| blob | 98cf90f2631d736021478528fab34281a79b5659 |
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.
226 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
228 acpi_pm_good [X86-32,X86-64]
229 Override the pmtimer bug detection: force the kernel
230 to assume that this machine's pmtimer latches its value
231 and always returns good values.
233 agp= [AGP]
234 { off | try_unsupported }
235 off: disable AGP support
236 try_unsupported: try to drive unsupported chipsets
237 (may crash computer or cause data corruption)
239 enable_timer_pin_1 [i386,x86-64]
240 Enable PIN 1 of APIC timer
241 Can be useful to work around chipset bugs
242 (in particular on some ATI chipsets).
243 The kernel tries to set a reasonable default.
245 disable_timer_pin_1 [i386,x86-64]
246 Disable PIN 1 of APIC timer
247 Can be useful to work around chipset bugs.
249 ad1848= [HW,OSS]
250 Format: <io>,<irq>,<dma>,<dma2>,<type>
252 advansys= [HW,SCSI]
253 See header of drivers/scsi/advansys.c.
255 advwdt= [HW,WDT] Advantech WDT
256 Format: <iostart>,<iostop>
258 aedsp16= [HW,OSS] Audio Excel DSP 16
259 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
260 See also header of sound/oss/aedsp16.c.
262 aha152x= [HW,SCSI]
263 See Documentation/scsi/aha152x.txt.
265 aha1542= [HW,SCSI]
266 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
268 aic7xxx= [HW,SCSI]
269 See Documentation/scsi/aic7xxx.txt.
271 aic79xx= [HW,SCSI]
272 See Documentation/scsi/aic79xx.txt.
274 amijoy.map= [HW,JOY] Amiga joystick support
275 Map of devices attached to JOY0DAT and JOY1DAT
276 Format: <a>,<b>
277 See also Documentation/kernel/input/joystick.txt
279 analog.map= [HW,JOY] Analog joystick and gamepad support
280 Specifies type or capabilities of an analog joystick
281 connected to one of 16 gameports
282 Format: <type1>,<type2>,..<type16>
284 apc= [HW,SPARC]
285 Power management functions (SPARCstation-4/5 + deriv.)
286 Format: noidle
287 Disable APC CPU standby support. SPARCstation-Fox does
288 not play well with APC CPU idle - disable it if you have
289 APC and your system crashes randomly.
291 apic= [APIC,i386] Advanced Programmable Interrupt Controller
292 Change the output verbosity whilst booting
293 Format: { quiet (default) | verbose | debug }
294 Change the amount of debugging information output
295 when initialising the APIC and IO-APIC components.
297 apm= [APM] Advanced Power Management
298 See header of arch/i386/kernel/apm.c.
300 applicom= [HW]
301 Format: <mem>,<irq>
303 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
304 Format: <io>,<irq>,<nodeID>
306 ataflop= [HW,M68k]
308 atarimouse= [HW,MOUSE] Atari Mouse
310 atascsi= [HW,SCSI] Atari SCSI
312 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
313 EzKey and similar keyboards
315 atkbd.reset= [HW] Reset keyboard during initialization
317 atkbd.set= [HW] Select keyboard code set
318 Format: <int> (2 = AT (default), 3 = PS/2)
320 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
321 keyboards
323 atkbd.softraw= [HW] Choose between synthetic and real raw mode
324 Format: <bool> (0 = real, 1 = synthetic (default))
326 atkbd.softrepeat= [HW]
327 Use software keyboard repeat
329 autotest [IA64]
331 baycom_epp= [HW,AX25]
332 Format: <io>,<mode>
334 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
335 Format: <io>,<mode>
336 See header of drivers/net/hamradio/baycom_par.c.
338 baycom_ser_fdx= [HW,AX25]
339 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
340 Format: <io>,<irq>,<mode>[,<baud>]
341 See header of drivers/net/hamradio/baycom_ser_fdx.c.
343 baycom_ser_hdx= [HW,AX25]
344 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
345 Format: <io>,<irq>,<mode>
346 See header of drivers/net/hamradio/baycom_ser_hdx.c.
348 blkmtd_device= [HW,MTD]
349 blkmtd_erasesz=
350 blkmtd_ro=
351 blkmtd_bs=
352 blkmtd_count=
354 boot_delay= Milliseconds to delay each printk during boot.
355 Values larger than 10 seconds (10000) are changed to
356 no delay (0).
357 Format: integer
359 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
360 bttv.radio= Most important insmod options are available as
361 kernel args too.
362 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
363 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
365 BusLogic= [HW,SCSI]
366 See drivers/scsi/BusLogic.c, comment before function
367 BusLogic_ParseDriverOptions().
369 c101= [NET] Moxa C101 synchronous serial card
371 cachesize= [BUGS=X86-32] Override level 2 CPU cache size detection.
372 Sometimes CPU hardware bugs make them report the cache
373 size incorrectly. The kernel will attempt work arounds
374 to fix known problems, but for some CPUs it is not
375 possible to determine what the correct size should be.
376 This option provides an override for these situations.
378 capability.disable=
379 [SECURITY] Disable capabilities. This would normally
380 be used only if an alternative security model is to be
381 configured. Potentially dangerous and should only be
382 used if you are entirely sure of the consequences.
384 chandev= [HW,NET] Generic channel device initialisation
386 checkreqprot [SELINUX] Set initial checkreqprot flag value.
387 Format: { "0" | "1" }
388 See security/selinux/Kconfig help text.
389 0 -- check protection applied by kernel (includes
390 any implied execute protection).
391 1 -- check protection requested by application.
392 Default value is set via a kernel config option.
393 Value can be changed at runtime via
394 /selinux/checkreqprot.
396 clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
397 [Deprecated]
398 Forces specified clocksource (if available) to be used
399 when calculating gettimeofday(). If specified
400 clocksource is not available, it defaults to PIT.
401 Format: { pit | tsc | cyclone | pmtmr }
403 clocksource= [GENERIC_TIME] Override the default clocksource
404 Format: <string>
405 Override the default clocksource and use the clocksource
406 with the name specified.
407 Some clocksource names to choose from, depending on
408 the platform:
409 [all] jiffies (this is the base, fallback clocksource)
410 [ACPI] acpi_pm
411 [ARM] imx_timer1,OSTS,netx_timer,mpu_timer2,
412 pxa_timer,timer3,32k_counter,timer0_1
413 [AVR32] avr32
414 [X86-32] pit,hpet,tsc,vmi-timer;
415 scx200_hrt on Geode; cyclone on IBM x440
416 [MIPS] MIPS
417 [PARISC] cr16
418 [S390] tod
419 [SH] SuperH
420 [SPARC64] tick
421 [X86-64] hpet,tsc
423 code_bytes [IA32] How many bytes of object code to print in an
424 oops report.
425 Range: 0 - 8192
426 Default: 64
428 disable_8254_timer
429 enable_8254_timer
430 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
431 over the 8254 in addition to over the IO-APIC. The
432 kernel tries to set a sensible default.
434 hpet= [X86-32,HPET] option to disable HPET and use PIT.
435 Format: disable
437 com20020= [HW,NET] ARCnet - COM20020 chipset
438 Format:
439 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
441 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
442 Format: <io>[,<irq>]
444 com90xx= [HW,NET]
445 ARCnet - COM90xx chipset (memory-mapped buffers)
446 Format: <io>[,<irq>[,<memstart>]]
448 condev= [HW,S390] console device
449 conmode=
451 console= [KNL] Output console device and options.
453 tty<n> Use the virtual console device <n>.
455 ttyS<n>[,options]
456 ttyUSB0[,options]
457 Use the specified serial port. The options are of
458 the form "bbbbpnf", where "bbbb" is the baud rate,
459 "p" is parity ("n", "o", or "e"), "n" is number of
460 bits, and "f" is flow control ("r" for RTS or
461 omit it). Default is "9600n8".
463 See Documentation/serial-console.txt for more
464 information. See
465 Documentation/networking/netconsole.txt for an
466 alternative.
468 uart[8250],io,<addr>[,options]
469 uart[8250],mmio,<addr>[,options]
470 Start an early, polled-mode console on the 8250/16550
471 UART at the specified I/O port or MMIO address,
472 switching to the matching ttyS device later. The
473 options are the same as for ttyS, above.
475 earlycon= [KNL] Output early console device and options.
476 uart[8250],io,<addr>[,options]
477 uart[8250],mmio,<addr>[,options]
478 Start an early, polled-mode console on the 8250/16550
479 UART at the specified I/O port or MMIO address.
480 The options are the same as for ttyS, above.
482 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
483 Format:
484 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
486 crashkernel=nn[KMG]@ss[KMG]
487 [KNL] Reserve a chunk of physical memory to
488 hold a kernel to switch to with kexec on panic.
490 cs4232= [HW,OSS]
491 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
493 cs89x0_dma= [HW,NET]
494 Format: <dma>
496 cs89x0_media= [HW,NET]
497 Format: { rj45 | aui | bnc }
499 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
501 dasd= [HW,NET]
502 See header of drivers/s390/block/dasd_devmap.c.
504 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
505 (one device per port)
506 Format: <port#>,<type>
507 See also Documentation/input/joystick-parport.txt
509 debug [KNL] Enable kernel debugging (events log level).
511 debug_locks_verbose=
512 [KNL] verbose self-tests
513 Format=<0|1>
514 Print debugging info while doing the locking API
515 self-tests.
516 We default to 0 (no extra messages), setting it to
517 1 will print _a lot_ more information - normally
518 only useful to kernel developers.
520 decnet= [HW,NET]
521 Format: <area>[,<node>]
522 See also Documentation/networking/decnet.txt.
524 default_blu= [VT]
525 Format: <blue0>,<blue1>,<blue2>,...,<blue15>
526 Change the default blue palette of the console.
527 This is a 16-member array composed of values
528 ranging from 0-255.
530 default_grn= [VT]
531 Format: <green0>,<green1>,<green2>,...,<green15>
532 Change the default green palette of the console.
533 This is a 16-member array composed of values
534 ranging from 0-255.
536 default_red= [VT]
537 Format: <red0>,<red1>,<red2>,...,<red15>
538 Change the default red palette of the console.
539 This is a 16-member array composed of values
540 ranging from 0-255.
542 default_utf8= [VT]
543 Format=<0|1>
544 Set system-wide default UTF-8 mode for all tty's.
545 Default is 0 and by setting to 1, it enables UTF-8
546 mode for all newly opened or allocated terminals.
548 dhash_entries= [KNL]
549 Set number of hash buckets for dentry cache.
551 digi= [HW,SERIAL]
552 IO parameters + enable/disable command.
554 digiepca= [HW,SERIAL]
555 See drivers/char/README.epca and
556 Documentation/digiepca.txt.
558 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
559 support available.
560 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
562 dmasound= [HW,OSS] Sound subsystem buffers
564 dscc4.setup= [NET]
566 dtc3181e= [HW,SCSI]
568 earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
569 earlyprintk=vga
570 earlyprintk=serial[,ttySn[,baudrate]]
572 Append ",keep" to not disable it when the real console
573 takes over.
575 Only vga or serial at a time, not both.
577 Currently only ttyS0 and ttyS1 are supported.
579 Interaction with the standard serial driver is not
580 very good.
582 The VGA output is eventually overwritten by the real
583 console.
585 eata= [HW,SCSI]
587 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
588 Format: <int>
589 0: polling mode
590 non-0: interrupt mode (default)
592 eda= [HW,PS2]
594 edb= [HW,PS2]
596 edd= [EDD]
597 Format: {"of[f]" | "sk[ipmbr]"}
598 See comment in arch/i386/boot/edd.S
600 eicon= [HW,ISDN]
601 Format: <id>,<membase>,<irq>
603 eisa_irq_edge= [PARISC,HW]
604 See header of drivers/parisc/eisa.c.
606 elanfreq= [X86-32]
607 See comment before function elanfreq_setup() in
608 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
610 elevator= [IOSCHED]
611 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
612 See Documentation/block/as-iosched.txt and
613 Documentation/block/deadline-iosched.txt for details.
615 elfcorehdr= [X86-32, X86_64]
616 Specifies physical address of start of kernel core
617 image elf header. Generally kexec loader will
618 pass this option to capture kernel.
619 See Documentation/kdump/kdump.txt for details.
621 enforcing [SELINUX] Set initial enforcing status.
622 Format: {"0" | "1"}
623 See security/selinux/Kconfig help text.
624 0 -- permissive (log only, no denials).
625 1 -- enforcing (deny and log).
626 Default value is 0.
627 Value can be changed at runtime via /selinux/enforce.
629 es1371= [HW,OSS]
630 Format: <spdif>,[<nomix>,[<amplifier>]]
631 See also header of sound/oss/es1371.c.
633 ether= [HW,NET] Ethernet cards parameters
634 This option is obsoleted by the "netdev=" option, which
635 has equivalent usage. See its documentation for details.
637 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
638 Format: <io>[,<irq>]
640 failslab=
641 fail_page_alloc=
642 fail_make_request=[KNL]
643 General fault injection mechanism.
644 Format: <interval>,<probability>,<space>,<times>
645 See also /Documentation/fault-injection/.
647 fd_mcs= [HW,SCSI]
648 See header of drivers/scsi/fd_mcs.c.
650 fdomain= [HW,SCSI]
651 See header of drivers/scsi/fdomain.c.
653 floppy= [HW]
654 See Documentation/floppy.txt.
656 gamecon.map[2|3]=
657 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
658 support via parallel port (up to 5 devices per port)
659 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
660 See also Documentation/input/joystick-parport.txt
662 gamma= [HW,DRM]
664 gdth= [HW,SCSI]
665 See header of drivers/scsi/gdth.c.
667 gpt [EFI] Forces disk with valid GPT signature but
668 invalid Protective MBR to be treated as GPT.
670 gvp11= [HW,SCSI]
672 hashdist= [KNL,NUMA] Large hashes allocated during boot
673 are distributed across NUMA nodes. Defaults on
674 for IA-64, off otherwise.
675 Format: 0 | 1 (for off | on)
677 hcl= [IA-64] SGI's Hardware Graph compatibility layer
679 hd= [EIDE] (E)IDE hard drive subsystem geometry
680 Format: <cyl>,<head>,<sect>
682 hd?= [HW] (E)IDE subsystem
683 hd?lun= See Documentation/ide.txt.
685 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
686 size of <nn>. This works even on boxes that have no
687 highmem otherwise. This also works to reduce highmem
688 size on bigger boxes.
690 highres= [KNL] Enable/disable high resolution timer mode.
691 Valid parameters: "on", "off"
692 Default: "on"
694 hisax= [HW,ISDN]
695 See Documentation/isdn/README.HiSax.
697 hugepages= [HW,X86-32,IA-64] Maximal number of HugeTLB pages.
699 i8042.direct [HW] Put keyboard port into non-translated mode
700 i8042.dumbkbd [HW] Pretend that controller can only read data from
701 keyboard and cannot control its state
702 (Don't attempt to blink the leds)
703 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
704 i8042.nokbd [HW] Don't check/create keyboard port
705 i8042.nomux [HW] Don't check presence of an active multiplexing
706 controller
707 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
708 controllers
709 i8042.panicblink=
710 [HW] Frequency with which keyboard LEDs should blink
711 when kernel panics (default is 0.5 sec)
712 i8042.reset [HW] Reset the controller during init and cleanup
713 i8042.unlock [HW] Unlock (ignore) the keylock
715 i810= [HW,DRM]
717 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
718 indicates that the driver is running on unsupported
719 hardware.
720 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
721 does not match list of supported models.
722 i8k.power_status
723 [HW] Report power status in /proc/i8k
724 (disabled by default)
725 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
726 capability is set.
728 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
729 See Documentation/mca.txt.
731 icn= [HW,ISDN]
732 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
734 ide= [HW] (E)IDE subsystem
735 Format: ide=nodma or ide=doubler or ide=reverse
736 See Documentation/ide.txt.
738 ide?= [HW] (E)IDE subsystem
739 Format: ide?=noprobe or chipset specific parameters.
740 See Documentation/ide.txt.
742 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
743 See Documentation/ide.txt.
745 idle= [X86]
746 Format: idle=poll or idle=mwait
747 Poll forces a polling idle loop that can slightly improves the performance
748 of waking up a idle CPU, but will use a lot of power and make the system
749 run hot. Not recommended.
750 idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
751 to not use it because it doesn't save as much power as a normal idle
752 loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
753 as idle=poll.
755 ignore_loglevel [KNL]
756 Ignore loglevel setting - this will print /all/
757 kernel messages to the console. Useful for debugging.
759 ihash_entries= [KNL]
760 Set number of hash buckets for inode cache.
762 in2000= [HW,SCSI]
763 See header of drivers/scsi/in2000.c.
765 init= [KNL]
766 Format: <full_path>
767 Run specified binary instead of /sbin/init as init
768 process.
770 initcall_debug [KNL] Trace initcalls as they are executed. Useful
771 for working out where the kernel is dying during
772 startup.
774 initrd= [BOOT] Specify the location of the initial ramdisk
776 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
777 Format: <irq>
779 inttest= [IA64]
781 io7= [HW] IO7 for Marvel based alpha systems
782 See comment before marvel_specify_io7 in
783 arch/alpha/kernel/core_marvel.c.
785 ip= [IP_PNP]
786 See Documentation/nfsroot.txt.
788 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
789 See comment before ip2_setup() in
790 drivers/char/ip2/ip2base.c.
792 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
793 See header of drivers/scsi/ips.c.
795 ports= [IP_VS_FTP] IPVS ftp helper module
796 Default is 21.
797 Up to 8 (IP_VS_APP_MAX_PORTS) ports
798 may be specified.
799 Format: <port>,<port>....
801 irqfixup [HW]
802 When an interrupt is not handled search all handlers
803 for it. Intended to get systems with badly broken
804 firmware running.
806 irqpoll [HW]
807 When an interrupt is not handled search all handlers
808 for it. Also check all handlers each timer
809 interrupt. Intended to get systems with badly broken
810 firmware running.
812 isapnp= [ISAPNP]
813 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
815 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
816 Format:
817 <cpu number>,...,<cpu number>
818 or
819 <cpu number>-<cpu number> (must be a positive range in ascending order)
820 or a mixture
821 <cpu number>,...,<cpu number>-<cpu number>
822 This option can be used to specify one or more CPUs
823 to isolate from the general SMP balancing and scheduling
824 algorithms. The only way to move a process onto or off
825 an "isolated" CPU is via the CPU affinity syscalls.
826 <cpu number> begins at 0 and the maximum value is
827 "number of CPUs in system - 1".
829 This option is the preferred way to isolate CPUs. The
830 alternative -- manually setting the CPU mask of all
831 tasks in the system -- can cause problems and
832 suboptimal load balancer performance.
834 iucv= [HW,NET]
836 js= [HW,JOY] Analog joystick
837 See Documentation/input/joystick.txt.
839 kernelcore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
840 specifies the amount of memory usable by the kernel
841 for non-movable allocations. The requested amount is
842 spread evenly throughout all nodes in the system. The
843 remaining memory in each node is used for Movable
844 pages. In the event, a node is too small to have both
845 kernelcore and Movable pages, kernelcore pages will
846 take priority and other nodes will have a larger number
847 of kernelcore pages. The Movable zone is used for the
848 allocation of pages that may be reclaimed or moved
849 by the page migration subsystem. This means that
850 HugeTLB pages may not be allocated from this zone.
851 Note that allocations like PTEs-from-HighMem still
852 use the HighMem zone if it exists, and the Normal
853 zone if it does not.
855 movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter
856 is similar to kernelcore except it specifies the
857 amount of memory used for migratable allocations.
858 If both kernelcore and movablecore is specified,
859 then kernelcore will be at *least* the specified
860 value but may be more. If movablecore on its own
861 is specified, the administrator must be careful
862 that the amount of memory usable for all allocations
863 is not too small.
865 keepinitrd [HW,ARM]
867 kstack=N [X86-32,X86-64] Print N words from the kernel stack
868 in oops dumps.
870 l2cr= [PPC]
872 lapic [X86-32,APIC] Enable the local APIC even if BIOS
873 disabled it.
875 lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
876 C2 power state.
878 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
879 Format: addr:<io>,irq:<irq>
881 libata.noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
882 when set.
883 Format: <int>
885 load_ramdisk= [RAM] List of ramdisks to load from floppy
886 See Documentation/ramdisk.txt.
888 lockd.nlm_grace_period=P [NFS] Assign grace period.
889 Format: <integer>
891 lockd.nlm_tcpport=N [NFS] Assign TCP port.
892 Format: <integer>
894 lockd.nlm_timeout=T [NFS] Assign timeout value.
895 Format: <integer>
897 lockd.nlm_udpport=M [NFS] Assign UDP port.
898 Format: <integer>
900 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
901 Format: <irq>
903 loglevel= All Kernel Messages with a loglevel smaller than the
904 console loglevel will be printed to the console. It can
905 also be changed with klogd or other programs. The
906 loglevels are defined as follows:
908 0 (KERN_EMERG) system is unusable
909 1 (KERN_ALERT) action must be taken immediately
910 2 (KERN_CRIT) critical conditions
911 3 (KERN_ERR) error conditions
912 4 (KERN_WARNING) warning conditions
913 5 (KERN_NOTICE) normal but significant condition
914 6 (KERN_INFO) informational
915 7 (KERN_DEBUG) debug-level messages
917 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
918 Format: { n | nk | nM }
919 n must be a power of two. The default size
920 is set in the kernel config file.
922 logo.nologo [FB] Disables display of the built-in Linux logo.
923 This may be used to provide more screen space for
924 kernel log messages and is useful when debugging
925 kernel boot problems.
927 lp=0 [LP] Specify parallel ports to use, e.g,
928 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
929 lp=reset first parallel port). 'lp=0' disables the
930 lp=auto printer driver. 'lp=reset' (which can be
931 specified in addition to the ports) causes
932 attached printers to be reset. Using
933 lp=port1,port2,... specifies the parallel ports
934 to associate lp devices with, starting with
935 lp0. A port specification may be 'none' to skip
936 that lp device, or a parport name such as
937 'parport0'. Specifying 'lp=auto' instead of a
938 port specification list means that device IDs
939 from each port should be examined, to see if
940 an IEEE 1284-compliant printer is attached; if
941 so, the driver will manage that printer.
942 See also header of drivers/char/lp.c.
944 lpj=n [KNL]
945 Sets loops_per_jiffy to given constant, thus avoiding
946 time-consuming boot-time autodetection (up to 250 ms per
947 CPU). 0 enables autodetection (default). To determine
948 the correct value for your kernel, boot with normal
949 autodetection and see what value is printed. Note that
950 on SMP systems the preset will be applied to all CPUs,
951 which is likely to cause problems if your CPUs need
952 significantly divergent settings. An incorrect value
953 will cause delays in the kernel to be wrong, leading to
954 unpredictable I/O errors and other breakage. Although
955 unlikely, in the extreme case this might damage your
956 hardware.
958 ltpc= [NET]
959 Format: <io>,<irq>,<dma>
961 mac5380= [HW,SCSI] Format:
962 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
964 mac53c9x= [HW,SCSI] Format:
965 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
967 machvec= [IA64] Force the use of a particular machine-vector
968 (machvec) in a generic kernel.
969 Example: machvec=hpzx1_swiotlb
971 max_loop= [LOOP] Maximum number of loopback devices that can
972 be mounted
973 Format: <1-256>
975 maxcpus= [SMP] Maximum number of processors that an SMP kernel
976 should make use of. maxcpus=n : n >= 0 limits the
977 kernel to using 'n' processors. n=0 is a special case,
978 it is equivalent to "nosmp", which also disables
979 the IO APIC.
981 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
982 equal to this physical address is ignored.
984 max_luns= [SCSI] Maximum number of LUNs to probe.
985 Should be between 1 and 2^32-1.
987 max_report_luns=
988 [SCSI] Maximum number of LUNs received.
989 Should be between 1 and 16384.
991 mca-pentium [BUGS=X86-32]
993 mcatest= [IA-64]
995 mce [X86-32] Machine Check Exception
997 mce=option [X86-64] See Documentation/x86_64/boot-options.txt
999 md= [HW] RAID subsystems devices and level
1000 See Documentation/md.txt.
1002 mdacon= [MDA]
1003 Format: <first>,<last>
1004 Specifies range of consoles to be captured by the MDA.
1006 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
1007 Amount of memory to be used when the kernel is not able
1008 to see the whole system memory or for test.
1009 [X86-32] Use together with memmap= to avoid physical
1010 address space collisions. Without memmap= PCI devices
1011 could be placed at addresses belonging to unused RAM.
1013 mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
1014 memory.
1016 memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact
1017 E820 memory map, as specified by the user.
1018 Such memmap=exactmap lines can be constructed based on
1019 BIOS output or other requirements. See the memmap=nn@ss
1020 option description.
1022 memmap=nn[KMG]@ss[KMG]
1023 [KNL] Force usage of a specific region of memory
1024 Region of memory to be used, from ss to ss+nn.
1026 memmap=nn[KMG]#ss[KMG]
1027 [KNL,ACPI] Mark specific memory as ACPI data.
1028 Region of memory to be used, from ss to ss+nn.
1030 memmap=nn[KMG]$ss[KMG]
1031 [KNL,ACPI] Mark specific memory as reserved.
1032 Region of memory to be used, from ss to ss+nn.
1034 meye.*= [HW] Set MotionEye Camera parameters
1035 See Documentation/video4linux/meye.txt.
1037 mfgpt_irq= [IA-32] Specify the IRQ to use for the
1038 Multi-Function General Purpose Timers on AMD Geode
1039 platforms.
1041 mga= [HW,DRM]
1043 mousedev.tap_time=
1044 [MOUSE] Maximum time between finger touching and
1045 leaving touchpad surface for touch to be considered
1046 a tap and be reported as a left button click (for
1047 touchpads working in absolute mode only).
1048 Format: <msecs>
1049 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
1050 reporting absolute coordinates, such as tablets
1051 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
1052 reporting absolute coordinates, such as tablets
1054 mpu401= [HW,OSS]
1055 Format: <io>,<irq>
1057 MTD_Partition= [MTD]
1058 Format: <name>,<region-number>,<size>,<offset>
1060 MTD_Region= [MTD] Format:
1061 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1063 mtdparts= [MTD]
1064 See drivers/mtd/cmdlinepart.c.
1066 mtouchusb.raw_coordinates=
1067 [HW] Make the MicroTouch USB driver use raw coordinates
1068 ('y', default) or cooked coordinates ('n')
1070 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1072 NCR_D700= [HW,SCSI]
1073 See header of drivers/scsi/NCR_D700.c.
1075 ncr5380= [HW,SCSI]
1077 ncr53c400= [HW,SCSI]
1079 ncr53c400a= [HW,SCSI]
1081 ncr53c406a= [HW,SCSI]
1083 ncr53c8xx= [HW,SCSI]
1085 netdev= [NET] Network devices parameters
1086 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1087 Note that mem_start is often overloaded to mean
1088 something different and driver-specific.
1089 This usage is only documented in each driver source
1090 file if at all.
1092 nfsaddrs= [NFS]
1093 See Documentation/nfsroot.txt.
1095 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1096 See Documentation/nfsroot.txt.
1098 nfs.callback_tcpport=
1099 [NFS] set the TCP port on which the NFSv4 callback
1100 channel should listen.
1102 nfs.idmap_cache_timeout=
1103 [NFS] set the maximum lifetime for idmapper cache
1104 entries.
1106 nfs.enable_ino64=
1107 [NFS] enable 64-bit inode numbers.
1108 If zero, the NFS client will fake up a 32-bit inode
1109 number for the readdir() and stat() syscalls instead
1110 of returning the full 64-bit number.
1111 The default is to return 64-bit inode numbers.
1113 nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
1115 no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
1116 emulation library even if a 387 maths coprocessor
1117 is present.
1119 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien
1120 caches in the slab allocator. Saves per-node memory,
1121 but will impact performance.
1123 noalign [KNL,ARM]
1125 noapic [SMP,APIC] Tells the kernel to not make use of any
1126 IOAPICs that may be present in the system.
1128 noasync [HW,M68K] Disables async and sync negotiation for
1129 all devices.
1131 nobats [PPC] Do not use BATs for mapping kernel lowmem
1132 on "Classic" PPC cores.
1134 nocache [ARM]
1136 nodelayacct [KNL] Disable per-task delay accounting
1138 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1140 noexec [IA-64]
1142 noexec [X86-32,X86-64]
1143 noexec=on: enable non-executable mappings (default)
1144 noexec=off: disable nn-executable mappings
1146 nofxsr [BUGS=X86-32] Disables x86 floating point extended
1147 register save and restore. The kernel will only save
1148 legacy floating-point registers on task switch.
1150 nohlt [BUGS=ARM]
1152 no-hlt [BUGS=X86-32] Tells the kernel that the hlt
1153 instruction doesn't work correctly and not to
1154 use it.
1156 nohalt [IA-64] Tells the kernel not to use the power saving
1157 function PAL_HALT_LIGHT when idle. This increases
1158 power-consumption. On the positive side, it reduces
1159 interrupt wake-up latency, which may improve performance
1160 in certain environments such as networked servers or
1161 real-time systems.
1163 nohz= [KNL] Boottime enable/disable dynamic ticks
1164 Valid arguments: on, off
1165 Default: on
1167 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1169 noirqdebug [X86-32] Disables the code which attempts to detect and
1170 disable unhandled interrupt sources.
1172 no_timer_check [X86-32,X86_64,APIC] Disables the code which tests for
1173 broken timer IRQ sources.
1175 noisapnp [ISAPNP] Disables ISA PnP code.
1177 noinitrd [RAM] Tells the kernel not to load any configured
1178 initial RAM disk.
1180 nointroute [IA-64]
1182 nojitter [IA64] Disables jitter checking for ITC timers.
1184 nolapic [X86-32,APIC] Do not enable or use the local APIC.
1186 nolapic_timer [X86-32,APIC] Do not use the local APIC timer.
1188 noltlbs [PPC] Do not use large page/tlb entries for kernel
1189 lowmem mapping on PPC40x.
1191 nomca [IA-64] Disable machine check abort handling
1193 nomce [X86-32] Machine Check Exception
1195 nomfgpt [X86-32] Disable Multi-Function General Purpose
1196 Timer usage (for AMD Geode machines).
1198 noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops
1200 noreplace-smp [X86-32,SMP] Don't replace SMP instructions
1201 with UP alternatives
1203 noresidual [PPC] Don't use residual data on PReP machines.
1205 noresume [SWSUSP] Disables resume and restores original swap
1206 space.
1208 no-scroll [VGA] Disables scrollback.
1209 This is required for the Braillex ib80-piezo Braille
1210 reader made by F.H. Papenmeier (Germany).
1212 nosbagart [IA-64]
1214 nosep [BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
1216 nosmp [SMP] Tells an SMP kernel to act as a UP kernel,
1217 and disable the IO APIC. legacy for "maxcpus=0".
1219 nosoftlockup [KNL] Disable the soft-lockup detector.
1221 nosync [HW,M68K] Disables sync negotiation for all devices.
1223 notsc [BUGS=X86-32] Disable Time Stamp Counter
1225 nousb [USB] Disable the USB subsystem
1227 nowb [ARM]
1229 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
1230 one of ['zone', 'node', 'default'] can be specified
1231 This can be set from sysctl after boot.
1232 See Documentation/sysctl/vm.txt for details.
1234 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1236 opl3= [HW,OSS]
1237 Format: <io>
1239 oprofile.timer= [HW]
1240 Use timer interrupt instead of performance counters
1242 osst= [HW,SCSI] SCSI Tape Driver
1243 Format: <buffer_size>,<write_threshold>
1244 See also Documentation/scsi/st.txt.
1246 panic= [KNL] Kernel behaviour on panic
1247 Format: <timeout>
1249 parkbd.port= [HW] Parallel port number the keyboard adapter is
1250 connected to, default is 0.
1251 Format: <parport#>
1252 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1253 0 for XT, 1 for AT (default is AT).
1254 Format: <mode>
1256 parport= [HW,PPT] Specify parallel ports. 0 disables.
1257 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1258 Use 'auto' to force the driver to use any
1259 IRQ/DMA settings detected (the default is to
1260 ignore detected IRQ/DMA settings because of
1261 possible conflicts). You can specify the base
1262 address, IRQ, and DMA settings; IRQ and DMA
1263 should be numbers, or 'auto' (for using detected
1264 settings on that particular port), or 'nofifo'
1265 (to avoid using a FIFO even if it is detected).
1266 Parallel ports are assigned in the order they
1267 are specified on the command line, starting
1268 with parport0.
1270 parport_init_mode= [HW,PPT]
1271 Configure VIA parallel port to operate in
1272 a specific mode. This is necessary on Pegasos
1273 computer where firmware has no options for setting
1274 up parallel port mode and sets it to spp.
1275 Currently this function knows 686a and 8231 chips.
1276 Format: [spp|ps2|epp|ecp|ecpepp]
1278 pas2= [HW,OSS] Format:
1279 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1281 pas16= [HW,SCSI]
1282 See header of drivers/scsi/pas16.c.
1284 pause_on_oops=
1285 Halt all CPUs after the first oops has been printed for
1286 the specified number of seconds. This is to be used if
1287 your oopses keep scrolling off the screen.
1289 pcbit= [HW,ISDN]
1291 pcd. [PARIDE]
1292 See header of drivers/block/paride/pcd.c.
1293 See also Documentation/paride.txt.
1295 pci=option[,option...] [PCI] various PCI subsystem options:
1296 off [X86-32] don't probe for the PCI bus
1297 bios [X86-32] force use of PCI BIOS, don't access
1298 the hardware directly. Use this if your machine
1299 has a non-standard PCI host bridge.
1300 nobios [X86-32] disallow use of PCI BIOS, only direct
1301 hardware access methods are allowed. Use this
1302 if you experience crashes upon bootup and you
1303 suspect they are caused by the BIOS.
1304 conf1 [X86-32] Force use of PCI Configuration
1305 Mechanism 1.
1306 conf2 [X86-32] Force use of PCI Configuration
1307 Mechanism 2.
1308 noaer [PCIE] If the PCIEAER kernel config parameter is
1309 enabled, this kernel boot option can be used to
1310 disable the use of PCIE advanced error reporting.
1311 nodomains [PCI] Disable support for multiple PCI
1312 root domains (aka PCI segments, in ACPI-speak).
1313 nommconf [X86-32,X86_64] Disable use of MMCONFIG for PCI
1314 Configuration
1315 nomsi [MSI] If the PCI_MSI kernel config parameter is
1316 enabled, this kernel boot option can be used to
1317 disable the use of MSI interrupts system-wide.
1318 nosort [X86-32] Don't sort PCI devices according to
1319 order given by the PCI BIOS. This sorting is
1320 done to get a device order compatible with
1321 older kernels.
1322 biosirq [X86-32] Use PCI BIOS calls to get the interrupt
1323 routing table. These calls are known to be buggy
1324 on several machines and they hang the machine
1325 when used, but on other computers it's the only
1326 way to get the interrupt routing table. Try
1327 this option if the kernel is unable to allocate
1328 IRQs or discover secondary PCI buses on your
1329 motherboard.
1330 rom [X86-32] Assign address space to expansion ROMs.
1331 Use with caution as certain devices share
1332 address decoders between ROMs and other
1333 resources.
1334 irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be
1335 assigned automatically to PCI devices. You can
1336 make the kernel exclude IRQs of your ISA cards
1337 this way.
1338 pirqaddr=0xAAAAA [X86-32] Specify the physical address
1339 of the PIRQ table (normally generated
1340 by the BIOS) if it is outside the
1341 F0000h-100000h range.
1342 lastbus=N [X86-32] Scan all buses thru bus #N. Can be
1343 useful if the kernel is unable to find your
1344 secondary buses and you want to tell it
1345 explicitly which ones they are.
1346 assign-busses [X86-32] Always assign all PCI bus
1347 numbers ourselves, overriding
1348 whatever the firmware may have done.
1349 usepirqmask [X86-32] Honor the possible IRQ mask stored
1350 in the BIOS $PIR table. This is needed on
1351 some systems with broken BIOSes, notably
1352 some HP Pavilion N5400 and Omnibook XE3
1353 notebooks. This will have no effect if ACPI
1354 IRQ routing is enabled.
1355 noacpi [X86-32] Do not use ACPI for IRQ routing
1356 or for PCI scanning.
1357 use_crs [X86-32] Use _CRS for PCI resource
1358 allocation.
1359 routeirq Do IRQ routing for all PCI devices.
1360 This is normally done in pci_enable_device(),
1361 so this option is a temporary workaround
1362 for broken drivers that don't call it.
1363 firmware [ARM] Do not re-enumerate the bus but instead
1364 just use the configuration from the
1365 bootloader. This is currently used on
1366 IXP2000 systems where the bus has to be
1367 configured a certain way for adjunct CPUs.
1368 noearly [X86] Don't do any early type 1 scanning.
1369 This might help on some broken boards which
1370 machine check when some devices' config space
1371 is read. But various workarounds are disabled
1372 and some IOMMU drivers will not work.
1373 bfsort Sort PCI devices into breadth-first order.
1374 This sorting is done to get a device
1375 order compatible with older (<= 2.4) kernels.
1376 nobfsort Don't sort PCI devices into breadth-first order.
1377 cbiosize=nn[KMG] The fixed amount of bus space which is
1378 reserved for the CardBus bridge's IO window.
1379 The default value is 256 bytes.
1380 cbmemsize=nn[KMG] The fixed amount of bus space which is
1381 reserved for the CardBus bridge's memory
1382 window. The default value is 64 megabytes.
1384 pcmv= [HW,PCMCIA] BadgePAD 4
1386 pd. [PARIDE]
1387 See Documentation/paride.txt.
1389 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1390 boot time.
1391 Format: { 0 | 1 }
1392 See arch/parisc/kernel/pdc_chassis.c
1394 pf. [PARIDE]
1395 See Documentation/paride.txt.
1397 pg. [PARIDE]
1398 See Documentation/paride.txt.
1400 pirq= [SMP,APIC] Manual mp-table setup
1401 See Documentation/i386/IO-APIC.txt.
1403 plip= [PPT,NET] Parallel port network link
1404 Format: { parport<nr> | timid | 0 }
1405 See also Documentation/parport.txt.
1407 pnpacpi= [ACPI]
1408 { off }
1410 pnpbios= [ISAPNP]
1411 { on | off | curr | res | no-curr | no-res }
1413 pnp_reserve_irq=
1414 [ISAPNP] Exclude IRQs for the autoconfiguration
1416 pnp_reserve_dma=
1417 [ISAPNP] Exclude DMAs for the autoconfiguration
1419 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1420 Ranges are in pairs (I/O port base and size).
1422 pnp_reserve_mem=
1423 [ISAPNP] Exclude memory regions for the
1424 autoconfiguration.
1425 Ranges are in pairs (memory base and size).
1427 print-fatal-signals=
1428 [KNL] debug: print fatal signals
1429 print-fatal-signals=1: print segfault info to
1430 the kernel console.
1431 default: off.
1433 printk.time= Show timing data prefixed to each printk message line
1434 Format: <bool> (1/Y/y=enable, 0/N/n=disable)
1436 profile= [KNL] Enable kernel profiling via /proc/profile
1437 Format: [schedule,]<number>
1438 Param: "schedule" - profile schedule points.
1439 Param: <number> - step/bucket size as a power of 2 for
1440 statistical time based profiling.
1441 Param: "sleep" - profile D-state sleeping (millisecs)
1443 processor.max_cstate= [HW,ACPI]
1444 Limit processor to maximum C-state
1445 max_cstate=9 overrides any DMI blacklist limit.
1447 processor.nocst [HW,ACPI]
1448 Ignore the _CST method to determine C-states,
1449 instead using the legacy FADT method
1451 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1452 before loading.
1453 See Documentation/ramdisk.txt.
1455 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1456 probe for; one of (bare|imps|exps|lifebook|any).
1457 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1458 per second.
1459 psmouse.resetafter= [HW,MOUSE]
1460 Try to reset the device after so many bad packets
1461 (0 = never).
1462 psmouse.resolution=
1463 [HW,MOUSE] Set desired mouse resolution, in dpi.
1464 psmouse.smartscroll=
1465 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1466 0 = disabled, 1 = enabled (default).
1468 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1469 Format:
1470 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1472 pt. [PARIDE]
1473 See Documentation/paride.txt.
1475 pty.legacy_count=
1476 [KNL] Number of legacy pty's. Overwrites compiled-in
1477 default number.
1479 quiet [KNL] Disable most log messages
1481 r128= [HW,DRM]
1483 raid= [HW,RAID]
1484 See Documentation/md.txt.
1486 ramdisk_blocksize= [RAM]
1487 See Documentation/ramdisk.txt.
1489 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1490 See Documentation/ramdisk.txt.
1492 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1493 RCU callbacks to process in one batch.
1495 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1496 RCU callbacks over which batch limiting is disabled.
1498 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1499 RCU callbacks below which batch limiting is re-enabled.
1501 rdinit= [KNL]
1502 Format: <full_path>
1503 Run specified binary instead of /init from the ramdisk,
1504 used for early userspace startup. See initrd.
1506 reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1507 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1508 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1510 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1512 reservetop= [X86-32]
1513 Format: nn[KMG]
1514 Reserves a hole at the top of the kernel virtual
1515 address space.
1517 reset_devices [KNL] Force drivers to reset the underlying device
1518 during initialization.
1520 resume= [SWSUSP]
1521 Specify the partition device for software suspend
1523 resume_offset= [SWSUSP]
1524 Specify the offset from the beginning of the partition
1525 given by "resume=" at which the swap header is located,
1526 in <PAGE_SIZE> units (needed only for swap files).
1527 See Documentation/power/swsusp-and-swap-files.txt
1529 retain_initrd [RAM] Keep initrd memory after extraction
1531 rhash_entries= [KNL,NET]
1532 Set number of hash buckets for route cache
1534 riscom8= [HW,SERIAL]
1535 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1537 ro [KNL] Mount root device read-only on boot
1539 root= [KNL] Root filesystem
1541 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1542 mount the root filesystem
1544 rootflags= [KNL] Set root filesystem mount option string
1546 rootfstype= [KNL] Set root filesystem type
1548 rootwait [KNL] Wait (indefinitely) for root device to show up.
1549 Useful for devices that are detected asynchronously
1550 (e.g. USB and MMC devices).
1552 root_plug.vendor_id=
1553 [ROOTPLUG] Override the default vendor ID
1555 root_plug.product_id=
1556 [ROOTPLUG] Override the default product ID
1558 root_plug.debug=
1559 [ROOTPLUG] Enable debugging output
1561 rw [KNL] Mount root device read-write on boot
1563 S [KNL] Run init in single mode
1565 sa1100ir [NET]
1566 See drivers/net/irda/sa1100_ir.c.
1568 sb= [HW,OSS]
1569 Format: <io>,<irq>,<dma>,<dma2>
1571 sbni= [NET] Granch SBNI12 leased line adapter
1573 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1574 Format: <io>[,<timeout>[,<isapnp>]]
1576 scsi_debug_*= [SCSI]
1577 See drivers/scsi/scsi_debug.c.
1579 scsi_default_dev_flags=
1580 [SCSI] SCSI default device flags
1581 Format: <integer>
1583 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1584 Format: <vendor>:<model>:<flags>
1585 (flags are integer value)
1587 scsi_logging= [SCSI]
1589 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1590 discovered. async scans them in kernel threads,
1591 allowing boot to proceed. none ignores them, expecting
1592 user space to do the scan.
1594 selinux [SELINUX] Disable or enable SELinux at boot time.
1595 Format: { "0" | "1" }
1596 See security/selinux/Kconfig help text.
1597 0 -- disable.
1598 1 -- enable.
1599 Default value is set via kernel config option.
1600 If enabled at boot time, /selinux/disable can be used
1601 later to disable prior to initial policy load.
1603 selinux_compat_net =
1604 [SELINUX] Set initial selinux_compat_net flag value.
1605 Format: { "0" | "1" }
1606 0 -- use new secmark-based packet controls
1607 1 -- use legacy packet controls
1608 Default value is 0 (preferred).
1609 Value can be changed at runtime via
1610 /selinux/compat_net.
1612 serialnumber [BUGS=X86-32]
1614 sg_def_reserved_size= [SCSI]
1616 shapers= [NET]
1617 Maximal number of shapers.
1619 sim710= [SCSI,HW]
1620 See header of drivers/scsi/sim710.c.
1622 simeth= [IA-64]
1623 simscsi=
1625 slram= [HW,MTD]
1627 slub_debug[=options[,slabs]] [MM, SLUB]
1628 Enabling slub_debug allows one to determine the
1629 culprit if slab objects become corrupted. Enabling
1630 slub_debug can create guard zones around objects and
1631 may poison objects when not in use. Also tracks the
1632 last alloc / free. For more information see
1633 Documentation/vm/slub.txt.
1635 slub_max_order= [MM, SLUB]
1636 Determines the maximum allowed order for slabs.
1637 A high setting may cause OOMs due to memory
1638 fragmentation. For more information see
1639 Documentation/vm/slub.txt.
1641 slub_min_objects= [MM, SLUB]
1642 The minimum number of objects per slab. SLUB will
1643 increase the slab order up to slub_max_order to
1644 generate a sufficiently large slab able to contain
1645 the number of objects indicated. The higher the number
1646 of objects the smaller the overhead of tracking slabs
1647 and the less frequently locks need to be acquired.
1648 For more information see Documentation/vm/slub.txt.
1650 slub_min_order= [MM, SLUB]
1651 Determines the mininum page order for slabs. Must be
1652 lower than slub_max_order.
1653 For more information see Documentation/vm/slub.txt.
1655 slub_nomerge [MM, SLUB]
1656 Disable merging of slabs with similar size. May be
1657 necessary if there is some reason to distinguish
1658 allocs to different slabs. Debug options disable
1659 merging on their own.
1660 For more information see Documentation/vm/slub.txt.
1662 smart2= [HW]
1663 Format: <io1>[,<io2>[,...,<io8>]]
1665 smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
1666 attempt to substitute SMP alternatives once at boot.
1668 smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
1669 smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
1670 smsc-ircc2.ircc_sir= [HW] SIR base I/O port
1671 smsc-ircc2.ircc_fir= [HW] FIR base I/O port
1672 smsc-ircc2.ircc_irq= [HW] IRQ line
1673 smsc-ircc2.ircc_dma= [HW] DMA channel
1674 smsc-ircc2.ircc_transceiver= [HW] Transceiver type:
1675 0: Toshiba Satellite 1800 (GP data pin select)
1676 1: Fast pin select (default)
1677 2: ATC IRMode
1679 snd-ad1816a= [HW,ALSA]
1681 snd-ad1848= [HW,ALSA]
1683 snd-ali5451= [HW,ALSA]
1685 snd-als100= [HW,ALSA]
1687 snd-als4000= [HW,ALSA]
1689 snd-azt2320= [HW,ALSA]
1691 snd-cmi8330= [HW,ALSA]
1693 snd-cmipci= [HW,ALSA]
1695 snd-cs4231= [HW,ALSA]
1697 snd-cs4232= [HW,ALSA]
1699 snd-cs4236= [HW,ALSA]
1701 snd-cs4281= [HW,ALSA]
1703 snd-cs46xx= [HW,ALSA]
1705 snd-dt019x= [HW,ALSA]
1707 snd-dummy= [HW,ALSA]
1709 snd-emu10k1= [HW,ALSA]
1711 snd-ens1370= [HW,ALSA]
1713 snd-ens1371= [HW,ALSA]
1715 snd-es968= [HW,ALSA]
1717 snd-es1688= [HW,ALSA]
1719 snd-es18xx= [HW,ALSA]
1721 snd-es1938= [HW,ALSA]
1723 snd-es1968= [HW,ALSA]
1725 snd-fm801= [HW,ALSA]
1727 snd-gusclassic= [HW,ALSA]
1729 snd-gusextreme= [HW,ALSA]
1731 snd-gusmax= [HW,ALSA]
1733 snd-hdsp= [HW,ALSA]
1735 snd-ice1712= [HW,ALSA]
1737 snd-intel8x0= [HW,ALSA]
1739 snd-interwave= [HW,ALSA]
1741 snd-interwave-stb=
1742 [HW,ALSA]
1744 snd-korg1212= [HW,ALSA]
1746 snd-maestro3= [HW,ALSA]
1748 snd-mpu401= [HW,ALSA]
1750 snd-mtpav= [HW,ALSA]
1752 snd-nm256= [HW,ALSA]
1754 snd-opl3sa2= [HW,ALSA]
1756 snd-opti92x-ad1848=
1757 [HW,ALSA]
1759 snd-opti92x-cs4231=
1760 [HW,ALSA]
1762 snd-opti93x= [HW,ALSA]
1764 snd-pmac= [HW,ALSA]
1766 snd-rme32= [HW,ALSA]
1768 snd-rme96= [HW,ALSA]
1770 snd-rme9652= [HW,ALSA]
1772 snd-sb8= [HW,ALSA]
1774 snd-sb16= [HW,ALSA]
1776 snd-sbawe= [HW,ALSA]
1778 snd-serial= [HW,ALSA]
1780 snd-sgalaxy= [HW,ALSA]
1782 snd-sonicvibes= [HW,ALSA]
1784 snd-sun-amd7930=
1785 [HW,ALSA]
1787 snd-sun-cs4231= [HW,ALSA]
1789 snd-trident= [HW,ALSA]
1791 snd-usb-audio= [HW,ALSA,USB]
1793 snd-via82xx= [HW,ALSA]
1795 snd-virmidi= [HW,ALSA]
1797 snd-wavefront= [HW,ALSA]
1799 snd-ymfpci= [HW,ALSA]
1801 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1802 See Documentation/sonypi.txt
1804 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1805 See Documentation/specialix.txt.
1807 spia_io_base= [HW,MTD]
1808 spia_fio_base=
1809 spia_pedr=
1810 spia_peddr=
1812 sscape= [HW,OSS]
1813 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1815 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1816 See Documentation/scsi/st.txt.
1818 st0x= [HW,SCSI]
1819 See header of drivers/scsi/seagate.c.
1821 sti= [PARISC,HW]
1822 Format: <num>
1823 Set the STI (builtin display/keyboard on the HP-PARISC
1824 machines) console (graphic card) which should be used
1825 as the initial boot-console.
1826 See also comment in drivers/video/console/sticore.c.
1828 sti_font= [HW]
1829 See comment in drivers/video/console/sticore.c.
1831 stifb= [HW]
1832 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1834 sunrpc.pool_mode=
1835 [NFS]
1836 Control how the NFS server code allocates CPUs to
1837 service thread pools. Depending on how many NICs
1838 you have and where their interrupts are bound, this
1839 option will affect which CPUs will do NFS serving.
1840 Note: this parameter cannot be changed while the
1841 NFS server is running.
1843 auto the server chooses an appropriate mode
1844 automatically using heuristics
1845 global a single global pool contains all CPUs
1846 percpu one pool for each CPU
1847 pernode one pool for each NUMA node (equivalent
1848 to global on non-NUMA machines)
1850 swiotlb= [IA-64] Number of I/O TLB slabs
1852 switches= [HW,M68k]
1854 sym53c416= [HW,SCSI]
1855 See header of drivers/scsi/sym53c416.c.
1857 sysrq_always_enabled
1858 [KNL]
1859 Ignore sysrq setting - this boot parameter will
1860 neutralize any effect of /proc/sys/kernel/sysrq.
1861 Useful for debugging.
1863 t128= [HW,SCSI]
1864 See header of drivers/scsi/t128.c.
1866 tdfx= [HW,DRM]
1868 thash_entries= [KNL,NET]
1869 Set number of hash buckets for TCP connection
1871 thermal.act= [HW,ACPI]
1872 -1: disable all active trip points in all thermal zones
1873 <degrees C>: override all lowest active trip points
1875 thermal.crt= [HW,ACPI]
1876 -1: disable all critical trip points in all thermal zones
1877 <degrees C>: lower all critical trip points
1879 thermal.nocrt= [HW,ACPI]
1880 Set to disable actions on ACPI thermal zone
1881 critical and hot trip points.
1883 thermal.off= [HW,ACPI]
1884 1: disable ACPI thermal control
1886 thermal.psv= [HW,ACPI]
1887 -1: disable all passive trip points
1888 <degrees C>: override all passive trip points to this value
1890 thermal.tzp= [HW,ACPI]
1891 Specify global default ACPI thermal zone polling rate
1892 <deci-seconds>: poll all this frequency
1893 0: no polling (default)
1895 time Show timing data prefixed to each printk message line
1896 [deprecated, see 'printk.time']
1898 tipar.timeout= [HW,PPT]
1899 Set communications timeout in tenths of a second
1900 (default 15).
1902 tipar.delay= [HW,PPT]
1903 Set inter-bit delay in microseconds (default 10).
1905 tmc8xx= [HW,SCSI]
1906 See header of drivers/scsi/seagate.c.
1908 tmscsim= [HW,SCSI]
1909 See comment before function dc390_setup() in
1910 drivers/scsi/tmscsim.c.
1912 tp720= [HW,PS2]
1914 trix= [HW,OSS] MediaTrix AudioTrix Pro
1915 Format:
1916 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1918 turbografx.map[2|3]= [HW,JOY]
1919 TurboGraFX parallel port interface
1920 Format:
1921 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1922 See also Documentation/input/joystick-parport.txt
1924 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1925 See header of drivers/scsi/u14-34f.c.
1927 uart401= [HW,OSS]
1928 Format: <io>,<irq>
1930 uart6850= [HW,OSS]
1931 Format: <io>,<irq>
1933 uhci-hcd.ignore_oc=
1934 [USB] Ignore overcurrent events (default N).
1935 Some badly-designed motherboards generate lots of
1936 bogus events, for ports that aren't wired to
1937 anything. Set this parameter to avoid log spamming.
1938 Note that genuine overcurrent events won't be
1939 reported either.
1941 usbcore.autosuspend=
1942 [USB] The autosuspend time delay (in seconds) used
1943 for newly-detected USB devices (default 2). This
1944 is the time required before an idle device will be
1945 autosuspended. Devices for which the delay is set
1946 to a negative value won't be autosuspended at all.
1948 usbhid.mousepoll=
1949 [USBHID] The interval which mice are to be polled at.
1951 vdso= [X86-32,SH,x86-64]
1952 vdso=2: enable compat VDSO (default with COMPAT_VDSO)
1953 vdso=1: enable VDSO (default)
1954 vdso=0: disable VDSO mapping
1956 vector= [IA-64,SMP]
1957 vector=percpu: enable percpu vector domain
1959 video= [FB] Frame buffer configuration
1960 See Documentation/fb/modedb.txt.
1962 vga= [BOOT,X86-32] Select a particular video mode
1963 See Documentation/i386/boot.txt and
1964 Documentation/svga.txt.
1965 Use vga=ask for menu.
1966 This is actually a boot loader parameter; the value is
1967 passed to the kernel using a special protocol.
1969 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1970 size of <nn>. This can be used to increase the
1971 minimum size (128MB on x86). It can also be used to
1972 decrease the size and leave more room for directly
1973 mapped kernel RAM.
1975 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1976 Format: <command>
1978 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1979 Format: <command>
1981 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1982 Format: <command>
1984 waveartist= [HW,OSS]
1985 Format: <io>,<irq>,<dma>,<dma2>
1987 wd33c93= [HW,SCSI]
1988 See header of drivers/scsi/wd33c93.c.
1990 wd7000= [HW,SCSI]
1991 See header of drivers/scsi/wd7000.c.
1993 wdt= [WDT] Watchdog
1994 See Documentation/watchdog/wdt.txt.
1996 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1997 xd_geo= See header of drivers/block/xd.c.
1999 xirc2ps_cs= [NET,PCMCIA]
2000 Format:
2001 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
2003 norandmaps Don't use address space randomization
2004 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
2006 unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
2007 This is useful to get more information why
2008 you got a "dwarf2 unwinder stuck"
2010 ______________________________________________________________________
2012 TODO:
2014 Add documentation for ALSA options.
2015 Add more DRM drivers.