view Documentation/kernel-parameters.txt @ 857:a3ad7a5f2dcd

dom0 linux: support SBDF with "guestdev=" and remove "reassigndev="

When we don't need to reassign resources and use device path,
pciback.hide= boot parameter can be used. The parameter is also needed
for backward compatibility.


When we need to reassign resources or use device path, guestdev= boot
parameter can be used. reassign_resources boot parameter is needed to
reassign resources, too.

guestdev=00:01.0,00:02.0 reassign_resources
guestdev=PNP0A08:0-1.0,PNP0A08:0-2.0 reassign_resources

Signed-off-by: Yuji Shimada <shimada-yxb@necst.nec.co.jp>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Apr 09 08:44:25 2009 +0100 (2009-04-09)
parents 071ee07f9226
children 8dec4aa9b8b9
line source
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 ALSA ALSA sound support is enabled.
34 APIC APIC support is enabled.
35 APM Advanced Power Management support is enabled.
36 AX25 Appropriate AX.25 support is enabled.
37 CD Appropriate CD support is enabled.
38 DRM Direct Rendering Management support is enabled.
39 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
40 EFI EFI Partitioning (GPT) is enabled
41 EIDE EIDE/ATAPI support is enabled.
42 FB The frame buffer device is enabled.
43 HW Appropriate hardware is enabled.
44 IA-32 IA-32 aka i386 architecture 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 LP Printer support is enabled.
52 LOOP Loopback device support is enabled.
53 M68k M68k architecture is enabled.
54 These options have more detailed description inside of
55 Documentation/m68k/kernel-options.txt.
56 MCA MCA bus support is enabled.
57 MDA MDA console support is enabled.
58 MOUSE Appropriate mouse support is enabled.
59 MSI Message Signaled Interrupts (PCI).
60 MTD MTD support is enabled.
61 NET Appropriate network support is enabled.
62 NUMA NUMA support is enabled.
63 GENERIC_TIME The generic timeofday code is enabled.
64 NFS Appropriate NFS support is enabled.
65 OSS OSS sound support is enabled.
66 PARIDE The ParIDE subsystem is enabled.
67 PARISC The PA-RISC architecture is enabled.
68 PCI PCI bus support is enabled.
69 PCMCIA The PCMCIA subsystem is enabled.
70 PNP Plug & Play support is enabled.
71 PPC PowerPC architecture is enabled.
72 PPT Parallel port support is enabled.
73 PS2 Appropriate PS/2 support is enabled.
74 RAM RAM disk support is enabled.
75 S390 S390 architecture is enabled.
76 SCSI Appropriate SCSI support is enabled.
77 A lot of drivers has their options described inside of
78 Documentation/scsi/.
79 SELINUX SELinux support is enabled.
80 SERIAL Serial support is enabled.
81 SMP The kernel is an SMP kernel.
82 SPARC Sparc architecture is enabled.
83 SWSUSP Software suspend is enabled.
84 TS Appropriate touchscreen support is enabled.
85 USB USB support is enabled.
86 USBHID USB Human Interface Device support is enabled.
87 V4L Video For Linux support is enabled.
88 VGA The VGA console has been enabled.
89 VT Virtual terminal support is enabled.
90 WDT Watchdog support is enabled.
91 XT IBM PC/XT MFM hard disk support is enabled.
92 X86-64 X86-64 architecture is enabled.
93 More X86-64 boot options can be found in
94 Documentation/x86_64/boot-options.txt .
96 In addition, the following text indicates that the option:
98 BUGS= Relates to possible processor bugs on the said processor.
99 KNL Is a kernel start-up parameter.
100 BOOT Is a boot loader parameter.
102 Parameters denoted with BOOT are actually interpreted by the boot
103 loader, and have no meaning to the kernel directly.
104 Do not modify the syntax of boot loader parameters without extreme
105 need or coordination with <Documentation/i386/boot.txt>.
107 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
108 a trailing = on the name of any parameter states that that parameter will
109 be entered as an environment variable, whereas its absence indicates that
110 it will appear as a kernel argument readable via /proc/cmdline by programs
111 running once the system is up.
113 53c7xx= [HW,SCSI] Amiga SCSI controllers
114 See header of drivers/scsi/53c7xx.c.
115 See also Documentation/scsi/ncr53c7xx.txt.
117 acpi= [HW,ACPI] Advanced Configuration and Power Interface
118 Format: { force | off | ht | strict | noirq }
119 force -- enable ACPI if default was off
120 off -- disable ACPI if default was on
121 noirq -- do not use ACPI for IRQ routing
122 ht -- run only enough ACPI to enable Hyper Threading
123 strict -- Be less tolerant of platforms that are not
124 strictly ACPI specification compliant.
126 See also Documentation/pm.txt, pci=noacpi
128 acpi_sleep= [HW,ACPI] Sleep options
129 Format: { s3_bios, s3_mode }
130 See Documentation/power/video.txt
132 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
133 Format: { level | edge | high | low }
135 acpi_irq_balance [HW,ACPI]
136 ACPI will balance active IRQs
137 default in APIC mode
139 acpi_irq_nobalance [HW,ACPI]
140 ACPI will not move active IRQs (default)
141 default in PIC mode
143 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
144 use by PCI
145 Format: <irq>,<irq>...
147 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
148 Format: <irq>,<irq>...
150 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
151 Format: To spoof as Windows 98: ="Microsoft Windows"
153 acpi_osi= [HW,ACPI] empty param disables _OSI
155 acpi_serialize [HW,ACPI] force serialization of AML methods
157 acpi_skip_timer_override [HW,ACPI]
158 Recognize and ignore IRQ0/pin2 Interrupt Override.
159 For broken nForce2 BIOS resulting in XT-PIC timer.
161 acpi_dbg_layer= [HW,ACPI]
162 Format: <int>
163 Each bit of the <int> indicates an ACPI debug layer,
164 1: enable, 0: disable. It is useful for boot time
165 debugging. After system has booted up, it can be set
166 via /proc/acpi/debug_layer.
168 acpi_dbg_level= [HW,ACPI]
169 Format: <int>
170 Each bit of the <int> indicates an ACPI debug level,
171 1: enable, 0: disable. It is useful for boot time
172 debugging. After system has booted up, it can be set
173 via /proc/acpi/debug_level.
175 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
177 acpi_generic_hotkey [HW,ACPI]
178 Allow consolidated generic hotkey driver to
179 override platform specific driver.
180 See also Documentation/acpi-hotkey.txt.
182 acpi_pm_good [IA-32,X86-64]
183 Override the pmtimer bug detection: force the kernel
184 to assume that this machine's pmtimer latches its value
185 and always returns good values.
187 enable_timer_pin_1 [i386,x86-64]
188 Enable PIN 1 of APIC timer
189 Can be useful to work around chipset bugs
190 (in particular on some ATI chipsets).
191 The kernel tries to set a reasonable default.
193 disable_timer_pin_1 [i386,x86-64]
194 Disable PIN 1 of APIC timer
195 Can be useful to work around chipset bugs.
197 ad1816= [HW,OSS]
198 Format: <io>,<irq>,<dma>,<dma2>
199 See also Documentation/sound/oss/AD1816.
201 ad1848= [HW,OSS]
202 Format: <io>,<irq>,<dma>,<dma2>,<type>
204 adlib= [HW,OSS]
205 Format: <io>
207 advansys= [HW,SCSI]
208 See header of drivers/scsi/advansys.c.
210 advwdt= [HW,WDT] Advantech WDT
211 Format: <iostart>,<iostop>
213 aedsp16= [HW,OSS] Audio Excel DSP 16
214 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
215 See also header of sound/oss/aedsp16.c.
217 aha152x= [HW,SCSI]
218 See Documentation/scsi/aha152x.txt.
220 aha1542= [HW,SCSI]
221 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
223 aic7xxx= [HW,SCSI]
224 See Documentation/scsi/aic7xxx.txt.
226 aic79xx= [HW,SCSI]
227 See Documentation/scsi/aic79xx.txt.
229 amijoy.map= [HW,JOY] Amiga joystick support
230 Map of devices attached to JOY0DAT and JOY1DAT
231 Format: <a>,<b>
232 See also Documentation/kernel/input/joystick.txt
234 analog.map= [HW,JOY] Analog joystick and gamepad support
235 Specifies type or capabilities of an analog joystick
236 connected to one of 16 gameports
237 Format: <type1>,<type2>,..<type16>
239 apc= [HW,SPARC]
240 Power management functions (SPARCstation-4/5 + deriv.)
241 Format: noidle
242 Disable APC CPU standby support. SPARCstation-Fox does
243 not play well with APC CPU idle - disable it if you have
244 APC and your system crashes randomly.
246 apic= [APIC,i386] Change the output verbosity whilst booting
247 Format: { quiet (default) | verbose | debug }
248 Change the amount of debugging information output
249 when initialising the APIC and IO-APIC components.
251 apm= [APM] Advanced Power Management
252 See header of arch/i386/kernel/apm.c.
254 applicom= [HW]
255 Format: <mem>,<irq>
257 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
258 Format: <io>,<irq>,<nodeID>
260 ataflop= [HW,M68k]
262 atarimouse= [HW,MOUSE] Atari Mouse
264 atascsi= [HW,SCSI] Atari SCSI
266 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
267 EzKey and similar keyboards
269 atkbd.reset= [HW] Reset keyboard during initialization
271 atkbd.set= [HW] Select keyboard code set
272 Format: <int> (2 = AT (default), 3 = PS/2)
274 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
275 keyboards
277 atkbd.softraw= [HW] Choose between synthetic and real raw mode
278 Format: <bool> (0 = real, 1 = synthetic (default))
280 atkbd.softrepeat= [HW]
281 Use software keyboard repeat
283 autotest [IA64]
285 awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
286 Format: <io>,<memsize>,<isapnp>
288 aztcd= [HW,CD] Aztech CD268 CDROM driver
289 Format: <io>,0x79 (?)
291 baycom_epp= [HW,AX25]
292 Format: <io>,<mode>
294 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
295 Format: <io>,<mode>
296 See header of drivers/net/hamradio/baycom_par.c.
298 baycom_ser_fdx= [HW,AX25]
299 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
300 Format: <io>,<irq>,<mode>[,<baud>]
301 See header of drivers/net/hamradio/baycom_ser_fdx.c.
303 baycom_ser_hdx= [HW,AX25]
304 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
305 Format: <io>,<irq>,<mode>
306 See header of drivers/net/hamradio/baycom_ser_hdx.c.
308 blkmtd_device= [HW,MTD]
309 blkmtd_erasesz=
310 blkmtd_ro=
311 blkmtd_bs=
312 blkmtd_count=
314 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
315 bttv.radio= Most important insmod options are available as
316 kernel args too.
317 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
318 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
320 BusLogic= [HW,SCSI]
321 See drivers/scsi/BusLogic.c, comment before function
322 BusLogic_ParseDriverOptions().
324 c101= [NET] Moxa C101 synchronous serial card
326 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
327 Sometimes CPU hardware bugs make them report the cache
328 size incorrectly. The kernel will attempt work arounds
329 to fix known problems, but for some CPUs it is not
330 possible to determine what the correct size should be.
331 This option provides an override for these situations.
333 cdu31a= [HW,CD]
334 Format: <io>,<irq>[,PAS]
335 See header of drivers/cdrom/cdu31a.c.
337 chandev= [HW,NET] Generic channel device initialisation
339 checkreqprot [SELINUX] Set initial checkreqprot flag value.
340 Format: { "0" | "1" }
341 See security/selinux/Kconfig help text.
342 0 -- check protection applied by kernel (includes
343 any implied execute protection).
344 1 -- check protection requested by application.
345 Default value is set via a kernel config option.
346 Value can be changed at runtime via
347 /selinux/checkreqprot.
349 clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
350 [Deprecated]
351 Forces specified clocksource (if avaliable) to be used
352 when calculating gettimeofday(). If specified
353 clocksource is not avalible, it defaults to PIT.
354 Format: { pit | tsc | cyclone | pmtmr }
356 disable_8254_timer
357 enable_8254_timer
358 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
359 over the 8254 in addition to over the IO-APIC. The
360 kernel tries to set a sensible default.
362 hpet= [IA-32,HPET] option to disable HPET and use PIT.
363 Format: disable
365 cm206= [HW,CD]
366 Format: { auto | [<io>,][<irq>] }
368 com20020= [HW,NET] ARCnet - COM20020 chipset
369 Format:
370 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
372 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
373 Format: <io>[,<irq>]
375 com90xx= [HW,NET]
376 ARCnet - COM90xx chipset (memory-mapped buffers)
377 Format: <io>[,<irq>[,<memstart>]]
379 condev= [HW,S390] console device
380 conmode=
382 console= [KNL] Output console device and options.
384 tty<n> Use the virtual console device <n>.
386 ttyS<n>[,options]
387 ttyUSB0[,options]
388 Use the specified serial port. The options are of
389 the form "bbbbpnf", where "bbbb" is the baud rate,
390 "p" is parity ("n", "o", or "e"), "n" is number of
391 bits, and "f" is flow control ("r" for RTS or
392 omit it). Default is "9600n8".
394 See Documentation/serial-console.txt for more
395 information. See
396 Documentation/networking/netconsole.txt for an
397 alternative.
399 uart,io,<addr>[,options]
400 uart,mmio,<addr>[,options]
401 Start an early, polled-mode console on the 8250/16550
402 UART at the specified I/O port or MMIO address,
403 switching to the matching ttyS device later. The
404 options are the same as for ttyS, above.
406 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
407 Format:
408 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
410 cpia_pp= [HW,PPT]
411 Format: { parport<nr> | auto | none }
413 crashkernel=nn[KMG]@ss[KMG]
414 [KNL] Reserve a chunk of physical memory to
415 hold a kernel to switch to with kexec on panic.
417 cs4232= [HW,OSS]
418 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
420 cs89x0_dma= [HW,NET]
421 Format: <dma>
423 cs89x0_media= [HW,NET]
424 Format: { rj45 | aui | bnc }
426 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
428 dasd= [HW,NET]
429 See header of drivers/s390/block/dasd_devmap.c.
431 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
432 (one device per port)
433 Format: <port#>,<type>
434 See also Documentation/input/joystick-parport.txt
436 debug [KNL] Enable kernel debugging (events log level).
438 debug_locks_verbose=
439 [KNL] verbose self-tests
440 Format=<0|1>
441 Print debugging info while doing the locking API
442 self-tests.
443 We default to 0 (no extra messages), setting it to
444 1 will print _a lot_ more information - normally
445 only useful to kernel developers.
447 decnet= [HW,NET]
448 Format: <area>[,<node>]
449 See also Documentation/networking/decnet.txt.
451 dhash_entries= [KNL]
452 Set number of hash buckets for dentry cache.
454 digi= [HW,SERIAL]
455 IO parameters + enable/disable command.
457 digiepca= [HW,SERIAL]
458 See drivers/char/README.epca and
459 Documentation/digiepca.txt.
461 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
462 support available.
463 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
465 dmasound= [HW,OSS] Sound subsystem buffers
467 dscc4.setup= [NET]
469 dtc3181e= [HW,SCSI]
471 earlyprintk= [IA-32,X86-64]
472 earlyprintk=vga
473 earlyprintk=serial[,ttySn[,baudrate]]
475 Append ",keep" to not disable it when the real console
476 takes over.
478 Only vga or serial at a time, not both.
480 Currently only ttyS0 and ttyS1 are supported.
482 Interaction with the standard serial driver is not
483 very good.
485 The VGA output is eventually overwritten by the real
486 console.
488 eata= [HW,SCSI]
490 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
491 Format: <int>
492 0: polling mode
493 non-0: interrupt mode (default)
495 eda= [HW,PS2]
497 edb= [HW,PS2]
499 edd= [EDD]
500 Format: {"of[f]" | "sk[ipmbr]"}
501 See comment in arch/i386/boot/edd.S
503 eicon= [HW,ISDN]
504 Format: <id>,<membase>,<irq>
506 eisa_irq_edge= [PARISC,HW]
507 See header of drivers/parisc/eisa.c.
509 elanfreq= [IA-32]
510 See comment before function elanfreq_setup() in
511 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
513 elevator= [IOSCHED]
514 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
515 See Documentation/block/as-iosched.txt and
516 Documentation/block/deadline-iosched.txt for details.
518 elfcorehdr= [IA-32, X86_64]
519 Specifies physical address of start of kernel core
520 image elf header. Generally kexec loader will
521 pass this option to capture kernel.
522 See Documentation/kdump/kdump.txt for details.
524 enforcing [SELINUX] Set initial enforcing status.
525 Format: {"0" | "1"}
526 See security/selinux/Kconfig help text.
527 0 -- permissive (log only, no denials).
528 1 -- enforcing (deny and log).
529 Default value is 0.
530 Value can be changed at runtime via /selinux/enforce.
532 es1370= [HW,OSS]
533 Format: <lineout>[,<micbias>]
534 See also header of sound/oss/es1370.c.
536 es1371= [HW,OSS]
537 Format: <spdif>,[<nomix>,[<amplifier>]]
538 See also header of sound/oss/es1371.c.
540 ether= [HW,NET] Ethernet cards parameters
541 This option is obsoleted by the "netdev=" option, which
542 has equivalent usage. See its documentation for details.
544 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
545 Format: <io>[,<irq>]
547 fd_mcs= [HW,SCSI]
548 See header of drivers/scsi/fd_mcs.c.
550 fdomain= [HW,SCSI]
551 See header of drivers/scsi/fdomain.c.
553 floppy= [HW]
554 See Documentation/floppy.txt.
556 ftape= [HW] Floppy Tape subsystem debugging options.
557 See Documentation/ftape.txt.
559 gamecon.map[2|3]=
560 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
561 support via parallel port (up to 5 devices per port)
562 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
563 See also Documentation/input/joystick-parport.txt
565 gamma= [HW,DRM]
567 gdth= [HW,SCSI]
568 See header of drivers/scsi/gdth.c.
570 gpt [EFI] Forces disk with valid GPT signature but
571 invalid Protective MBR to be treated as GPT.
573 gscd= [HW,CD]
574 Format: <io>
576 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
578 guestdev= [PCI,ACPI]
579 Format: {<device path>|<sbdf>}][,{<device path>|<sbdf>}[,...]]
580 Format of device path: <hid>[:<uid>]-<dev>.<func>[-<dev>.<func>[,...]]
581 Format of sbdf: [<segment>:]<bus>:<dev>.<func>
582 Specifies PCI device for guest domain.
583 If PCI-PCI bridge is specified, all PCI devices
584 behind PCI-PCI bridge are reserved.
586 gus= [HW,OSS]
587 Format: <io>,<irq>,<dma>,<dma16>
589 gvp11= [HW,SCSI]
591 hashdist= [KNL,NUMA] Large hashes allocated during boot
592 are distributed across NUMA nodes. Defaults on
593 for IA-64, off otherwise.
594 Format: 0 | 1 (for off | on)
596 hcl= [IA-64] SGI's Hardware Graph compatibility layer
598 hd= [EIDE] (E)IDE hard drive subsystem geometry
599 Format: <cyl>,<head>,<sect>
601 hd?= [HW] (E)IDE subsystem
602 hd?lun= See Documentation/ide.txt.
604 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
605 size of <nn>. This works even on boxes that have no
606 highmem otherwise. This also works to reduce highmem
607 size on bigger boxes.
609 hisax= [HW,ISDN]
610 See Documentation/isdn/README.HiSax.
612 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
614 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
616 i8042.direct [HW] Put keyboard port into non-translated mode
617 i8042.dumbkbd [HW] Pretend that controlled can only read data from
618 keyboard and can not control its state
619 (Don't attempt to blink the leds)
620 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
621 i8042.nokbd [HW] Don't check/create keyboard port
622 i8042.nomux [HW] Don't check presence of an active multiplexing
623 controller
624 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
625 controllers
626 i8042.panicblink=
627 [HW] Frequency with which keyboard LEDs should blink
628 when kernel panics (default is 0.5 sec)
629 i8042.reset [HW] Reset the controller during init and cleanup
630 i8042.unlock [HW] Unlock (ignore) the keylock
632 i810= [HW,DRM]
634 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
635 indicates that the driver is running on unsupported
636 hardware.
637 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
638 does not match list of supported models.
639 i8k.power_status
640 [HW] Report power status in /proc/i8k
641 (disabled by default)
642 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
643 capability is set.
645 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
646 See Documentation/mca.txt.
648 icn= [HW,ISDN]
649 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
651 ide= [HW] (E)IDE subsystem
652 Format: ide=nodma or ide=doubler or ide=reverse
653 See Documentation/ide.txt.
655 ide?= [HW] (E)IDE subsystem
656 Format: ide?=noprobe or chipset specific parameters.
657 See Documentation/ide.txt.
659 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
660 See Documentation/ide.txt.
662 idle= [HW]
663 Format: idle=poll or idle=halt
665 ihash_entries= [KNL]
666 Set number of hash buckets for inode cache.
668 in2000= [HW,SCSI]
669 See header of drivers/scsi/in2000.c.
671 init= [KNL]
672 Format: <full_path>
673 Run specified binary instead of /sbin/init as init
674 process.
676 initcall_debug [KNL] Trace initcalls as they are executed. Useful
677 for working out where the kernel is dying during
678 startup.
680 initrd= [BOOT] Specify the location of the initial ramdisk
682 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
683 Format: <irq>
685 combined_mode= [HW] control which driver uses IDE ports in combined
686 mode: legacy IDE driver, libata, or both
687 (in the libata case, libata.atapi_enabled=1 may be
688 useful as well). Note that using the ide or libata
689 options may affect your device naming (e.g. by
690 changing hdc to sdb).
691 Format: combined (default), ide, or libata
693 inttest= [IA64]
695 io7= [HW] IO7 for Marvel based alpha systems
696 See comment before marvel_specify_io7 in
697 arch/alpha/kernel/core_marvel.c.
699 ip= [IP_PNP]
700 See Documentation/nfsroot.txt.
702 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
703 See comment before ip2_setup() in drivers/char/ip2.c.
705 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
706 See header of drivers/scsi/ips.c.
708 ports= [IP_VS_FTP] IPVS ftp helper module
709 Default is 21.
710 Up to 8 (IP_VS_APP_MAX_PORTS) ports
711 may be specified.
712 Format: <port>,<port>....
714 irqfixup [HW]
715 When an interrupt is not handled search all handlers
716 for it. Intended to get systems with badly broken
717 firmware running.
719 irqpoll [HW]
720 When an interrupt is not handled search all handlers
721 for it. Also check all handlers each timer
722 interrupt. Intended to get systems with badly broken
723 firmware running.
725 isapnp= [ISAPNP]
726 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
728 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
729 Format: <cpu number>,...,<cpu number>
730 This option can be used to specify one or more CPUs
731 to isolate from the general SMP balancing and scheduling
732 algorithms. The only way to move a process onto or off
733 an "isolated" CPU is via the CPU affinity syscalls.
734 <cpu number> begins at 0 and the maximum value is
735 "number of CPUs in system - 1".
737 This option is the preferred way to isolate CPUs. The
738 alternative -- manually setting the CPU mask of all
739 tasks in the system -- can cause problems and
740 suboptimal load balancer performance.
742 isp16= [HW,CD]
743 Format: <io>,<irq>,<dma>,<setup>
745 iucv= [HW,NET]
747 js= [HW,JOY] Analog joystick
748 See Documentation/input/joystick.txt.
750 keepinitrd [HW,ARM]
752 kstack=N [IA-32,X86-64] Print N words from the kernel stack
753 in oops dumps.
755 l2cr= [PPC]
757 lapic [IA-32,APIC] Enable the local APIC even if BIOS
758 disabled it.
760 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
761 Format: addr:<io>,irq:<irq>
763 llsc*= [IA64] See function print_params() in
764 arch/ia64/sn/kernel/llsc4.c.
766 load_ramdisk= [RAM] List of ramdisks to load from floppy
767 See Documentation/ramdisk.txt.
769 lockd.nlm_grace_period=P [NFS] Assign grace period.
770 Format: <integer>
772 lockd.nlm_tcpport=N [NFS] Assign TCP port.
773 Format: <integer>
775 lockd.nlm_timeout=T [NFS] Assign timeout value.
776 Format: <integer>
778 lockd.nlm_udpport=M [NFS] Assign UDP port.
779 Format: <integer>
781 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
782 Format: <irq>
784 loglevel= All Kernel Messages with a loglevel smaller than the
785 console loglevel will be printed to the console. It can
786 also be changed with klogd or other programs. The
787 loglevels are defined as follows:
789 0 (KERN_EMERG) system is unusable
790 1 (KERN_ALERT) action must be taken immediately
791 2 (KERN_CRIT) critical conditions
792 3 (KERN_ERR) error conditions
793 4 (KERN_WARNING) warning conditions
794 5 (KERN_NOTICE) normal but significant condition
795 6 (KERN_INFO) informational
796 7 (KERN_DEBUG) debug-level messages
798 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
799 Format: { n | nk | nM }
800 n must be a power of two. The default size
801 is set in the kernel config file.
803 lp=0 [LP] Specify parallel ports to use, e.g,
804 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
805 lp=reset first parallel port). 'lp=0' disables the
806 lp=auto printer driver. 'lp=reset' (which can be
807 specified in addition to the ports) causes
808 attached printers to be reset. Using
809 lp=port1,port2,... specifies the parallel ports
810 to associate lp devices with, starting with
811 lp0. A port specification may be 'none' to skip
812 that lp device, or a parport name such as
813 'parport0'. Specifying 'lp=auto' instead of a
814 port specification list means that device IDs
815 from each port should be examined, to see if
816 an IEEE 1284-compliant printer is attached; if
817 so, the driver will manage that printer.
818 See also header of drivers/char/lp.c.
820 lpj=n [KNL]
821 Sets loops_per_jiffy to given constant, thus avoiding
822 time-consuming boot-time autodetection (up to 250 ms per
823 CPU). 0 enables autodetection (default). To determine
824 the correct value for your kernel, boot with normal
825 autodetection and see what value is printed. Note that
826 on SMP systems the preset will be applied to all CPUs,
827 which is likely to cause problems if your CPUs need
828 significantly divergent settings. An incorrect value
829 will cause delays in the kernel to be wrong, leading to
830 unpredictable I/O errors and other breakage. Although
831 unlikely, in the extreme case this might damage your
832 hardware.
834 ltpc= [NET]
835 Format: <io>,<irq>,<dma>
837 mac5380= [HW,SCSI] Format:
838 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
840 mac53c9x= [HW,SCSI] Format:
841 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
843 machvec= [IA64] Force the use of a particular machine-vector
844 (machvec) in a generic kernel.
845 Example: machvec=hpzx1_swiotlb
847 mad16= [HW,OSS] Format:
848 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
850 maui= [HW,OSS]
851 Format: <io>,<irq>
853 max_loop= [LOOP] Maximum number of loopback devices that can
854 be mounted
855 Format: <1-256>
857 maxcpus= [SMP] Maximum number of processors that an SMP kernel
858 should make use of
860 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
861 equal to this physical address is ignored.
863 max_luns= [SCSI] Maximum number of LUNs to probe.
864 Should be between 1 and 2^32-1.
866 max_report_luns=
867 [SCSI] Maximum number of LUNs received.
868 Should be between 1 and 16384.
870 mca-pentium [BUGS=IA-32]
872 mcatest= [IA-64]
874 mcd= [HW,CD]
875 Format: <port>,<irq>,<mitsumi_bug_93_wait>
877 mcdx= [HW,CD]
879 mce [IA-32] Machine Check Exception
881 md= [HW] RAID subsystems devices and level
882 See Documentation/md.txt.
884 mdacon= [MDA]
885 Format: <first>,<last>
886 Specifies range of consoles to be captured by the MDA.
888 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
889 Amount of memory to be used when the kernel is not able
890 to see the whole system memory or for test.
891 [IA-32] Use together with memmap= to avoid physical
892 address space collisions. Without memmap= PCI devices
893 could be placed at addresses belonging to unused RAM.
895 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
896 memory.
898 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
899 E820 memory map, as specified by the user.
900 Such memmap=exactmap lines can be constructed based on
901 BIOS output or other requirements. See the memmap=nn@ss
902 option description.
904 memmap=nn[KMG]@ss[KMG]
905 [KNL] Force usage of a specific region of memory
906 Region of memory to be used, from ss to ss+nn.
908 memmap=nn[KMG]#ss[KMG]
909 [KNL,ACPI] Mark specific memory as ACPI data.
910 Region of memory to be used, from ss to ss+nn.
912 memmap=nn[KMG]$ss[KMG]
913 [KNL,ACPI] Mark specific memory as reserved.
914 Region of memory to be used, from ss to ss+nn.
916 meye.*= [HW] Set MotionEye Camera parameters
917 See Documentation/video4linux/meye.txt.
919 mga= [HW,DRM]
921 migration_cost=
922 [KNL,SMP] debug: override scheduler migration costs
923 Format: <level-1-usecs>,<level-2-usecs>,...
924 This debugging option can be used to override the
925 default scheduler migration cost matrix. The numbers
926 are indexed by 'CPU domain distance'.
927 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
928 box will set up an intra-core migration cost of
929 1 msec, an inter-core migration cost of 2 msecs,
930 and an inter-node migration cost of 3 msecs.
932 WARNING: using the wrong values here can break
933 scheduler performance, so it's only for scheduler
934 development purposes, not production environments.
936 migration_debug=
937 [KNL,SMP] migration cost auto-detect verbosity
938 Format=<0|1|2>
939 If a system's migration matrix reported at bootup
940 seems erroneous then this option can be used to
941 increase verbosity of the detection process.
942 We default to 0 (no extra messages), 1 will print
943 some more information, and 2 will be really
944 verbose (probably only useful if you also have a
945 serial console attached to the system).
947 migration_factor=
948 [KNL,SMP] multiply/divide migration costs by a factor
949 Format=<percent>
950 This debug option can be used to proportionally
951 increase or decrease the auto-detected migration
952 costs for all entries of the migration matrix.
953 E.g. migration_factor=150 will increase migration
954 costs by 50%. (and thus the scheduler will be less
955 eager migrating cache-hot tasks)
956 migration_factor=80 will decrease migration costs
957 by 20%. (thus the scheduler will be more eager to
958 migrate tasks)
960 WARNING: using the wrong values here can break
961 scheduler performance, so it's only for scheduler
962 development purposes, not production environments.
964 mousedev.tap_time=
965 [MOUSE] Maximum time between finger touching and
966 leaving touchpad surface for touch to be considered
967 a tap and be reported as a left button click (for
968 touchpads working in absolute mode only).
969 Format: <msecs>
970 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
971 reporting absolute coordinates, such as tablets
972 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
973 reporting absolute coordinates, such as tablets
975 mpu401= [HW,OSS]
976 Format: <io>,<irq>
978 MTD_Partition= [MTD]
979 Format: <name>,<region-number>,<size>,<offset>
981 MTD_Region= [MTD] Format:
982 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
984 mtdparts= [MTD]
985 See drivers/mtd/cmdline.c.
987 mtouchusb.raw_coordinates=
988 [HW] Make the MicroTouch USB driver use raw coordinates
989 ('y', default) or cooked coordinates ('n')
991 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
993 NCR_D700= [HW,SCSI]
994 See header of drivers/scsi/NCR_D700.c.
996 ncr5380= [HW,SCSI]
998 ncr53c400= [HW,SCSI]
1000 ncr53c400a= [HW,SCSI]
1002 ncr53c406a= [HW,SCSI]
1004 ncr53c8xx= [HW,SCSI]
1006 netdev= [NET] Network devices parameters
1007 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1008 Note that mem_start is often overloaded to mean
1009 something different and driver-specific.
1010 This usage is only documented in each driver source
1011 file if at all.
1013 nfsaddrs= [NFS]
1014 See Documentation/nfsroot.txt.
1016 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1017 See Documentation/nfsroot.txt.
1019 nfs.callback_tcpport=
1020 [NFS] set the TCP port on which the NFSv4 callback
1021 channel should listen.
1023 nfs.idmap_cache_timeout=
1024 [NFS] set the maximum lifetime for idmapper cache
1025 entries.
1027 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1029 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1030 emulation library even if a 387 maths coprocessor
1031 is present.
1033 noalign [KNL,ARM]
1035 noapic [SMP,APIC] Tells the kernel to not make use of any
1036 IOAPICs that may be present in the system.
1038 noasync [HW,M68K] Disables async and sync negotiation for
1039 all devices.
1041 nobats [PPC] Do not use BATs for mapping kernel lowmem
1042 on "Classic" PPC cores.
1044 nocache [ARM]
1046 nodelayacct [KNL] Disable per-task delay accounting
1048 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1050 noexec [IA-64]
1052 noexec [IA-32,X86-64]
1053 noexec=on: enable non-executable mappings (default)
1054 noexec=off: disable nn-executable mappings
1056 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1057 register save and restore. The kernel will only save
1058 legacy floating-point registers on task switch.
1060 nohlt [BUGS=ARM]
1062 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1063 instruction doesn't work correctly and not to
1064 use it.
1066 nohalt [IA-64] Tells the kernel not to use the power saving
1067 function PAL_HALT_LIGHT when idle. This increases
1068 power-consumption. On the positive side, it reduces
1069 interrupt wake-up latency, which may improve performance
1070 in certain environments such as networked servers or
1071 real-time systems.
1073 noirqdebug [IA-32] Disables the code which attempts to detect and
1074 disable unhandled interrupt sources.
1076 noisapnp [ISAPNP] Disables ISA PnP code.
1078 noinitrd [RAM] Tells the kernel not to load any configured
1079 initial RAM disk.
1081 nointroute [IA-64]
1083 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1085 noltlbs [PPC] Do not use large page/tlb entries for kernel
1086 lowmem mapping on PPC40x.
1088 nomca [IA-64] Disable machine check abort handling
1090 nomce [IA-32] Machine Check Exception
1092 noresidual [PPC] Don't use residual data on PReP machines.
1094 noresume [SWSUSP] Disables resume and restores original swap
1095 space.
1097 no-scroll [VGA] Disables scrollback.
1098 This is required for the Braillex ib80-piezo Braille
1099 reader made by F.H. Papenmeier (Germany).
1101 nosbagart [IA-64]
1103 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1105 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1107 nosync [HW,M68K] Disables sync negotiation for all devices.
1109 notsc [BUGS=IA-32] Disable Time Stamp Counter
1111 nousb [USB] Disable the USB subsystem
1113 nowb [ARM]
1115 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1117 opl3= [HW,OSS]
1118 Format: <io>
1120 opl3sa= [HW,OSS]
1121 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1123 opl3sa2= [HW,OSS] Format:
1124 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1126 oprofile.timer= [HW]
1127 Use timer interrupt instead of performance counters
1129 optcd= [HW,CD]
1130 Format: <io>
1132 osst= [HW,SCSI] SCSI Tape Driver
1133 Format: <buffer_size>,<write_threshold>
1134 See also Documentation/scsi/st.txt.
1136 panic= [KNL] Kernel behaviour on panic
1137 Format: <timeout>
1139 parkbd.port= [HW] Parallel port number the keyboard adapter is
1140 connected to, default is 0.
1141 Format: <parport#>
1142 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1143 0 for XT, 1 for AT (default is AT).
1144 Format: <mode>
1146 parport= [HW,PPT] Specify parallel ports. 0 disables.
1147 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1148 Use 'auto' to force the driver to use any
1149 IRQ/DMA settings detected (the default is to
1150 ignore detected IRQ/DMA settings because of
1151 possible conflicts). You can specify the base
1152 address, IRQ, and DMA settings; IRQ and DMA
1153 should be numbers, or 'auto' (for using detected
1154 settings on that particular port), or 'nofifo'
1155 (to avoid using a FIFO even if it is detected).
1156 Parallel ports are assigned in the order they
1157 are specified on the command line, starting
1158 with parport0.
1160 parport_init_mode= [HW,PPT]
1161 Configure VIA parallel port to operate in
1162 a specific mode. This is necessary on Pegasos
1163 computer where firmware has no options for setting
1164 up parallel port mode and sets it to spp.
1165 Currently this function knows 686a and 8231 chips.
1166 Format: [spp|ps2|epp|ecp|ecpepp]
1168 pas2= [HW,OSS] Format:
1169 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1171 pas16= [HW,SCSI]
1172 See header of drivers/scsi/pas16.c.
1174 pause_on_oops=
1175 Halt all CPUs after the first oops has been printed for
1176 the specified number of seconds. This is to be used if
1177 your oopses keep scrolling off the screen.
1179 pcbit= [HW,ISDN]
1181 pcd. [PARIDE]
1182 See header of drivers/block/paride/pcd.c.
1183 See also Documentation/paride.txt.
1185 pci=option[,option...] [PCI] various PCI subsystem options:
1186 off [IA-32] don't probe for the PCI bus
1187 bios [IA-32] force use of PCI BIOS, don't access
1188 the hardware directly. Use this if your machine
1189 has a non-standard PCI host bridge.
1190 nobios [IA-32] disallow use of PCI BIOS, only direct
1191 hardware access methods are allowed. Use this
1192 if you experience crashes upon bootup and you
1193 suspect they are caused by the BIOS.
1194 conf1 [IA-32] Force use of PCI Configuration
1195 Mechanism 1.
1196 conf2 [IA-32] Force use of PCI Configuration
1197 Mechanism 2.
1198 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1199 Configuration
1200 nomsi [MSI] If the PCI_MSI kernel config parameter is
1201 enabled, this kernel boot option can be used to
1202 disable the use of MSI interrupts system-wide.
1203 nosort [IA-32] Don't sort PCI devices according to
1204 order given by the PCI BIOS. This sorting is
1205 done to get a device order compatible with
1206 older kernels.
1207 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1208 routing table. These calls are known to be buggy
1209 on several machines and they hang the machine
1210 when used, but on other computers it's the only
1211 way to get the interrupt routing table. Try
1212 this option if the kernel is unable to allocate
1213 IRQs or discover secondary PCI buses on your
1214 motherboard.
1215 rom [IA-32] Assign address space to expansion ROMs.
1216 Use with caution as certain devices share
1217 address decoders between ROMs and other
1218 resources.
1219 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1220 assigned automatically to PCI devices. You can
1221 make the kernel exclude IRQs of your ISA cards
1222 this way.
1223 pirqaddr=0xAAAAA [IA-32] Specify the physical address
1224 of the PIRQ table (normally generated
1225 by the BIOS) if it is outside the
1226 F0000h-100000h range.
1227 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1228 useful if the kernel is unable to find your
1229 secondary buses and you want to tell it
1230 explicitly which ones they are.
1231 assign-busses [IA-32] Always assign all PCI bus
1232 numbers ourselves, overriding
1233 whatever the firmware may have done.
1234 usepirqmask [IA-32] Honor the possible IRQ mask stored
1235 in the BIOS $PIR table. This is needed on
1236 some systems with broken BIOSes, notably
1237 some HP Pavilion N5400 and Omnibook XE3
1238 notebooks. This will have no effect if ACPI
1239 IRQ routing is enabled.
1240 noacpi [IA-32] Do not use ACPI for IRQ routing
1241 or for PCI scanning.
1242 routeirq Do IRQ routing for all PCI devices.
1243 This is normally done in pci_enable_device(),
1244 so this option is a temporary workaround
1245 for broken drivers that don't call it.
1246 firmware [ARM] Do not re-enumerate the bus but instead
1247 just use the configuration from the
1248 bootloader. This is currently used on
1249 IXP2000 systems where the bus has to be
1250 configured a certain way for adjunct CPUs.
1252 pcmv= [HW,PCMCIA] BadgePAD 4
1254 pd. [PARIDE]
1255 See Documentation/paride.txt.
1257 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1258 boot time.
1259 Format: { 0 | 1 }
1260 See arch/parisc/kernel/pdc_chassis.c
1262 pf. [PARIDE]
1263 See Documentation/paride.txt.
1265 pg. [PARIDE]
1266 See Documentation/paride.txt.
1268 pirq= [SMP,APIC] Manual mp-table setup
1269 See Documentation/i386/IO-APIC.txt.
1271 plip= [PPT,NET] Parallel port network link
1272 Format: { parport<nr> | timid | 0 }
1273 See also Documentation/parport.txt.
1275 pnpacpi= [ACPI]
1276 { off }
1278 pnpbios= [ISAPNP]
1279 { on | off | curr | res | no-curr | no-res }
1281 pnp_reserve_irq=
1282 [ISAPNP] Exclude IRQs for the autoconfiguration
1284 pnp_reserve_dma=
1285 [ISAPNP] Exclude DMAs for the autoconfiguration
1287 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1288 Ranges are in pairs (I/O port base and size).
1290 pnp_reserve_mem=
1291 [ISAPNP] Exclude memory regions for the
1292 autoconfiguration.
1293 Ranges are in pairs (memory base and size).
1295 profile= [KNL] Enable kernel profiling via /proc/profile
1296 Format: [schedule,]<number>
1297 Param: "schedule" - profile schedule points.
1298 Param: <number> - step/bucket size as a power of 2 for
1299 statistical time based profiling.
1301 processor.max_cstate= [HW,ACPI]
1302 Limit processor to maximum C-state
1303 max_cstate=9 overrides any DMI blacklist limit.
1305 processor.nocst [HW,ACPI]
1306 Ignore the _CST method to determine C-states,
1307 instead using the legacy FADT method
1309 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1310 before loading.
1311 See Documentation/ramdisk.txt.
1313 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1314 probe for; one of (bare|imps|exps|lifebook|any).
1315 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1316 per second.
1317 psmouse.resetafter= [HW,MOUSE]
1318 Try to reset the device after so many bad packets
1319 (0 = never).
1320 psmouse.resolution=
1321 [HW,MOUSE] Set desired mouse resolution, in dpi.
1322 psmouse.smartscroll=
1323 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1324 0 = disabled, 1 = enabled (default).
1326 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1327 Format:
1328 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1330 pt. [PARIDE]
1331 See Documentation/paride.txt.
1333 quiet= [KNL] Disable log messages
1335 r128= [HW,DRM]
1337 raid= [HW,RAID]
1338 See Documentation/md.txt.
1340 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1341 See Documentation/ramdisk.txt.
1343 ramdisk_blocksize= [RAM]
1344 See Documentation/ramdisk.txt.
1346 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1347 New name for the ramdisk parameter.
1348 See Documentation/ramdisk.txt.
1350 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1351 RCU callbacks to process in one batch.
1353 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1354 RCU callbacks over which batch limiting is disabled.
1356 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1357 RCU callbacks below which batch limiting is re-enabled.
1359 rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
1360 RCU callbacks to queued before forcing reschedule
1361 on all cpus.
1363 rdinit= [KNL]
1364 Format: <full_path>
1365 Run specified binary instead of /init from the ramdisk,
1366 used for early userspace startup. See initrd.
1368 reassign_resources
1369 [PCI,ACPI] Use guestdev parameter to reassign device's
1370 resources.
1372 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1373 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1374 See arch/*/kernel/reboot.c.
1376 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1378 resume= [SWSUSP]
1379 Specify the partition device for software suspend
1381 rhash_entries= [KNL,NET]
1382 Set number of hash buckets for route cache
1384 riscom8= [HW,SERIAL]
1385 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1387 ro [KNL] Mount root device read-only on boot
1389 root= [KNL] Root filesystem
1391 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1392 mount the root filesystem
1394 rootflags= [KNL] Set root filesystem mount option string
1396 rootfstype= [KNL] Set root filesystem type
1398 rw [KNL] Mount root device read-write on boot
1400 S [KNL] Run init in single mode
1402 sa1100ir [NET]
1403 See drivers/net/irda/sa1100_ir.c.
1405 sb= [HW,OSS]
1406 Format: <io>,<irq>,<dma>,<dma2>
1408 sbni= [NET] Granch SBNI12 leased line adapter
1410 sbpcd= [HW,CD] Soundblaster CD adapter
1411 Format: <io>,<type>
1412 See a comment before function sbpcd_setup() in
1413 drivers/cdrom/sbpcd.c.
1415 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1416 Format: <io>[,<timeout>[,<isapnp>]]
1418 scsi_debug_*= [SCSI]
1419 See drivers/scsi/scsi_debug.c.
1421 scsi_default_dev_flags=
1422 [SCSI] SCSI default device flags
1423 Format: <integer>
1425 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1426 Format: <vendor>:<model>:<flags>
1427 (flags are integer value)
1429 scsi_logging= [SCSI]
1431 selinux [SELINUX] Disable or enable SELinux at boot time.
1432 Format: { "0" | "1" }
1433 See security/selinux/Kconfig help text.
1434 0 -- disable.
1435 1 -- enable.
1436 Default value is set via kernel config option.
1437 If enabled at boot time, /selinux/disable can be used
1438 later to disable prior to initial policy load.
1440 selinux_compat_net =
1441 [SELINUX] Set initial selinux_compat_net flag value.
1442 Format: { "0" | "1" }
1443 0 -- use new secmark-based packet controls
1444 1 -- use legacy packet controls
1445 Default value is 0 (preferred).
1446 Value can be changed at runtime via
1447 /selinux/compat_net.
1449 serialnumber [BUGS=IA-32]
1451 sg_def_reserved_size= [SCSI]
1453 sgalaxy= [HW,OSS]
1454 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1456 shapers= [NET]
1457 Maximal number of shapers.
1459 sim710= [SCSI,HW]
1460 See header of drivers/scsi/sim710.c.
1462 simeth= [IA-64]
1463 simscsi=
1465 sjcd= [HW,CD]
1466 Format: <io>,<irq>,<dma>
1467 See header of drivers/cdrom/sjcd.c.
1469 slram= [HW,MTD]
1471 smart2= [HW]
1472 Format: <io1>[,<io2>[,...,<io8>]]
1474 snd-ad1816a= [HW,ALSA]
1476 snd-ad1848= [HW,ALSA]
1478 snd-ali5451= [HW,ALSA]
1480 snd-als100= [HW,ALSA]
1482 snd-als4000= [HW,ALSA]
1484 snd-azt2320= [HW,ALSA]
1486 snd-cmi8330= [HW,ALSA]
1488 snd-cmipci= [HW,ALSA]
1490 snd-cs4231= [HW,ALSA]
1492 snd-cs4232= [HW,ALSA]
1494 snd-cs4236= [HW,ALSA]
1496 snd-cs4281= [HW,ALSA]
1498 snd-cs46xx= [HW,ALSA]
1500 snd-dt019x= [HW,ALSA]
1502 snd-dummy= [HW,ALSA]
1504 snd-emu10k1= [HW,ALSA]
1506 snd-ens1370= [HW,ALSA]
1508 snd-ens1371= [HW,ALSA]
1510 snd-es968= [HW,ALSA]
1512 snd-es1688= [HW,ALSA]
1514 snd-es18xx= [HW,ALSA]
1516 snd-es1938= [HW,ALSA]
1518 snd-es1968= [HW,ALSA]
1520 snd-fm801= [HW,ALSA]
1522 snd-gusclassic= [HW,ALSA]
1524 snd-gusextreme= [HW,ALSA]
1526 snd-gusmax= [HW,ALSA]
1528 snd-hdsp= [HW,ALSA]
1530 snd-ice1712= [HW,ALSA]
1532 snd-intel8x0= [HW,ALSA]
1534 snd-interwave= [HW,ALSA]
1536 snd-interwave-stb=
1537 [HW,ALSA]
1539 snd-korg1212= [HW,ALSA]
1541 snd-maestro3= [HW,ALSA]
1543 snd-mpu401= [HW,ALSA]
1545 snd-mtpav= [HW,ALSA]
1547 snd-nm256= [HW,ALSA]
1549 snd-opl3sa2= [HW,ALSA]
1551 snd-opti92x-ad1848=
1552 [HW,ALSA]
1554 snd-opti92x-cs4231=
1555 [HW,ALSA]
1557 snd-opti93x= [HW,ALSA]
1559 snd-pmac= [HW,ALSA]
1561 snd-rme32= [HW,ALSA]
1563 snd-rme96= [HW,ALSA]
1565 snd-rme9652= [HW,ALSA]
1567 snd-sb8= [HW,ALSA]
1569 snd-sb16= [HW,ALSA]
1571 snd-sbawe= [HW,ALSA]
1573 snd-serial= [HW,ALSA]
1575 snd-sgalaxy= [HW,ALSA]
1577 snd-sonicvibes= [HW,ALSA]
1579 snd-sun-amd7930=
1580 [HW,ALSA]
1582 snd-sun-cs4231= [HW,ALSA]
1584 snd-trident= [HW,ALSA]
1586 snd-usb-audio= [HW,ALSA,USB]
1588 snd-via82xx= [HW,ALSA]
1590 snd-virmidi= [HW,ALSA]
1592 snd-wavefront= [HW,ALSA]
1594 snd-ymfpci= [HW,ALSA]
1596 sonicvibes= [HW,OSS]
1597 Format: <reverb>
1599 sonycd535= [HW,CD]
1600 Format: <io>[,<irq>]
1602 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1603 See Documentation/sonypi.txt
1605 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1606 See Documentation/specialix.txt.
1608 spia_io_base= [HW,MTD]
1609 spia_fio_base=
1610 spia_pedr=
1611 spia_peddr=
1613 sscape= [HW,OSS]
1614 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1616 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1617 See Documentation/scsi/st.txt.
1619 st0x= [HW,SCSI]
1620 See header of drivers/scsi/seagate.c.
1622 sti= [PARISC,HW]
1623 Format: <num>
1624 Set the STI (builtin display/keyboard on the HP-PARISC
1625 machines) console (graphic card) which should be used
1626 as the initial boot-console.
1627 See also comment in drivers/video/console/sticore.c.
1629 sti_font= [HW]
1630 See comment in drivers/video/console/sticore.c.
1632 stifb= [HW]
1633 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1635 swiotlb= [IA-64] Number of I/O TLB slabs
1637 switches= [HW,M68k]
1639 sym53c416= [HW,SCSI]
1640 See header of drivers/scsi/sym53c416.c.
1642 t128= [HW,SCSI]
1643 See header of drivers/scsi/t128.c.
1645 tdfx= [HW,DRM]
1647 thash_entries= [KNL,NET]
1648 Set number of hash buckets for TCP connection
1650 time Show timing data prefixed to each printk message line
1652 clocksource= [GENERIC_TIME] Override the default clocksource
1653 Override the default clocksource and use the clocksource
1654 with the name specified.
1656 tipar.timeout= [HW,PPT]
1657 Set communications timeout in tenths of a second
1658 (default 15).
1660 tipar.delay= [HW,PPT]
1661 Set inter-bit delay in microseconds (default 10).
1663 tmc8xx= [HW,SCSI]
1664 See header of drivers/scsi/seagate.c.
1666 tmscsim= [HW,SCSI]
1667 See comment before function dc390_setup() in
1668 drivers/scsi/tmscsim.c.
1670 tp720= [HW,PS2]
1672 trix= [HW,OSS] MediaTrix AudioTrix Pro
1673 Format:
1674 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1676 tsdev.xres= [TS] Horizontal screen resolution.
1677 tsdev.yres= [TS] Vertical screen resolution.
1679 turbografx.map[2|3]= [HW,JOY]
1680 TurboGraFX parallel port interface
1681 Format:
1682 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1683 See also Documentation/input/joystick-parport.txt
1685 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1686 See header of drivers/scsi/u14-34f.c.
1688 uart401= [HW,OSS]
1689 Format: <io>,<irq>
1691 uart6850= [HW,OSS]
1692 Format: <io>,<irq>
1694 usbhid.mousepoll=
1695 [USBHID] The interval which mice are to be polled at.
1697 vdso= [IA-32]
1698 vdso=1: enable VDSO (default)
1699 vdso=0: disable VDSO mapping
1701 video= [FB] Frame buffer configuration
1702 See Documentation/fb/modedb.txt.
1704 vga= [BOOT,IA-32] Select a particular video mode
1705 See Documentation/i386/boot.txt and
1706 Documentation/svga.txt.
1707 Use vga=ask for menu.
1708 This is actually a boot loader parameter; the value is
1709 passed to the kernel using a special protocol.
1711 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1712 size of <nn>. This can be used to increase the
1713 minimum size (128MB on x86). It can also be used to
1714 decrease the size and leave more room for directly
1715 mapped kernel RAM.
1717 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1718 Format: <command>
1720 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1721 Format: <command>
1723 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1724 Format: <command>
1726 waveartist= [HW,OSS]
1727 Format: <io>,<irq>,<dma>,<dma2>
1729 wd33c93= [HW,SCSI]
1730 See header of drivers/scsi/wd33c93.c.
1732 wd7000= [HW,SCSI]
1733 See header of drivers/scsi/wd7000.c.
1735 wdt= [WDT] Watchdog
1736 See Documentation/watchdog/watchdog.txt.
1738 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1739 xd_geo= See header of drivers/block/xd.c.
1741 xirc2ps_cs= [NET,PCMCIA]
1742 Format:
1743 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1745 norandmaps Don't use address space randomization
1746 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1749 ______________________________________________________________________
1751 TODO:
1753 Add documentation for ALSA options.
1754 Add more DRM drivers.