ia64/linux-2.6.18-xen.hg

view Documentation/kernel-parameters.txt @ 835:071ee07f9226

dom0 linux: Fix descriptions in kernel-parameters.txt

Signed-off-by: Yuji Shimada <shimada-yxb@necst.nec.co.jp>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Mar 19 10:05:39 2009 +0000 (2009-03-19)
parents cfb171ddbb33
children a3ad7a5f2dcd
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>[,<device path>[,...]]
580 Format of device path: <hid>[:<uid>]-<dev>.<func>[-<dev>.<func>[...]]
581 Specifies PCI device for guest domain.
582 If PCI-PCI bridge is specified, all PCI devices
583 behind PCI-PCI bridge are reserved.
585 gus= [HW,OSS]
586 Format: <io>,<irq>,<dma>,<dma16>
588 gvp11= [HW,SCSI]
590 hashdist= [KNL,NUMA] Large hashes allocated during boot
591 are distributed across NUMA nodes. Defaults on
592 for IA-64, off otherwise.
593 Format: 0 | 1 (for off | on)
595 hcl= [IA-64] SGI's Hardware Graph compatibility layer
597 hd= [EIDE] (E)IDE hard drive subsystem geometry
598 Format: <cyl>,<head>,<sect>
600 hd?= [HW] (E)IDE subsystem
601 hd?lun= See Documentation/ide.txt.
603 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
604 size of <nn>. This works even on boxes that have no
605 highmem otherwise. This also works to reduce highmem
606 size on bigger boxes.
608 hisax= [HW,ISDN]
609 See Documentation/isdn/README.HiSax.
611 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
613 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
615 i8042.direct [HW] Put keyboard port into non-translated mode
616 i8042.dumbkbd [HW] Pretend that controlled can only read data from
617 keyboard and can not control its state
618 (Don't attempt to blink the leds)
619 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
620 i8042.nokbd [HW] Don't check/create keyboard port
621 i8042.nomux [HW] Don't check presence of an active multiplexing
622 controller
623 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
624 controllers
625 i8042.panicblink=
626 [HW] Frequency with which keyboard LEDs should blink
627 when kernel panics (default is 0.5 sec)
628 i8042.reset [HW] Reset the controller during init and cleanup
629 i8042.unlock [HW] Unlock (ignore) the keylock
631 i810= [HW,DRM]
633 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
634 indicates that the driver is running on unsupported
635 hardware.
636 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
637 does not match list of supported models.
638 i8k.power_status
639 [HW] Report power status in /proc/i8k
640 (disabled by default)
641 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
642 capability is set.
644 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
645 See Documentation/mca.txt.
647 icn= [HW,ISDN]
648 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
650 ide= [HW] (E)IDE subsystem
651 Format: ide=nodma or ide=doubler or ide=reverse
652 See Documentation/ide.txt.
654 ide?= [HW] (E)IDE subsystem
655 Format: ide?=noprobe or chipset specific parameters.
656 See Documentation/ide.txt.
658 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
659 See Documentation/ide.txt.
661 idle= [HW]
662 Format: idle=poll or idle=halt
664 ihash_entries= [KNL]
665 Set number of hash buckets for inode cache.
667 in2000= [HW,SCSI]
668 See header of drivers/scsi/in2000.c.
670 init= [KNL]
671 Format: <full_path>
672 Run specified binary instead of /sbin/init as init
673 process.
675 initcall_debug [KNL] Trace initcalls as they are executed. Useful
676 for working out where the kernel is dying during
677 startup.
679 initrd= [BOOT] Specify the location of the initial ramdisk
681 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
682 Format: <irq>
684 combined_mode= [HW] control which driver uses IDE ports in combined
685 mode: legacy IDE driver, libata, or both
686 (in the libata case, libata.atapi_enabled=1 may be
687 useful as well). Note that using the ide or libata
688 options may affect your device naming (e.g. by
689 changing hdc to sdb).
690 Format: combined (default), ide, or libata
692 inttest= [IA64]
694 io7= [HW] IO7 for Marvel based alpha systems
695 See comment before marvel_specify_io7 in
696 arch/alpha/kernel/core_marvel.c.
698 ip= [IP_PNP]
699 See Documentation/nfsroot.txt.
701 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
702 See comment before ip2_setup() in drivers/char/ip2.c.
704 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
705 See header of drivers/scsi/ips.c.
707 ports= [IP_VS_FTP] IPVS ftp helper module
708 Default is 21.
709 Up to 8 (IP_VS_APP_MAX_PORTS) ports
710 may be specified.
711 Format: <port>,<port>....
713 irqfixup [HW]
714 When an interrupt is not handled search all handlers
715 for it. Intended to get systems with badly broken
716 firmware running.
718 irqpoll [HW]
719 When an interrupt is not handled search all handlers
720 for it. Also check all handlers each timer
721 interrupt. Intended to get systems with badly broken
722 firmware running.
724 isapnp= [ISAPNP]
725 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
727 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
728 Format: <cpu number>,...,<cpu number>
729 This option can be used to specify one or more CPUs
730 to isolate from the general SMP balancing and scheduling
731 algorithms. The only way to move a process onto or off
732 an "isolated" CPU is via the CPU affinity syscalls.
733 <cpu number> begins at 0 and the maximum value is
734 "number of CPUs in system - 1".
736 This option is the preferred way to isolate CPUs. The
737 alternative -- manually setting the CPU mask of all
738 tasks in the system -- can cause problems and
739 suboptimal load balancer performance.
741 isp16= [HW,CD]
742 Format: <io>,<irq>,<dma>,<setup>
744 iucv= [HW,NET]
746 js= [HW,JOY] Analog joystick
747 See Documentation/input/joystick.txt.
749 keepinitrd [HW,ARM]
751 kstack=N [IA-32,X86-64] Print N words from the kernel stack
752 in oops dumps.
754 l2cr= [PPC]
756 lapic [IA-32,APIC] Enable the local APIC even if BIOS
757 disabled it.
759 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
760 Format: addr:<io>,irq:<irq>
762 llsc*= [IA64] See function print_params() in
763 arch/ia64/sn/kernel/llsc4.c.
765 load_ramdisk= [RAM] List of ramdisks to load from floppy
766 See Documentation/ramdisk.txt.
768 lockd.nlm_grace_period=P [NFS] Assign grace period.
769 Format: <integer>
771 lockd.nlm_tcpport=N [NFS] Assign TCP port.
772 Format: <integer>
774 lockd.nlm_timeout=T [NFS] Assign timeout value.
775 Format: <integer>
777 lockd.nlm_udpport=M [NFS] Assign UDP port.
778 Format: <integer>
780 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
781 Format: <irq>
783 loglevel= All Kernel Messages with a loglevel smaller than the
784 console loglevel will be printed to the console. It can
785 also be changed with klogd or other programs. The
786 loglevels are defined as follows:
788 0 (KERN_EMERG) system is unusable
789 1 (KERN_ALERT) action must be taken immediately
790 2 (KERN_CRIT) critical conditions
791 3 (KERN_ERR) error conditions
792 4 (KERN_WARNING) warning conditions
793 5 (KERN_NOTICE) normal but significant condition
794 6 (KERN_INFO) informational
795 7 (KERN_DEBUG) debug-level messages
797 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
798 Format: { n | nk | nM }
799 n must be a power of two. The default size
800 is set in the kernel config file.
802 lp=0 [LP] Specify parallel ports to use, e.g,
803 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
804 lp=reset first parallel port). 'lp=0' disables the
805 lp=auto printer driver. 'lp=reset' (which can be
806 specified in addition to the ports) causes
807 attached printers to be reset. Using
808 lp=port1,port2,... specifies the parallel ports
809 to associate lp devices with, starting with
810 lp0. A port specification may be 'none' to skip
811 that lp device, or a parport name such as
812 'parport0'. Specifying 'lp=auto' instead of a
813 port specification list means that device IDs
814 from each port should be examined, to see if
815 an IEEE 1284-compliant printer is attached; if
816 so, the driver will manage that printer.
817 See also header of drivers/char/lp.c.
819 lpj=n [KNL]
820 Sets loops_per_jiffy to given constant, thus avoiding
821 time-consuming boot-time autodetection (up to 250 ms per
822 CPU). 0 enables autodetection (default). To determine
823 the correct value for your kernel, boot with normal
824 autodetection and see what value is printed. Note that
825 on SMP systems the preset will be applied to all CPUs,
826 which is likely to cause problems if your CPUs need
827 significantly divergent settings. An incorrect value
828 will cause delays in the kernel to be wrong, leading to
829 unpredictable I/O errors and other breakage. Although
830 unlikely, in the extreme case this might damage your
831 hardware.
833 ltpc= [NET]
834 Format: <io>,<irq>,<dma>
836 mac5380= [HW,SCSI] Format:
837 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
839 mac53c9x= [HW,SCSI] Format:
840 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
842 machvec= [IA64] Force the use of a particular machine-vector
843 (machvec) in a generic kernel.
844 Example: machvec=hpzx1_swiotlb
846 mad16= [HW,OSS] Format:
847 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
849 maui= [HW,OSS]
850 Format: <io>,<irq>
852 max_loop= [LOOP] Maximum number of loopback devices that can
853 be mounted
854 Format: <1-256>
856 maxcpus= [SMP] Maximum number of processors that an SMP kernel
857 should make use of
859 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
860 equal to this physical address is ignored.
862 max_luns= [SCSI] Maximum number of LUNs to probe.
863 Should be between 1 and 2^32-1.
865 max_report_luns=
866 [SCSI] Maximum number of LUNs received.
867 Should be between 1 and 16384.
869 mca-pentium [BUGS=IA-32]
871 mcatest= [IA-64]
873 mcd= [HW,CD]
874 Format: <port>,<irq>,<mitsumi_bug_93_wait>
876 mcdx= [HW,CD]
878 mce [IA-32] Machine Check Exception
880 md= [HW] RAID subsystems devices and level
881 See Documentation/md.txt.
883 mdacon= [MDA]
884 Format: <first>,<last>
885 Specifies range of consoles to be captured by the MDA.
887 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
888 Amount of memory to be used when the kernel is not able
889 to see the whole system memory or for test.
890 [IA-32] Use together with memmap= to avoid physical
891 address space collisions. Without memmap= PCI devices
892 could be placed at addresses belonging to unused RAM.
894 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
895 memory.
897 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
898 E820 memory map, as specified by the user.
899 Such memmap=exactmap lines can be constructed based on
900 BIOS output or other requirements. See the memmap=nn@ss
901 option description.
903 memmap=nn[KMG]@ss[KMG]
904 [KNL] Force usage of a specific region of memory
905 Region of memory to be used, from ss to ss+nn.
907 memmap=nn[KMG]#ss[KMG]
908 [KNL,ACPI] Mark specific memory as ACPI data.
909 Region of memory to be used, from ss to ss+nn.
911 memmap=nn[KMG]$ss[KMG]
912 [KNL,ACPI] Mark specific memory as reserved.
913 Region of memory to be used, from ss to ss+nn.
915 meye.*= [HW] Set MotionEye Camera parameters
916 See Documentation/video4linux/meye.txt.
918 mga= [HW,DRM]
920 migration_cost=
921 [KNL,SMP] debug: override scheduler migration costs
922 Format: <level-1-usecs>,<level-2-usecs>,...
923 This debugging option can be used to override the
924 default scheduler migration cost matrix. The numbers
925 are indexed by 'CPU domain distance'.
926 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
927 box will set up an intra-core migration cost of
928 1 msec, an inter-core migration cost of 2 msecs,
929 and an inter-node migration cost of 3 msecs.
931 WARNING: using the wrong values here can break
932 scheduler performance, so it's only for scheduler
933 development purposes, not production environments.
935 migration_debug=
936 [KNL,SMP] migration cost auto-detect verbosity
937 Format=<0|1|2>
938 If a system's migration matrix reported at bootup
939 seems erroneous then this option can be used to
940 increase verbosity of the detection process.
941 We default to 0 (no extra messages), 1 will print
942 some more information, and 2 will be really
943 verbose (probably only useful if you also have a
944 serial console attached to the system).
946 migration_factor=
947 [KNL,SMP] multiply/divide migration costs by a factor
948 Format=<percent>
949 This debug option can be used to proportionally
950 increase or decrease the auto-detected migration
951 costs for all entries of the migration matrix.
952 E.g. migration_factor=150 will increase migration
953 costs by 50%. (and thus the scheduler will be less
954 eager migrating cache-hot tasks)
955 migration_factor=80 will decrease migration costs
956 by 20%. (thus the scheduler will be more eager to
957 migrate tasks)
959 WARNING: using the wrong values here can break
960 scheduler performance, so it's only for scheduler
961 development purposes, not production environments.
963 mousedev.tap_time=
964 [MOUSE] Maximum time between finger touching and
965 leaving touchpad surface for touch to be considered
966 a tap and be reported as a left button click (for
967 touchpads working in absolute mode only).
968 Format: <msecs>
969 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
970 reporting absolute coordinates, such as tablets
971 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
972 reporting absolute coordinates, such as tablets
974 mpu401= [HW,OSS]
975 Format: <io>,<irq>
977 MTD_Partition= [MTD]
978 Format: <name>,<region-number>,<size>,<offset>
980 MTD_Region= [MTD] Format:
981 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
983 mtdparts= [MTD]
984 See drivers/mtd/cmdline.c.
986 mtouchusb.raw_coordinates=
987 [HW] Make the MicroTouch USB driver use raw coordinates
988 ('y', default) or cooked coordinates ('n')
990 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
992 NCR_D700= [HW,SCSI]
993 See header of drivers/scsi/NCR_D700.c.
995 ncr5380= [HW,SCSI]
997 ncr53c400= [HW,SCSI]
999 ncr53c400a= [HW,SCSI]
1001 ncr53c406a= [HW,SCSI]
1003 ncr53c8xx= [HW,SCSI]
1005 netdev= [NET] Network devices parameters
1006 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1007 Note that mem_start is often overloaded to mean
1008 something different and driver-specific.
1009 This usage is only documented in each driver source
1010 file if at all.
1012 nfsaddrs= [NFS]
1013 See Documentation/nfsroot.txt.
1015 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1016 See Documentation/nfsroot.txt.
1018 nfs.callback_tcpport=
1019 [NFS] set the TCP port on which the NFSv4 callback
1020 channel should listen.
1022 nfs.idmap_cache_timeout=
1023 [NFS] set the maximum lifetime for idmapper cache
1024 entries.
1026 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1028 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1029 emulation library even if a 387 maths coprocessor
1030 is present.
1032 noalign [KNL,ARM]
1034 noapic [SMP,APIC] Tells the kernel to not make use of any
1035 IOAPICs that may be present in the system.
1037 noasync [HW,M68K] Disables async and sync negotiation for
1038 all devices.
1040 nobats [PPC] Do not use BATs for mapping kernel lowmem
1041 on "Classic" PPC cores.
1043 nocache [ARM]
1045 nodelayacct [KNL] Disable per-task delay accounting
1047 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1049 noexec [IA-64]
1051 noexec [IA-32,X86-64]
1052 noexec=on: enable non-executable mappings (default)
1053 noexec=off: disable nn-executable mappings
1055 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1056 register save and restore. The kernel will only save
1057 legacy floating-point registers on task switch.
1059 nohlt [BUGS=ARM]
1061 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1062 instruction doesn't work correctly and not to
1063 use it.
1065 nohalt [IA-64] Tells the kernel not to use the power saving
1066 function PAL_HALT_LIGHT when idle. This increases
1067 power-consumption. On the positive side, it reduces
1068 interrupt wake-up latency, which may improve performance
1069 in certain environments such as networked servers or
1070 real-time systems.
1072 noirqdebug [IA-32] Disables the code which attempts to detect and
1073 disable unhandled interrupt sources.
1075 noisapnp [ISAPNP] Disables ISA PnP code.
1077 noinitrd [RAM] Tells the kernel not to load any configured
1078 initial RAM disk.
1080 nointroute [IA-64]
1082 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1084 noltlbs [PPC] Do not use large page/tlb entries for kernel
1085 lowmem mapping on PPC40x.
1087 nomca [IA-64] Disable machine check abort handling
1089 nomce [IA-32] Machine Check Exception
1091 noresidual [PPC] Don't use residual data on PReP machines.
1093 noresume [SWSUSP] Disables resume and restores original swap
1094 space.
1096 no-scroll [VGA] Disables scrollback.
1097 This is required for the Braillex ib80-piezo Braille
1098 reader made by F.H. Papenmeier (Germany).
1100 nosbagart [IA-64]
1102 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1104 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1106 nosync [HW,M68K] Disables sync negotiation for all devices.
1108 notsc [BUGS=IA-32] Disable Time Stamp Counter
1110 nousb [USB] Disable the USB subsystem
1112 nowb [ARM]
1114 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1116 opl3= [HW,OSS]
1117 Format: <io>
1119 opl3sa= [HW,OSS]
1120 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1122 opl3sa2= [HW,OSS] Format:
1123 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1125 oprofile.timer= [HW]
1126 Use timer interrupt instead of performance counters
1128 optcd= [HW,CD]
1129 Format: <io>
1131 osst= [HW,SCSI] SCSI Tape Driver
1132 Format: <buffer_size>,<write_threshold>
1133 See also Documentation/scsi/st.txt.
1135 panic= [KNL] Kernel behaviour on panic
1136 Format: <timeout>
1138 parkbd.port= [HW] Parallel port number the keyboard adapter is
1139 connected to, default is 0.
1140 Format: <parport#>
1141 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1142 0 for XT, 1 for AT (default is AT).
1143 Format: <mode>
1145 parport= [HW,PPT] Specify parallel ports. 0 disables.
1146 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1147 Use 'auto' to force the driver to use any
1148 IRQ/DMA settings detected (the default is to
1149 ignore detected IRQ/DMA settings because of
1150 possible conflicts). You can specify the base
1151 address, IRQ, and DMA settings; IRQ and DMA
1152 should be numbers, or 'auto' (for using detected
1153 settings on that particular port), or 'nofifo'
1154 (to avoid using a FIFO even if it is detected).
1155 Parallel ports are assigned in the order they
1156 are specified on the command line, starting
1157 with parport0.
1159 parport_init_mode= [HW,PPT]
1160 Configure VIA parallel port to operate in
1161 a specific mode. This is necessary on Pegasos
1162 computer where firmware has no options for setting
1163 up parallel port mode and sets it to spp.
1164 Currently this function knows 686a and 8231 chips.
1165 Format: [spp|ps2|epp|ecp|ecpepp]
1167 pas2= [HW,OSS] Format:
1168 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1170 pas16= [HW,SCSI]
1171 See header of drivers/scsi/pas16.c.
1173 pause_on_oops=
1174 Halt all CPUs after the first oops has been printed for
1175 the specified number of seconds. This is to be used if
1176 your oopses keep scrolling off the screen.
1178 pcbit= [HW,ISDN]
1180 pcd. [PARIDE]
1181 See header of drivers/block/paride/pcd.c.
1182 See also Documentation/paride.txt.
1184 pci=option[,option...] [PCI] various PCI subsystem options:
1185 off [IA-32] don't probe for the PCI bus
1186 bios [IA-32] force use of PCI BIOS, don't access
1187 the hardware directly. Use this if your machine
1188 has a non-standard PCI host bridge.
1189 nobios [IA-32] disallow use of PCI BIOS, only direct
1190 hardware access methods are allowed. Use this
1191 if you experience crashes upon bootup and you
1192 suspect they are caused by the BIOS.
1193 conf1 [IA-32] Force use of PCI Configuration
1194 Mechanism 1.
1195 conf2 [IA-32] Force use of PCI Configuration
1196 Mechanism 2.
1197 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1198 Configuration
1199 nomsi [MSI] If the PCI_MSI kernel config parameter is
1200 enabled, this kernel boot option can be used to
1201 disable the use of MSI interrupts system-wide.
1202 nosort [IA-32] Don't sort PCI devices according to
1203 order given by the PCI BIOS. This sorting is
1204 done to get a device order compatible with
1205 older kernels.
1206 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1207 routing table. These calls are known to be buggy
1208 on several machines and they hang the machine
1209 when used, but on other computers it's the only
1210 way to get the interrupt routing table. Try
1211 this option if the kernel is unable to allocate
1212 IRQs or discover secondary PCI buses on your
1213 motherboard.
1214 rom [IA-32] Assign address space to expansion ROMs.
1215 Use with caution as certain devices share
1216 address decoders between ROMs and other
1217 resources.
1218 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1219 assigned automatically to PCI devices. You can
1220 make the kernel exclude IRQs of your ISA cards
1221 this way.
1222 pirqaddr=0xAAAAA [IA-32] Specify the physical address
1223 of the PIRQ table (normally generated
1224 by the BIOS) if it is outside the
1225 F0000h-100000h range.
1226 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1227 useful if the kernel is unable to find your
1228 secondary buses and you want to tell it
1229 explicitly which ones they are.
1230 assign-busses [IA-32] Always assign all PCI bus
1231 numbers ourselves, overriding
1232 whatever the firmware may have done.
1233 usepirqmask [IA-32] Honor the possible IRQ mask stored
1234 in the BIOS $PIR table. This is needed on
1235 some systems with broken BIOSes, notably
1236 some HP Pavilion N5400 and Omnibook XE3
1237 notebooks. This will have no effect if ACPI
1238 IRQ routing is enabled.
1239 noacpi [IA-32] Do not use ACPI for IRQ routing
1240 or for PCI scanning.
1241 routeirq Do IRQ routing for all PCI devices.
1242 This is normally done in pci_enable_device(),
1243 so this option is a temporary workaround
1244 for broken drivers that don't call it.
1245 firmware [ARM] Do not re-enumerate the bus but instead
1246 just use the configuration from the
1247 bootloader. This is currently used on
1248 IXP2000 systems where the bus has to be
1249 configured a certain way for adjunct CPUs.
1251 pcmv= [HW,PCMCIA] BadgePAD 4
1253 pd. [PARIDE]
1254 See Documentation/paride.txt.
1256 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1257 boot time.
1258 Format: { 0 | 1 }
1259 See arch/parisc/kernel/pdc_chassis.c
1261 pf. [PARIDE]
1262 See Documentation/paride.txt.
1264 pg. [PARIDE]
1265 See Documentation/paride.txt.
1267 pirq= [SMP,APIC] Manual mp-table setup
1268 See Documentation/i386/IO-APIC.txt.
1270 plip= [PPT,NET] Parallel port network link
1271 Format: { parport<nr> | timid | 0 }
1272 See also Documentation/parport.txt.
1274 pnpacpi= [ACPI]
1275 { off }
1277 pnpbios= [ISAPNP]
1278 { on | off | curr | res | no-curr | no-res }
1280 pnp_reserve_irq=
1281 [ISAPNP] Exclude IRQs for the autoconfiguration
1283 pnp_reserve_dma=
1284 [ISAPNP] Exclude DMAs for the autoconfiguration
1286 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1287 Ranges are in pairs (I/O port base and size).
1289 pnp_reserve_mem=
1290 [ISAPNP] Exclude memory regions for the
1291 autoconfiguration.
1292 Ranges are in pairs (memory base and size).
1294 profile= [KNL] Enable kernel profiling via /proc/profile
1295 Format: [schedule,]<number>
1296 Param: "schedule" - profile schedule points.
1297 Param: <number> - step/bucket size as a power of 2 for
1298 statistical time based profiling.
1300 processor.max_cstate= [HW,ACPI]
1301 Limit processor to maximum C-state
1302 max_cstate=9 overrides any DMI blacklist limit.
1304 processor.nocst [HW,ACPI]
1305 Ignore the _CST method to determine C-states,
1306 instead using the legacy FADT method
1308 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1309 before loading.
1310 See Documentation/ramdisk.txt.
1312 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1313 probe for; one of (bare|imps|exps|lifebook|any).
1314 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1315 per second.
1316 psmouse.resetafter= [HW,MOUSE]
1317 Try to reset the device after so many bad packets
1318 (0 = never).
1319 psmouse.resolution=
1320 [HW,MOUSE] Set desired mouse resolution, in dpi.
1321 psmouse.smartscroll=
1322 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1323 0 = disabled, 1 = enabled (default).
1325 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1326 Format:
1327 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1329 pt. [PARIDE]
1330 See Documentation/paride.txt.
1332 quiet= [KNL] Disable log messages
1334 r128= [HW,DRM]
1336 raid= [HW,RAID]
1337 See Documentation/md.txt.
1339 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1340 See Documentation/ramdisk.txt.
1342 ramdisk_blocksize= [RAM]
1343 See Documentation/ramdisk.txt.
1345 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1346 New name for the ramdisk parameter.
1347 See Documentation/ramdisk.txt.
1349 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1350 RCU callbacks to process in one batch.
1352 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1353 RCU callbacks over which batch limiting is disabled.
1355 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1356 RCU callbacks below which batch limiting is re-enabled.
1358 rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
1359 RCU callbacks to queued before forcing reschedule
1360 on all cpus.
1362 rdinit= [KNL]
1363 Format: <full_path>
1364 Run specified binary instead of /init from the ramdisk,
1365 used for early userspace startup. See initrd.
1367 reassigndev= [PCI]
1368 Format: [<segment>:]<bus>:<dev>.<func>[,[<segment>:]<bus>:<dev>.<func>[,...]]
1369 Specifies device to reassign page-aligned memory
1370 resources. PCI-PCI bridge can be specified, if
1371 resource windows need to be expanded.
1373 reassign_resources
1374 [PCI,ACPI] Use guestdev parameter to reassign device's
1375 resources.
1377 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1378 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1379 See arch/*/kernel/reboot.c.
1381 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1383 resume= [SWSUSP]
1384 Specify the partition device for software suspend
1386 rhash_entries= [KNL,NET]
1387 Set number of hash buckets for route cache
1389 riscom8= [HW,SERIAL]
1390 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1392 ro [KNL] Mount root device read-only on boot
1394 root= [KNL] Root filesystem
1396 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1397 mount the root filesystem
1399 rootflags= [KNL] Set root filesystem mount option string
1401 rootfstype= [KNL] Set root filesystem type
1403 rw [KNL] Mount root device read-write on boot
1405 S [KNL] Run init in single mode
1407 sa1100ir [NET]
1408 See drivers/net/irda/sa1100_ir.c.
1410 sb= [HW,OSS]
1411 Format: <io>,<irq>,<dma>,<dma2>
1413 sbni= [NET] Granch SBNI12 leased line adapter
1415 sbpcd= [HW,CD] Soundblaster CD adapter
1416 Format: <io>,<type>
1417 See a comment before function sbpcd_setup() in
1418 drivers/cdrom/sbpcd.c.
1420 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1421 Format: <io>[,<timeout>[,<isapnp>]]
1423 scsi_debug_*= [SCSI]
1424 See drivers/scsi/scsi_debug.c.
1426 scsi_default_dev_flags=
1427 [SCSI] SCSI default device flags
1428 Format: <integer>
1430 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1431 Format: <vendor>:<model>:<flags>
1432 (flags are integer value)
1434 scsi_logging= [SCSI]
1436 selinux [SELINUX] Disable or enable SELinux at boot time.
1437 Format: { "0" | "1" }
1438 See security/selinux/Kconfig help text.
1439 0 -- disable.
1440 1 -- enable.
1441 Default value is set via kernel config option.
1442 If enabled at boot time, /selinux/disable can be used
1443 later to disable prior to initial policy load.
1445 selinux_compat_net =
1446 [SELINUX] Set initial selinux_compat_net flag value.
1447 Format: { "0" | "1" }
1448 0 -- use new secmark-based packet controls
1449 1 -- use legacy packet controls
1450 Default value is 0 (preferred).
1451 Value can be changed at runtime via
1452 /selinux/compat_net.
1454 serialnumber [BUGS=IA-32]
1456 sg_def_reserved_size= [SCSI]
1458 sgalaxy= [HW,OSS]
1459 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1461 shapers= [NET]
1462 Maximal number of shapers.
1464 sim710= [SCSI,HW]
1465 See header of drivers/scsi/sim710.c.
1467 simeth= [IA-64]
1468 simscsi=
1470 sjcd= [HW,CD]
1471 Format: <io>,<irq>,<dma>
1472 See header of drivers/cdrom/sjcd.c.
1474 slram= [HW,MTD]
1476 smart2= [HW]
1477 Format: <io1>[,<io2>[,...,<io8>]]
1479 snd-ad1816a= [HW,ALSA]
1481 snd-ad1848= [HW,ALSA]
1483 snd-ali5451= [HW,ALSA]
1485 snd-als100= [HW,ALSA]
1487 snd-als4000= [HW,ALSA]
1489 snd-azt2320= [HW,ALSA]
1491 snd-cmi8330= [HW,ALSA]
1493 snd-cmipci= [HW,ALSA]
1495 snd-cs4231= [HW,ALSA]
1497 snd-cs4232= [HW,ALSA]
1499 snd-cs4236= [HW,ALSA]
1501 snd-cs4281= [HW,ALSA]
1503 snd-cs46xx= [HW,ALSA]
1505 snd-dt019x= [HW,ALSA]
1507 snd-dummy= [HW,ALSA]
1509 snd-emu10k1= [HW,ALSA]
1511 snd-ens1370= [HW,ALSA]
1513 snd-ens1371= [HW,ALSA]
1515 snd-es968= [HW,ALSA]
1517 snd-es1688= [HW,ALSA]
1519 snd-es18xx= [HW,ALSA]
1521 snd-es1938= [HW,ALSA]
1523 snd-es1968= [HW,ALSA]
1525 snd-fm801= [HW,ALSA]
1527 snd-gusclassic= [HW,ALSA]
1529 snd-gusextreme= [HW,ALSA]
1531 snd-gusmax= [HW,ALSA]
1533 snd-hdsp= [HW,ALSA]
1535 snd-ice1712= [HW,ALSA]
1537 snd-intel8x0= [HW,ALSA]
1539 snd-interwave= [HW,ALSA]
1541 snd-interwave-stb=
1542 [HW,ALSA]
1544 snd-korg1212= [HW,ALSA]
1546 snd-maestro3= [HW,ALSA]
1548 snd-mpu401= [HW,ALSA]
1550 snd-mtpav= [HW,ALSA]
1552 snd-nm256= [HW,ALSA]
1554 snd-opl3sa2= [HW,ALSA]
1556 snd-opti92x-ad1848=
1557 [HW,ALSA]
1559 snd-opti92x-cs4231=
1560 [HW,ALSA]
1562 snd-opti93x= [HW,ALSA]
1564 snd-pmac= [HW,ALSA]
1566 snd-rme32= [HW,ALSA]
1568 snd-rme96= [HW,ALSA]
1570 snd-rme9652= [HW,ALSA]
1572 snd-sb8= [HW,ALSA]
1574 snd-sb16= [HW,ALSA]
1576 snd-sbawe= [HW,ALSA]
1578 snd-serial= [HW,ALSA]
1580 snd-sgalaxy= [HW,ALSA]
1582 snd-sonicvibes= [HW,ALSA]
1584 snd-sun-amd7930=
1585 [HW,ALSA]
1587 snd-sun-cs4231= [HW,ALSA]
1589 snd-trident= [HW,ALSA]
1591 snd-usb-audio= [HW,ALSA,USB]
1593 snd-via82xx= [HW,ALSA]
1595 snd-virmidi= [HW,ALSA]
1597 snd-wavefront= [HW,ALSA]
1599 snd-ymfpci= [HW,ALSA]
1601 sonicvibes= [HW,OSS]
1602 Format: <reverb>
1604 sonycd535= [HW,CD]
1605 Format: <io>[,<irq>]
1607 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1608 See Documentation/sonypi.txt
1610 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1611 See Documentation/specialix.txt.
1613 spia_io_base= [HW,MTD]
1614 spia_fio_base=
1615 spia_pedr=
1616 spia_peddr=
1618 sscape= [HW,OSS]
1619 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1621 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1622 See Documentation/scsi/st.txt.
1624 st0x= [HW,SCSI]
1625 See header of drivers/scsi/seagate.c.
1627 sti= [PARISC,HW]
1628 Format: <num>
1629 Set the STI (builtin display/keyboard on the HP-PARISC
1630 machines) console (graphic card) which should be used
1631 as the initial boot-console.
1632 See also comment in drivers/video/console/sticore.c.
1634 sti_font= [HW]
1635 See comment in drivers/video/console/sticore.c.
1637 stifb= [HW]
1638 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1640 swiotlb= [IA-64] Number of I/O TLB slabs
1642 switches= [HW,M68k]
1644 sym53c416= [HW,SCSI]
1645 See header of drivers/scsi/sym53c416.c.
1647 t128= [HW,SCSI]
1648 See header of drivers/scsi/t128.c.
1650 tdfx= [HW,DRM]
1652 thash_entries= [KNL,NET]
1653 Set number of hash buckets for TCP connection
1655 time Show timing data prefixed to each printk message line
1657 clocksource= [GENERIC_TIME] Override the default clocksource
1658 Override the default clocksource and use the clocksource
1659 with the name specified.
1661 tipar.timeout= [HW,PPT]
1662 Set communications timeout in tenths of a second
1663 (default 15).
1665 tipar.delay= [HW,PPT]
1666 Set inter-bit delay in microseconds (default 10).
1668 tmc8xx= [HW,SCSI]
1669 See header of drivers/scsi/seagate.c.
1671 tmscsim= [HW,SCSI]
1672 See comment before function dc390_setup() in
1673 drivers/scsi/tmscsim.c.
1675 tp720= [HW,PS2]
1677 trix= [HW,OSS] MediaTrix AudioTrix Pro
1678 Format:
1679 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1681 tsdev.xres= [TS] Horizontal screen resolution.
1682 tsdev.yres= [TS] Vertical screen resolution.
1684 turbografx.map[2|3]= [HW,JOY]
1685 TurboGraFX parallel port interface
1686 Format:
1687 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1688 See also Documentation/input/joystick-parport.txt
1690 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1691 See header of drivers/scsi/u14-34f.c.
1693 uart401= [HW,OSS]
1694 Format: <io>,<irq>
1696 uart6850= [HW,OSS]
1697 Format: <io>,<irq>
1699 usbhid.mousepoll=
1700 [USBHID] The interval which mice are to be polled at.
1702 vdso= [IA-32]
1703 vdso=1: enable VDSO (default)
1704 vdso=0: disable VDSO mapping
1706 video= [FB] Frame buffer configuration
1707 See Documentation/fb/modedb.txt.
1709 vga= [BOOT,IA-32] Select a particular video mode
1710 See Documentation/i386/boot.txt and
1711 Documentation/svga.txt.
1712 Use vga=ask for menu.
1713 This is actually a boot loader parameter; the value is
1714 passed to the kernel using a special protocol.
1716 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1717 size of <nn>. This can be used to increase the
1718 minimum size (128MB on x86). It can also be used to
1719 decrease the size and leave more room for directly
1720 mapped kernel RAM.
1722 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1723 Format: <command>
1725 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1726 Format: <command>
1728 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1729 Format: <command>
1731 waveartist= [HW,OSS]
1732 Format: <io>,<irq>,<dma>,<dma2>
1734 wd33c93= [HW,SCSI]
1735 See header of drivers/scsi/wd33c93.c.
1737 wd7000= [HW,SCSI]
1738 See header of drivers/scsi/wd7000.c.
1740 wdt= [WDT] Watchdog
1741 See Documentation/watchdog/watchdog.txt.
1743 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1744 xd_geo= See header of drivers/block/xd.c.
1746 xirc2ps_cs= [NET,PCMCIA]
1747 Format:
1748 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1750 norandmaps Don't use address space randomization
1751 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1754 ______________________________________________________________________
1756 TODO:
1758 Add documentation for ALSA options.
1759 Add more DRM drivers.