| blob | b884ade006ca4bb1d22713c65d63a3607e0e6664 |
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 applicom= [HW]
298 Format: <mem>,<irq>
300 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
301 Format: <io>,<irq>,<nodeID>
303 ataflop= [HW,M68k]
305 atarimouse= [HW,MOUSE] Atari Mouse
307 atascsi= [HW,SCSI] Atari SCSI
309 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
310 EzKey and similar keyboards
312 atkbd.reset= [HW] Reset keyboard during initialization
314 atkbd.set= [HW] Select keyboard code set
315 Format: <int> (2 = AT (default), 3 = PS/2)
317 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
318 keyboards
320 atkbd.softraw= [HW] Choose between synthetic and real raw mode
321 Format: <bool> (0 = real, 1 = synthetic (default))
323 atkbd.softrepeat= [HW]
324 Use software keyboard repeat
326 autotest [IA64]
328 baycom_epp= [HW,AX25]
329 Format: <io>,<mode>
331 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
332 Format: <io>,<mode>
333 See header of drivers/net/hamradio/baycom_par.c.
335 baycom_ser_fdx= [HW,AX25]
336 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
337 Format: <io>,<irq>,<mode>[,<baud>]
338 See header of drivers/net/hamradio/baycom_ser_fdx.c.
340 baycom_ser_hdx= [HW,AX25]
341 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
342 Format: <io>,<irq>,<mode>
343 See header of drivers/net/hamradio/baycom_ser_hdx.c.
345 blkmtd_device= [HW,MTD]
346 blkmtd_erasesz=
347 blkmtd_ro=
348 blkmtd_bs=
349 blkmtd_count=
351 boot_delay= Milliseconds to delay each printk during boot.
352 Values larger than 10 seconds (10000) are changed to
353 no delay (0).
354 Format: integer
356 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
357 bttv.radio= Most important insmod options are available as
358 kernel args too.
359 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
360 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
362 BusLogic= [HW,SCSI]
363 See drivers/scsi/BusLogic.c, comment before function
364 BusLogic_ParseDriverOptions().
366 c101= [NET] Moxa C101 synchronous serial card
368 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
369 Sometimes CPU hardware bugs make them report the cache
370 size incorrectly. The kernel will attempt work arounds
371 to fix known problems, but for some CPUs it is not
372 possible to determine what the correct size should be.
373 This option provides an override for these situations.
375 capability.disable=
376 [SECURITY] Disable capabilities. This would normally
377 be used only if an alternative security model is to be
378 configured. Potentially dangerous and should only be
379 used if you are entirely sure of the consequences.
381 chandev= [HW,NET] Generic channel device initialisation
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.
393 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
394 [Deprecated]
395 Forces specified clocksource (if available) to be used
396 when calculating gettimeofday(). If specified
397 clocksource is not available, it defaults to PIT.
398 Format: { pit | tsc | cyclone | pmtmr }
400 clocksource= [GENERIC_TIME] Override the default clocksource
401 Format: <string>
402 Override the default clocksource and use the clocksource
403 with the name specified.
404 Some clocksource names to choose from, depending on
405 the platform:
406 [all] jiffies (this is the base, fallback clocksource)
407 [ACPI] acpi_pm
408 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
409 pxa_timer,timer3,32k_counter,timer0_1
410 [AVR32] avr32
411 [X86-32] pit,hpet,tsc,vmi-timer;
412 scx200_hrt on Geode; cyclone on IBM x440
413 [MIPS] MIPS
414 [PARISC] cr16
415 [S390] tod
416 [SH] SuperH
417 [SPARC64] tick
418 [X86-64] hpet,tsc
420 code_bytes [IA32] How many bytes of object code to print in an
421 oops report.
422 Range: 0 - 8192
423 Default: 64
425 disable_8254_timer
426 enable_8254_timer
427 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
428 over the 8254 in addition to over the IO-APIC. The
429 kernel tries to set a sensible default.
431 hpet= [X86-32,HPET] option to disable HPET and use PIT.
432 Format: disable
434 com20020= [HW,NET] ARCnet - COM20020 chipset
435 Format:
436 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
438 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
439 Format: <io>[,<irq>]
441 com90xx= [HW,NET]
442 ARCnet - COM90xx chipset (memory-mapped buffers)
443 Format: <io>[,<irq>[,<memstart>]]
445 condev= [HW,S390] console device
446 conmode=
448 console= [KNL] Output console device and options.
450 tty<n> Use the virtual console device <n>.
452 ttyS<n>[,options]
453 ttyUSB0[,options]
454 Use the specified serial port. The options are of
455 the form "bbbbpnf", where "bbbb" is the baud rate,
456 "p" is parity ("n", "o", or "e"), "n" is number of
457 bits, and "f" is flow control ("r" for RTS or
458 omit it). Default is "9600n8".
460 See Documentation/serial-console.txt for more
461 information. See
462 Documentation/networking/netconsole.txt for an
463 alternative.
465 uart[8250],io,<addr>[,options]
466 uart[8250],mmio,<addr>[,options]
467 Start an early, polled-mode console on the 8250/16550
468 UART at the specified I/O port or MMIO address,
469 switching to the matching ttyS device later. The
470 options are the same as for ttyS, above.
472 earlycon= [KNL] Output early console device and options.
473 uart[8250],io,<addr>[,options]
474 uart[8250],mmio,<addr>[,options]
475 Start an early, polled-mode console on the 8250/16550
476 UART at the specified I/O port or MMIO address.
477 The options are the same as for ttyS, above.
479 no_console_suspend
480 [HW] Never suspend the console
481 Disable suspending of consoles during suspend and
482 hibernate operations. Once disabled, debugging
483 messages can reach various consoles while the rest
484 of the system is being put to sleep (ie, while
485 debugging driver suspend/resume hooks). This may
486 not work reliably with all consoles, but is known
487 to work with serial and VGA consoles.
489 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
490 Format:
491 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
493 crashkernel=nn[KMG]@ss[KMG]
494 [KNL] Reserve a chunk of physical memory to
495 hold a kernel to switch to with kexec on panic.
497 crashkernel=range1:size1[,range2:size2,...][@offset]
498 [KNL] Same as above, but depends on the memory
499 in the running system. The syntax of range is
500 start-[end] where start and end are both
501 a memory unit (amount[KMG]). See also
502 Documentation/kdump/kdump.txt for a example.
504 cs4232= [HW,OSS]
505 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
507 cs89x0_dma= [HW,NET]
508 Format: <dma>
510 cs89x0_media= [HW,NET]
511 Format: { rj45 | aui | bnc }
513 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
515 dasd= [HW,NET]
516 See header of drivers/s390/block/dasd_devmap.c.
518 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
519 (one device per port)
520 Format: <port#>,<type>
521 See also Documentation/input/joystick-parport.txt
523 debug [KNL] Enable kernel debugging (events log level).
525 debug_locks_verbose=
526 [KNL] verbose self-tests
527 Format=<0|1>
528 Print debugging info while doing the locking API
529 self-tests.
530 We default to 0 (no extra messages), setting it to
531 1 will print _a lot_ more information - normally
532 only useful to kernel developers.
534 decnet= [HW,NET]
535 Format: <area>[,<node>]
536 See also Documentation/networking/decnet.txt.
538 default_blu= [VT]
539 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
540 Change the default blue palette of the console.
541 This is a 16-member array composed of values
542 ranging from 0-255.
544 default_grn= [VT]
545 Format: <green0>,<green1>,<green2>,...,<green15>
546 Change the default green palette of the console.
547 This is a 16-member array composed of values
548 ranging from 0-255.
550 default_red= [VT]
551 Format: <red0>,<red1>,<red2>,...,<red15>
552 Change the default red palette of the console.
553 This is a 16-member array composed of values
554 ranging from 0-255.
556 default_utf8= [VT]
557 Format=<0|1>
558 Set system-wide default UTF-8 mode for all tty's.
559 Default is 0 and by setting to 1, it enables UTF-8
560 mode for all newly opened or allocated terminals.
562 dhash_entries= [KNL]
563 Set number of hash buckets for dentry cache.
565 digi= [HW,SERIAL]
566 IO parameters + enable/disable command.
568 digiepca= [HW,SERIAL]
569 See drivers/char/README.epca and
570 Documentation/digiepca.txt.
572 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
573 support available.
574 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
576 dmasound= [HW,OSS] Sound subsystem buffers
578 dscc4.setup= [NET]
580 dtc3181e= [HW,SCSI]
582 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
583 earlyprintk=vga
584 earlyprintk=serial[,ttySn[,baudrate]]
586 Append ",keep" to not disable it when the real console
587 takes over.
589 Only vga or serial at a time, not both.
591 Currently only ttyS0 and ttyS1 are supported.
593 Interaction with the standard serial driver is not
594 very good.
596 The VGA output is eventually overwritten by the real
597 console.
599 eata= [HW,SCSI]
601 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
602 Format: <int>
603 0: polling mode
604 non-0: interrupt mode (default)
606 eda= [HW,PS2]
608 edb= [HW,PS2]
610 edd= [EDD]
611 Format: {"of[f]" | "sk[ipmbr]"}
612 See comment in arch/i386/boot/edd.S
614 eisa_irq_edge= [PARISC,HW]
615 See header of drivers/parisc/eisa.c.
617 elanfreq= [X86-32]
618 See comment before function elanfreq_setup() in
619 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
621 elevator= [IOSCHED]
622 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
623 See Documentation/block/as-iosched.txt and
624 Documentation/block/deadline-iosched.txt for details.
626 elfcorehdr= [X86-32, X86_64]
627 Specifies physical address of start of kernel core
628 image elf header. Generally kexec loader will
629 pass this option to capture kernel.
630 See Documentation/kdump/kdump.txt for details.
632 enforcing [SELINUX] Set initial enforcing status.
633 Format: {"0" | "1"}
634 See security/selinux/Kconfig help text.
635 0 -- permissive (log only, no denials).
636 1 -- enforcing (deny and log).
637 Default value is 0.
638 Value can be changed at runtime via /selinux/enforce.
640 es1371= [HW,OSS]
641 Format: <spdif>,[<nomix>,[<amplifier>]]
642 See also header of sound/oss/es1371.c.
644 ether= [HW,NET] Ethernet cards parameters
645 This option is obsoleted by the "netdev=" option, which
646 has equivalent usage. See its documentation for details.
648 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
649 Format: <io>[,<irq>]
651 failslab=
652 fail_page_alloc=
653 fail_make_request=[KNL]
654 General fault injection mechanism.
655 Format: <interval>,<probability>,<space>,<times>
656 See also /Documentation/fault-injection/.
658 fd_mcs= [HW,SCSI]
659 See header of drivers/scsi/fd_mcs.c.
661 fdomain= [HW,SCSI]
662 See header of drivers/scsi/fdomain.c.
664 floppy= [HW]
665 See Documentation/floppy.txt.
667 gamecon.map[2|3]=
668 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
669 support via parallel port (up to 5 devices per port)
670 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
671 See also Documentation/input/joystick-parport.txt
673 gamma= [HW,DRM]
675 gdth= [HW,SCSI]
676 See header of drivers/scsi/gdth.c.
678 gpt [EFI] Forces disk with valid GPT signature but
679 invalid Protective MBR to be treated as GPT.
681 gvp11= [HW,SCSI]
683 hashdist= [KNL,NUMA] Large hashes allocated during boot
684 are distributed across NUMA nodes. Defaults on
685 for IA-64, off otherwise.
686 Format: 0 | 1 (for off | on)
688 hcl= [IA-64] SGI's Hardware Graph compatibility layer
690 hd= [EIDE] (E)IDE hard drive subsystem geometry
691 Format: <cyl>,<head>,<sect>
693 hd?= [HW] (E)IDE subsystem
694 hd?lun= See Documentation/ide.txt.
696 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
697 size of <nn>. This works even on boxes that have no
698 highmem otherwise. This also works to reduce highmem
699 size on bigger boxes.
701 highres= [KNL] Enable/disable high resolution timer mode.
702 Valid parameters: "on", "off"
703 Default: "on"
705 hisax= [HW,ISDN]
706 See Documentation/isdn/README.HiSax.
708 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
710 i8042.direct [HW] Put keyboard port into non-translated mode
711 i8042.dumbkbd [HW] Pretend that controller can only read data from
712 keyboard and cannot control its state
713 (Don't attempt to blink the leds)
714 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
715 i8042.nokbd [HW] Don't check/create keyboard port
716 i8042.nomux [HW] Don't check presence of an active multiplexing
717 controller
718 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
719 controllers
720 i8042.panicblink=
721 [HW] Frequency with which keyboard LEDs should blink
722 when kernel panics (default is 0.5 sec)
723 i8042.reset [HW] Reset the controller during init and cleanup
724 i8042.unlock [HW] Unlock (ignore) the keylock
726 i810= [HW,DRM]
728 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
729 indicates that the driver is running on unsupported
730 hardware.
731 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
732 does not match list of supported models.
733 i8k.power_status
734 [HW] Report power status in /proc/i8k
735 (disabled by default)
736 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
737 capability is set.
739 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
740 See Documentation/mca.txt.
742 icn= [HW,ISDN]
743 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
745 ide= [HW] (E)IDE subsystem
746 Format: ide=nodma or ide=doubler or ide=reverse
747 See Documentation/ide.txt.
749 ide?= [HW] (E)IDE subsystem
750 Format: ide?=noprobe or chipset specific parameters.
751 See Documentation/ide.txt.
753 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
754 See Documentation/ide.txt.
756 idle= [X86]
757 Format: idle=poll or idle=mwait
758 Poll forces a polling idle loop that can slightly improves the performance
759 of waking up a idle CPU, but will use a lot of power and make the system
760 run hot. Not recommended.
761 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
762 to not use it because it doesn't save as much power as a normal idle
763 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
764 as idle=poll.
766 ignore_loglevel [KNL]
767 Ignore loglevel setting - this will print /all/
768 kernel messages to the console. Useful for debugging.
770 ihash_entries= [KNL]
771 Set number of hash buckets for inode cache.
773 in2000= [HW,SCSI]
774 See header of drivers/scsi/in2000.c.
776 init= [KNL]
777 Format: <full_path>
778 Run specified binary instead of /sbin/init as init
779 process.
781 initcall_debug [KNL] Trace initcalls as they are executed. Useful
782 for working out where the kernel is dying during
783 startup.
785 initrd= [BOOT] Specify the location of the initial ramdisk
787 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
788 Format: <irq>
790 inttest= [IA64]
792 io7= [HW] IO7 for Marvel based alpha systems
793 See comment before marvel_specify_io7 in
794 arch/alpha/kernel/core_marvel.c.
796 ip= [IP_PNP]
797 See Documentation/nfsroot.txt.
799 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
800 See comment before ip2_setup() in
801 drivers/char/ip2/ip2base.c.
803 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
804 See header of drivers/scsi/ips.c.
806 ports= [IP_VS_FTP] IPVS ftp helper module
807 Default is 21.
808 Up to 8 (IP_VS_APP_MAX_PORTS) ports
809 may be specified.
810 Format: <port>,<port>....
812 irqfixup [HW]
813 When an interrupt is not handled search all handlers
814 for it. Intended to get systems with badly broken
815 firmware running.
817 irqpoll [HW]
818 When an interrupt is not handled search all handlers
819 for it. Also check all handlers each timer
820 interrupt. Intended to get systems with badly broken
821 firmware running.
823 isapnp= [ISAPNP]
824 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
826 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
827 Format:
828 <cpu number>,...,<cpu number>
829 or
830 <cpu number>-<cpu number> (must be a positive range in ascending order)
831 or a mixture
832 <cpu number>,...,<cpu number>-<cpu number>
833 This option can be used to specify one or more CPUs
834 to isolate from the general SMP balancing and scheduling
835 algorithms. The only way to move a process onto or off
836 an "isolated" CPU is via the CPU affinity syscalls.
837 <cpu number> begins at 0 and the maximum value is
838 "number of CPUs in system - 1".
840 This option is the preferred way to isolate CPUs. The
841 alternative -- manually setting the CPU mask of all
842 tasks in the system -- can cause problems and
843 suboptimal load balancer performance.
845 iucv= [HW,NET]
847 js= [HW,JOY] Analog joystick
848 See Documentation/input/joystick.txt.
850 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
851 specifies the amount of memory usable by the kernel
852 for non-movable allocations. The requested amount is
853 spread evenly throughout all nodes in the system. The
854 remaining memory in each node is used for Movable
855 pages. In the event, a node is too small to have both
856 kernelcore and Movable pages, kernelcore pages will
857 take priority and other nodes will have a larger number
858 of kernelcore pages. The Movable zone is used for the
859 allocation of pages that may be reclaimed or moved
860 by the page migration subsystem. This means that
861 HugeTLB pages may not be allocated from this zone.
862 Note that allocations like PTEs-from-HighMem still
863 use the HighMem zone if it exists, and the Normal
864 zone if it does not.
866 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
867 is similar to kernelcore except it specifies the
868 amount of memory used for migratable allocations.
869 If both kernelcore and movablecore is specified,
870 then kernelcore will be at *least* the specified
871 value but may be more. If movablecore on its own
872 is specified, the administrator must be careful
873 that the amount of memory usable for all allocations
874 is not too small.
876 keepinitrd [HW,ARM]
878 kstack=N [X86-32,X86-64] Print N words from the kernel stack
879 in oops dumps.
881 l2cr= [PPC]
883 lapic [X86-32,APIC] Enable the local APIC even if BIOS
884 disabled it.
886 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
887 C2 power state.
889 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
890 Format: addr:<io>,irq:<irq>
892 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
893 when set.
894 Format: <int>
896 load_ramdisk= [RAM] List of ramdisks to load from floppy
897 See Documentation/ramdisk.txt.
899 lockd.nlm_grace_period=P [NFS] Assign grace period.
900 Format: <integer>
902 lockd.nlm_tcpport=N [NFS] Assign TCP port.
903 Format: <integer>
905 lockd.nlm_timeout=T [NFS] Assign timeout value.
906 Format: <integer>
908 lockd.nlm_udpport=M [NFS] Assign UDP port.
909 Format: <integer>
911 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
912 Format: <irq>
914 loglevel= All Kernel Messages with a loglevel smaller than the
915 console loglevel will be printed to the console. It can
916 also be changed with klogd or other programs. The
917 loglevels are defined as follows:
919 0 (KERN_EMERG) system is unusable
920 1 (KERN_ALERT) action must be taken immediately
921 2 (KERN_CRIT) critical conditions
922 3 (KERN_ERR) error conditions
923 4 (KERN_WARNING) warning conditions
924 5 (KERN_NOTICE) normal but significant condition
925 6 (KERN_INFO) informational
926 7 (KERN_DEBUG) debug-level messages
928 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
929 Format: { n | nk | nM }
930 n must be a power of two. The default size
931 is set in the kernel config file.
933 logo.nologo [FB] Disables display of the built-in Linux logo.
934 This may be used to provide more screen space for
935 kernel log messages and is useful when debugging
936 kernel boot problems.
938 lp=0 [LP] Specify parallel ports to use, e.g,
939 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
940 lp=reset first parallel port). 'lp=0' disables the
941 lp=auto printer driver. 'lp=reset' (which can be
942 specified in addition to the ports) causes
943 attached printers to be reset. Using
944 lp=port1,port2,... specifies the parallel ports
945 to associate lp devices with, starting with
946 lp0. A port specification may be 'none' to skip
947 that lp device, or a parport name such as
948 'parport0'. Specifying 'lp=auto' instead of a
949 port specification list means that device IDs
950 from each port should be examined, to see if
951 an IEEE 1284-compliant printer is attached; if
952 so, the driver will manage that printer.
953 See also header of drivers/char/lp.c.
955 lpj=n [KNL]
956 Sets loops_per_jiffy to given constant, thus avoiding
957 time-consuming boot-time autodetection (up to 250 ms per
958 CPU). 0 enables autodetection (default). To determine
959 the correct value for your kernel, boot with normal
960 autodetection and see what value is printed. Note that
961 on SMP systems the preset will be applied to all CPUs,
962 which is likely to cause problems if your CPUs need
963 significantly divergent settings. An incorrect value
964 will cause delays in the kernel to be wrong, leading to
965 unpredictable I/O errors and other breakage. Although
966 unlikely, in the extreme case this might damage your
967 hardware.
969 ltpc= [NET]
970 Format: <io>,<irq>,<dma>
972 mac5380= [HW,SCSI] Format:
973 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
975 mac53c9x= [HW,SCSI] Format:
976 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
978 machvec= [IA64] Force the use of a particular machine-vector
979 (machvec) in a generic kernel.
980 Example: machvec=hpzx1_swiotlb
982 max_loop= [LOOP] Maximum number of loopback devices that can
983 be mounted
984 Format: <1-256>
986 maxcpus= [SMP] Maximum number of processors that an SMP kernel
987 should make use of. maxcpus=n : n >= 0 limits the
988 kernel to using 'n' processors. n=0 is a special case,
989 it is equivalent to "nosmp", which also disables
990 the IO APIC.
992 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
993 equal to this physical address is ignored.
995 max_luns= [SCSI] Maximum number of LUNs to probe.
996 Should be between 1 and 2^32-1.
998 max_report_luns=
999 [SCSI] Maximum number of LUNs received.
1000 Should be between 1 and 16384.
1002 mca-pentium [BUGS=X86-32]
1004 mcatest= [IA-64]
1006 mce [X86-32] Machine Check Exception
1008 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
1010 md= [HW] RAID subsystems devices and level
1011 See Documentation/md.txt.
1013 mdacon= [MDA]
1014 Format: <first>,<last>
1015 Specifies range of consoles to be captured by the MDA.
1017 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1018 Amount of memory to be used when the kernel is not able
1019 to see the whole system memory or for test.
1020 [X86-32] Use together with memmap= to avoid physical
1021 address space collisions. Without memmap= PCI devices
1022 could be placed at addresses belonging to unused RAM.
1024 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1025 memory.
1027 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1028 E820 memory map, as specified by the user.
1029 Such memmap=exactmap lines can be constructed based on
1030 BIOS output or other requirements. See the memmap=nn@ss
1031 option description.
1033 memmap=nn[KMG]@ss[KMG]
1034 [KNL] Force usage of a specific region of memory
1035 Region of memory to be used, from ss to ss+nn.
1037 memmap=nn[KMG]#ss[KMG]
1038 [KNL,ACPI] Mark specific memory as ACPI data.
1039 Region of memory to be used, from ss to ss+nn.
1041 memmap=nn[KMG]$ss[KMG]
1042 [KNL,ACPI] Mark specific memory as reserved.
1043 Region of memory to be used, from ss to ss+nn.
1045 meye.*= [HW] Set MotionEye Camera parameters
1046 See Documentation/video4linux/meye.txt.
1048 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1049 Multi-Function General Purpose Timers on AMD Geode
1050 platforms.
1052 mga= [HW,DRM]
1054 mousedev.tap_time=
1055 [MOUSE] Maximum time between finger touching and
1056 leaving touchpad surface for touch to be considered
1057 a tap and be reported as a left button click (for
1058 touchpads working in absolute mode only).
1059 Format: <msecs>
1060 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1061 reporting absolute coordinates, such as tablets
1062 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1063 reporting absolute coordinates, such as tablets
1065 mpu401= [HW,OSS]
1066 Format: <io>,<irq>
1068 MTD_Partition= [MTD]
1069 Format: <name>,<region-number>,<size>,<offset>
1071 MTD_Region= [MTD] Format:
1072 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1074 mtdparts= [MTD]
1075 See drivers/mtd/cmdlinepart.c.
1077 mtouchusb.raw_coordinates=
1078 [HW] Make the MicroTouch USB driver use raw coordinates
1079 ('y', default) or cooked coordinates ('n')
1081 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1083 NCR_D700= [HW,SCSI]
1084 See header of drivers/scsi/NCR_D700.c.
1086 ncr5380= [HW,SCSI]
1088 ncr53c400= [HW,SCSI]
1090 ncr53c400a= [HW,SCSI]
1092 ncr53c406a= [HW,SCSI]
1094 ncr53c8xx= [HW,SCSI]
1096 netdev= [NET] Network devices parameters
1097 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1098 Note that mem_start is often overloaded to mean
1099 something different and driver-specific.
1100 This usage is only documented in each driver source
1101 file if at all.
1103 nfsaddrs= [NFS]
1104 See Documentation/nfsroot.txt.
1106 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1107 See Documentation/nfsroot.txt.
1109 nfs.callback_tcpport=
1110 [NFS] set the TCP port on which the NFSv4 callback
1111 channel should listen.
1113 nfs.idmap_cache_timeout=
1114 [NFS] set the maximum lifetime for idmapper cache
1115 entries.
1117 nfs.enable_ino64=
1118 [NFS] enable 64-bit inode numbers.
1119 If zero, the NFS client will fake up a 32-bit inode
1120 number for the readdir() and stat() syscalls instead
1121 of returning the full 64-bit number.
1122 The default is to return 64-bit inode numbers.
1124 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1126 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1127 emulation library even if a 387 maths coprocessor
1128 is present.
1130 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1131 caches in the slab allocator. Saves per-node memory,
1132 but will impact performance.
1134 noalign [KNL,ARM]
1136 noapic [SMP,APIC] Tells the kernel to not make use of any
1137 IOAPICs that may be present in the system.
1139 noasync [HW,M68K] Disables async and sync negotiation for
1140 all devices.
1142 nobats [PPC] Do not use BATs for mapping kernel lowmem
1143 on "Classic" PPC cores.
1145 nocache [ARM]
1147 nodelayacct [KNL] Disable per-task delay accounting
1149 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1151 noexec [IA-64]
1153 noexec [X86-32,X86-64]
1154 noexec=on: enable non-executable mappings (default)
1155 noexec=off: disable nn-executable mappings
1157 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1158 register save and restore. The kernel will only save
1159 legacy floating-point registers on task switch.
1161 nohlt [BUGS=ARM]
1163 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1164 instruction doesn't work correctly and not to
1165 use it.
1167 nohalt [IA-64] Tells the kernel not to use the power saving
1168 function PAL_HALT_LIGHT when idle. This increases
1169 power-consumption. On the positive side, it reduces
1170 interrupt wake-up latency, which may improve performance
1171 in certain environments such as networked servers or
1172 real-time systems.
1174 nohz= [KNL] Boottime enable/disable dynamic ticks
1175 Valid arguments: on, off
1176 Default: on
1178 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1180 noirqdebug [X86-32] Disables the code which attempts to detect and
1181 disable unhandled interrupt sources.
1183 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1184 broken timer IRQ sources.
1186 noisapnp [ISAPNP] Disables ISA PnP code.
1188 noinitrd [RAM] Tells the kernel not to load any configured
1189 initial RAM disk.
1191 nointroute [IA-64]
1193 nojitter [IA64] Disables jitter checking for ITC timers.
1195 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1197 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1199 noltlbs [PPC] Do not use large page/tlb entries for kernel
1200 lowmem mapping on PPC40x.
1202 nomca [IA-64] Disable machine check abort handling
1204 nomce [X86-32] Machine Check Exception
1206 nomfgpt [X86-32] Disable Multi-Function General Purpose
1207 Timer usage (for AMD Geode machines).
1209 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1211 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1212 with UP alternatives
1214 noresidual [PPC] Don't use residual data on PReP machines.
1216 noresume [SWSUSP] Disables resume and restores original swap
1217 space.
1219 no-scroll [VGA] Disables scrollback.
1220 This is required for the Braillex ib80-piezo Braille
1221 reader made by F.H. Papenmeier (Germany).
1223 nosbagart [IA-64]
1225 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1227 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1228 and disable the IO APIC. legacy for "maxcpus=0".
1230 nosoftlockup [KNL] Disable the soft-lockup detector.
1232 nosync [HW,M68K] Disables sync negotiation for all devices.
1234 notsc [BUGS=X86-32] Disable Time Stamp Counter
1236 nousb [USB] Disable the USB subsystem
1238 nowb [ARM]
1240 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1241 one of ['zone', 'node', 'default'] can be specified
1242 This can be set from sysctl after boot.
1243 See Documentation/sysctl/vm.txt for details.
1245 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1247 opl3= [HW,OSS]
1248 Format: <io>
1250 oprofile.timer= [HW]
1251 Use timer interrupt instead of performance counters
1253 osst= [HW,SCSI] SCSI Tape Driver
1254 Format: <buffer_size>,<write_threshold>
1255 See also Documentation/scsi/st.txt.
1257 panic= [KNL] Kernel behaviour on panic
1258 Format: <timeout>
1260 parkbd.port= [HW] Parallel port number the keyboard adapter is
1261 connected to, default is 0.
1262 Format: <parport#>
1263 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1264 0 for XT, 1 for AT (default is AT).
1265 Format: <mode>
1267 parport= [HW,PPT] Specify parallel ports. 0 disables.
1268 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1269 Use 'auto' to force the driver to use any
1270 IRQ/DMA settings detected (the default is to
1271 ignore detected IRQ/DMA settings because of
1272 possible conflicts). You can specify the base
1273 address, IRQ, and DMA settings; IRQ and DMA
1274 should be numbers, or 'auto' (for using detected
1275 settings on that particular port), or 'nofifo'
1276 (to avoid using a FIFO even if it is detected).
1277 Parallel ports are assigned in the order they
1278 are specified on the command line, starting
1279 with parport0.
1281 parport_init_mode= [HW,PPT]
1282 Configure VIA parallel port to operate in
1283 a specific mode. This is necessary on Pegasos
1284 computer where firmware has no options for setting
1285 up parallel port mode and sets it to spp.
1286 Currently this function knows 686a and 8231 chips.
1287 Format: [spp|ps2|epp|ecp|ecpepp]
1289 pas2= [HW,OSS] Format:
1290 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1292 pas16= [HW,SCSI]
1293 See header of drivers/scsi/pas16.c.
1295 pause_on_oops=
1296 Halt all CPUs after the first oops has been printed for
1297 the specified number of seconds. This is to be used if
1298 your oopses keep scrolling off the screen.
1300 pcbit= [HW,ISDN]
1302 pcd. [PARIDE]
1303 See header of drivers/block/paride/pcd.c.
1304 See also Documentation/paride.txt.
1306 pci=option[,option...] [PCI] various PCI subsystem options:
1307 off [X86-32] don't probe for the PCI bus
1308 bios [X86-32] force use of PCI BIOS, don't access
1309 the hardware directly. Use this if your machine
1310 has a non-standard PCI host bridge.
1311 nobios [X86-32] disallow use of PCI BIOS, only direct
1312 hardware access methods are allowed. Use this
1313 if you experience crashes upon bootup and you
1314 suspect they are caused by the BIOS.
1315 conf1 [X86-32] Force use of PCI Configuration
1316 Mechanism 1.
1317 conf2 [X86-32] Force use of PCI Configuration
1318 Mechanism 2.
1319 noaer [PCIE] If the PCIEAER kernel config parameter is
1320 enabled, this kernel boot option can be used to
1321 disable the use of PCIE advanced error reporting.
1322 nodomains [PCI] Disable support for multiple PCI
1323 root domains (aka PCI segments, in ACPI-speak).
1324 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1325 Configuration
1326 nomsi [MSI] If the PCI_MSI kernel config parameter is
1327 enabled, this kernel boot option can be used to
1328 disable the use of MSI interrupts system-wide.
1329 nosort [X86-32] Don't sort PCI devices according to
1330 order given by the PCI BIOS. This sorting is
1331 done to get a device order compatible with
1332 older kernels.
1333 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1334 routing table. These calls are known to be buggy
1335 on several machines and they hang the machine
1336 when used, but on other computers it's the only
1337 way to get the interrupt routing table. Try
1338 this option if the kernel is unable to allocate
1339 IRQs or discover secondary PCI buses on your
1340 motherboard.
1341 rom [X86-32] Assign address space to expansion ROMs.
1342 Use with caution as certain devices share
1343 address decoders between ROMs and other
1344 resources.
1345 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1346 assigned automatically to PCI devices. You can
1347 make the kernel exclude IRQs of your ISA cards
1348 this way.
1349 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1350 of the PIRQ table (normally generated
1351 by the BIOS) if it is outside the
1352 F0000h-100000h range.
1353 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1354 useful if the kernel is unable to find your
1355 secondary buses and you want to tell it
1356 explicitly which ones they are.
1357 assign-busses [X86-32] Always assign all PCI bus
1358 numbers ourselves, overriding
1359 whatever the firmware may have done.
1360 usepirqmask [X86-32] Honor the possible IRQ mask stored
1361 in the BIOS $PIR table. This is needed on
1362 some systems with broken BIOSes, notably
1363 some HP Pavilion N5400 and Omnibook XE3
1364 notebooks. This will have no effect if ACPI
1365 IRQ routing is enabled.
1366 noacpi [X86-32] Do not use ACPI for IRQ routing
1367 or for PCI scanning.
1368 use_crs [X86-32] Use _CRS for PCI resource
1369 allocation.
1370 routeirq Do IRQ routing for all PCI devices.
1371 This is normally done in pci_enable_device(),
1372 so this option is a temporary workaround
1373 for broken drivers that don't call it.
1374 firmware [ARM] Do not re-enumerate the bus but instead
1375 just use the configuration from the
1376 bootloader. This is currently used on
1377 IXP2000 systems where the bus has to be
1378 configured a certain way for adjunct CPUs.
1379 noearly [X86] Don't do any early type 1 scanning.
1380 This might help on some broken boards which
1381 machine check when some devices' config space
1382 is read. But various workarounds are disabled
1383 and some IOMMU drivers will not work.
1384 bfsort Sort PCI devices into breadth-first order.
1385 This sorting is done to get a device
1386 order compatible with older (<= 2.4) kernels.
1387 nobfsort Don't sort PCI devices into breadth-first order.
1388 cbiosize=nn[KMG] The fixed amount of bus space which is
1389 reserved for the CardBus bridge's IO window.
1390 The default value is 256 bytes.
1391 cbmemsize=nn[KMG] The fixed amount of bus space which is
1392 reserved for the CardBus bridge's memory
1393 window. The default value is 64 megabytes.
1395 pcmv= [HW,PCMCIA] BadgePAD 4
1397 pd. [PARIDE]
1398 See Documentation/paride.txt.
1400 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1401 boot time.
1402 Format: { 0 | 1 }
1403 See arch/parisc/kernel/pdc_chassis.c
1405 pf. [PARIDE]
1406 See Documentation/paride.txt.
1408 pg. [PARIDE]
1409 See Documentation/paride.txt.
1411 pirq= [SMP,APIC] Manual mp-table setup
1412 See Documentation/i386/IO-APIC.txt.
1414 plip= [PPT,NET] Parallel port network link
1415 Format: { parport<nr> | timid | 0 }
1416 See also Documentation/parport.txt.
1418 pnpacpi= [ACPI]
1419 { off }
1421 pnpbios= [ISAPNP]
1422 { on | off | curr | res | no-curr | no-res }
1424 pnp_reserve_irq=
1425 [ISAPNP] Exclude IRQs for the autoconfiguration
1427 pnp_reserve_dma=
1428 [ISAPNP] Exclude DMAs for the autoconfiguration
1430 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1431 Ranges are in pairs (I/O port base and size).
1433 pnp_reserve_mem=
1434 [ISAPNP] Exclude memory regions for the
1435 autoconfiguration.
1436 Ranges are in pairs (memory base and size).
1438 print-fatal-signals=
1439 [KNL] debug: print fatal signals
1440 print-fatal-signals=1: print segfault info to
1441 the kernel console.
1442 default: off.
1444 printk.time= Show timing data prefixed to each printk message line
1445 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1447 profile= [KNL] Enable kernel profiling via /proc/profile
1448 Format: [schedule,]<number>
1449 Param: "schedule" - profile schedule points.
1450 Param: <number> - step/bucket size as a power of 2 for
1451 statistical time based profiling.
1452 Param: "sleep" - profile D-state sleeping (millisecs)
1454 processor.max_cstate= [HW,ACPI]
1455 Limit processor to maximum C-state
1456 max_cstate=9 overrides any DMI blacklist limit.
1458 processor.nocst [HW,ACPI]
1459 Ignore the _CST method to determine C-states,
1460 instead using the legacy FADT method
1462 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1463 before loading.
1464 See Documentation/ramdisk.txt.
1466 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1467 probe for; one of (bare|imps|exps|lifebook|any).
1468 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1469 per second.
1470 psmouse.resetafter= [HW,MOUSE]
1471 Try to reset the device after so many bad packets
1472 (0 = never).
1473 psmouse.resolution=
1474 [HW,MOUSE] Set desired mouse resolution, in dpi.
1475 psmouse.smartscroll=
1476 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1477 0 = disabled, 1 = enabled (default).
1479 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1480 Format:
1481 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1483 pt. [PARIDE]
1484 See Documentation/paride.txt.
1486 pty.legacy_count=
1487 [KNL] Number of legacy pty's. Overwrites compiled-in
1488 default number.
1490 quiet [KNL] Disable most log messages
1492 r128= [HW,DRM]
1494 raid= [HW,RAID]
1495 See Documentation/md.txt.
1497 ramdisk_blocksize= [RAM]
1498 See Documentation/ramdisk.txt.
1500 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1501 See Documentation/ramdisk.txt.
1503 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1504 RCU callbacks to process in one batch.
1506 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1507 RCU callbacks over which batch limiting is disabled.
1509 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1510 RCU callbacks below which batch limiting is re-enabled.
1512 rdinit= [KNL]
1513 Format: <full_path>
1514 Run specified binary instead of /init from the ramdisk,
1515 used for early userspace startup. See initrd.
1517 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1518 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1519 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1521 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1523 reservetop= [X86-32]
1524 Format: nn[KMG]
1525 Reserves a hole at the top of the kernel virtual
1526 address space.
1528 reset_devices [KNL] Force drivers to reset the underlying device
1529 during initialization.
1531 resume= [SWSUSP]
1532 Specify the partition device for software suspend
1534 resume_offset= [SWSUSP]
1535 Specify the offset from the beginning of the partition
1536 given by "resume=" at which the swap header is located,
1537 in <PAGE_SIZE> units (needed only for swap files).
1538 See Documentation/power/swsusp-and-swap-files.txt
1540 retain_initrd [RAM] Keep initrd memory after extraction
1542 rhash_entries= [KNL,NET]
1543 Set number of hash buckets for route cache
1545 riscom8= [HW,SERIAL]
1546 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1548 ro [KNL] Mount root device read-only on boot
1550 root= [KNL] Root filesystem
1552 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1553 mount the root filesystem
1555 rootflags= [KNL] Set root filesystem mount option string
1557 rootfstype= [KNL] Set root filesystem type
1559 rootwait [KNL] Wait (indefinitely) for root device to show up.
1560 Useful for devices that are detected asynchronously
1561 (e.g. USB and MMC devices).
1563 root_plug.vendor_id=
1564 [ROOTPLUG] Override the default vendor ID
1566 root_plug.product_id=
1567 [ROOTPLUG] Override the default product ID
1569 root_plug.debug=
1570 [ROOTPLUG] Enable debugging output
1572 rw [KNL] Mount root device read-write on boot
1574 S [KNL] Run init in single mode
1576 sa1100ir [NET]
1577 See drivers/net/irda/sa1100_ir.c.
1579 sbni= [NET] Granch SBNI12 leased line adapter
1581 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1582 Format: <io>[,<timeout>[,<isapnp>]]
1584 scsi_debug_*= [SCSI]
1585 See drivers/scsi/scsi_debug.c.
1587 scsi_default_dev_flags=
1588 [SCSI] SCSI default device flags
1589 Format: <integer>
1591 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1592 Format: <vendor>:<model>:<flags>
1593 (flags are integer value)
1595 scsi_logging= [SCSI]
1597 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1598 discovered. async scans them in kernel threads,
1599 allowing boot to proceed. none ignores them, expecting
1600 user space to do the scan.
1602 selinux [SELINUX] Disable or enable SELinux at boot time.
1603 Format: { "0" | "1" }
1604 See security/selinux/Kconfig help text.
1605 0 -- disable.
1606 1 -- enable.
1607 Default value is set via kernel config option.
1608 If enabled at boot time, /selinux/disable can be used
1609 later to disable prior to initial policy load.
1611 selinux_compat_net =
1612 [SELINUX] Set initial selinux_compat_net flag value.
1613 Format: { "0" | "1" }
1614 0 -- use new secmark-based packet controls
1615 1 -- use legacy packet controls
1616 Default value is 0 (preferred).
1617 Value can be changed at runtime via
1618 /selinux/compat_net.
1620 serialnumber [BUGS=X86-32]
1622 shapers= [NET]
1623 Maximal number of shapers.
1625 sim710= [SCSI,HW]
1626 See header of drivers/scsi/sim710.c.
1628 simeth= [IA-64]
1629 simscsi=
1631 slram= [HW,MTD]
1633 slub_debug[=options[,slabs]] [MM, SLUB]
1634 Enabling slub_debug allows one to determine the
1635 culprit if slab objects become corrupted. Enabling
1636 slub_debug can create guard zones around objects and
1637 may poison objects when not in use. Also tracks the
1638 last alloc / free. For more information see
1639 Documentation/vm/slub.txt.
1641 slub_max_order= [MM, SLUB]
1642 Determines the maximum allowed order for slabs.
1643 A high setting may cause OOMs due to memory
1644 fragmentation. For more information see
1645 Documentation/vm/slub.txt.
1647 slub_min_objects= [MM, SLUB]
1648 The minimum number of objects per slab. SLUB will
1649 increase the slab order up to slub_max_order to
1650 generate a sufficiently large slab able to contain
1651 the number of objects indicated. The higher the number
1652 of objects the smaller the overhead of tracking slabs
1653 and the less frequently locks need to be acquired.
1654 For more information see Documentation/vm/slub.txt.
1656 slub_min_order= [MM, SLUB]
1657 Determines the mininum page order for slabs. Must be
1658 lower than slub_max_order.
1659 For more information see Documentation/vm/slub.txt.
1661 slub_nomerge [MM, SLUB]
1662 Disable merging of slabs with similar size. May be
1663 necessary if there is some reason to distinguish
1664 allocs to different slabs. Debug options disable
1665 merging on their own.
1666 For more information see Documentation/vm/slub.txt.
1668 smart2= [HW]
1669 Format: <io1>[,<io2>[,...,<io8>]]
1671 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1672 attempt to substitute SMP alternatives once at boot.
1674 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1675 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1676 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1677 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1678 smsc-ircc2.ircc_irq= [HW] IRQ line
1679 smsc-ircc2.ircc_dma= [HW] DMA channel
1680 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1681 0: Toshiba Satellite 1800 (GP data pin select)
1682 1: Fast pin select (default)
1683 2: ATC IRMode
1685 snd-ad1816a= [HW,ALSA]
1687 snd-ad1848= [HW,ALSA]
1689 snd-ali5451= [HW,ALSA]
1691 snd-als100= [HW,ALSA]
1693 snd-als4000= [HW,ALSA]
1695 snd-azt2320= [HW,ALSA]
1697 snd-cmi8330= [HW,ALSA]
1699 snd-cmipci= [HW,ALSA]
1701 snd-cs4231= [HW,ALSA]
1703 snd-cs4232= [HW,ALSA]
1705 snd-cs4236= [HW,ALSA]
1707 snd-cs4281= [HW,ALSA]
1709 snd-cs46xx= [HW,ALSA]
1711 snd-dt019x= [HW,ALSA]
1713 snd-dummy= [HW,ALSA]
1715 snd-emu10k1= [HW,ALSA]
1717 snd-ens1370= [HW,ALSA]
1719 snd-ens1371= [HW,ALSA]
1721 snd-es968= [HW,ALSA]
1723 snd-es1688= [HW,ALSA]
1725 snd-es18xx= [HW,ALSA]
1727 snd-es1938= [HW,ALSA]
1729 snd-es1968= [HW,ALSA]
1731 snd-fm801= [HW,ALSA]
1733 snd-gusclassic= [HW,ALSA]
1735 snd-gusextreme= [HW,ALSA]
1737 snd-gusmax= [HW,ALSA]
1739 snd-hdsp= [HW,ALSA]
1741 snd-ice1712= [HW,ALSA]
1743 snd-intel8x0= [HW,ALSA]
1745 snd-interwave= [HW,ALSA]
1747 snd-interwave-stb=
1748 [HW,ALSA]
1750 snd-korg1212= [HW,ALSA]
1752 snd-maestro3= [HW,ALSA]
1754 snd-mpu401= [HW,ALSA]
1756 snd-mtpav= [HW,ALSA]
1758 snd-nm256= [HW,ALSA]
1760 snd-opl3sa2= [HW,ALSA]
1762 snd-opti92x-ad1848=
1763 [HW,ALSA]
1765 snd-opti92x-cs4231=
1766 [HW,ALSA]
1768 snd-opti93x= [HW,ALSA]
1770 snd-pmac= [HW,ALSA]
1772 snd-rme32= [HW,ALSA]
1774 snd-rme96= [HW,ALSA]
1776 snd-rme9652= [HW,ALSA]
1778 snd-sb8= [HW,ALSA]
1780 snd-sb16= [HW,ALSA]
1782 snd-sbawe= [HW,ALSA]
1784 snd-serial= [HW,ALSA]
1786 snd-sgalaxy= [HW,ALSA]
1788 snd-sonicvibes= [HW,ALSA]
1790 snd-sun-amd7930=
1791 [HW,ALSA]
1793 snd-sun-cs4231= [HW,ALSA]
1795 snd-trident= [HW,ALSA]
1797 snd-usb-audio= [HW,ALSA,USB]
1799 snd-via82xx= [HW,ALSA]
1801 snd-virmidi= [HW,ALSA]
1803 snd-wavefront= [HW,ALSA]
1805 snd-ymfpci= [HW,ALSA]
1807 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1808 See Documentation/sonypi.txt
1810 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1811 See Documentation/specialix.txt.
1813 spia_io_base= [HW,MTD]
1814 spia_fio_base=
1815 spia_pedr=
1816 spia_peddr=
1818 sscape= [HW,OSS]
1819 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1821 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1822 See Documentation/scsi/st.txt.
1824 st0x= [HW,SCSI]
1825 See header of drivers/scsi/seagate.c.
1827 sti= [PARISC,HW]
1828 Format: <num>
1829 Set the STI (builtin display/keyboard on the HP-PARISC
1830 machines) console (graphic card) which should be used
1831 as the initial boot-console.
1832 See also comment in drivers/video/console/sticore.c.
1834 sti_font= [HW]
1835 See comment in drivers/video/console/sticore.c.
1837 stifb= [HW]
1838 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1840 sunrpc.pool_mode=
1841 [NFS]
1842 Control how the NFS server code allocates CPUs to
1843 service thread pools. Depending on how many NICs
1844 you have and where their interrupts are bound, this
1845 option will affect which CPUs will do NFS serving.
1846 Note: this parameter cannot be changed while the
1847 NFS server is running.
1849 auto the server chooses an appropriate mode
1850 automatically using heuristics
1851 global a single global pool contains all CPUs
1852 percpu one pool for each CPU
1853 pernode one pool for each NUMA node (equivalent
1854 to global on non-NUMA machines)
1856 swiotlb= [IA-64] Number of I/O TLB slabs
1858 switches= [HW,M68k]
1860 sym53c416= [HW,SCSI]
1861 See header of drivers/scsi/sym53c416.c.
1863 sysrq_always_enabled
1864 [KNL]
1865 Ignore sysrq setting - this boot parameter will
1866 neutralize any effect of /proc/sys/kernel/sysrq.
1867 Useful for debugging.
1869 t128= [HW,SCSI]
1870 See header of drivers/scsi/t128.c.
1872 tdfx= [HW,DRM]
1874 thash_entries= [KNL,NET]
1875 Set number of hash buckets for TCP connection
1877 thermal.act= [HW,ACPI]
1878 -1: disable all active trip points in all thermal zones
1879 <degrees C>: override all lowest active trip points
1881 thermal.crt= [HW,ACPI]
1882 -1: disable all critical trip points in all thermal zones
1883 <degrees C>: lower all critical trip points
1885 thermal.nocrt= [HW,ACPI]
1886 Set to disable actions on ACPI thermal zone
1887 critical and hot trip points.
1889 thermal.off= [HW,ACPI]
1890 1: disable ACPI thermal control
1892 thermal.psv= [HW,ACPI]
1893 -1: disable all passive trip points
1894 <degrees C>: override all passive trip points to this value
1896 thermal.tzp= [HW,ACPI]
1897 Specify global default ACPI thermal zone polling rate
1898 <deci-seconds>: poll all this frequency
1899 0: no polling (default)
1901 time Show timing data prefixed to each printk message line
1902 [deprecated, see 'printk.time']
1904 tipar.timeout= [HW,PPT]
1905 Set communications timeout in tenths of a second
1906 (default 15).
1908 tipar.delay= [HW,PPT]
1909 Set inter-bit delay in microseconds (default 10).
1911 tmc8xx= [HW,SCSI]
1912 See header of drivers/scsi/seagate.c.
1914 tmscsim= [HW,SCSI]
1915 See comment before function dc390_setup() in
1916 drivers/scsi/tmscsim.c.
1918 tp720= [HW,PS2]
1920 trix= [HW,OSS] MediaTrix AudioTrix Pro
1921 Format:
1922 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1924 turbografx.map[2|3]= [HW,JOY]
1925 TurboGraFX parallel port interface
1926 Format:
1927 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1928 See also Documentation/input/joystick-parport.txt
1930 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1931 See header of drivers/scsi/u14-34f.c.
1933 uart401= [HW,OSS]
1934 Format: <io>,<irq>
1936 uart6850= [HW,OSS]
1937 Format: <io>,<irq>
1939 uhci-hcd.ignore_oc=
1940 [USB] Ignore overcurrent events (default N).
1941 Some badly-designed motherboards generate lots of
1942 bogus events, for ports that aren't wired to
1943 anything. Set this parameter to avoid log spamming.
1944 Note that genuine overcurrent events won't be
1945 reported either.
1947 usbcore.autosuspend=
1948 [USB] The autosuspend time delay (in seconds) used
1949 for newly-detected USB devices (default 2). This
1950 is the time required before an idle device will be
1951 autosuspended. Devices for which the delay is set
1952 to a negative value won't be autosuspended at all.
1954 usbhid.mousepoll=
1955 [USBHID] The interval which mice are to be polled at.
1957 vdso= [X86-32,SH,x86-64]
1958 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
1959 vdso=1: enable VDSO (default)
1960 vdso=0: disable VDSO mapping
1962 vector= [IA-64,SMP]
1963 vector=percpu: enable percpu vector domain
1965 video= [FB] Frame buffer configuration
1966 See Documentation/fb/modedb.txt.
1968 vga= [BOOT,X86-32] Select a particular video mode
1969 See Documentation/i386/boot.txt and
1970 Documentation/svga.txt.
1971 Use vga=ask for menu.
1972 This is actually a boot loader parameter; the value is
1973 passed to the kernel using a special protocol.
1975 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1976 size of <nn>. This can be used to increase the
1977 minimum size (128MB on x86). It can also be used to
1978 decrease the size and leave more room for directly
1979 mapped kernel RAM.
1981 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1982 Format: <command>
1984 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1985 Format: <command>
1987 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1988 Format: <command>
1990 waveartist= [HW,OSS]
1991 Format: <io>,<irq>,<dma>,<dma2>
1993 wd33c93= [HW,SCSI]
1994 See header of drivers/scsi/wd33c93.c.
1996 wd7000= [HW,SCSI]
1997 See header of drivers/scsi/wd7000.c.
1999 wdt= [WDT] Watchdog
2000 See Documentation/watchdog/wdt.txt.
2002 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
2003 xd_geo= See header of drivers/block/xd.c.
2005 xirc2ps_cs= [NET,PCMCIA]
2006 Format:
2007 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2009 norandmaps Don't use address space randomization
2010 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2012 unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
2013 This is useful to get more information why
2014 you got a "dwarf2 unwinder stuck"
2016 ______________________________________________________________________
2018 TODO:
2020 Add documentation for ALSA options.
2021 Add more DRM drivers.