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1 Kernel Parameters
2 ~~~~~~~~~~~~~~~~~
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.
9 Module parameters for loadable modules are specified only as the
10 parameter name with optional '=' and value as appropriate, such as:
12 modprobe usbcore blinkenlights=1
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:
18 usbcore.blinkenlights=1
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}".
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:
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 AX25 Appropriate AX.25 support is enabled.
38 BLACKFIN Blackfin architecture is enabled.
39 DRM Direct Rendering Management support is enabled.
40 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
41 EFI EFI Partitioning (GPT) is enabled
42 EIDE EIDE/ATAPI support is enabled.
43 FB The frame buffer device is enabled.
44 HW Appropriate hardware is enabled.
45 IA-64 IA-64 architecture is enabled.
46 IOSCHED More than one I/O scheduler is enabled.
47 IP_PNP IP DHCP, BOOTP, or RARP is enabled.
48 ISAPNP ISA PnP code is enabled.
49 ISDN Appropriate ISDN support is enabled.
50 JOY Appropriate joystick support is enabled.
51 LIBATA Libata driver is enabled
52 LP Printer support is enabled.
53 LOOP Loopback device support is enabled.
54 M68k M68k architecture is enabled.
55 These options have more detailed description inside of
56 Documentation/m68k/kernel-options.txt.
57 MCA MCA bus support is enabled.
58 MDA MDA console support is enabled.
59 MOUSE Appropriate mouse support is enabled.
60 MSI Message Signaled Interrupts (PCI).
61 MTD MTD (Memory Technology Device) support is enabled.
62 NET Appropriate network support is enabled.
63 NUMA NUMA support is enabled.
64 GENERIC_TIME The generic timeofday code is enabled.
65 NFS Appropriate NFS support is enabled.
66 OSS OSS sound support is enabled.
67 PV_OPS A paravirtualized kernel is enabled.
68 PARIDE The ParIDE (parallel port IDE) subsystem is enabled.
69 PARISC The PA-RISC architecture is enabled.
70 PCI PCI bus support is enabled.
71 PCIE PCI Express support is enabled.
72 PCMCIA The PCMCIA subsystem is enabled.
73 PNP Plug & Play support is enabled.
74 PPC PowerPC architecture is enabled.
75 PPT Parallel port support is enabled.
76 PS2 Appropriate PS/2 support is enabled.
77 RAM RAM disk support is enabled.
78 ROOTPLUG The example Root Plug LSM is enabled.
79 S390 S390 architecture is enabled.
80 SCSI Appropriate SCSI support is enabled.
81 A lot of drivers has their options described inside of
82 Documentation/scsi/.
83 SECURITY Different security models are enabled.
84 SELINUX SELinux support is enabled.
85 SERIAL Serial support is enabled.
86 SH SuperH architecture is enabled.
87 SMP The kernel is an SMP kernel.
88 SPARC Sparc architecture is enabled.
89 SWSUSP Software suspend is enabled.
90 TS Appropriate touchscreen support is enabled.
91 USB USB support is enabled.
92 USBHID USB Human Interface Device support is enabled.
93 V4L Video For Linux support is enabled.
94 VGA The VGA console has been enabled.
95 VT Virtual terminal support is enabled.
96 WDT Watchdog support is enabled.
97 XT IBM PC/XT MFM hard disk support is enabled.
98 X86-32 X86-32, aka i386 architecture is enabled.
99 X86-64 X86-64 architecture is enabled.
100 More X86-64 boot options can be found in
101 Documentation/x86_64/boot-options.txt .
103 In addition, the following text indicates that the option:
105 BUGS= Relates to possible processor bugs on the said processor.
106 KNL Is a kernel start-up parameter.
107 BOOT Is a boot loader parameter.
109 Parameters denoted with BOOT are actually interpreted by the boot
110 loader, and have no meaning to the kernel directly.
111 Do not modify the syntax of boot loader parameters without extreme
112 need or coordination with <Documentation/i386/boot.txt>.
114 There are also arch-specific kernel-parameters not documented here.
115 See for example <Documentation/x86_64/boot-options.txt>.
117 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
118 a trailing = on the name of any parameter states that that parameter will
119 be entered as an environment variable, whereas its absence indicates that
120 it will appear as a kernel argument readable via /proc/cmdline by programs
121 running once the system is up.
123 The number of kernel parameters is not limited, but the length of the
124 complete command line (parameters including spaces etc.) is limited to
125 a fixed number of characters. This limit depends on the architecture
126 and is between 256 and 4096 characters. It is defined in the file
127 ./include/asm/setup.h as COMMAND_LINE_SIZE.
130 acpi= [HW,ACPI,X86-64,i386]
131 Advanced Configuration and Power Interface
132 Format: { force | off | ht | strict | noirq }
133 force -- enable ACPI if default was off
134 off -- disable ACPI if default was on
135 noirq -- do not use ACPI for IRQ routing
136 ht -- run only enough ACPI to enable Hyper Threading
137 strict -- Be less tolerant of platforms that are not
138 strictly ACPI specification compliant.
140 See also Documentation/pm.txt, pci=noacpi
142 acpi_apic_instance= [ACPI, IOAPIC]
143 Format: <int>
144 2: use 2nd APIC table, if available
145 1,0: use 1st APIC table
146 default: 0
148 acpi_sleep= [HW,ACPI] Sleep options
149 Format: { s3_bios, s3_mode }
150 See Documentation/power/video.txt
152 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
153 Format: { level | edge | high | low }
155 acpi_irq_balance [HW,ACPI]
156 ACPI will balance active IRQs
157 default in APIC mode
159 acpi_irq_nobalance [HW,ACPI]
160 ACPI will not move active IRQs (default)
161 default in PIC mode
163 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
164 use by PCI
165 Format: <irq>,<irq>...
167 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
168 Format: <irq>,<irq>...
170 acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT
172 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
173 Format: To spoof as Windows 98: ="Microsoft Windows"
175 acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
176 acpi_osi="string1" # add string1 -- only one string
177 acpi_osi="!string2" # remove built-in string2
178 acpi_osi= # disable all strings
180 acpi_serialize [HW,ACPI] force serialization of AML methods
182 acpi_skip_timer_override [HW,ACPI]
183 Recognize and ignore IRQ0/pin2 Interrupt Override.
184 For broken nForce2 BIOS resulting in XT-PIC timer.
185 acpi_use_timer_override [HW,ACPI}
186 Use timer override. For some broken Nvidia NF5 boards
187 that require a timer override, but don't have
188 HPET
190 acpi.debug_layer= [HW,ACPI]
191 Format: <int>
192 Each bit of the <int> indicates an ACPI debug layer,
193 1: enable, 0: disable. It is useful for boot time
194 debugging. After system has booted up, it can be set
195 via /sys/module/acpi/parameters/debug_layer.
196 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
197 Available bits (add the numbers together) to enable debug output
198 for specific parts of the ACPI subsystem:
199 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
200 0x10 namespace 0x20 parser 0x40 dispatcher
201 0x80 executer 0x100 resources 0x200 acpica debugger
202 0x400 os services 0x800 acpica disassembler.
203 The number can be in decimal or prefixed with 0x in hex.
204 Warning: Many of these options can produce a lot of
205 output and make your system unusable. Be very careful.
207 acpi.debug_level= [HW,ACPI]
208 Format: <int>
209 Each bit of the <int> indicates an ACPI debug level,
210 1: enable, 0: disable. It is useful for boot time
211 debugging. After system has booted up, it can be set
212 via /sys/module/acpi/parameters/debug_level.
213 CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
214 Available bits (add the numbers together) to enable different
215 debug output levels of the ACPI subsystem:
216 0x01 error 0x02 warn 0x04 init 0x08 debug object
217 0x10 info 0x20 init names 0x40 parse 0x80 load
218 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
219 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
220 0x10000 resources 0x20000 user requests 0x40000 package.
221 The number can be in decimal or prefixed with 0x in hex.
222 Warning: Many of these options can produce a lot of
223 output and make your system unusable. Be very careful.
225 acpi_pm_good [X86-32,X86-64]
226 Override the pmtimer bug detection: force the kernel
227 to assume that this machine's pmtimer latches its value
228 and always returns good values.
230 agp= [AGP]
231 { off | try_unsupported }
232 off: disable AGP support
233 try_unsupported: try to drive unsupported chipsets
234 (may crash computer or cause data corruption)
236 enable_timer_pin_1 [i386,x86-64]
237 Enable PIN 1 of APIC timer
238 Can be useful to work around chipset bugs
239 (in particular on some ATI chipsets).
240 The kernel tries to set a reasonable default.
242 disable_timer_pin_1 [i386,x86-64]
243 Disable PIN 1 of APIC timer
244 Can be useful to work around chipset bugs.
246 ad1848= [HW,OSS]
247 Format: <io>,<irq>,<dma>,<dma2>,<type>
249 advansys= [HW,SCSI]
250 See header of drivers/scsi/advansys.c.
252 advwdt= [HW,WDT] Advantech WDT
253 Format: <iostart>,<iostop>
255 aedsp16= [HW,OSS] Audio Excel DSP 16
256 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
257 See also header of sound/oss/aedsp16.c.
259 aha152x= [HW,SCSI]
260 See Documentation/scsi/aha152x.txt.
262 aha1542= [HW,SCSI]
263 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
265 aic7xxx= [HW,SCSI]
266 See Documentation/scsi/aic7xxx.txt.
268 aic79xx= [HW,SCSI]
269 See Documentation/scsi/aic79xx.txt.
271 amijoy.map= [HW,JOY] Amiga joystick support
272 Map of devices attached to JOY0DAT and JOY1DAT
273 Format: <a>,<b>
274 See also Documentation/kernel/input/joystick.txt
276 analog.map= [HW,JOY] Analog joystick and gamepad support
277 Specifies type or capabilities of an analog joystick
278 connected to one of 16 gameports
279 Format: <type1>,<type2>,..<type16>
281 apc= [HW,SPARC]
282 Power management functions (SPARCstation-4/5 + deriv.)
283 Format: noidle
284 Disable APC CPU standby support. SPARCstation-Fox does
285 not play well with APC CPU idle - disable it if you have
286 APC and your system crashes randomly.
288 apic= [APIC,i386] Advanced Programmable Interrupt Controller
289 Change the output verbosity whilst booting
290 Format: { quiet (default) | verbose | debug }
291 Change the amount of debugging information output
292 when initialising the APIC and IO-APIC components.
294 apm= [APM] Advanced Power Management
295 See header of arch/i386/kernel/apm.c.
297 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
298 Format: <io>,<irq>,<nodeID>
300 ataflop= [HW,M68k]
302 atarimouse= [HW,MOUSE] Atari Mouse
304 atascsi= [HW,SCSI] Atari SCSI
306 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
307 EzKey and similar keyboards
309 atkbd.reset= [HW] Reset keyboard during initialization
311 atkbd.set= [HW] Select keyboard code set
312 Format: <int> (2 = AT (default), 3 = PS/2)
314 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
315 keyboards
317 atkbd.softraw= [HW] Choose between synthetic and real raw mode
318 Format: <bool> (0 = real, 1 = synthetic (default))
320 atkbd.softrepeat= [HW]
321 Use software keyboard repeat
323 autotest [IA64]
325 baycom_epp= [HW,AX25]
326 Format: <io>,<mode>
328 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
329 Format: <io>,<mode>
330 See header of drivers/net/hamradio/baycom_par.c.
332 baycom_ser_fdx= [HW,AX25]
333 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
334 Format: <io>,<irq>,<mode>[,<baud>]
335 See header of drivers/net/hamradio/baycom_ser_fdx.c.
337 baycom_ser_hdx= [HW,AX25]
338 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
339 Format: <io>,<irq>,<mode>
340 See header of drivers/net/hamradio/baycom_ser_hdx.c.
342 boot_delay= Milliseconds to delay each printk during boot.
343 Values larger than 10 seconds (10000) are changed to
344 no delay (0).
345 Format: integer
347 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
348 bttv.radio= Most important insmod options are available as
349 kernel args too.
350 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
351 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
353 BusLogic= [HW,SCSI]
354 See drivers/scsi/BusLogic.c, comment before function
355 BusLogic_ParseDriverOptions().
357 c101= [NET] Moxa C101 synchronous serial card
359 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
360 Sometimes CPU hardware bugs make them report the cache
361 size incorrectly. The kernel will attempt work arounds
362 to fix known problems, but for some CPUs it is not
363 possible to determine what the correct size should be.
364 This option provides an override for these situations.
366 capability.disable=
367 [SECURITY] Disable capabilities. This would normally
368 be used only if an alternative security model is to be
369 configured. Potentially dangerous and should only be
370 used if you are entirely sure of the consequences.
372 chandev= [HW,NET] Generic channel device initialisation
374 checkreqprot [SELINUX] Set initial checkreqprot flag value.
375 Format: { "0" | "1" }
376 See security/selinux/Kconfig help text.
377 0 -- check protection applied by kernel (includes
378 any implied execute protection).
379 1 -- check protection requested by application.
380 Default value is set via a kernel config option.
381 Value can be changed at runtime via
382 /selinux/checkreqprot.
384 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
385 [Deprecated]
386 Forces specified clocksource (if available) to be used
387 when calculating gettimeofday(). If specified
388 clocksource is not available, it defaults to PIT.
389 Format: { pit | tsc | cyclone | pmtmr }
391 clocksource= [GENERIC_TIME] Override the default clocksource
392 Format: <string>
393 Override the default clocksource and use the clocksource
394 with the name specified.
395 Some clocksource names to choose from, depending on
396 the platform:
397 [all] jiffies (this is the base, fallback clocksource)
398 [ACPI] acpi_pm
399 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
400 pxa_timer,timer3,32k_counter,timer0_1
401 [AVR32] avr32
402 [X86-32] pit,hpet,tsc,vmi-timer;
403 scx200_hrt on Geode; cyclone on IBM x440
404 [MIPS] MIPS
405 [PARISC] cr16
406 [S390] tod
407 [SH] SuperH
408 [SPARC64] tick
409 [X86-64] hpet,tsc
411 code_bytes [IA32] How many bytes of object code to print in an
412 oops report.
413 Range: 0 - 8192
414 Default: 64
416 disable_8254_timer
417 enable_8254_timer
418 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
419 over the 8254 in addition to over the IO-APIC. The
420 kernel tries to set a sensible default.
422 hpet= [X86-32,HPET] option to control HPET usage
423 Format: { enable (default) | disable | force }
424 disable: disable HPET and use PIT instead
425 force: allow force enabled of undocumented chips (ICH4,
426 VIA, nVidia)
428 com20020= [HW,NET] ARCnet - COM20020 chipset
429 Format:
430 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
432 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
433 Format: <io>[,<irq>]
435 com90xx= [HW,NET]
436 ARCnet - COM90xx chipset (memory-mapped buffers)
437 Format: <io>[,<irq>[,<memstart>]]
439 condev= [HW,S390] console device
440 conmode=
442 console= [KNL] Output console device and options.
444 tty<n> Use the virtual console device <n>.
446 ttyS<n>[,options]
447 ttyUSB0[,options]
448 Use the specified serial port. The options are of
449 the form "bbbbpnf", where "bbbb" is the baud rate,
450 "p" is parity ("n", "o", or "e"), "n" is number of
451 bits, and "f" is flow control ("r" for RTS or
452 omit it). Default is "9600n8".
454 See Documentation/serial-console.txt for more
455 information. See
456 Documentation/networking/netconsole.txt for an
457 alternative.
459 uart[8250],io,<addr>[,options]
460 uart[8250],mmio,<addr>[,options]
461 Start an early, polled-mode console on the 8250/16550
462 UART at the specified I/O port or MMIO address,
463 switching to the matching ttyS device later. The
464 options are the same as for ttyS, above.
466 earlycon= [KNL] Output early console device and options.
467 uart[8250],io,<addr>[,options]
468 uart[8250],mmio,<addr>[,options]
469 Start an early, polled-mode console on the 8250/16550
470 UART at the specified I/O port or MMIO address.
471 The options are the same as for ttyS, above.
473 no_console_suspend
474 [HW] Never suspend the console
475 Disable suspending of consoles during suspend and
476 hibernate operations. Once disabled, debugging
477 messages can reach various consoles while the rest
478 of the system is being put to sleep (ie, while
479 debugging driver suspend/resume hooks). This may
480 not work reliably with all consoles, but is known
481 to work with serial and VGA consoles.
483 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
484 Format:
485 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
487 crashkernel=nn[KMG]@ss[KMG]
488 [KNL] Reserve a chunk of physical memory to
489 hold a kernel to switch to with kexec on panic.
491 crashkernel=range1:size1[,range2:size2,...][@offset]
492 [KNL] Same as above, but depends on the memory
493 in the running system. The syntax of range is
494 start-[end] where start and end are both
495 a memory unit (amount[KMG]). See also
496 Documentation/kdump/kdump.txt for a example.
498 cs4232= [HW,OSS]
499 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
501 cs89x0_dma= [HW,NET]
502 Format: <dma>
504 cs89x0_media= [HW,NET]
505 Format: { rj45 | aui | bnc }
507 dasd= [HW,NET]
508 See header of drivers/s390/block/dasd_devmap.c.
510 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
511 (one device per port)
512 Format: <port#>,<type>
513 See also Documentation/input/joystick-parport.txt
515 debug [KNL] Enable kernel debugging (events log level).
517 debug_locks_verbose=
518 [KNL] verbose self-tests
519 Format=<0|1>
520 Print debugging info while doing the locking API
521 self-tests.
522 We default to 0 (no extra messages), setting it to
523 1 will print _a lot_ more information - normally
524 only useful to kernel developers.
526 decnet= [HW,NET]
527 Format: <area>[,<node>]
528 See also Documentation/networking/decnet.txt.
530 default_blu= [VT]
531 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
532 Change the default blue palette of the console.
533 This is a 16-member array composed of values
534 ranging from 0-255.
536 default_grn= [VT]
537 Format: <green0>,<green1>,<green2>,...,<green15>
538 Change the default green palette of the console.
539 This is a 16-member array composed of values
540 ranging from 0-255.
542 default_red= [VT]
543 Format: <red0>,<red1>,<red2>,...,<red15>
544 Change the default red palette of the console.
545 This is a 16-member array composed of values
546 ranging from 0-255.
548 default_utf8= [VT]
549 Format=<0|1>
550 Set system-wide default UTF-8 mode for all tty's.
551 Default is 0 and by setting to 1, it enables UTF-8
552 mode for all newly opened or allocated terminals.
554 dhash_entries= [KNL]
555 Set number of hash buckets for dentry cache.
557 digi= [HW,SERIAL]
558 IO parameters + enable/disable command.
560 digiepca= [HW,SERIAL]
561 See drivers/char/README.epca and
562 Documentation/digiepca.txt.
564 dmasound= [HW,OSS] Sound subsystem buffers
566 dscc4.setup= [NET]
568 dtc3181e= [HW,SCSI]
570 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
571 earlyprintk=vga
572 earlyprintk=serial[,ttySn[,baudrate]]
574 Append ",keep" to not disable it when the real console
575 takes over.
577 Only vga or serial at a time, not both.
579 Currently only ttyS0 and ttyS1 are supported.
581 Interaction with the standard serial driver is not
582 very good.
584 The VGA output is eventually overwritten by the real
585 console.
587 eata= [HW,SCSI]
589 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
590 Format: <int>
591 0: polling mode
592 non-0: interrupt mode (default)
594 edd= [EDD]
595 Format: {"of[f]" | "sk[ipmbr]"}
596 See comment in arch/i386/boot/edd.S
598 eisa_irq_edge= [PARISC,HW]
599 See header of drivers/parisc/eisa.c.
601 elanfreq= [X86-32]
602 See comment before function elanfreq_setup() in
603 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
605 elevator= [IOSCHED]
606 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
607 See Documentation/block/as-iosched.txt and
608 Documentation/block/deadline-iosched.txt for details.
610 elfcorehdr= [X86-32, X86_64]
611 Specifies physical address of start of kernel core
612 image elf header. Generally kexec loader will
613 pass this option to capture kernel.
614 See Documentation/kdump/kdump.txt for details.
616 enforcing [SELINUX] Set initial enforcing status.
617 Format: {"0" | "1"}
618 See security/selinux/Kconfig help text.
619 0 -- permissive (log only, no denials).
620 1 -- enforcing (deny and log).
621 Default value is 0.
622 Value can be changed at runtime via /selinux/enforce.
624 es1371= [HW,OSS]
625 Format: <spdif>,[<nomix>,[<amplifier>]]
626 See also header of sound/oss/es1371.c.
628 ether= [HW,NET] Ethernet cards parameters
629 This option is obsoleted by the "netdev=" option, which
630 has equivalent usage. See its documentation for details.
632 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
633 Format: <io>[,<irq>]
635 failslab=
636 fail_page_alloc=
637 fail_make_request=[KNL]
638 General fault injection mechanism.
639 Format: <interval>,<probability>,<space>,<times>
640 See also /Documentation/fault-injection/.
642 fd_mcs= [HW,SCSI]
643 See header of drivers/scsi/fd_mcs.c.
645 fdomain= [HW,SCSI]
646 See header of drivers/scsi/fdomain.c.
648 floppy= [HW]
649 See Documentation/floppy.txt.
651 gamecon.map[2|3]=
652 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
653 support via parallel port (up to 5 devices per port)
654 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
655 See also Documentation/input/joystick-parport.txt
657 gamma= [HW,DRM]
659 gdth= [HW,SCSI]
660 See header of drivers/scsi/gdth.c.
662 gpt [EFI] Forces disk with valid GPT signature but
663 invalid Protective MBR to be treated as GPT.
665 gvp11= [HW,SCSI]
667 hashdist= [KNL,NUMA] Large hashes allocated during boot
668 are distributed across NUMA nodes. Defaults on
669 for IA-64, off otherwise.
670 Format: 0 | 1 (for off | on)
672 hcl= [IA-64] SGI's Hardware Graph compatibility layer
674 hd= [EIDE] (E)IDE hard drive subsystem geometry
675 Format: <cyl>,<head>,<sect>
677 hd?= [HW] (E)IDE subsystem
678 hd?lun= See Documentation/ide.txt.
680 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
681 size of <nn>. This works even on boxes that have no
682 highmem otherwise. This also works to reduce highmem
683 size on bigger boxes.
685 highres= [KNL] Enable/disable high resolution timer mode.
686 Valid parameters: "on", "off"
687 Default: "on"
689 hisax= [HW,ISDN]
690 See Documentation/isdn/README.HiSax.
692 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
694 i8042.direct [HW] Put keyboard port into non-translated mode
695 i8042.dumbkbd [HW] Pretend that controller can only read data from
696 keyboard and cannot control its state
697 (Don't attempt to blink the leds)
698 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
699 i8042.nokbd [HW] Don't check/create keyboard port
700 i8042.nomux [HW] Don't check presence of an active multiplexing
701 controller
702 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
703 controllers
704 i8042.panicblink=
705 [HW] Frequency with which keyboard LEDs should blink
706 when kernel panics (default is 0.5 sec)
707 i8042.reset [HW] Reset the controller during init and cleanup
708 i8042.unlock [HW] Unlock (ignore) the keylock
710 i810= [HW,DRM]
712 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
713 indicates that the driver is running on unsupported
714 hardware.
715 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
716 does not match list of supported models.
717 i8k.power_status
718 [HW] Report power status in /proc/i8k
719 (disabled by default)
720 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
721 capability is set.
723 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
724 See Documentation/mca.txt.
726 icn= [HW,ISDN]
727 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
729 ide= [HW] (E)IDE subsystem
730 Format: ide=nodma or ide=doubler or ide=reverse
731 See Documentation/ide.txt.
733 ide?= [HW] (E)IDE subsystem
734 Format: ide?=noprobe or chipset specific parameters.
735 See Documentation/ide.txt.
737 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
738 See Documentation/ide.txt.
740 idle= [X86]
741 Format: idle=poll or idle=mwait
742 Poll forces a polling idle loop that can slightly improves the performance
743 of waking up a idle CPU, but will use a lot of power and make the system
744 run hot. Not recommended.
745 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
746 to not use it because it doesn't save as much power as a normal idle
747 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
748 as idle=poll.
750 ignore_loglevel [KNL]
751 Ignore loglevel setting - this will print /all/
752 kernel messages to the console. Useful for debugging.
754 ihash_entries= [KNL]
755 Set number of hash buckets for inode cache.
757 in2000= [HW,SCSI]
758 See header of drivers/scsi/in2000.c.
760 init= [KNL]
761 Format: <full_path>
762 Run specified binary instead of /sbin/init as init
763 process.
765 initcall_debug [KNL] Trace initcalls as they are executed. Useful
766 for working out where the kernel is dying during
767 startup.
769 initrd= [BOOT] Specify the location of the initial ramdisk
771 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
772 Format: <irq>
774 inttest= [IA64]
776 intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option
777 off
778 Disable intel iommu driver.
779 igfx_off [Default Off]
780 By default, gfx is mapped as normal device. If a gfx
781 device has a dedicated DMAR unit, the DMAR unit is
782 bypassed by not enabling DMAR with this option. In
783 this case, gfx device will use physical address for
784 DMA.
785 forcedac [x86_64]
786 With this option iommu will not optimize to look
787 for io virtual address below 32 bit forcing dual
788 address cycle on pci bus for cards supporting greater
789 than 32 bit addressing. The default is to look
790 for translation below 32 bit and if not available
791 then look in the higher range.
793 io7= [HW] IO7 for Marvel based alpha systems
794 See comment before marvel_specify_io7 in
795 arch/alpha/kernel/core_marvel.c.
797 ip= [IP_PNP]
798 See Documentation/nfsroot.txt.
800 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
801 See comment before ip2_setup() in
802 drivers/char/ip2/ip2base.c.
804 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
805 See header of drivers/scsi/ips.c.
807 ports= [IP_VS_FTP] IPVS ftp helper module
808 Default is 21.
809 Up to 8 (IP_VS_APP_MAX_PORTS) ports
810 may be specified.
811 Format: <port>,<port>....
813 irqfixup [HW]
814 When an interrupt is not handled search all handlers
815 for it. Intended to get systems with badly broken
816 firmware running.
818 irqpoll [HW]
819 When an interrupt is not handled search all handlers
820 for it. Also check all handlers each timer
821 interrupt. Intended to get systems with badly broken
822 firmware running.
824 isapnp= [ISAPNP]
825 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
827 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
828 Format:
829 <cpu number>,...,<cpu number>
830 or
831 <cpu number>-<cpu number> (must be a positive range in ascending order)
832 or a mixture
833 <cpu number>,...,<cpu number>-<cpu number>
834 This option can be used to specify one or more CPUs
835 to isolate from the general SMP balancing and scheduling
836 algorithms. The only way to move a process onto or off
837 an "isolated" CPU is via the CPU affinity syscalls.
838 <cpu number> begins at 0 and the maximum value is
839 "number of CPUs in system - 1".
841 This option is the preferred way to isolate CPUs. The
842 alternative -- manually setting the CPU mask of all
843 tasks in the system -- can cause problems and
844 suboptimal load balancer performance.
846 iucv= [HW,NET]
848 js= [HW,JOY] Analog joystick
849 See Documentation/input/joystick.txt.
851 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
852 specifies the amount of memory usable by the kernel
853 for non-movable allocations. The requested amount is
854 spread evenly throughout all nodes in the system. The
855 remaining memory in each node is used for Movable
856 pages. In the event, a node is too small to have both
857 kernelcore and Movable pages, kernelcore pages will
858 take priority and other nodes will have a larger number
859 of kernelcore pages. The Movable zone is used for the
860 allocation of pages that may be reclaimed or moved
861 by the page migration subsystem. This means that
862 HugeTLB pages may not be allocated from this zone.
863 Note that allocations like PTEs-from-HighMem still
864 use the HighMem zone if it exists, and the Normal
865 zone if it does not.
867 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
868 is similar to kernelcore except it specifies the
869 amount of memory used for migratable allocations.
870 If both kernelcore and movablecore is specified,
871 then kernelcore will be at *least* the specified
872 value but may be more. If movablecore on its own
873 is specified, the administrator must be careful
874 that the amount of memory usable for all allocations
875 is not too small.
877 keepinitrd [HW,ARM]
879 kstack=N [X86-32,X86-64] Print N words from the kernel stack
880 in oops dumps.
882 l2cr= [PPC]
884 lapic [X86-32,APIC] Enable the local APIC even if BIOS
885 disabled it.
887 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
888 C2 power state.
890 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
891 when set.
892 Format: <int>
894 load_ramdisk= [RAM] List of ramdisks to load from floppy
895 See Documentation/ramdisk.txt.
897 lockd.nlm_grace_period=P [NFS] Assign grace period.
898 Format: <integer>
900 lockd.nlm_tcpport=N [NFS] Assign TCP port.
901 Format: <integer>
903 lockd.nlm_timeout=T [NFS] Assign timeout value.
904 Format: <integer>
906 lockd.nlm_udpport=M [NFS] Assign UDP port.
907 Format: <integer>
909 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
910 Format: <irq>
912 loglevel= All Kernel Messages with a loglevel smaller than the
913 console loglevel will be printed to the console. It can
914 also be changed with klogd or other programs. The
915 loglevels are defined as follows:
917 0 (KERN_EMERG) system is unusable
918 1 (KERN_ALERT) action must be taken immediately
919 2 (KERN_CRIT) critical conditions
920 3 (KERN_ERR) error conditions
921 4 (KERN_WARNING) warning conditions
922 5 (KERN_NOTICE) normal but significant condition
923 6 (KERN_INFO) informational
924 7 (KERN_DEBUG) debug-level messages
926 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
927 Format: { n | nk | nM }
928 n must be a power of two. The default size
929 is set in the kernel config file.
931 logo.nologo [FB] Disables display of the built-in Linux logo.
932 This may be used to provide more screen space for
933 kernel log messages and is useful when debugging
934 kernel boot problems.
936 lp=0 [LP] Specify parallel ports to use, e.g,
937 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
938 lp=reset first parallel port). 'lp=0' disables the
939 lp=auto printer driver. 'lp=reset' (which can be
940 specified in addition to the ports) causes
941 attached printers to be reset. Using
942 lp=port1,port2,... specifies the parallel ports
943 to associate lp devices with, starting with
944 lp0. A port specification may be 'none' to skip
945 that lp device, or a parport name such as
946 'parport0'. Specifying 'lp=auto' instead of a
947 port specification list means that device IDs
948 from each port should be examined, to see if
949 an IEEE 1284-compliant printer is attached; if
950 so, the driver will manage that printer.
951 See also header of drivers/char/lp.c.
953 lpj=n [KNL]
954 Sets loops_per_jiffy to given constant, thus avoiding
955 time-consuming boot-time autodetection (up to 250 ms per
956 CPU). 0 enables autodetection (default). To determine
957 the correct value for your kernel, boot with normal
958 autodetection and see what value is printed. Note that
959 on SMP systems the preset will be applied to all CPUs,
960 which is likely to cause problems if your CPUs need
961 significantly divergent settings. An incorrect value
962 will cause delays in the kernel to be wrong, leading to
963 unpredictable I/O errors and other breakage. Although
964 unlikely, in the extreme case this might damage your
965 hardware.
967 ltpc= [NET]
968 Format: <io>,<irq>,<dma>
970 mac5380= [HW,SCSI] Format:
971 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
973 mac53c9x= [HW,SCSI] Format:
974 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
976 machvec= [IA64] Force the use of a particular machine-vector
977 (machvec) in a generic kernel.
978 Example: machvec=hpzx1_swiotlb
980 max_loop= [LOOP] Maximum number of loopback devices that can
981 be mounted
982 Format: <1-256>
984 maxcpus= [SMP] Maximum number of processors that an SMP kernel
985 should make use of. maxcpus=n : n >= 0 limits the
986 kernel to using 'n' processors. n=0 is a special case,
987 it is equivalent to "nosmp", which also disables
988 the IO APIC.
990 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
991 equal to this physical address is ignored.
993 max_luns= [SCSI] Maximum number of LUNs to probe.
994 Should be between 1 and 2^32-1.
996 max_report_luns=
997 [SCSI] Maximum number of LUNs received.
998 Should be between 1 and 16384.
1000 mca-pentium [BUGS=X86-32]
1002 mcatest= [IA-64]
1004 mce [X86-32] Machine Check Exception
1006 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1008 md= [HW] RAID subsystems devices and level
1009 See Documentation/md.txt.
1011 mdacon= [MDA]
1012 Format: <first>,<last>
1013 Specifies range of consoles to be captured by the MDA.
1015 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1016 Amount of memory to be used when the kernel is not able
1017 to see the whole system memory or for test.
1018 [X86-32] Use together with memmap= to avoid physical
1019 address space collisions. Without memmap= PCI devices
1020 could be placed at addresses belonging to unused RAM.
1022 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1023 memory.
1025 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1026 E820 memory map, as specified by the user.
1027 Such memmap=exactmap lines can be constructed based on
1028 BIOS output or other requirements. See the memmap=nn@ss
1029 option description.
1031 memmap=nn[KMG]@ss[KMG]
1032 [KNL] Force usage of a specific region of memory
1033 Region of memory to be used, from ss to ss+nn.
1035 memmap=nn[KMG]#ss[KMG]
1036 [KNL,ACPI] Mark specific memory as ACPI data.
1037 Region of memory to be used, from ss to ss+nn.
1039 memmap=nn[KMG]$ss[KMG]
1040 [KNL,ACPI] Mark specific memory as reserved.
1041 Region of memory to be used, from ss to ss+nn.
1043 meye.*= [HW] Set MotionEye Camera parameters
1044 See Documentation/video4linux/meye.txt.
1046 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1047 Multi-Function General Purpose Timers on AMD Geode
1048 platforms.
1050 mga= [HW,DRM]
1052 mousedev.tap_time=
1053 [MOUSE] Maximum time between finger touching and
1054 leaving touchpad surface for touch to be considered
1055 a tap and be reported as a left button click (for
1056 touchpads working in absolute mode only).
1057 Format: <msecs>
1058 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1059 reporting absolute coordinates, such as tablets
1060 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1061 reporting absolute coordinates, such as tablets
1063 mpu401= [HW,OSS]
1064 Format: <io>,<irq>
1066 MTD_Partition= [MTD]
1067 Format: <name>,<region-number>,<size>,<offset>
1069 MTD_Region= [MTD] Format:
1070 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1072 mtdparts= [MTD]
1073 See drivers/mtd/cmdlinepart.c.
1075 mtouchusb.raw_coordinates=
1076 [HW] Make the MicroTouch USB driver use raw coordinates
1077 ('y', default) or cooked coordinates ('n')
1079 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1081 NCR_D700= [HW,SCSI]
1082 See header of drivers/scsi/NCR_D700.c.
1084 ncr5380= [HW,SCSI]
1086 ncr53c400= [HW,SCSI]
1088 ncr53c400a= [HW,SCSI]
1090 ncr53c406a= [HW,SCSI]
1092 ncr53c8xx= [HW,SCSI]
1094 netdev= [NET] Network devices parameters
1095 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1096 Note that mem_start is often overloaded to mean
1097 something different and driver-specific.
1098 This usage is only documented in each driver source
1099 file if at all.
1101 nfsaddrs= [NFS]
1102 See Documentation/nfsroot.txt.
1104 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1105 See Documentation/nfsroot.txt.
1107 nfs.callback_tcpport=
1108 [NFS] set the TCP port on which the NFSv4 callback
1109 channel should listen.
1111 nfs.idmap_cache_timeout=
1112 [NFS] set the maximum lifetime for idmapper cache
1113 entries.
1115 nfs.enable_ino64=
1116 [NFS] enable 64-bit inode numbers.
1117 If zero, the NFS client will fake up a 32-bit inode
1118 number for the readdir() and stat() syscalls instead
1119 of returning the full 64-bit number.
1120 The default is to return 64-bit inode numbers.
1122 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1124 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1125 emulation library even if a 387 maths coprocessor
1126 is present.
1128 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1129 caches in the slab allocator. Saves per-node memory,
1130 but will impact performance.
1132 noalign [KNL,ARM]
1134 noapic [SMP,APIC] Tells the kernel to not make use of any
1135 IOAPICs that may be present in the system.
1137 nobats [PPC] Do not use BATs for mapping kernel lowmem
1138 on "Classic" PPC cores.
1140 nocache [ARM]
1142 nodelayacct [KNL] Disable per-task delay accounting
1144 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1146 noexec [IA-64]
1148 noexec [X86-32,X86-64]
1149 noexec=on: enable non-executable mappings (default)
1150 noexec=off: disable nn-executable mappings
1152 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1153 register save and restore. The kernel will only save
1154 legacy floating-point registers on task switch.
1156 nohlt [BUGS=ARM]
1158 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1159 instruction doesn't work correctly and not to
1160 use it.
1162 nohalt [IA-64] Tells the kernel not to use the power saving
1163 function PAL_HALT_LIGHT when idle. This increases
1164 power-consumption. On the positive side, it reduces
1165 interrupt wake-up latency, which may improve performance
1166 in certain environments such as networked servers or
1167 real-time systems.
1169 nohz= [KNL] Boottime enable/disable dynamic ticks
1170 Valid arguments: on, off
1171 Default: on
1173 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1175 noirqdebug [X86-32] Disables the code which attempts to detect and
1176 disable unhandled interrupt sources.
1178 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1179 broken timer IRQ sources.
1181 noisapnp [ISAPNP] Disables ISA PnP code.
1183 noinitrd [RAM] Tells the kernel not to load any configured
1184 initial RAM disk.
1186 nointroute [IA-64]
1188 nojitter [IA64] Disables jitter checking for ITC timers.
1190 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1192 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1194 noltlbs [PPC] Do not use large page/tlb entries for kernel
1195 lowmem mapping on PPC40x.
1197 nomca [IA-64] Disable machine check abort handling
1199 nomce [X86-32] Machine Check Exception
1201 nomfgpt [X86-32] Disable Multi-Function General Purpose
1202 Timer usage (for AMD Geode machines).
1204 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1206 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1207 with UP alternatives
1209 noresidual [PPC] Don't use residual data on PReP machines.
1211 noresume [SWSUSP] Disables resume and restores original swap
1212 space.
1214 no-scroll [VGA] Disables scrollback.
1215 This is required for the Braillex ib80-piezo Braille
1216 reader made by F.H. Papenmeier (Germany).
1218 nosbagart [IA-64]
1220 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1222 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1223 and disable the IO APIC. legacy for "maxcpus=0".
1225 nosoftlockup [KNL] Disable the soft-lockup detector.
1227 nosync [HW,M68K] Disables sync negotiation for all devices.
1229 notsc [BUGS=X86-32] Disable Time Stamp Counter
1231 nousb [USB] Disable the USB subsystem
1233 nowb [ARM]
1235 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1236 one of ['zone', 'node', 'default'] can be specified
1237 This can be set from sysctl after boot.
1238 See Documentation/sysctl/vm.txt for details.
1240 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1242 opl3= [HW,OSS]
1243 Format: <io>
1245 oprofile.timer= [HW]
1246 Use timer interrupt instead of performance counters
1248 osst= [HW,SCSI] SCSI Tape Driver
1249 Format: <buffer_size>,<write_threshold>
1250 See also Documentation/scsi/st.txt.
1252 panic= [KNL] Kernel behaviour on panic
1253 Format: <timeout>
1255 parkbd.port= [HW] Parallel port number the keyboard adapter is
1256 connected to, default is 0.
1257 Format: <parport#>
1258 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1259 0 for XT, 1 for AT (default is AT).
1260 Format: <mode>
1262 parport= [HW,PPT] Specify parallel ports. 0 disables.
1263 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1264 Use 'auto' to force the driver to use any
1265 IRQ/DMA settings detected (the default is to
1266 ignore detected IRQ/DMA settings because of
1267 possible conflicts). You can specify the base
1268 address, IRQ, and DMA settings; IRQ and DMA
1269 should be numbers, or 'auto' (for using detected
1270 settings on that particular port), or 'nofifo'
1271 (to avoid using a FIFO even if it is detected).
1272 Parallel ports are assigned in the order they
1273 are specified on the command line, starting
1274 with parport0.
1276 parport_init_mode= [HW,PPT]
1277 Configure VIA parallel port to operate in
1278 a specific mode. This is necessary on Pegasos
1279 computer where firmware has no options for setting
1280 up parallel port mode and sets it to spp.
1281 Currently this function knows 686a and 8231 chips.
1282 Format: [spp|ps2|epp|ecp|ecpepp]
1284 pas2= [HW,OSS] Format:
1285 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1287 pas16= [HW,SCSI]
1288 See header of drivers/scsi/pas16.c.
1290 pause_on_oops=
1291 Halt all CPUs after the first oops has been printed for
1292 the specified number of seconds. This is to be used if
1293 your oopses keep scrolling off the screen.
1295 pcbit= [HW,ISDN]
1297 pcd. [PARIDE]
1298 See header of drivers/block/paride/pcd.c.
1299 See also Documentation/paride.txt.
1301 pci=option[,option...] [PCI] various PCI subsystem options:
1302 off [X86-32] don't probe for the PCI bus
1303 bios [X86-32] force use of PCI BIOS, don't access
1304 the hardware directly. Use this if your machine
1305 has a non-standard PCI host bridge.
1306 nobios [X86-32] disallow use of PCI BIOS, only direct
1307 hardware access methods are allowed. Use this
1308 if you experience crashes upon bootup and you
1309 suspect they are caused by the BIOS.
1310 conf1 [X86-32] Force use of PCI Configuration
1311 Mechanism 1.
1312 conf2 [X86-32] Force use of PCI Configuration
1313 Mechanism 2.
1314 noaer [PCIE] If the PCIEAER kernel config parameter is
1315 enabled, this kernel boot option can be used to
1316 disable the use of PCIE advanced error reporting.
1317 nodomains [PCI] Disable support for multiple PCI
1318 root domains (aka PCI segments, in ACPI-speak).
1319 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1320 Configuration
1321 nomsi [MSI] If the PCI_MSI kernel config parameter is
1322 enabled, this kernel boot option can be used to
1323 disable the use of MSI interrupts system-wide.
1324 nosort [X86-32] Don't sort PCI devices according to
1325 order given by the PCI BIOS. This sorting is
1326 done to get a device order compatible with
1327 older kernels.
1328 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1329 routing table. These calls are known to be buggy
1330 on several machines and they hang the machine
1331 when used, but on other computers it's the only
1332 way to get the interrupt routing table. Try
1333 this option if the kernel is unable to allocate
1334 IRQs or discover secondary PCI buses on your
1335 motherboard.
1336 rom [X86-32] Assign address space to expansion ROMs.
1337 Use with caution as certain devices share
1338 address decoders between ROMs and other
1339 resources.
1340 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1341 assigned automatically to PCI devices. You can
1342 make the kernel exclude IRQs of your ISA cards
1343 this way.
1344 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1345 of the PIRQ table (normally generated
1346 by the BIOS) if it is outside the
1347 F0000h-100000h range.
1348 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1349 useful if the kernel is unable to find your
1350 secondary buses and you want to tell it
1351 explicitly which ones they are.
1352 assign-busses [X86-32] Always assign all PCI bus
1353 numbers ourselves, overriding
1354 whatever the firmware may have done.
1355 usepirqmask [X86-32] Honor the possible IRQ mask stored
1356 in the BIOS $PIR table. This is needed on
1357 some systems with broken BIOSes, notably
1358 some HP Pavilion N5400 and Omnibook XE3
1359 notebooks. This will have no effect if ACPI
1360 IRQ routing is enabled.
1361 noacpi [X86-32] Do not use ACPI for IRQ routing
1362 or for PCI scanning.
1363 use_crs [X86-32] Use _CRS for PCI resource
1364 allocation.
1365 routeirq Do IRQ routing for all PCI devices.
1366 This is normally done in pci_enable_device(),
1367 so this option is a temporary workaround
1368 for broken drivers that don't call it.
1369 firmware [ARM] Do not re-enumerate the bus but instead
1370 just use the configuration from the
1371 bootloader. This is currently used on
1372 IXP2000 systems where the bus has to be
1373 configured a certain way for adjunct CPUs.
1374 noearly [X86] Don't do any early type 1 scanning.
1375 This might help on some broken boards which
1376 machine check when some devices' config space
1377 is read. But various workarounds are disabled
1378 and some IOMMU drivers will not work.
1379 bfsort Sort PCI devices into breadth-first order.
1380 This sorting is done to get a device
1381 order compatible with older (<= 2.4) kernels.
1382 nobfsort Don't sort PCI devices into breadth-first order.
1383 cbiosize=nn[KMG] The fixed amount of bus space which is
1384 reserved for the CardBus bridge's IO window.
1385 The default value is 256 bytes.
1386 cbmemsize=nn[KMG] The fixed amount of bus space which is
1387 reserved for the CardBus bridge's memory
1388 window. The default value is 64 megabytes.
1390 pcmv= [HW,PCMCIA] BadgePAD 4
1392 pd. [PARIDE]
1393 See Documentation/paride.txt.
1395 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1396 boot time.
1397 Format: { 0 | 1 }
1398 See arch/parisc/kernel/pdc_chassis.c
1400 pf. [PARIDE]
1401 See Documentation/paride.txt.
1403 pg. [PARIDE]
1404 See Documentation/paride.txt.
1406 pirq= [SMP,APIC] Manual mp-table setup
1407 See Documentation/i386/IO-APIC.txt.
1409 plip= [PPT,NET] Parallel port network link
1410 Format: { parport<nr> | timid | 0 }
1411 See also Documentation/parport.txt.
1413 pnpacpi= [ACPI]
1414 { off }
1416 pnpbios= [ISAPNP]
1417 { on | off | curr | res | no-curr | no-res }
1419 pnp_reserve_irq=
1420 [ISAPNP] Exclude IRQs for the autoconfiguration
1422 pnp_reserve_dma=
1423 [ISAPNP] Exclude DMAs for the autoconfiguration
1425 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1426 Ranges are in pairs (I/O port base and size).
1428 pnp_reserve_mem=
1429 [ISAPNP] Exclude memory regions for the
1430 autoconfiguration.
1431 Ranges are in pairs (memory base and size).
1433 print-fatal-signals=
1434 [KNL] debug: print fatal signals
1435 print-fatal-signals=1: print segfault info to
1436 the kernel console.
1437 default: off.
1439 printk.time= Show timing data prefixed to each printk message line
1440 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1442 profile= [KNL] Enable kernel profiling via /proc/profile
1443 Format: [schedule,]<number>
1444 Param: "schedule" - profile schedule points.
1445 Param: <number> - step/bucket size as a power of 2 for
1446 statistical time based profiling.
1447 Param: "sleep" - profile D-state sleeping (millisecs)
1448 Param: "kvm" - profile VM exits.
1450 processor.max_cstate= [HW,ACPI]
1451 Limit processor to maximum C-state
1452 max_cstate=9 overrides any DMI blacklist limit.
1454 processor.nocst [HW,ACPI]
1455 Ignore the _CST method to determine C-states,
1456 instead using the legacy FADT method
1458 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1459 before loading.
1460 See Documentation/ramdisk.txt.
1462 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1463 probe for; one of (bare|imps|exps|lifebook|any).
1464 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1465 per second.
1466 psmouse.resetafter= [HW,MOUSE]
1467 Try to reset the device after so many bad packets
1468 (0 = never).
1469 psmouse.resolution=
1470 [HW,MOUSE] Set desired mouse resolution, in dpi.
1471 psmouse.smartscroll=
1472 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1473 0 = disabled, 1 = enabled (default).
1475 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1476 Format:
1477 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1479 pt. [PARIDE]
1480 See Documentation/paride.txt.
1482 pty.legacy_count=
1483 [KNL] Number of legacy pty's. Overwrites compiled-in
1484 default number.
1486 quiet [KNL] Disable most log messages
1488 r128= [HW,DRM]
1490 raid= [HW,RAID]
1491 See Documentation/md.txt.
1493 ramdisk_blocksize= [RAM]
1494 See Documentation/ramdisk.txt.
1496 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1497 See Documentation/ramdisk.txt.
1499 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1500 RCU callbacks to process in one batch.
1502 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1503 RCU callbacks over which batch limiting is disabled.
1505 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1506 RCU callbacks below which batch limiting is re-enabled.
1508 rdinit= [KNL]
1509 Format: <full_path>
1510 Run specified binary instead of /init from the ramdisk,
1511 used for early userspace startup. See initrd.
1513 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1514 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1515 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1517 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1519 reservetop= [X86-32]
1520 Format: nn[KMG]
1521 Reserves a hole at the top of the kernel virtual
1522 address space.
1524 reset_devices [KNL] Force drivers to reset the underlying device
1525 during initialization.
1527 resume= [SWSUSP]
1528 Specify the partition device for software suspend
1530 resume_offset= [SWSUSP]
1531 Specify the offset from the beginning of the partition
1532 given by "resume=" at which the swap header is located,
1533 in <PAGE_SIZE> units (needed only for swap files).
1534 See Documentation/power/swsusp-and-swap-files.txt
1536 retain_initrd [RAM] Keep initrd memory after extraction
1538 rhash_entries= [KNL,NET]
1539 Set number of hash buckets for route cache
1541 riscom8= [HW,SERIAL]
1542 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1544 ro [KNL] Mount root device read-only on boot
1546 root= [KNL] Root filesystem
1548 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1549 mount the root filesystem
1551 rootflags= [KNL] Set root filesystem mount option string
1553 rootfstype= [KNL] Set root filesystem type
1555 rootwait [KNL] Wait (indefinitely) for root device to show up.
1556 Useful for devices that are detected asynchronously
1557 (e.g. USB and MMC devices).
1559 root_plug.vendor_id=
1560 [ROOTPLUG] Override the default vendor ID
1562 root_plug.product_id=
1563 [ROOTPLUG] Override the default product ID
1565 root_plug.debug=
1566 [ROOTPLUG] Enable debugging output
1568 rw [KNL] Mount root device read-write on boot
1570 S [KNL] Run init in single mode
1572 sa1100ir [NET]
1573 See drivers/net/irda/sa1100_ir.c.
1575 sbni= [NET] Granch SBNI12 leased line adapter
1577 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1578 Format: <io>[,<timeout>[,<isapnp>]]
1580 scsi_debug_*= [SCSI]
1581 See drivers/scsi/scsi_debug.c.
1583 scsi_default_dev_flags=
1584 [SCSI] SCSI default device flags
1585 Format: <integer>
1587 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1588 Format: <vendor>:<model>:<flags>
1589 (flags are integer value)
1591 scsi_logging= [SCSI]
1593 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1594 discovered. async scans them in kernel threads,
1595 allowing boot to proceed. none ignores them, expecting
1596 user space to do the scan.
1598 selinux [SELINUX] Disable or enable SELinux at boot time.
1599 Format: { "0" | "1" }
1600 See security/selinux/Kconfig help text.
1601 0 -- disable.
1602 1 -- enable.
1603 Default value is set via kernel config option.
1604 If enabled at boot time, /selinux/disable can be used
1605 later to disable prior to initial policy load.
1607 selinux_compat_net =
1608 [SELINUX] Set initial selinux_compat_net flag value.
1609 Format: { "0" | "1" }
1610 0 -- use new secmark-based packet controls
1611 1 -- use legacy packet controls
1612 Default value is 0 (preferred).
1613 Value can be changed at runtime via
1614 /selinux/compat_net.
1616 serialnumber [BUGS=X86-32]
1618 shapers= [NET]
1619 Maximal number of shapers.
1621 sim710= [SCSI,HW]
1622 See header of drivers/scsi/sim710.c.
1624 simeth= [IA-64]
1625 simscsi=
1627 slram= [HW,MTD]
1629 slub_debug[=options[,slabs]] [MM, SLUB]
1630 Enabling slub_debug allows one to determine the
1631 culprit if slab objects become corrupted. Enabling
1632 slub_debug can create guard zones around objects and
1633 may poison objects when not in use. Also tracks the
1634 last alloc / free. For more information see
1635 Documentation/vm/slub.txt.
1637 slub_max_order= [MM, SLUB]
1638 Determines the maximum allowed order for slabs.
1639 A high setting may cause OOMs due to memory
1640 fragmentation. For more information see
1641 Documentation/vm/slub.txt.
1643 slub_min_objects= [MM, SLUB]
1644 The minimum number of objects per slab. SLUB will
1645 increase the slab order up to slub_max_order to
1646 generate a sufficiently large slab able to contain
1647 the number of objects indicated. The higher the number
1648 of objects the smaller the overhead of tracking slabs
1649 and the less frequently locks need to be acquired.
1650 For more information see Documentation/vm/slub.txt.
1652 slub_min_order= [MM, SLUB]
1653 Determines the mininum page order for slabs. Must be
1654 lower than slub_max_order.
1655 For more information see Documentation/vm/slub.txt.
1657 slub_nomerge [MM, SLUB]
1658 Disable merging of slabs with similar size. May be
1659 necessary if there is some reason to distinguish
1660 allocs to different slabs. Debug options disable
1661 merging on their own.
1662 For more information see Documentation/vm/slub.txt.
1664 smart2= [HW]
1665 Format: <io1>[,<io2>[,...,<io8>]]
1667 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1668 attempt to substitute SMP alternatives once at boot.
1670 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1671 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1672 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1673 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1674 smsc-ircc2.ircc_irq= [HW] IRQ line
1675 smsc-ircc2.ircc_dma= [HW] DMA channel
1676 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1677 0: Toshiba Satellite 1800 (GP data pin select)
1678 1: Fast pin select (default)
1679 2: ATC IRMode
1681 snd-ad1816a= [HW,ALSA]
1683 snd-ad1848= [HW,ALSA]
1685 snd-ali5451= [HW,ALSA]
1687 snd-als100= [HW,ALSA]
1689 snd-als4000= [HW,ALSA]
1691 snd-azt2320= [HW,ALSA]
1693 snd-cmi8330= [HW,ALSA]
1695 snd-cmipci= [HW,ALSA]
1697 snd-cs4231= [HW,ALSA]
1699 snd-cs4232= [HW,ALSA]
1701 snd-cs4236= [HW,ALSA]
1703 snd-cs4281= [HW,ALSA]
1705 snd-cs46xx= [HW,ALSA]
1707 snd-dt019x= [HW,ALSA]
1709 snd-dummy= [HW,ALSA]
1711 snd-emu10k1= [HW,ALSA]
1713 snd-ens1370= [HW,ALSA]
1715 snd-ens1371= [HW,ALSA]
1717 snd-es968= [HW,ALSA]
1719 snd-es1688= [HW,ALSA]
1721 snd-es18xx= [HW,ALSA]
1723 snd-es1938= [HW,ALSA]
1725 snd-es1968= [HW,ALSA]
1727 snd-fm801= [HW,ALSA]
1729 snd-gusclassic= [HW,ALSA]
1731 snd-gusextreme= [HW,ALSA]
1733 snd-gusmax= [HW,ALSA]
1735 snd-hdsp= [HW,ALSA]
1737 snd-ice1712= [HW,ALSA]
1739 snd-intel8x0= [HW,ALSA]
1741 snd-interwave= [HW,ALSA]
1743 snd-interwave-stb=
1744 [HW,ALSA]
1746 snd-korg1212= [HW,ALSA]
1748 snd-maestro3= [HW,ALSA]
1750 snd-mpu401= [HW,ALSA]
1752 snd-mtpav= [HW,ALSA]
1754 snd-nm256= [HW,ALSA]
1756 snd-opl3sa2= [HW,ALSA]
1758 snd-opti92x-ad1848=
1759 [HW,ALSA]
1761 snd-opti92x-cs4231=
1762 [HW,ALSA]
1764 snd-opti93x= [HW,ALSA]
1766 snd-pmac= [HW,ALSA]
1768 snd-rme32= [HW,ALSA]
1770 snd-rme96= [HW,ALSA]
1772 snd-rme9652= [HW,ALSA]
1774 snd-sb8= [HW,ALSA]
1776 snd-sb16= [HW,ALSA]
1778 snd-sbawe= [HW,ALSA]
1780 snd-serial= [HW,ALSA]
1782 snd-sgalaxy= [HW,ALSA]
1784 snd-sonicvibes= [HW,ALSA]
1786 snd-sun-amd7930=
1787 [HW,ALSA]
1789 snd-sun-cs4231= [HW,ALSA]
1791 snd-trident= [HW,ALSA]
1793 snd-usb-audio= [HW,ALSA,USB]
1795 snd-via82xx= [HW,ALSA]
1797 snd-virmidi= [HW,ALSA]
1799 snd-wavefront= [HW,ALSA]
1801 snd-ymfpci= [HW,ALSA]
1803 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1804 See Documentation/sonypi.txt
1806 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1807 See Documentation/specialix.txt.
1809 spia_io_base= [HW,MTD]
1810 spia_fio_base=
1811 spia_pedr=
1812 spia_peddr=
1814 sscape= [HW,OSS]
1815 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1817 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1818 See Documentation/scsi/st.txt.
1820 st0x= [HW,SCSI]
1821 See header of drivers/scsi/seagate.c.
1823 sti= [PARISC,HW]
1824 Format: <num>
1825 Set the STI (builtin display/keyboard on the HP-PARISC
1826 machines) console (graphic card) which should be used
1827 as the initial boot-console.
1828 See also comment in drivers/video/console/sticore.c.
1830 sti_font= [HW]
1831 See comment in drivers/video/console/sticore.c.
1833 stifb= [HW]
1834 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1836 sunrpc.pool_mode=
1837 [NFS]
1838 Control how the NFS server code allocates CPUs to
1839 service thread pools. Depending on how many NICs
1840 you have and where their interrupts are bound, this
1841 option will affect which CPUs will do NFS serving.
1842 Note: this parameter cannot be changed while the
1843 NFS server is running.
1845 auto the server chooses an appropriate mode
1846 automatically using heuristics
1847 global a single global pool contains all CPUs
1848 percpu one pool for each CPU
1849 pernode one pool for each NUMA node (equivalent
1850 to global on non-NUMA machines)
1852 swiotlb= [IA-64] Number of I/O TLB slabs
1854 switches= [HW,M68k]
1856 sym53c416= [HW,SCSI]
1857 See header of drivers/scsi/sym53c416.c.
1859 sysrq_always_enabled
1860 [KNL]
1861 Ignore sysrq setting - this boot parameter will
1862 neutralize any effect of /proc/sys/kernel/sysrq.
1863 Useful for debugging.
1865 t128= [HW,SCSI]
1866 See header of drivers/scsi/t128.c.
1868 tdfx= [HW,DRM]
1870 thash_entries= [KNL,NET]
1871 Set number of hash buckets for TCP connection
1873 thermal.act= [HW,ACPI]
1874 -1: disable all active trip points in all thermal zones
1875 <degrees C>: override all lowest active trip points
1877 thermal.crt= [HW,ACPI]
1878 -1: disable all critical trip points in all thermal zones
1879 <degrees C>: lower all critical trip points
1881 thermal.nocrt= [HW,ACPI]
1882 Set to disable actions on ACPI thermal zone
1883 critical and hot trip points.
1885 thermal.off= [HW,ACPI]
1886 1: disable ACPI thermal control
1888 thermal.psv= [HW,ACPI]
1889 -1: disable all passive trip points
1890 <degrees C>: override all passive trip points to this value
1892 thermal.tzp= [HW,ACPI]
1893 Specify global default ACPI thermal zone polling rate
1894 <deci-seconds>: poll all this frequency
1895 0: no polling (default)
1897 time Show timing data prefixed to each printk message line
1898 [deprecated, see 'printk.time']
1900 tipar.timeout= [HW,PPT]
1901 Set communications timeout in tenths of a second
1902 (default 15).
1904 tipar.delay= [HW,PPT]
1905 Set inter-bit delay in microseconds (default 10).
1907 tmc8xx= [HW,SCSI]
1908 See header of drivers/scsi/seagate.c.
1910 tmscsim= [HW,SCSI]
1911 See comment before function dc390_setup() in
1912 drivers/scsi/tmscsim.c.
1914 tp720= [HW,PS2]
1916 trix= [HW,OSS] MediaTrix AudioTrix Pro
1917 Format:
1918 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1920 turbografx.map[2|3]= [HW,JOY]
1921 TurboGraFX parallel port interface
1922 Format:
1923 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1924 See also Documentation/input/joystick-parport.txt
1926 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1927 See header of drivers/scsi/u14-34f.c.
1929 uart401= [HW,OSS]
1930 Format: <io>,<irq>
1932 uart6850= [HW,OSS]
1933 Format: <io>,<irq>
1935 uhci-hcd.ignore_oc=
1936 [USB] Ignore overcurrent events (default N).
1937 Some badly-designed motherboards generate lots of
1938 bogus events, for ports that aren't wired to
1939 anything. Set this parameter to avoid log spamming.
1940 Note that genuine overcurrent events won't be
1941 reported either.
1943 usbcore.autosuspend=
1944 [USB] The autosuspend time delay (in seconds) used
1945 for newly-detected USB devices (default 2). This
1946 is the time required before an idle device will be
1947 autosuspended. Devices for which the delay is set
1948 to a negative value won't be autosuspended at all.
1950 usbhid.mousepoll=
1951 [USBHID] The interval which mice are to be polled at.
1953 vdso= [X86-32,SH,x86-64]
1954 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
1955 vdso=1: enable VDSO (default)
1956 vdso=0: disable VDSO mapping
1958 vector= [IA-64,SMP]
1959 vector=percpu: enable percpu vector domain
1961 video= [FB] Frame buffer configuration
1962 See Documentation/fb/modedb.txt.
1964 vga= [BOOT,X86-32] Select a particular video mode
1965 See Documentation/i386/boot.txt and
1966 Documentation/svga.txt.
1967 Use vga=ask for menu.
1968 This is actually a boot loader parameter; the value is
1969 passed to the kernel using a special protocol.
1971 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1972 size of <nn>. This can be used to increase the
1973 minimum size (128MB on x86). It can also be used to
1974 decrease the size and leave more room for directly
1975 mapped kernel RAM.
1977 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1978 Format: <command>
1980 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1981 Format: <command>
1983 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1984 Format: <command>
1986 waveartist= [HW,OSS]
1987 Format: <io>,<irq>,<dma>,<dma2>
1989 wd33c93= [HW,SCSI]
1990 See header of drivers/scsi/wd33c93.c.
1992 wd7000= [HW,SCSI]
1993 See header of drivers/scsi/wd7000.c.
1995 wdt= [WDT] Watchdog
1996 See Documentation/watchdog/wdt.txt.
1998 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1999 xd_geo= See header of drivers/block/xd.c.
2001 xirc2ps_cs= [NET,PCMCIA]
2002 Format:
2003 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2005 norandmaps Don't use address space randomization
2006 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2008 ______________________________________________________________________
2010 TODO:
2012 Add documentation for ALSA options.
2013 Add more DRM drivers.