view Documentation/kernel-parameters.txt @ 882:8dec4aa9b8b9

PCI pass through: PCIe IO space multiplexing

This is required for more than 16 HVM domain to boot from
PCIe pass through device.

Linux as dom0 exclusively assigns IO space to downstream PCI bridges
and the assignment unit of PCI bridge IO space is 4K. So the only up
to 16 PCIe device can be accessed via IO space within 64K IO ports.
PCI expansion ROM BIOS often uses IO port access to boot from the
device, so on virtualized environment, it means only up to 16 guest
domain can boot from pass-through device.

This patch allows PCIe IO space sharing of pass-through device.
- reassign IO space of PCIe devices specified by
to be shared.
This is implemented as Linux PCI quirk fixup.

The sharing unit is PCIe switch. Ie IO space of the end point
devices under the same switch will be shared. If there are more than
one switches, two areas of IO space will be used.

- And the driver which arbitrates the accesses to the multiplexed PCIe
IO space. Later qemu-dm will use this.

IO port of IO shared devices can't be accessed from dom0 Linux device
driver. But this wouldn't be a big issue because PCIe specification
discourages the use of IO space and recommends that IO space should be
used only for bootable device with ROM code. OS device driver should
work without IO space access.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
author Keir Fraser <keir.fraser@citrix.com>
date Thu May 28 09:57:49 2009 +0100 (2009-05-28)
parents a3ad7a5f2dcd
children b998614e2e2a
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 guestiomuldev= [PCI]
587 Format: [sbd][,<sbd>][,...]
588 Format of sbdf: [<segment>:]<bus>:<dev>
589 Note: function shouldn't be specified.
590 Specifies PCI device for IO port multiplexing driver.
592 gus= [HW,OSS]
593 Format: <io>,<irq>,<dma>,<dma16>
595 gvp11= [HW,SCSI]
597 hashdist= [KNL,NUMA] Large hashes allocated during boot
598 are distributed across NUMA nodes. Defaults on
599 for IA-64, off otherwise.
600 Format: 0 | 1 (for off | on)
602 hcl= [IA-64] SGI's Hardware Graph compatibility layer
604 hd= [EIDE] (E)IDE hard drive subsystem geometry
605 Format: <cyl>,<head>,<sect>
607 hd?= [HW] (E)IDE subsystem
608 hd?lun= See Documentation/ide.txt.
610 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
611 size of <nn>. This works even on boxes that have no
612 highmem otherwise. This also works to reduce highmem
613 size on bigger boxes.
615 hisax= [HW,ISDN]
616 See Documentation/isdn/README.HiSax.
618 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
620 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
622 i8042.direct [HW] Put keyboard port into non-translated mode
623 i8042.dumbkbd [HW] Pretend that controlled can only read data from
624 keyboard and can not control its state
625 (Don't attempt to blink the leds)
626 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
627 i8042.nokbd [HW] Don't check/create keyboard port
628 i8042.nomux [HW] Don't check presence of an active multiplexing
629 controller
630 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
631 controllers
632 i8042.panicblink=
633 [HW] Frequency with which keyboard LEDs should blink
634 when kernel panics (default is 0.5 sec)
635 i8042.reset [HW] Reset the controller during init and cleanup
636 i8042.unlock [HW] Unlock (ignore) the keylock
638 i810= [HW,DRM]
640 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
641 indicates that the driver is running on unsupported
642 hardware.
643 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
644 does not match list of supported models.
645 i8k.power_status
646 [HW] Report power status in /proc/i8k
647 (disabled by default)
648 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
649 capability is set.
651 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
652 See Documentation/mca.txt.
654 icn= [HW,ISDN]
655 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
657 ide= [HW] (E)IDE subsystem
658 Format: ide=nodma or ide=doubler or ide=reverse
659 See Documentation/ide.txt.
661 ide?= [HW] (E)IDE subsystem
662 Format: ide?=noprobe or chipset specific parameters.
663 See Documentation/ide.txt.
665 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
666 See Documentation/ide.txt.
668 idle= [HW]
669 Format: idle=poll or idle=halt
671 ihash_entries= [KNL]
672 Set number of hash buckets for inode cache.
674 in2000= [HW,SCSI]
675 See header of drivers/scsi/in2000.c.
677 init= [KNL]
678 Format: <full_path>
679 Run specified binary instead of /sbin/init as init
680 process.
682 initcall_debug [KNL] Trace initcalls as they are executed. Useful
683 for working out where the kernel is dying during
684 startup.
686 initrd= [BOOT] Specify the location of the initial ramdisk
688 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
689 Format: <irq>
691 combined_mode= [HW] control which driver uses IDE ports in combined
692 mode: legacy IDE driver, libata, or both
693 (in the libata case, libata.atapi_enabled=1 may be
694 useful as well). Note that using the ide or libata
695 options may affect your device naming (e.g. by
696 changing hdc to sdb).
697 Format: combined (default), ide, or libata
699 inttest= [IA64]
701 io7= [HW] IO7 for Marvel based alpha systems
702 See comment before marvel_specify_io7 in
703 arch/alpha/kernel/core_marvel.c.
705 ip= [IP_PNP]
706 See Documentation/nfsroot.txt.
708 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
709 See comment before ip2_setup() in drivers/char/ip2.c.
711 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
712 See header of drivers/scsi/ips.c.
714 ports= [IP_VS_FTP] IPVS ftp helper module
715 Default is 21.
716 Up to 8 (IP_VS_APP_MAX_PORTS) ports
717 may be specified.
718 Format: <port>,<port>....
720 irqfixup [HW]
721 When an interrupt is not handled search all handlers
722 for it. Intended to get systems with badly broken
723 firmware running.
725 irqpoll [HW]
726 When an interrupt is not handled search all handlers
727 for it. Also check all handlers each timer
728 interrupt. Intended to get systems with badly broken
729 firmware running.
731 isapnp= [ISAPNP]
732 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
734 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
735 Format: <cpu number>,...,<cpu number>
736 This option can be used to specify one or more CPUs
737 to isolate from the general SMP balancing and scheduling
738 algorithms. The only way to move a process onto or off
739 an "isolated" CPU is via the CPU affinity syscalls.
740 <cpu number> begins at 0 and the maximum value is
741 "number of CPUs in system - 1".
743 This option is the preferred way to isolate CPUs. The
744 alternative -- manually setting the CPU mask of all
745 tasks in the system -- can cause problems and
746 suboptimal load balancer performance.
748 isp16= [HW,CD]
749 Format: <io>,<irq>,<dma>,<setup>
751 iucv= [HW,NET]
753 js= [HW,JOY] Analog joystick
754 See Documentation/input/joystick.txt.
756 keepinitrd [HW,ARM]
758 kstack=N [IA-32,X86-64] Print N words from the kernel stack
759 in oops dumps.
761 l2cr= [PPC]
763 lapic [IA-32,APIC] Enable the local APIC even if BIOS
764 disabled it.
766 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
767 Format: addr:<io>,irq:<irq>
769 llsc*= [IA64] See function print_params() in
770 arch/ia64/sn/kernel/llsc4.c.
772 load_ramdisk= [RAM] List of ramdisks to load from floppy
773 See Documentation/ramdisk.txt.
775 lockd.nlm_grace_period=P [NFS] Assign grace period.
776 Format: <integer>
778 lockd.nlm_tcpport=N [NFS] Assign TCP port.
779 Format: <integer>
781 lockd.nlm_timeout=T [NFS] Assign timeout value.
782 Format: <integer>
784 lockd.nlm_udpport=M [NFS] Assign UDP port.
785 Format: <integer>
787 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
788 Format: <irq>
790 loglevel= All Kernel Messages with a loglevel smaller than the
791 console loglevel will be printed to the console. It can
792 also be changed with klogd or other programs. The
793 loglevels are defined as follows:
795 0 (KERN_EMERG) system is unusable
796 1 (KERN_ALERT) action must be taken immediately
797 2 (KERN_CRIT) critical conditions
798 3 (KERN_ERR) error conditions
799 4 (KERN_WARNING) warning conditions
800 5 (KERN_NOTICE) normal but significant condition
801 6 (KERN_INFO) informational
802 7 (KERN_DEBUG) debug-level messages
804 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
805 Format: { n | nk | nM }
806 n must be a power of two. The default size
807 is set in the kernel config file.
809 lp=0 [LP] Specify parallel ports to use, e.g,
810 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
811 lp=reset first parallel port). 'lp=0' disables the
812 lp=auto printer driver. 'lp=reset' (which can be
813 specified in addition to the ports) causes
814 attached printers to be reset. Using
815 lp=port1,port2,... specifies the parallel ports
816 to associate lp devices with, starting with
817 lp0. A port specification may be 'none' to skip
818 that lp device, or a parport name such as
819 'parport0'. Specifying 'lp=auto' instead of a
820 port specification list means that device IDs
821 from each port should be examined, to see if
822 an IEEE 1284-compliant printer is attached; if
823 so, the driver will manage that printer.
824 See also header of drivers/char/lp.c.
826 lpj=n [KNL]
827 Sets loops_per_jiffy to given constant, thus avoiding
828 time-consuming boot-time autodetection (up to 250 ms per
829 CPU). 0 enables autodetection (default). To determine
830 the correct value for your kernel, boot with normal
831 autodetection and see what value is printed. Note that
832 on SMP systems the preset will be applied to all CPUs,
833 which is likely to cause problems if your CPUs need
834 significantly divergent settings. An incorrect value
835 will cause delays in the kernel to be wrong, leading to
836 unpredictable I/O errors and other breakage. Although
837 unlikely, in the extreme case this might damage your
838 hardware.
840 ltpc= [NET]
841 Format: <io>,<irq>,<dma>
843 mac5380= [HW,SCSI] Format:
844 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
846 mac53c9x= [HW,SCSI] Format:
847 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
849 machvec= [IA64] Force the use of a particular machine-vector
850 (machvec) in a generic kernel.
851 Example: machvec=hpzx1_swiotlb
853 mad16= [HW,OSS] Format:
854 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
856 maui= [HW,OSS]
857 Format: <io>,<irq>
859 max_loop= [LOOP] Maximum number of loopback devices that can
860 be mounted
861 Format: <1-256>
863 maxcpus= [SMP] Maximum number of processors that an SMP kernel
864 should make use of
866 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
867 equal to this physical address is ignored.
869 max_luns= [SCSI] Maximum number of LUNs to probe.
870 Should be between 1 and 2^32-1.
872 max_report_luns=
873 [SCSI] Maximum number of LUNs received.
874 Should be between 1 and 16384.
876 mca-pentium [BUGS=IA-32]
878 mcatest= [IA-64]
880 mcd= [HW,CD]
881 Format: <port>,<irq>,<mitsumi_bug_93_wait>
883 mcdx= [HW,CD]
885 mce [IA-32] Machine Check Exception
887 md= [HW] RAID subsystems devices and level
888 See Documentation/md.txt.
890 mdacon= [MDA]
891 Format: <first>,<last>
892 Specifies range of consoles to be captured by the MDA.
894 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
895 Amount of memory to be used when the kernel is not able
896 to see the whole system memory or for test.
897 [IA-32] Use together with memmap= to avoid physical
898 address space collisions. Without memmap= PCI devices
899 could be placed at addresses belonging to unused RAM.
901 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
902 memory.
904 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
905 E820 memory map, as specified by the user.
906 Such memmap=exactmap lines can be constructed based on
907 BIOS output or other requirements. See the memmap=nn@ss
908 option description.
910 memmap=nn[KMG]@ss[KMG]
911 [KNL] Force usage of a specific region of memory
912 Region of memory to be used, from ss to ss+nn.
914 memmap=nn[KMG]#ss[KMG]
915 [KNL,ACPI] Mark specific memory as ACPI data.
916 Region of memory to be used, from ss to ss+nn.
918 memmap=nn[KMG]$ss[KMG]
919 [KNL,ACPI] Mark specific memory as reserved.
920 Region of memory to be used, from ss to ss+nn.
922 meye.*= [HW] Set MotionEye Camera parameters
923 See Documentation/video4linux/meye.txt.
925 mga= [HW,DRM]
927 migration_cost=
928 [KNL,SMP] debug: override scheduler migration costs
929 Format: <level-1-usecs>,<level-2-usecs>,...
930 This debugging option can be used to override the
931 default scheduler migration cost matrix. The numbers
932 are indexed by 'CPU domain distance'.
933 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
934 box will set up an intra-core migration cost of
935 1 msec, an inter-core migration cost of 2 msecs,
936 and an inter-node migration cost of 3 msecs.
938 WARNING: using the wrong values here can break
939 scheduler performance, so it's only for scheduler
940 development purposes, not production environments.
942 migration_debug=
943 [KNL,SMP] migration cost auto-detect verbosity
944 Format=<0|1|2>
945 If a system's migration matrix reported at bootup
946 seems erroneous then this option can be used to
947 increase verbosity of the detection process.
948 We default to 0 (no extra messages), 1 will print
949 some more information, and 2 will be really
950 verbose (probably only useful if you also have a
951 serial console attached to the system).
953 migration_factor=
954 [KNL,SMP] multiply/divide migration costs by a factor
955 Format=<percent>
956 This debug option can be used to proportionally
957 increase or decrease the auto-detected migration
958 costs for all entries of the migration matrix.
959 E.g. migration_factor=150 will increase migration
960 costs by 50%. (and thus the scheduler will be less
961 eager migrating cache-hot tasks)
962 migration_factor=80 will decrease migration costs
963 by 20%. (thus the scheduler will be more eager to
964 migrate tasks)
966 WARNING: using the wrong values here can break
967 scheduler performance, so it's only for scheduler
968 development purposes, not production environments.
970 mousedev.tap_time=
971 [MOUSE] Maximum time between finger touching and
972 leaving touchpad surface for touch to be considered
973 a tap and be reported as a left button click (for
974 touchpads working in absolute mode only).
975 Format: <msecs>
976 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
977 reporting absolute coordinates, such as tablets
978 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
979 reporting absolute coordinates, such as tablets
981 mpu401= [HW,OSS]
982 Format: <io>,<irq>
984 MTD_Partition= [MTD]
985 Format: <name>,<region-number>,<size>,<offset>
987 MTD_Region= [MTD] Format:
988 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
990 mtdparts= [MTD]
991 See drivers/mtd/cmdline.c.
993 mtouchusb.raw_coordinates=
994 [HW] Make the MicroTouch USB driver use raw coordinates
995 ('y', default) or cooked coordinates ('n')
997 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
999 NCR_D700= [HW,SCSI]
1000 See header of drivers/scsi/NCR_D700.c.
1002 ncr5380= [HW,SCSI]
1004 ncr53c400= [HW,SCSI]
1006 ncr53c400a= [HW,SCSI]
1008 ncr53c406a= [HW,SCSI]
1010 ncr53c8xx= [HW,SCSI]
1012 netdev= [NET] Network devices parameters
1013 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1014 Note that mem_start is often overloaded to mean
1015 something different and driver-specific.
1016 This usage is only documented in each driver source
1017 file if at all.
1019 nfsaddrs= [NFS]
1020 See Documentation/nfsroot.txt.
1022 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1023 See Documentation/nfsroot.txt.
1025 nfs.callback_tcpport=
1026 [NFS] set the TCP port on which the NFSv4 callback
1027 channel should listen.
1029 nfs.idmap_cache_timeout=
1030 [NFS] set the maximum lifetime for idmapper cache
1031 entries.
1033 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1035 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1036 emulation library even if a 387 maths coprocessor
1037 is present.
1039 noalign [KNL,ARM]
1041 noapic [SMP,APIC] Tells the kernel to not make use of any
1042 IOAPICs that may be present in the system.
1044 noasync [HW,M68K] Disables async and sync negotiation for
1045 all devices.
1047 nobats [PPC] Do not use BATs for mapping kernel lowmem
1048 on "Classic" PPC cores.
1050 nocache [ARM]
1052 nodelayacct [KNL] Disable per-task delay accounting
1054 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1056 noexec [IA-64]
1058 noexec [IA-32,X86-64]
1059 noexec=on: enable non-executable mappings (default)
1060 noexec=off: disable nn-executable mappings
1062 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1063 register save and restore. The kernel will only save
1064 legacy floating-point registers on task switch.
1066 nohlt [BUGS=ARM]
1068 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1069 instruction doesn't work correctly and not to
1070 use it.
1072 nohalt [IA-64] Tells the kernel not to use the power saving
1073 function PAL_HALT_LIGHT when idle. This increases
1074 power-consumption. On the positive side, it reduces
1075 interrupt wake-up latency, which may improve performance
1076 in certain environments such as networked servers or
1077 real-time systems.
1079 noirqdebug [IA-32] Disables the code which attempts to detect and
1080 disable unhandled interrupt sources.
1082 noisapnp [ISAPNP] Disables ISA PnP code.
1084 noinitrd [RAM] Tells the kernel not to load any configured
1085 initial RAM disk.
1087 nointroute [IA-64]
1089 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1091 noltlbs [PPC] Do not use large page/tlb entries for kernel
1092 lowmem mapping on PPC40x.
1094 nomca [IA-64] Disable machine check abort handling
1096 nomce [IA-32] Machine Check Exception
1098 noresidual [PPC] Don't use residual data on PReP machines.
1100 noresume [SWSUSP] Disables resume and restores original swap
1101 space.
1103 no-scroll [VGA] Disables scrollback.
1104 This is required for the Braillex ib80-piezo Braille
1105 reader made by F.H. Papenmeier (Germany).
1107 nosbagart [IA-64]
1109 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1111 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1113 nosync [HW,M68K] Disables sync negotiation for all devices.
1115 notsc [BUGS=IA-32] Disable Time Stamp Counter
1117 nousb [USB] Disable the USB subsystem
1119 nowb [ARM]
1121 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1123 opl3= [HW,OSS]
1124 Format: <io>
1126 opl3sa= [HW,OSS]
1127 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1129 opl3sa2= [HW,OSS] Format:
1130 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1132 oprofile.timer= [HW]
1133 Use timer interrupt instead of performance counters
1135 optcd= [HW,CD]
1136 Format: <io>
1138 osst= [HW,SCSI] SCSI Tape Driver
1139 Format: <buffer_size>,<write_threshold>
1140 See also Documentation/scsi/st.txt.
1142 panic= [KNL] Kernel behaviour on panic
1143 Format: <timeout>
1145 parkbd.port= [HW] Parallel port number the keyboard adapter is
1146 connected to, default is 0.
1147 Format: <parport#>
1148 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1149 0 for XT, 1 for AT (default is AT).
1150 Format: <mode>
1152 parport= [HW,PPT] Specify parallel ports. 0 disables.
1153 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1154 Use 'auto' to force the driver to use any
1155 IRQ/DMA settings detected (the default is to
1156 ignore detected IRQ/DMA settings because of
1157 possible conflicts). You can specify the base
1158 address, IRQ, and DMA settings; IRQ and DMA
1159 should be numbers, or 'auto' (for using detected
1160 settings on that particular port), or 'nofifo'
1161 (to avoid using a FIFO even if it is detected).
1162 Parallel ports are assigned in the order they
1163 are specified on the command line, starting
1164 with parport0.
1166 parport_init_mode= [HW,PPT]
1167 Configure VIA parallel port to operate in
1168 a specific mode. This is necessary on Pegasos
1169 computer where firmware has no options for setting
1170 up parallel port mode and sets it to spp.
1171 Currently this function knows 686a and 8231 chips.
1172 Format: [spp|ps2|epp|ecp|ecpepp]
1174 pas2= [HW,OSS] Format:
1175 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1177 pas16= [HW,SCSI]
1178 See header of drivers/scsi/pas16.c.
1180 pause_on_oops=
1181 Halt all CPUs after the first oops has been printed for
1182 the specified number of seconds. This is to be used if
1183 your oopses keep scrolling off the screen.
1185 pcbit= [HW,ISDN]
1187 pcd. [PARIDE]
1188 See header of drivers/block/paride/pcd.c.
1189 See also Documentation/paride.txt.
1191 pci=option[,option...] [PCI] various PCI subsystem options:
1192 off [IA-32] don't probe for the PCI bus
1193 bios [IA-32] force use of PCI BIOS, don't access
1194 the hardware directly. Use this if your machine
1195 has a non-standard PCI host bridge.
1196 nobios [IA-32] disallow use of PCI BIOS, only direct
1197 hardware access methods are allowed. Use this
1198 if you experience crashes upon bootup and you
1199 suspect they are caused by the BIOS.
1200 conf1 [IA-32] Force use of PCI Configuration
1201 Mechanism 1.
1202 conf2 [IA-32] Force use of PCI Configuration
1203 Mechanism 2.
1204 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1205 Configuration
1206 nomsi [MSI] If the PCI_MSI kernel config parameter is
1207 enabled, this kernel boot option can be used to
1208 disable the use of MSI interrupts system-wide.
1209 nosort [IA-32] Don't sort PCI devices according to
1210 order given by the PCI BIOS. This sorting is
1211 done to get a device order compatible with
1212 older kernels.
1213 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1214 routing table. These calls are known to be buggy
1215 on several machines and they hang the machine
1216 when used, but on other computers it's the only
1217 way to get the interrupt routing table. Try
1218 this option if the kernel is unable to allocate
1219 IRQs or discover secondary PCI buses on your
1220 motherboard.
1221 rom [IA-32] Assign address space to expansion ROMs.
1222 Use with caution as certain devices share
1223 address decoders between ROMs and other
1224 resources.
1225 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1226 assigned automatically to PCI devices. You can
1227 make the kernel exclude IRQs of your ISA cards
1228 this way.
1229 pirqaddr=0xAAAAA [IA-32] Specify the physical address
1230 of the PIRQ table (normally generated
1231 by the BIOS) if it is outside the
1232 F0000h-100000h range.
1233 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1234 useful if the kernel is unable to find your
1235 secondary buses and you want to tell it
1236 explicitly which ones they are.
1237 assign-busses [IA-32] Always assign all PCI bus
1238 numbers ourselves, overriding
1239 whatever the firmware may have done.
1240 usepirqmask [IA-32] Honor the possible IRQ mask stored
1241 in the BIOS $PIR table. This is needed on
1242 some systems with broken BIOSes, notably
1243 some HP Pavilion N5400 and Omnibook XE3
1244 notebooks. This will have no effect if ACPI
1245 IRQ routing is enabled.
1246 noacpi [IA-32] Do not use ACPI for IRQ routing
1247 or for PCI scanning.
1248 routeirq Do IRQ routing for all PCI devices.
1249 This is normally done in pci_enable_device(),
1250 so this option is a temporary workaround
1251 for broken drivers that don't call it.
1252 firmware [ARM] Do not re-enumerate the bus but instead
1253 just use the configuration from the
1254 bootloader. This is currently used on
1255 IXP2000 systems where the bus has to be
1256 configured a certain way for adjunct CPUs.
1258 pcmv= [HW,PCMCIA] BadgePAD 4
1260 pd. [PARIDE]
1261 See Documentation/paride.txt.
1263 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1264 boot time.
1265 Format: { 0 | 1 }
1266 See arch/parisc/kernel/pdc_chassis.c
1268 pf. [PARIDE]
1269 See Documentation/paride.txt.
1271 pg. [PARIDE]
1272 See Documentation/paride.txt.
1274 pirq= [SMP,APIC] Manual mp-table setup
1275 See Documentation/i386/IO-APIC.txt.
1277 plip= [PPT,NET] Parallel port network link
1278 Format: { parport<nr> | timid | 0 }
1279 See also Documentation/parport.txt.
1281 pnpacpi= [ACPI]
1282 { off }
1284 pnpbios= [ISAPNP]
1285 { on | off | curr | res | no-curr | no-res }
1287 pnp_reserve_irq=
1288 [ISAPNP] Exclude IRQs for the autoconfiguration
1290 pnp_reserve_dma=
1291 [ISAPNP] Exclude DMAs for the autoconfiguration
1293 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1294 Ranges are in pairs (I/O port base and size).
1296 pnp_reserve_mem=
1297 [ISAPNP] Exclude memory regions for the
1298 autoconfiguration.
1299 Ranges are in pairs (memory base and size).
1301 profile= [KNL] Enable kernel profiling via /proc/profile
1302 Format: [schedule,]<number>
1303 Param: "schedule" - profile schedule points.
1304 Param: <number> - step/bucket size as a power of 2 for
1305 statistical time based profiling.
1307 processor.max_cstate= [HW,ACPI]
1308 Limit processor to maximum C-state
1309 max_cstate=9 overrides any DMI blacklist limit.
1311 processor.nocst [HW,ACPI]
1312 Ignore the _CST method to determine C-states,
1313 instead using the legacy FADT method
1315 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1316 before loading.
1317 See Documentation/ramdisk.txt.
1319 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1320 probe for; one of (bare|imps|exps|lifebook|any).
1321 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1322 per second.
1323 psmouse.resetafter= [HW,MOUSE]
1324 Try to reset the device after so many bad packets
1325 (0 = never).
1326 psmouse.resolution=
1327 [HW,MOUSE] Set desired mouse resolution, in dpi.
1328 psmouse.smartscroll=
1329 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1330 0 = disabled, 1 = enabled (default).
1332 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1333 Format:
1334 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1336 pt. [PARIDE]
1337 See Documentation/paride.txt.
1339 quiet= [KNL] Disable log messages
1341 r128= [HW,DRM]
1343 raid= [HW,RAID]
1344 See Documentation/md.txt.
1346 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1347 See Documentation/ramdisk.txt.
1349 ramdisk_blocksize= [RAM]
1350 See Documentation/ramdisk.txt.
1352 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1353 New name for the ramdisk parameter.
1354 See Documentation/ramdisk.txt.
1356 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1357 RCU callbacks to process in one batch.
1359 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1360 RCU callbacks over which batch limiting is disabled.
1362 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1363 RCU callbacks below which batch limiting is re-enabled.
1365 rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
1366 RCU callbacks to queued before forcing reschedule
1367 on all cpus.
1369 rdinit= [KNL]
1370 Format: <full_path>
1371 Run specified binary instead of /init from the ramdisk,
1372 used for early userspace startup. See initrd.
1374 reassign_resources
1375 [PCI,ACPI] Use guestdev parameter to reassign device's
1376 resources.
1378 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1379 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1380 See arch/*/kernel/reboot.c.
1382 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1384 resume= [SWSUSP]
1385 Specify the partition device for software suspend
1387 rhash_entries= [KNL,NET]
1388 Set number of hash buckets for route cache
1390 riscom8= [HW,SERIAL]
1391 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1393 ro [KNL] Mount root device read-only on boot
1395 root= [KNL] Root filesystem
1397 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1398 mount the root filesystem
1400 rootflags= [KNL] Set root filesystem mount option string
1402 rootfstype= [KNL] Set root filesystem type
1404 rw [KNL] Mount root device read-write on boot
1406 S [KNL] Run init in single mode
1408 sa1100ir [NET]
1409 See drivers/net/irda/sa1100_ir.c.
1411 sb= [HW,OSS]
1412 Format: <io>,<irq>,<dma>,<dma2>
1414 sbni= [NET] Granch SBNI12 leased line adapter
1416 sbpcd= [HW,CD] Soundblaster CD adapter
1417 Format: <io>,<type>
1418 See a comment before function sbpcd_setup() in
1419 drivers/cdrom/sbpcd.c.
1421 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1422 Format: <io>[,<timeout>[,<isapnp>]]
1424 scsi_debug_*= [SCSI]
1425 See drivers/scsi/scsi_debug.c.
1427 scsi_default_dev_flags=
1428 [SCSI] SCSI default device flags
1429 Format: <integer>
1431 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1432 Format: <vendor>:<model>:<flags>
1433 (flags are integer value)
1435 scsi_logging= [SCSI]
1437 selinux [SELINUX] Disable or enable SELinux at boot time.
1438 Format: { "0" | "1" }
1439 See security/selinux/Kconfig help text.
1440 0 -- disable.
1441 1 -- enable.
1442 Default value is set via kernel config option.
1443 If enabled at boot time, /selinux/disable can be used
1444 later to disable prior to initial policy load.
1446 selinux_compat_net =
1447 [SELINUX] Set initial selinux_compat_net flag value.
1448 Format: { "0" | "1" }
1449 0 -- use new secmark-based packet controls
1450 1 -- use legacy packet controls
1451 Default value is 0 (preferred).
1452 Value can be changed at runtime via
1453 /selinux/compat_net.
1455 serialnumber [BUGS=IA-32]
1457 sg_def_reserved_size= [SCSI]
1459 sgalaxy= [HW,OSS]
1460 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1462 shapers= [NET]
1463 Maximal number of shapers.
1465 sim710= [SCSI,HW]
1466 See header of drivers/scsi/sim710.c.
1468 simeth= [IA-64]
1469 simscsi=
1471 sjcd= [HW,CD]
1472 Format: <io>,<irq>,<dma>
1473 See header of drivers/cdrom/sjcd.c.
1475 slram= [HW,MTD]
1477 smart2= [HW]
1478 Format: <io1>[,<io2>[,...,<io8>]]
1480 snd-ad1816a= [HW,ALSA]
1482 snd-ad1848= [HW,ALSA]
1484 snd-ali5451= [HW,ALSA]
1486 snd-als100= [HW,ALSA]
1488 snd-als4000= [HW,ALSA]
1490 snd-azt2320= [HW,ALSA]
1492 snd-cmi8330= [HW,ALSA]
1494 snd-cmipci= [HW,ALSA]
1496 snd-cs4231= [HW,ALSA]
1498 snd-cs4232= [HW,ALSA]
1500 snd-cs4236= [HW,ALSA]
1502 snd-cs4281= [HW,ALSA]
1504 snd-cs46xx= [HW,ALSA]
1506 snd-dt019x= [HW,ALSA]
1508 snd-dummy= [HW,ALSA]
1510 snd-emu10k1= [HW,ALSA]
1512 snd-ens1370= [HW,ALSA]
1514 snd-ens1371= [HW,ALSA]
1516 snd-es968= [HW,ALSA]
1518 snd-es1688= [HW,ALSA]
1520 snd-es18xx= [HW,ALSA]
1522 snd-es1938= [HW,ALSA]
1524 snd-es1968= [HW,ALSA]
1526 snd-fm801= [HW,ALSA]
1528 snd-gusclassic= [HW,ALSA]
1530 snd-gusextreme= [HW,ALSA]
1532 snd-gusmax= [HW,ALSA]
1534 snd-hdsp= [HW,ALSA]
1536 snd-ice1712= [HW,ALSA]
1538 snd-intel8x0= [HW,ALSA]
1540 snd-interwave= [HW,ALSA]
1542 snd-interwave-stb=
1543 [HW,ALSA]
1545 snd-korg1212= [HW,ALSA]
1547 snd-maestro3= [HW,ALSA]
1549 snd-mpu401= [HW,ALSA]
1551 snd-mtpav= [HW,ALSA]
1553 snd-nm256= [HW,ALSA]
1555 snd-opl3sa2= [HW,ALSA]
1557 snd-opti92x-ad1848=
1558 [HW,ALSA]
1560 snd-opti92x-cs4231=
1561 [HW,ALSA]
1563 snd-opti93x= [HW,ALSA]
1565 snd-pmac= [HW,ALSA]
1567 snd-rme32= [HW,ALSA]
1569 snd-rme96= [HW,ALSA]
1571 snd-rme9652= [HW,ALSA]
1573 snd-sb8= [HW,ALSA]
1575 snd-sb16= [HW,ALSA]
1577 snd-sbawe= [HW,ALSA]
1579 snd-serial= [HW,ALSA]
1581 snd-sgalaxy= [HW,ALSA]
1583 snd-sonicvibes= [HW,ALSA]
1585 snd-sun-amd7930=
1586 [HW,ALSA]
1588 snd-sun-cs4231= [HW,ALSA]
1590 snd-trident= [HW,ALSA]
1592 snd-usb-audio= [HW,ALSA,USB]
1594 snd-via82xx= [HW,ALSA]
1596 snd-virmidi= [HW,ALSA]
1598 snd-wavefront= [HW,ALSA]
1600 snd-ymfpci= [HW,ALSA]
1602 sonicvibes= [HW,OSS]
1603 Format: <reverb>
1605 sonycd535= [HW,CD]
1606 Format: <io>[,<irq>]
1608 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1609 See Documentation/sonypi.txt
1611 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1612 See Documentation/specialix.txt.
1614 spia_io_base= [HW,MTD]
1615 spia_fio_base=
1616 spia_pedr=
1617 spia_peddr=
1619 sscape= [HW,OSS]
1620 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1622 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1623 See Documentation/scsi/st.txt.
1625 st0x= [HW,SCSI]
1626 See header of drivers/scsi/seagate.c.
1628 sti= [PARISC,HW]
1629 Format: <num>
1630 Set the STI (builtin display/keyboard on the HP-PARISC
1631 machines) console (graphic card) which should be used
1632 as the initial boot-console.
1633 See also comment in drivers/video/console/sticore.c.
1635 sti_font= [HW]
1636 See comment in drivers/video/console/sticore.c.
1638 stifb= [HW]
1639 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1641 swiotlb= [IA-64] Number of I/O TLB slabs
1643 switches= [HW,M68k]
1645 sym53c416= [HW,SCSI]
1646 See header of drivers/scsi/sym53c416.c.
1648 t128= [HW,SCSI]
1649 See header of drivers/scsi/t128.c.
1651 tdfx= [HW,DRM]
1653 thash_entries= [KNL,NET]
1654 Set number of hash buckets for TCP connection
1656 time Show timing data prefixed to each printk message line
1658 clocksource= [GENERIC_TIME] Override the default clocksource
1659 Override the default clocksource and use the clocksource
1660 with the name specified.
1662 tipar.timeout= [HW,PPT]
1663 Set communications timeout in tenths of a second
1664 (default 15).
1666 tipar.delay= [HW,PPT]
1667 Set inter-bit delay in microseconds (default 10).
1669 tmc8xx= [HW,SCSI]
1670 See header of drivers/scsi/seagate.c.
1672 tmscsim= [HW,SCSI]
1673 See comment before function dc390_setup() in
1674 drivers/scsi/tmscsim.c.
1676 tp720= [HW,PS2]
1678 trix= [HW,OSS] MediaTrix AudioTrix Pro
1679 Format:
1680 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1682 tsdev.xres= [TS] Horizontal screen resolution.
1683 tsdev.yres= [TS] Vertical screen resolution.
1685 turbografx.map[2|3]= [HW,JOY]
1686 TurboGraFX parallel port interface
1687 Format:
1688 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1689 See also Documentation/input/joystick-parport.txt
1691 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1692 See header of drivers/scsi/u14-34f.c.
1694 uart401= [HW,OSS]
1695 Format: <io>,<irq>
1697 uart6850= [HW,OSS]
1698 Format: <io>,<irq>
1700 usbhid.mousepoll=
1701 [USBHID] The interval which mice are to be polled at.
1703 vdso= [IA-32]
1704 vdso=1: enable VDSO (default)
1705 vdso=0: disable VDSO mapping
1707 video= [FB] Frame buffer configuration
1708 See Documentation/fb/modedb.txt.
1710 vga= [BOOT,IA-32] Select a particular video mode
1711 See Documentation/i386/boot.txt and
1712 Documentation/svga.txt.
1713 Use vga=ask for menu.
1714 This is actually a boot loader parameter; the value is
1715 passed to the kernel using a special protocol.
1717 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1718 size of <nn>. This can be used to increase the
1719 minimum size (128MB on x86). It can also be used to
1720 decrease the size and leave more room for directly
1721 mapped kernel RAM.
1723 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1724 Format: <command>
1726 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1727 Format: <command>
1729 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1730 Format: <command>
1732 waveartist= [HW,OSS]
1733 Format: <io>,<irq>,<dma>,<dma2>
1735 wd33c93= [HW,SCSI]
1736 See header of drivers/scsi/wd33c93.c.
1738 wd7000= [HW,SCSI]
1739 See header of drivers/scsi/wd7000.c.
1741 wdt= [WDT] Watchdog
1742 See Documentation/watchdog/watchdog.txt.
1744 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1745 xd_geo= See header of drivers/block/xd.c.
1747 xirc2ps_cs= [NET,PCMCIA]
1748 Format:
1749 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1751 norandmaps Don't use address space randomization
1752 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1755 ______________________________________________________________________
1757 TODO:
1759 Add documentation for ALSA options.
1760 Add more DRM drivers.