424 [X86-64] hpet,tsc
425
426 clearcpuid=BITNUM [X86]
427 Disable CPUID feature X for the kernel. See
428 include/asm-x86/cpufeature.h for the valid bit numbers.
429 Note the Linux specific bits are not necessarily
430 stable over kernel options, but the vendor specific
431 ones should be.
432 Also note that user programs calling CPUID directly
433 or using the feature without checking anything
434 will still see it. This just prevents it from
435 being used by the kernel or shown in /proc/cpuinfo.
436 Also note the kernel might malfunction if you disable
437 some critical bits.
438
439 code_bytes [IA32/X86_64] How many bytes of object code to print
440 in an oops report.
441 Range: 0 - 8192
442 Default: 64
443
444 disable_8254_timer
445 enable_8254_timer
446 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
447 over the 8254 in addition to over the IO-APIC. The
448 kernel tries to set a sensible default.
449
450 hpet= [X86-32,HPET] option to control HPET usage
451 Format: { enable (default) | disable | force }
452 disable: disable HPET and use PIT instead
453 force: allow force enabled of undocumented chips (ICH4,
454 VIA, nVidia)
455
456 com20020= [HW,NET] ARCnet - COM20020 chipset
457 Format:
458 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
459
460 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
461 Format: <io>[,<irq>]
462
463 com90xx= [HW,NET]
464 ARCnet - COM90xx chipset (memory-mapped buffers)
465 Format: <io>[,<irq>[,<memstart>]]
466
467 condev= [HW,S390] console device
468 conmode=
469
470 console= [KNL] Output console device and options.
471
472 tty<n> Use the virtual console device <n>.
473
474 ttyS<n>[,options]
475 ttyUSB0[,options]
476 Use the specified serial port. The options are of
477 the form "bbbbpnf", where "bbbb" is the baud rate,
478 "p" is parity ("n", "o", or "e"), "n" is number of
479 bits, and "f" is flow control ("r" for RTS or
480 omit it). Default is "9600n8".
481
482 See Documentation/serial-console.txt for more
483 information. See
484 Documentation/networking/netconsole.txt for an
485 alternative.
486
487 uart[8250],io,<addr>[,options]
488 uart[8250],mmio,<addr>[,options]
489 Start an early, polled-mode console on the 8250/16550
490 UART at the specified I/O port or MMIO address,
491 switching to the matching ttyS device later. The
492 options are the same as for ttyS, above.
493
494 earlycon= [KNL] Output early console device and options.
495 uart[8250],io,<addr>[,options]
496 uart[8250],mmio,<addr>[,options]
497 Start an early, polled-mode console on the 8250/16550
498 UART at the specified I/O port or MMIO address.
499 The options are the same as for ttyS, above.
500
501 no_console_suspend
502 [HW] Never suspend the console
503 Disable suspending of consoles during suspend and
504 hibernate operations. Once disabled, debugging
505 messages can reach various consoles while the rest
506 of the system is being put to sleep (ie, while
507 debugging driver suspend/resume hooks). This may
508 not work reliably with all consoles, but is known
509 to work with serial and VGA consoles.
510
511 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
512 Format:
513 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
514
515 crashkernel=nn[KMG]@ss[KMG]
516 [KNL] Reserve a chunk of physical memory to
517 hold a kernel to switch to with kexec on panic.
518
519 crashkernel=range1:size1[,range2:size2,...][@offset]
520 [KNL] Same as above, but depends on the memory
521 in the running system. The syntax of range is
522 start-[end] where start and end are both
523 a memory unit (amount[KMG]). See also
524 Documentation/kdump/kdump.txt for a example.
525
526 cs4232= [HW,OSS]
527 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
528
529 cs89x0_dma= [HW,NET]
530 Format: <dma>
531
532 cs89x0_media= [HW,NET]
533 Format: { rj45 | aui | bnc }
534
535 dasd= [HW,NET]
536 See header of drivers/s390/block/dasd_devmap.c.
537
538 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
539 (one device per port)
540 Format: <port#>,<type>
541 See also Documentation/input/joystick-parport.txt
542
543 debug [KNL] Enable kernel debugging (events log level).
544
545 debug_locks_verbose=
546 [KNL] verbose self-tests
547 Format=<0|1>
548 Print debugging info while doing the locking API
549 self-tests.
550 We default to 0 (no extra messages), setting it to
551 1 will print _a lot_ more information - normally
552 only useful to kernel developers.
553
554 decnet.addr= [HW,NET]
555 Format: <area>[,<node>]
556 See also Documentation/networking/decnet.txt.
557
558 vt.default_blu= [VT]
559 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
560 Change the default blue palette of the console.
561 This is a 16-member array composed of values
562 ranging from 0-255.
563
564 vt.default_grn= [VT]
565 Format: <green0>,<green1>,<green2>,...,<green15>
566 Change the default green palette of the console.
567 This is a 16-member array composed of values
568 ranging from 0-255.
569
570 vt.default_red= [VT]
571 Format: <red0>,<red1>,<red2>,...,<red15>
572 Change the default red palette of the console.
573 This is a 16-member array composed of values
574 ranging from 0-255.
575
576 vt.default_utf8=
577 [VT]
578 Format=<0|1>
579 Set system-wide default UTF-8 mode for all tty's.
580 Default is 1, i.e. UTF-8 mode is enabled for all
581 newly opened terminals.
582
583 dhash_entries= [KNL]
584 Set number of hash buckets for dentry cache.
585
586 digi= [HW,SERIAL]
587 IO parameters + enable/disable command.
588
589 digiepca= [HW,SERIAL]
590 See drivers/char/README.epca and
591 Documentation/digiepca.txt.
592
593 disable_mtrr_trim [X86, Intel and AMD only]
594 By default the kernel will trim any uncacheable
595 memory out of your available memory pool based on
596 MTRR settings. This parameter disables that behavior,
597 possibly causing your machine to run very slowly.
598
599 dmasound= [HW,OSS] Sound subsystem buffers
600
601 dscc4.setup= [NET]
602
603 dtc3181e= [HW,SCSI]
604
605 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
606 earlyprintk=vga
607 earlyprintk=serial[,ttySn[,baudrate]]
608
609 Append ",keep" to not disable it when the real console
610 takes over.
611
612 Only vga or serial at a time, not both.
613
614 Currently only ttyS0 and ttyS1 are supported.
615
616 Interaction with the standard serial driver is not
617 very good.
618
619 The VGA output is eventually overwritten by the real
620 console.
621
622 eata= [HW,SCSI]
623
624 edd= [EDD]
625 Format: {"of[f]" | "sk[ipmbr]"}
626 See comment in arch/i386/boot/edd.S
627
628 eisa_irq_edge= [PARISC,HW]
629 See header of drivers/parisc/eisa.c.
630
631 elanfreq= [X86-32]
632 See comment before function elanfreq_setup() in
633 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
634
635 elevator= [IOSCHED]
636 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
637 See Documentation/block/as-iosched.txt and
638 Documentation/block/deadline-iosched.txt for details.
639
640 elfcorehdr= [X86-32, X86_64]
641 Specifies physical address of start of kernel core
642 image elf header. Generally kexec loader will
643 pass this option to capture kernel.
644 See Documentation/kdump/kdump.txt for details.
645
646 enforcing [SELINUX] Set initial enforcing status.
647 Format: {"0" | "1"}
648 See security/selinux/Kconfig help text.
649 0 -- permissive (log only, no denials).
650 1 -- enforcing (deny and log).
651 Default value is 0.
652 Value can be changed at runtime via /selinux/enforce.
653
654 es1371= [HW,OSS]
655 Format: <spdif>,[<nomix>,[<amplifier>]]
656 See also header of sound/oss/es1371.c.
657
658 ether= [HW,NET] Ethernet cards parameters
659 This option is obsoleted by the "netdev=" option, which
660 has equivalent usage. See its documentation for details.
661
662 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
663 Format: <io>[,<irq>]
664
665 failslab=
666 fail_page_alloc=
667 fail_make_request=[KNL]
668 General fault injection mechanism.
669 Format: <interval>,<probability>,<space>,<times>
670 See also /Documentation/fault-injection/.
671
672 fd_mcs= [HW,SCSI]
673 See header of drivers/scsi/fd_mcs.c.
674
675 fdomain= [HW,SCSI]
676 See header of drivers/scsi/fdomain.c.
677
678 floppy= [HW]
679 See Documentation/floppy.txt.
680
681 gamecon.map[2|3]=
682 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
683 support via parallel port (up to 5 devices per port)
684 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
685 See also Documentation/input/joystick-parport.txt
686
687 gamma= [HW,DRM]
688
689 gart_fix_e820= [X86_64] disable the fix e820 for K8 GART
690 Format: off | on
691 default: on
692
693 gdth= [HW,SCSI]
694 See header of drivers/scsi/gdth.c.
695
696 gpt [EFI] Forces disk with valid GPT signature but
697 invalid Protective MBR to be treated as GPT.
698
699 gvp11= [HW,SCSI]
700
701 hashdist= [KNL,NUMA] Large hashes allocated during boot
702 are distributed across NUMA nodes. Defaults on
703 for IA-64, off otherwise.
704 Format: 0 | 1 (for off | on)
705
706 hcl= [IA-64] SGI's Hardware Graph compatibility layer
707
708 hd= [EIDE] (E)IDE hard drive subsystem geometry
709 Format: <cyl>,<head>,<sect>
710
711 hd?= [HW] (E)IDE subsystem
712 hd?lun= See Documentation/ide/ide.txt.
713
714 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
715 size of <nn>. This works even on boxes that have no
716 highmem otherwise. This also works to reduce highmem
717 size on bigger boxes.
718
719 highres= [KNL] Enable/disable high resolution timer mode.
720 Valid parameters: "on", "off"
721 Default: "on"
722
723 hisax= [HW,ISDN]
724 See Documentation/isdn/README.HiSax.
725
726 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
727 hugepagesz= [HW,IA-64,PPC] The size of the HugeTLB pages.
728
729 i8042.direct [HW] Put keyboard port into non-translated mode
730 i8042.dumbkbd [HW] Pretend that controller can only read data from
731 keyboard and cannot control its state
732 (Don't attempt to blink the leds)
733 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
734 i8042.nokbd [HW] Don't check/create keyboard port
735 i8042.noloop [HW] Disable the AUX Loopback command while probing
736 for the AUX port
737 i8042.nomux [HW] Don't check presence of an active multiplexing
738 controller
739 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
740 controllers
741 i8042.panicblink=
742 [HW] Frequency with which keyboard LEDs should blink
743 when kernel panics (default is 0.5 sec)
744 i8042.reset [HW] Reset the controller during init and cleanup
745 i8042.unlock [HW] Unlock (ignore) the keylock
746
747 i810= [HW,DRM]
748
749 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
750 indicates that the driver is running on unsupported
751 hardware.
752 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
753 does not match list of supported models.
754 i8k.power_status
755 [HW] Report power status in /proc/i8k
756 (disabled by default)
757 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
758 capability is set.
759
760 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
761 See Documentation/mca.txt.
762
763 icn= [HW,ISDN]
764 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
765
766 ide= [HW] (E)IDE subsystem
767 Format: ide=nodma or ide=doubler or ide=reverse
768 See Documentation/ide/ide.txt.
769
770 ide?= [HW] (E)IDE subsystem
771 Format: ide?=noprobe or chipset specific parameters.
772 See Documentation/ide/ide.txt.
773
774 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
775 See Documentation/ide/ide.txt.
776
777 idle= [X86]
778 Format: idle=poll or idle=mwait
779 Poll forces a polling idle loop that can slightly improves the performance
780 of waking up a idle CPU, but will use a lot of power and make the system
781 run hot. Not recommended.
782 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
783 to not use it because it doesn't save as much power as a normal idle
784 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
785 as idle=poll.
786
787 ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
788 Claim all unknown PCI IDE storage controllers.
789
790 ignore_loglevel [KNL]
791 Ignore loglevel setting - this will print /all/
792 kernel messages to the console. Useful for debugging.
793
794 ihash_entries= [KNL]
795 Set number of hash buckets for inode cache.
796
797 in2000= [HW,SCSI]
798 See header of drivers/scsi/in2000.c.
799
800 init= [KNL]
801 Format: <full_path>
802 Run specified binary instead of /sbin/init as init
803 process.
804
805 initcall_debug [KNL] Trace initcalls as they are executed. Useful
806 for working out where the kernel is dying during
807 startup.
808
809 initrd= [BOOT] Specify the location of the initial ramdisk
810
811 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
812 Format: <irq>
813
814 inttest= [IA64]
815
816 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
817 off
818 Disable intel iommu driver.
819 igfx_off [Default Off]
820 By default, gfx is mapped as normal device. If a gfx
821 device has a dedicated DMAR unit, the DMAR unit is
822 bypassed by not enabling DMAR with this option. In
823 this case, gfx device will use physical address for
824 DMA.
825 forcedac [x86_64]
826 With this option iommu will not optimize to look
827 for io virtual address below 32 bit forcing dual
828 address cycle on pci bus for cards supporting greater
829 than 32 bit addressing. The default is to look
830 for translation below 32 bit and if not available
831 then look in the higher range.
832
833 io_delay= [X86-32,X86-64] I/O delay method
834 0x80
835 Standard port 0x80 based delay
836 0xed
837 Alternate port 0xed based delay (needed on some systems)
838 udelay
839 Simple two microseconds delay
840 none
841 No delay
842
843 io7= [HW] IO7 for Marvel based alpha systems
844 See comment before marvel_specify_io7 in
845 arch/alpha/kernel/core_marvel.c.
846
847 ip= [IP_PNP]
848 See Documentation/nfsroot.txt.
849
850 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
851 See comment before ip2_setup() in
852 drivers/char/ip2/ip2base.c.
853
854 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
855 See header of drivers/scsi/ips.c.
856
857 ports= [IP_VS_FTP] IPVS ftp helper module
858 Default is 21.
859 Up to 8 (IP_VS_APP_MAX_PORTS) ports
860 may be specified.
861 Format: <port>,<port>....
862
863 irqfixup [HW]
864 When an interrupt is not handled search all handlers
865 for it. Intended to get systems with badly broken
866 firmware running.
867
868 irqpoll [HW]
869 When an interrupt is not handled search all handlers
870 for it. Also check all handlers each timer
871 interrupt. Intended to get systems with badly broken
872 firmware running.
873
874 isapnp= [ISAPNP]
875 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
876
877 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
878 Format:
879 <cpu number>,...,<cpu number>
880 or
881 <cpu number>-<cpu number> (must be a positive range in ascending order)
882 or a mixture
883 <cpu number>,...,<cpu number>-<cpu number>
884 This option can be used to specify one or more CPUs
885 to isolate from the general SMP balancing and scheduling
886 algorithms. The only way to move a process onto or off
887 an "isolated" CPU is via the CPU affinity syscalls.
888 <cpu number> begins at 0 and the maximum value is
889 "number of CPUs in system - 1".
890
891 This option is the preferred way to isolate CPUs. The
892 alternative -- manually setting the CPU mask of all
893 tasks in the system -- can cause problems and
894 suboptimal load balancer performance.
895
896 iucv= [HW,NET]
897
898 js= [HW,JOY] Analog joystick
899 See Documentation/input/joystick.txt.
900
901 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
902 specifies the amount of memory usable by the kernel
903 for non-movable allocations. The requested amount is
904 spread evenly throughout all nodes in the system. The
905 remaining memory in each node is used for Movable
906 pages. In the event, a node is too small to have both
907 kernelcore and Movable pages, kernelcore pages will
908 take priority and other nodes will have a larger number
909 of kernelcore pages. The Movable zone is used for the
910 allocation of pages that may be reclaimed or moved
911 by the page migration subsystem. This means that
912 HugeTLB pages may not be allocated from this zone.
913 Note that allocations like PTEs-from-HighMem still
914 use the HighMem zone if it exists, and the Normal
915 zone if it does not.
916
917 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
918 is similar to kernelcore except it specifies the
919 amount of memory used for migratable allocations.
920 If both kernelcore and movablecore is specified,
921 then kernelcore will be at *least* the specified
922 value but may be more. If movablecore on its own
923 is specified, the administrator must be careful
924 that the amount of memory usable for all allocations
925 is not too small.
926
927 keepinitrd [HW,ARM]
928
929 kstack=N [X86-32,X86-64] Print N words from the kernel stack
930 in oops dumps.
931
932 l2cr= [PPC]
933
934 lapic [X86-32,APIC] Enable the local APIC even if BIOS
935 disabled it.
936
937 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
938 C2 power state.
939
940 libata.dma= [LIBATA] DMA control
941 libata.dma=0 Disable all PATA and SATA DMA
942 libata.dma=1 PATA and SATA Disk DMA only
943 libata.dma=2 ATAPI (CDROM) DMA only
944 libata.dma=4 Compact Flash DMA only
945 Combinations also work, so libata.dma=3 enables DMA
946 for disks and CDROMs, but not CFs.
947
948 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
949 when set.
950 Format: <int>
951
952 libata.force= [LIBATA] Force configurations. The format is comma
953 separated list of "[ID:]VAL" where ID is
954 PORT[:DEVICE]. PORT and DEVICE are decimal numbers
955 matching port, link or device. Basically, it matches
956 the ATA ID string printed on console by libata. If
957 the whole ID part is omitted, the last PORT and DEVICE
958 values are used. If ID hasn't been specified yet, the
959 configuration applies to all ports, links and devices.
960
961 If only DEVICE is omitted, the parameter applies to
962 the port and all links and devices behind it. DEVICE
963 number of 0 either selects the first device or the
964 first fan-out link behind PMP device. It does not
965 select the host link. DEVICE number of 15 selects the
966 host link and device attached to it.
967
968 The VAL specifies the configuration to force. As long
969 as there's no ambiguity shortcut notation is allowed.
970 For example, both 1.5 and 1.5G would work for 1.5Gbps.
971 The following configurations can be forced.
972
973 * Cable type: 40c, 80c, short40c, unk, ign or sata.
974 Any ID with matching PORT is used.
975
976 * SATA link speed limit: 1.5Gbps or 3.0Gbps.
977
978 * Transfer mode: pio[0-7], mwdma[0-4] and udma[0-7].
979 udma[/][16,25,33,44,66,100,133] notation is also
980 allowed.
981
982 * [no]ncq: Turn on or off NCQ.
983
984 If there are multiple matching configurations changing
985 the same attribute, the last one is used.
986
987 load_ramdisk= [RAM] List of ramdisks to load from floppy
988 See Documentation/ramdisk.txt.
989
990 lockd.nlm_grace_period=P [NFS] Assign grace period.
991 Format: <integer>
992
993 lockd.nlm_tcpport=N [NFS] Assign TCP port.
994 Format: <integer>
995
996 lockd.nlm_timeout=T [NFS] Assign timeout value.
997 Format: <integer>
998
999 lockd.nlm_udpport=M [NFS] Assign UDP port.
1000 Format: <integer>
1001
1002 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
1003 Format: <irq>
1004
1005 loglevel= All Kernel Messages with a loglevel smaller than the
1006 console loglevel will be printed to the console. It can
1007 also be changed with klogd or other programs. The
1008 loglevels are defined as follows:
1009
1010 0 (KERN_EMERG) system is unusable
1011 1 (KERN_ALERT) action must be taken immediately
1012 2 (KERN_CRIT) critical conditions
1013 3 (KERN_ERR) error conditions
1014 4 (KERN_WARNING) warning conditions
1015 5 (KERN_NOTICE) normal but significant condition
1016 6 (KERN_INFO) informational
1017 7 (KERN_DEBUG) debug-level messages
1018
1019 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
1020 Format: { n | nk | nM }
1021 n must be a power of two. The default size
1022 is set in the kernel config file.
1023
1024 logo.nologo [FB] Disables display of the built-in Linux logo.
1025 This may be used to provide more screen space for
1026 kernel log messages and is useful when debugging
1027 kernel boot problems.
1028
1029 lp=0 [LP] Specify parallel ports to use, e.g,
1030 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
1031 lp=reset first parallel port). 'lp=0' disables the
1032 lp=auto printer driver. 'lp=reset' (which can be
1033 specified in addition to the ports) causes
1034 attached printers to be reset. Using
1035 lp=port1,port2,... specifies the parallel ports
1036 to associate lp devices with, starting with
1037 lp0. A port specification may be 'none' to skip
1038 that lp device, or a parport name such as
1039 'parport0'. Specifying 'lp=auto' instead of a
1040 port specification list means that device IDs
1041 from each port should be examined, to see if
1042 an IEEE 1284-compliant printer is attached; if
1043 so, the driver will manage that printer.
1044 See also header of drivers/char/lp.c.
1045
1046 lpj=n [KNL]
1047 Sets loops_per_jiffy to given constant, thus avoiding
1048 time-consuming boot-time autodetection (up to 250 ms per
1049 CPU). 0 enables autodetection (default). To determine
1050 the correct value for your kernel, boot with normal
1051 autodetection and see what value is printed. Note that
1052 on SMP systems the preset will be applied to all CPUs,
1053 which is likely to cause problems if your CPUs need
1054 significantly divergent settings. An incorrect value
1055 will cause delays in the kernel to be wrong, leading to
1056 unpredictable I/O errors and other breakage. Although
1057 unlikely, in the extreme case this might damage your
1058 hardware.
1059
1060 ltpc= [NET]
1061 Format: <io>,<irq>,<dma>
1062
1063 mac5380= [HW,SCSI] Format:
1064 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1065
1066 mac53c9x= [HW,SCSI] Format:
1067 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
1068
1069 machvec= [IA64] Force the use of a particular machine-vector
1070 (machvec) in a generic kernel.
1071 Example: machvec=hpzx1_swiotlb
1072
1073 max_loop= [LOOP] Maximum number of loopback devices that can
1074 be mounted
1075 Format: <1-256>
1076
1077 maxcpus= [SMP] Maximum number of processors that an SMP kernel
1078 should make use of. maxcpus=n : n >= 0 limits the
1079 kernel to using 'n' processors. n=0 is a special case,
1080 it is equivalent to "nosmp", which also disables
1081 the IO APIC.
1082
1083 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
1084 equal to this physical address is ignored.
1085
1086 max_luns= [SCSI] Maximum number of LUNs to probe.
1087 Should be between 1 and 2^32-1.
1088
1089 max_report_luns=
1090 [SCSI] Maximum number of LUNs received.
1091 Should be between 1 and 16384.
1092
1093 mcatest= [IA-64]
1094
1095 mce [X86-32] Machine Check Exception
1096
1097 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1098
1099 md= [HW] RAID subsystems devices and level
1100 See Documentation/md.txt.
1101
1102 mdacon= [MDA]
1103 Format: <first>,<last>
1104 Specifies range of consoles to be captured by the MDA.
1105
1106 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1107 Amount of memory to be used when the kernel is not able
1108 to see the whole system memory or for test.
1109 [X86-32] Use together with memmap= to avoid physical
1110 address space collisions. Without memmap= PCI devices
1111 could be placed at addresses belonging to unused RAM.
1112
1113 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1114 memory.
1115
1116 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1117 E820 memory map, as specified by the user.
1118 Such memmap=exactmap lines can be constructed based on
1119 BIOS output or other requirements. See the memmap=nn@ss
1120 option description.
1121
1122 memmap=nn[KMG]@ss[KMG]
1123 [KNL] Force usage of a specific region of memory
1124 Region of memory to be used, from ss to ss+nn.
1125
1126 memmap=nn[KMG]#ss[KMG]
1127 [KNL,ACPI] Mark specific memory as ACPI data.
1128 Region of memory to be used, from ss to ss+nn.
1129
1130 memmap=nn[KMG]$ss[KMG]
1131 [KNL,ACPI] Mark specific memory as reserved.
1132 Region of memory to be used, from ss to ss+nn.
1133
1134 meye.*= [HW] Set MotionEye Camera parameters
1135 See Documentation/video4linux/meye.txt.
1136
1137 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1138 Multi-Function General Purpose Timers on AMD Geode
1139 platforms.
1140
1141 mfgptfix [X86-32] Fix MFGPT timers on AMD Geode platforms when
1142 the BIOS has incorrectly applied a workaround. TinyBIOS
1143 version 0.98 is known to be affected, 0.99 fixes the
1144 problem by letting the user disable the workaround.
1145
1146 mga= [HW,DRM]
1147
1148 mousedev.tap_time=
1149 [MOUSE] Maximum time between finger touching and
1150 leaving touchpad surface for touch to be considered
1151 a tap and be reported as a left button click (for
1152 touchpads working in absolute mode only).
1153 Format: <msecs>
1154 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1155 reporting absolute coordinates, such as tablets
1156 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1157 reporting absolute coordinates, such as tablets
1158
1159 mpu401= [HW,OSS]
1160 Format: <io>,<irq>
1161
1162 MTD_Partition= [MTD]
1163 Format: <name>,<region-number>,<size>,<offset>
1164
1165 MTD_Region= [MTD] Format:
1166 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1167
1168 mtdparts= [MTD]
1169 See drivers/mtd/cmdlinepart.c.
1170
1171 mtouchusb.raw_coordinates=
1172 [HW] Make the MicroTouch USB driver use raw coordinates
1173 ('y', default) or cooked coordinates ('n')
1174
1175 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1176
1177 NCR_D700= [HW,SCSI]
1178 See header of drivers/scsi/NCR_D700.c.
1179
1180 ncr5380= [HW,SCSI]
1181
1182 ncr53c400= [HW,SCSI]
1183
1184 ncr53c400a= [HW,SCSI]
1185
1186 ncr53c406a= [HW,SCSI]
1187
1188 ncr53c8xx= [HW,SCSI]
1189
1190 netdev= [NET] Network devices parameters
1191 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1192 Note that mem_start is often overloaded to mean
1193 something different and driver-specific.
1194 This usage is only documented in each driver source
1195 file if at all.
1196
1197 nfsaddrs= [NFS]
1198 See Documentation/nfsroot.txt.
1199
1200 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1201 See Documentation/nfsroot.txt.
1202
1203 nfs.callback_tcpport=
1204 [NFS] set the TCP port on which the NFSv4 callback
1205 channel should listen.
1206
1207 nfs.idmap_cache_timeout=
1208 [NFS] set the maximum lifetime for idmapper cache
1209 entries.
1210
1211 nfs.enable_ino64=
1212 [NFS] enable 64-bit inode numbers.
1213 If zero, the NFS client will fake up a 32-bit inode
1214 number for the readdir() and stat() syscalls instead
1215 of returning the full 64-bit number.
1216 The default is to return 64-bit inode numbers.
1217
1218 nmi_debug= [KNL,AVR32] Specify one or more actions to take
1219 when a NMI is triggered.
1220 Format: [state][,regs][,debounce][,die]
1221
1222 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1223
1224 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1225 emulation library even if a 387 maths coprocessor
1226 is present.
1227
1228 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1229 caches in the slab allocator. Saves per-node memory,
1230 but will impact performance.
1231
1232 noalign [KNL,ARM]
1233
1234 noapic [SMP,APIC] Tells the kernel to not make use of any
1235 IOAPICs that may be present in the system.
1236
1237 nobats [PPC] Do not use BATs for mapping kernel lowmem
1238 on "Classic" PPC cores.
1239
1240 nocache [ARM]
1241
1242 nodelayacct [KNL] Disable per-task delay accounting
1243
1244 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1245
1246 noefi [X86-32,X86-64] Disable EFI runtime services support.
1247
1248 noexec [IA-64]
1249
1250 noexec [X86-32,X86-64]
1251 noexec=on: enable non-executable mappings (default)
1252 noexec=off: disable nn-executable mappings
1253
1254 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1255 register save and restore. The kernel will only save
1256 legacy floating-point registers on task switch.
1257
1258 noclflush [BUGS=X86] Don't use the CLFLUSH instruction
1259
1260 nohlt [BUGS=ARM]
1261
1262 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1263 instruction doesn't work correctly and not to
1264 use it.
1265
1266 nohalt [IA-64] Tells the kernel not to use the power saving
1267 function PAL_HALT_LIGHT when idle. This increases
1268 power-consumption. On the positive side, it reduces
1269 interrupt wake-up latency, which may improve performance
1270 in certain environments such as networked servers or
1271 real-time systems.
1272
1273 nohz= [KNL] Boottime enable/disable dynamic ticks
1274 Valid arguments: on, off
1275 Default: on
1276
1277 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1278
1279 noirqdebug [X86-32] Disables the code which attempts to detect and
1280 disable unhandled interrupt sources.
1281
1282 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1283 broken timer IRQ sources.
1284
1285 noisapnp [ISAPNP] Disables ISA PnP code.
1286
1287 noinitrd [RAM] Tells the kernel not to load any configured
1288 initial RAM disk.
1289
1290 nointroute [IA-64]
1291
1292 nojitter [IA64] Disables jitter checking for ITC timers.
1293
1294 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1295
1296 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1297
1298 noltlbs [PPC] Do not use large page/tlb entries for kernel
1299 lowmem mapping on PPC40x.
1300
1301 nomca [IA-64] Disable machine check abort handling
1302
1303 nomce [X86-32] Machine Check Exception
1304
1305 nomfgpt [X86-32] Disable Multi-Function General Purpose
1306 Timer usage (for AMD Geode machines).
1307
1308 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1309
1310 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1311 with UP alternatives
1312
1313 noresidual [PPC] Don't use residual data on PReP machines.
1314
1315 noresume [SWSUSP] Disables resume and restores original swap
1316 space.
1317
1318 no-scroll [VGA] Disables scrollback.
1319 This is required for the Braillex ib80-piezo Braille
1320 reader made by F.H. Papenmeier (Germany).
1321
1322 nosbagart [IA-64]
1323
1324 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1325
1326 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1327 and disable the IO APIC. legacy for "maxcpus=0".
1328
1329 nosoftlockup [KNL] Disable the soft-lockup detector.
1330
1331 nosync [HW,M68K] Disables sync negotiation for all devices.
1332
1333 notsc [BUGS=X86-32] Disable Time Stamp Counter
1334
1335 nousb [USB] Disable the USB subsystem
1336
1337 nowb [ARM]
1338
1339 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1340 one of ['zone', 'node', 'default'] can be specified
1341 This can be set from sysctl after boot.
1342 See Documentation/sysctl/vm.txt for details.
1343
1344 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1345
1346 opl3= [HW,OSS]
1347 Format: <io>
1348
1349 oprofile.timer= [HW]
1350 Use timer interrupt instead of performance counters
1351
1352 osst= [HW,SCSI] SCSI Tape Driver
1353 Format: <buffer_size>,<write_threshold>
1354 See also Documentation/scsi/st.txt.
1355
1356 panic= [KNL] Kernel behaviour on panic
1357 Format: <timeout>
1358
1359 parkbd.port= [HW] Parallel port number the keyboard adapter is
1360 connected to, default is 0.
1361 Format: <parport#>
1362 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1363 0 for XT, 1 for AT (default is AT).
1364 Format: <mode>
1365
1366 parport= [HW,PPT] Specify parallel ports. 0 disables.
1367 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1368 Use 'auto' to force the driver to use any
1369 IRQ/DMA settings detected (the default is to
1370 ignore detected IRQ/DMA settings because of
1371 possible conflicts). You can specify the base
1372 address, IRQ, and DMA settings; IRQ and DMA
1373 should be numbers, or 'auto' (for using detected
1374 settings on that particular port), or 'nofifo'
1375 (to avoid using a FIFO even if it is detected).
1376 Parallel ports are assigned in the order they
1377 are specified on the command line, starting
1378 with parport0.
1379
1380 parport_init_mode= [HW,PPT]
1381 Configure VIA parallel port to operate in
1382 a specific mode. This is necessary on Pegasos
1383 computer where firmware has no options for setting
1384 up parallel port mode and sets it to spp.
1385 Currently this function knows 686a and 8231 chips.
1386 Format: [spp|ps2|epp|ecp|ecpepp]
1387
1388 pas2= [HW,OSS] Format:
1389 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1390
1391 pas16= [HW,SCSI]
1392 See header of drivers/scsi/pas16.c.
1393
1394 pause_on_oops=
1395 Halt all CPUs after the first oops has been printed for
1396 the specified number of seconds. This is to be used if
1397 your oopses keep scrolling off the screen.
1398
1399 pcbit= [HW,ISDN]
1400
1401 pcd. [PARIDE]
1402 See header of drivers/block/paride/pcd.c.
1403 See also Documentation/paride.txt.
1404
1405 pci=option[,option...] [PCI] various PCI subsystem options:
1406 off [X86-32] don't probe for the PCI bus
1407 bios [X86-32] force use of PCI BIOS, don't access
1408 the hardware directly. Use this if your machine
1409 has a non-standard PCI host bridge.
1410 nobios [X86-32] disallow use of PCI BIOS, only direct
1411 hardware access methods are allowed. Use this
1412 if you experience crashes upon bootup and you
1413 suspect they are caused by the BIOS.
1414 conf1 [X86-32] Force use of PCI Configuration
1415 Mechanism 1.
1416 conf2 [X86-32] Force use of PCI Configuration
1417 Mechanism 2.
1418 noaer [PCIE] If the PCIEAER kernel config parameter is
1419 enabled, this kernel boot option can be used to
1420 disable the use of PCIE advanced error reporting.
1421 nodomains [PCI] Disable support for multiple PCI
1422 root domains (aka PCI segments, in ACPI-speak).
1423 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1424 Configuration
1425 nomsi [MSI] If the PCI_MSI kernel config parameter is
1426 enabled, this kernel boot option can be used to
1427 disable the use of MSI interrupts system-wide.
1428 nosort [X86-32] Don't sort PCI devices according to
1429 order given by the PCI BIOS. This sorting is
1430 done to get a device order compatible with
1431 older kernels.
1432 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1433 routing table. These calls are known to be buggy
1434 on several machines and they hang the machine
1435 when used, but on other computers it's the only
1436 way to get the interrupt routing table. Try
1437 this option if the kernel is unable to allocate
1438 IRQs or discover secondary PCI buses on your
1439 motherboard.
1440 rom [X86-32] Assign address space to expansion ROMs.
1441 Use with caution as certain devices share
1442 address decoders between ROMs and other
1443 resources.
1444 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1445 assigned automatically to PCI devices. You can
1446 make the kernel exclude IRQs of your ISA cards
1447 this way.
1448 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1449 of the PIRQ table (normally generated
1450 by the BIOS) if it is outside the
1451 F0000h-100000h range.
1452 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1453 useful if the kernel is unable to find your
1454 secondary buses and you want to tell it
1455 explicitly which ones they are.
1456 assign-busses [X86-32] Always assign all PCI bus
1457 numbers ourselves, overriding
1458 whatever the firmware may have done.
1459 usepirqmask [X86-32] Honor the possible IRQ mask stored
1460 in the BIOS $PIR table. This is needed on
1461 some systems with broken BIOSes, notably
1462 some HP Pavilion N5400 and Omnibook XE3
1463 notebooks. This will have no effect if ACPI
1464 IRQ routing is enabled.
1465 noacpi [X86-32] Do not use ACPI for IRQ routing
1466 or for PCI scanning.
1467 use_crs [X86-32] Use _CRS for PCI resource
1468 allocation.
1469 routeirq Do IRQ routing for all PCI devices.
1470 This is normally done in pci_enable_device(),
1471 so this option is a temporary workaround
1472 for broken drivers that don't call it.
1473 firmware [ARM] Do not re-enumerate the bus but instead
1474 just use the configuration from the
1475 bootloader. This is currently used on
1476 IXP2000 systems where the bus has to be
1477 configured a certain way for adjunct CPUs.
1478 noearly [X86] Don't do any early type 1 scanning.
1479 This might help on some broken boards which
1480 machine check when some devices' config space
1481 is read. But various workarounds are disabled
1482 and some IOMMU drivers will not work.
1483 bfsort Sort PCI devices into breadth-first order.
1484 This sorting is done to get a device
1485 order compatible with older (<= 2.4) kernels.
1486 nobfsort Don't sort PCI devices into breadth-first order.
1487 cbiosize=nn[KMG] The fixed amount of bus space which is
1488 reserved for the CardBus bridge's IO window.
1489 The default value is 256 bytes.
1490 cbmemsize=nn[KMG] The fixed amount of bus space which is
1491 reserved for the CardBus bridge's memory
1492 window. The default value is 64 megabytes.
1493
1494 pcmv= [HW,PCMCIA] BadgePAD 4
1495
1496 pd. [PARIDE]
1497 See Documentation/paride.txt.
1498
1499 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1500 boot time.
1501 Format: { 0 | 1 }
1502 See arch/parisc/kernel/pdc_chassis.c
1503
1504 pf. [PARIDE]
1505 See Documentation/paride.txt.
1506
1507 pg. [PARIDE]
1508 See Documentation/paride.txt.
1509
1510 pirq= [SMP,APIC] Manual mp-table setup
1511 See Documentation/i386/IO-APIC.txt.
1512
1513 plip= [PPT,NET] Parallel port network link
1514 Format: { parport<nr> | timid | 0 }
1515 See also Documentation/parport.txt.
1516
1517 pnpacpi= [ACPI]
1518 { off }
1519
1520 pnpbios= [ISAPNP]
1521 { on | off | curr | res | no-curr | no-res }
1522
1523 pnp_reserve_irq=
1524 [ISAPNP] Exclude IRQs for the autoconfiguration
1525
1526 pnp_reserve_dma=
1527 [ISAPNP] Exclude DMAs for the autoconfiguration
1528
1529 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1530 Ranges are in pairs (I/O port base and size).
1531
1532 pnp_reserve_mem=
1533 [ISAPNP] Exclude memory regions for the
1534 autoconfiguration.
1535 Ranges are in pairs (memory base and size).
1536
1537 print-fatal-signals=
1538 [KNL] debug: print fatal signals
1539 print-fatal-signals=1: print segfault info to
1540 the kernel console.
1541 default: off.
1542
1543 printk.time= Show timing data prefixed to each printk message line
1544 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1545
1546 profile= [KNL] Enable kernel profiling via /proc/profile
1547 Format: [schedule,]<number>
1548 Param: "schedule" - profile schedule points.
1549 Param: <number> - step/bucket size as a power of 2 for
1550 statistical time based profiling.
1551 Param: "sleep" - profile D-state sleeping (millisecs).
1552 Requires CONFIG_SCHEDSTATS
1553 Param: "kvm" - profile VM exits.
1554
1555 processor.max_cstate= [HW,ACPI]
1556 Limit processor to maximum C-state
1557 max_cstate=9 overrides any DMI blacklist limit.
1558
1559 processor.nocst [HW,ACPI]
1560 Ignore the _CST method to determine C-states,
1561 instead using the legacy FADT method
1562
1563 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1564 before loading.
1565 See Documentation/ramdisk.txt.
1566
1567 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1568 probe for; one of (bare|imps|exps|lifebook|any).
1569 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1570 per second.
1571 psmouse.resetafter= [HW,MOUSE]
1572 Try to reset the device after so many bad packets
1573 (0 = never).
1574 psmouse.resolution=
1575 [HW,MOUSE] Set desired mouse resolution, in dpi.
1576 psmouse.smartscroll=
1577 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1578 0 = disabled, 1 = enabled (default).
1579
1580 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1581 Format:
1582 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1583
1584 pt. [PARIDE]
1585 See Documentation/paride.txt.
1586
1587 pty.legacy_count=
1588 [KNL] Number of legacy pty's. Overwrites compiled-in
1589 default number.
1590
1591 quiet [KNL] Disable most log messages
1592
1593 r128= [HW,DRM]
1594
1595 raid= [HW,RAID]
1596 See Documentation/md.txt.
1597
1598 ramdisk_blocksize= [RAM]
1599 See Documentation/ramdisk.txt.
1600
1601 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1602 See Documentation/ramdisk.txt.
1603
1604 rcupdate.blimit= [KNL,BOOT]
1605 Set maximum number of finished RCU callbacks to process
1606 in one batch.
1607
1608 rcupdate.qhimark= [KNL,BOOT]
1609 Set threshold of queued
1610 RCU callbacks over which batch limiting is disabled.
1611
1612 rcupdate.qlowmark= [KNL,BOOT]
1613 Set threshold of queued RCU callbacks below which
1614 batch limiting is re-enabled.
1615
1616 rdinit= [KNL]
1617 Format: <full_path>
1618 Run specified binary instead of /init from the ramdisk,
1619 used for early userspace startup. See initrd.
1620
1621 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1622 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1623 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1624
1625 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1626
1627 reservetop= [X86-32]
1628 Format: nn[KMG]
1629 Reserves a hole at the top of the kernel virtual
1630 address space.
1631
1632 reset_devices [KNL] Force drivers to reset the underlying device
1633 during initialization.
1634
1635 resume= [SWSUSP]
1636 Specify the partition device for software suspend
1637
1638 resume_offset= [SWSUSP]
1639 Specify the offset from the beginning of the partition
1640 given by "resume=" at which the swap header is located,
1641 in <PAGE_SIZE> units (needed only for swap files).
1642 See Documentation/power/swsusp-and-swap-files.txt
1643
1644 retain_initrd [RAM] Keep initrd memory after extraction
1645
1646 rhash_entries= [KNL,NET]
1647 Set number of hash buckets for route cache
1648
1649 riscom8= [HW,SERIAL]
1650 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1651
1652 ro [KNL] Mount root device read-only on boot
1653
1654 root= [KNL] Root filesystem
1655
1656 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1657 mount the root filesystem
1658
1659 rootflags= [KNL] Set root filesystem mount option string
1660
1661 rootfstype= [KNL] Set root filesystem type
1662
1663 rootwait [KNL] Wait (indefinitely) for root device to show up.
1664 Useful for devices that are detected asynchronously
1665 (e.g. USB and MMC devices).
1666
1667 root_plug.vendor_id=
1668 [ROOTPLUG] Override the default vendor ID
1669
1670 root_plug.product_id=
1671 [ROOTPLUG] Override the default product ID
1672
1673 root_plug.debug=
1674 [ROOTPLUG] Enable debugging output
1675
1676 rw [KNL] Mount root device read-write on boot
1677
1678 S [KNL] Run init in single mode
1679
1680 sa1100ir [NET]
1681 See drivers/net/irda/sa1100_ir.c.
1682
1683 sbni= [NET] Granch SBNI12 leased line adapter
1684
1685 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1686 Format: <io>[,<timeout>[,<isapnp>]]
1687
1688 scsi_debug_*= [SCSI]
1689 See drivers/scsi/scsi_debug.c.
1690
1691 scsi_default_dev_flags=
1692 [SCSI] SCSI default device flags
1693 Format: <integer>
1694
1695 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1696 Format: <vendor>:<model>:<flags>
1697 (flags are integer value)
1698
1699 scsi_logging_level= [SCSI] a bit mask of logging levels
1700 See drivers/scsi/scsi_logging.h for bits. Also
1701 settable via sysctl at dev.scsi.logging_level
1702 (/proc/sys/dev/scsi/logging_level).
1703 There is also a nice 'scsi_logging_level' script in the
1704 S390-tools package, available for download at
1705 http://www-128.ibm.com/developerworks/linux/linux390/s390-tools-1.5.4.html
1706
1707 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1708 discovered. async scans them in kernel threads,
1709 allowing boot to proceed. none ignores them, expecting
1710 user space to do the scan.
1711
1712 selinux [SELINUX] Disable or enable SELinux at boot time.
1713 Format: { "0" | "1" }
1714 See security/selinux/Kconfig help text.
1715 0 -- disable.
1716 1 -- enable.
1717 Default value is set via kernel config option.
1718 If enabled at boot time, /selinux/disable can be used
1719 later to disable prior to initial policy load.
1720
1721 selinux_compat_net =
1722 [SELINUX] Set initial selinux_compat_net flag value.
1723 Format: { "0" | "1" }
1724 0 -- use new secmark-based packet controls
1725 1 -- use legacy packet controls
1726 Default value is 0 (preferred).
1727 Value can be changed at runtime via
1728 /selinux/compat_net.
1729
1730 serialnumber [BUGS=X86-32]
1731
1732 shapers= [NET]
1733 Maximal number of shapers.
1734
1735 sim710= [SCSI,HW]
1736 See header of drivers/scsi/sim710.c.
1737
1738 simeth= [IA-64]
1739 simscsi=
1740
1741 slram= [HW,MTD]
1742
1743 slub_debug[=options[,slabs]] [MM, SLUB]
1744 Enabling slub_debug allows one to determine the
1745 culprit if slab objects become corrupted. Enabling
1746 slub_debug can create guard zones around objects and
1747 may poison objects when not in use. Also tracks the
1748 last alloc / free. For more information see
1749 Documentation/vm/slub.txt.
1750
1751 slub_max_order= [MM, SLUB]
1752 Determines the maximum allowed order for slabs.
1753 A high setting may cause OOMs due to memory
1754 fragmentation. For more information see
1755 Documentation/vm/slub.txt.
1756
1757 slub_min_objects= [MM, SLUB]
1758 The minimum number of objects per slab. SLUB will
1759 increase the slab order up to slub_max_order to
1760 generate a sufficiently large slab able to contain
1761 the number of objects indicated. The higher the number
1762 of objects the smaller the overhead of tracking slabs
1763 and the less frequently locks need to be acquired.
1764 For more information see Documentation/vm/slub.txt.
1765
1766 slub_min_order= [MM, SLUB]
1767 Determines the mininum page order for slabs. Must be
1768 lower than slub_max_order.
1769 For more information see Documentation/vm/slub.txt.
1770
1771 slub_nomerge [MM, SLUB]
1772 Disable merging of slabs with similar size. May be
1773 necessary if there is some reason to distinguish
1774 allocs to different slabs. Debug options disable
1775 merging on their own.
1776 For more information see Documentation/vm/slub.txt.
1777
1778 smart2= [HW]
1779 Format: <io1>[,<io2>[,...,<io8>]]
1780
1781 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1782 attempt to substitute SMP alternatives once at boot.
1783
1784 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1785 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1786 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1787 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1788 smsc-ircc2.ircc_irq= [HW] IRQ line
1789 smsc-ircc2.ircc_dma= [HW] DMA channel
1790 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1791 0: Toshiba Satellite 1800 (GP data pin select)
1792 1: Fast pin select (default)
1793 2: ATC IRMode
1794
1795 snd-ad1816a= [HW,ALSA]
1796
1797 snd-ad1848= [HW,ALSA]
1798
1799 snd-ali5451= [HW,ALSA]
1800
1801 snd-als100= [HW,ALSA]
1802
1803 snd-als4000= [HW,ALSA]
1804
1805 snd-azt2320= [HW,ALSA]
1806
1807 snd-cmi8330= [HW,ALSA]
1808
1809 snd-cmipci= [HW,ALSA]
1810
1811 snd-cs4231= [HW,ALSA]
1812
1813 snd-cs4232= [HW,ALSA]
1814
1815 snd-cs4236= [HW,ALSA]
1816
1817 snd-cs4281= [HW,ALSA]
1818
1819 snd-cs46xx= [HW,ALSA]
1820
1821 snd-dt019x= [HW,ALSA]
1822
1823 snd-dummy= [HW,ALSA]
1824
1825 snd-emu10k1= [HW,ALSA]
1826
1827 snd-ens1370= [HW,ALSA]
1828
1829 snd-ens1371= [HW,ALSA]
1830
1831 snd-es968= [HW,ALSA]
1832
1833 snd-es1688= [HW,ALSA]
1834
1835 snd-es18xx= [HW,ALSA]
1836
1837 snd-es1938= [HW,ALSA]
1838
1839 snd-es1968= [HW,ALSA]
1840
1841 snd-fm801= [HW,ALSA]
1842
1843 snd-gusclassic= [HW,ALSA]
1844
1845 snd-gusextreme= [HW,ALSA]
1846
1847 snd-gusmax= [HW,ALSA]
1848
1849 snd-hdsp= [HW,ALSA]
1850
1851 snd-ice1712= [HW,ALSA]
1852
1853 snd-intel8x0= [HW,ALSA]
1854
1855 snd-interwave= [HW,ALSA]
1856
1857 snd-interwave-stb=
1858 [HW,ALSA]
1859
1860 snd-korg1212= [HW,ALSA]
1861
1862 snd-maestro3= [HW,ALSA]
1863
1864 snd-mpu401= [HW,ALSA]
1865
1866 snd-mtpav= [HW,ALSA]
1867
1868 snd-nm256= [HW,ALSA]
1869
1870 snd-opl3sa2= [HW,ALSA]
1871
1872 snd-opti92x-ad1848=
1873 [HW,ALSA]
1874
1875 snd-opti92x-cs4231=
1876 [HW,ALSA]
1877
1878 snd-opti93x= [HW,ALSA]
1879
1880 snd-pmac= [HW,ALSA]
1881
1882 snd-rme32= [HW,ALSA]
1883
1884 snd-rme96= [HW,ALSA]
1885
1886 snd-rme9652= [HW,ALSA]
1887
1888 snd-sb8= [HW,ALSA]
1889
1890 snd-sb16= [HW,ALSA]
1891
1892 snd-sbawe= [HW,ALSA]
1893
1894 snd-serial= [HW,ALSA]
1895
1896 snd-sgalaxy= [HW,ALSA]
1897
1898 snd-sonicvibes= [HW,ALSA]
1899
1900 snd-sun-amd7930=
1901 [HW,ALSA]
1902
1903 snd-sun-cs4231= [HW,ALSA]
1904
1905 snd-trident= [HW,ALSA]
1906
1907 snd-usb-audio= [HW,ALSA,USB]
1908
1909 snd-via82xx= [HW,ALSA]
1910
1911 snd-virmidi= [HW,ALSA]
1912
1913 snd-wavefront= [HW,ALSA]
1914
1915 snd-ymfpci= [HW,ALSA]
1916
1917 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1918 See Documentation/sonypi.txt
1919
1920 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1921 See Documentation/specialix.txt.
1922
1923 spia_io_base= [HW,MTD]
1924 spia_fio_base=
1925 spia_pedr=
1926 spia_peddr=
1927
1928 sscape= [HW,OSS]
1929 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1930
1931 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1932 See Documentation/scsi/st.txt.
1933
1934 sti= [PARISC,HW]
1935 Format: <num>
1936 Set the STI (builtin display/keyboard on the HP-PARISC
1937 machines) console (graphic card) which should be used
1938 as the initial boot-console.
1939 See also comment in drivers/video/console/sticore.c.
1940
1941 sti_font= [HW]
1942 See comment in drivers/video/console/sticore.c.
1943
1944 stifb= [HW]
1945 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1946
1947 sunrpc.pool_mode=
1948 [NFS]
1949 Control how the NFS server code allocates CPUs to
1950 service thread pools. Depending on how many NICs
1951 you have and where their interrupts are bound, this
1952 option will affect which CPUs will do NFS serving.
1953 Note: this parameter cannot be changed while the
1954 NFS server is running.
1955
1956 auto the server chooses an appropriate mode
1957 automatically using heuristics
1958 global a single global pool contains all CPUs
1959 percpu one pool for each CPU
1960 pernode one pool for each NUMA node (equivalent
1961 to global on non-NUMA machines)
1962
1963 swiotlb= [IA-64] Number of I/O TLB slabs
1964
1965 switches= [HW,M68k]
1966
1967 sym53c416= [HW,SCSI]
1968 See header of drivers/scsi/sym53c416.c.
1969
1970 sysrq_always_enabled
1971 [KNL]
1972 Ignore sysrq setting - this boot parameter will
1973 neutralize any effect of /proc/sys/kernel/sysrq.
1974 Useful for debugging.
1975
1976 t128= [HW,SCSI]
1977 See header of drivers/scsi/t128.c.
1978
1979 tdfx= [HW,DRM]
1980
1981 thash_entries= [KNL,NET]
1982 Set number of hash buckets for TCP connection
1983
1984 thermal.act= [HW,ACPI]
1985 -1: disable all active trip points in all thermal zones
1986 <degrees C>: override all lowest active trip points
1987
1988 thermal.crt= [HW,ACPI]
1989 -1: disable all critical trip points in all thermal zones
1990 <degrees C>: lower all critical trip points
1991
1992 thermal.nocrt= [HW,ACPI]
1993 Set to disable actions on ACPI thermal zone
1994 critical and hot trip points.
1995
1996 thermal.off= [HW,ACPI]
1997 1: disable ACPI thermal control
1998
1999 thermal.psv= [HW,ACPI]
2000 -1: disable all passive trip points
2001 <degrees C>: override all passive trip points to this value
2002
2003 thermal.tzp= [HW,ACPI]
2004 Specify global default ACPI thermal zone polling rate
2005 <deci-seconds>: poll all this frequency
2006 0: no polling (default)
2007
2008 tipar.timeout= [HW,PPT]
2009 Set communications timeout in tenths of a second
2010 (default 15).
2011
2012 tipar.delay= [HW,PPT]
2013 Set inter-bit delay in microseconds (default 10).
2014
2015 tmscsim= [HW,SCSI]
2016 See comment before function dc390_setup() in
2017 drivers/scsi/tmscsim.c.
2018
2019 tp720= [HW,PS2]
2020
2021 trix= [HW,OSS] MediaTrix AudioTrix Pro
2022 Format:
2023 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
2024
2025 turbografx.map[2|3]= [HW,JOY]
2026 TurboGraFX parallel port interface
2027 Format:
2028 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
2029 See also Documentation/input/joystick-parport.txt
2030
2031 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
2032 See header of drivers/scsi/u14-34f.c.
2033
2034 uart401= [HW,OSS]
2035 Format: <io>,<irq>
2036
2037 uart6850= [HW,OSS]
2038 Format: <io>,<irq>
2039
2040 uhci-hcd.ignore_oc=
2041 [USB] Ignore overcurrent events (default N).
2042 Some badly-designed motherboards generate lots of
2043 bogus events, for ports that aren't wired to
2044 anything. Set this parameter to avoid log spamming.
2045 Note that genuine overcurrent events won't be
2046 reported either.
2047
2048 usbcore.autosuspend=
2049 [USB] The autosuspend time delay (in seconds) used
2050 for newly-detected USB devices (default 2). This
2051 is the time required before an idle device will be
2052 autosuspended. Devices for which the delay is set
2053 to a negative value won't be autosuspended at all.
2054
2055 usbhid.mousepoll=
2056 [USBHID] The interval which mice are to be polled at.
2057
2058 vdso= [X86-32,SH,x86-64]
2059 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
2060 vdso=1: enable VDSO (default)
2061 vdso=0: disable VDSO mapping
2062
2063 vdso32= [X86-32,X86-64]
2064 vdso32=2: enable compat VDSO (default with COMPAT_VDSO)
2065 vdso32=1: enable 32-bit VDSO (default)
2066 vdso32=0: disable 32-bit VDSO mapping
2067
2068 vector= [IA-64,SMP]
2069 vector=percpu: enable percpu vector domain
2070
2071 video= [FB] Frame buffer configuration
2072 See Documentation/fb/modedb.txt.
2073
2074 vga= [BOOT,X86-32] Select a particular video mode
2075 See Documentation/i386/boot.txt and
2076 Documentation/svga.txt.
2077 Use vga=ask for menu.
2078 This is actually a boot loader parameter; the value is
2079 passed to the kernel using a special protocol.
2080
2081 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
2082 size of <nn>. This can be used to increase the
2083 minimum size (128MB on x86). It can also be used to
2084 decrease the size and leave more room for directly
2085 mapped kernel RAM.
2086
2087 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
2088 Format: <command>
2089
2090 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
2091 Format: <command>
2092
2093 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
2094 Format: <command>
2095
2096 waveartist= [HW,OSS]
2097 Format: <io>,<irq>,<dma>,<dma2>
2098
2099 wd33c93= [HW,SCSI]
2100 See header of drivers/scsi/wd33c93.c.
2101
2102 wd7000= [HW,SCSI]
2103 See header of drivers/scsi/wd7000.c.
2104
2105 wdt= [WDT] Watchdog
2106 See Documentation/watchdog/wdt.txt.
2107
2108 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2109 xd_geo= See header of drivers/block/xd.c.
2110
2111 xirc2ps_cs= [NET,PCMCIA]
2112 Format:
2113 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2114
2115 norandmaps Don't use address space randomization
2116 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2117
2118 ______________________________________________________________________
2119
2120 TODO:
2121
2122 Add documentation for ALSA options.
2123 Add more DRM drivers.