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 LIBATA Libata driver is enabled
52 LP Printer support is enabled.
53 LOOP Loopback device support is enabled.
54 M68k M68k architecture is enabled.
55 These options have more detailed description inside of
56 Documentation/m68k/kernel-options.txt.
57 MCA MCA bus support is enabled.
58 MDA MDA console support is enabled.
59 MOUSE Appropriate mouse support is enabled.
60 MSI Message Signaled Interrupts (PCI).
61 MTD MTD support is enabled.
62 NET Appropriate network support is enabled.
63 NUMA NUMA support is enabled.
64 GENERIC_TIME The generic timeofday code is enabled.
65 NFS Appropriate NFS support is enabled.
66 OSS OSS sound support is enabled.
67 PARIDE The ParIDE subsystem is enabled.
68 PARISC The PA-RISC architecture is enabled.
69 PCI PCI bus support is enabled.
70 PCMCIA The PCMCIA subsystem is enabled.
71 PNP Plug & Play support is enabled.
72 PPC PowerPC architecture is enabled.
73 PPT Parallel port support is enabled.
74 PS2 Appropriate PS/2 support is enabled.
75 RAM RAM disk support is enabled.
76 S390 S390 architecture is enabled.
77 SCSI Appropriate SCSI support is enabled.
78 A lot of drivers has their options described inside of
80 SELINUX SELinux support is enabled.
81 SERIAL Serial support is enabled.
82 SH SuperH architecture is enabled.
83 SMP The kernel is an SMP kernel.
84 SPARC Sparc architecture is enabled.
85 SWSUSP Software suspend is enabled.
86 TS Appropriate touchscreen support is enabled.
87 USB USB support is enabled.
88 USBHID USB Human Interface Device support is enabled.
89 V4L Video For Linux support is enabled.
90 VGA The VGA console has been enabled.
91 VT Virtual terminal support is enabled.
92 WDT Watchdog support is enabled.
93 XT IBM PC/XT MFM hard disk support is enabled.
94 X86-64 X86-64 architecture is enabled.
95 More X86-64 boot options can be found in
96 Documentation/x86_64/boot-options.txt .
98 In addition, the following text indicates that the option:
100 BUGS= Relates to possible processor bugs on the said processor.
101 KNL Is a kernel start-up parameter.
102 BOOT Is a boot loader parameter.
104 Parameters denoted with BOOT are actually interpreted by the boot
105 loader, and have no meaning to the kernel directly.
106 Do not modify the syntax of boot loader parameters without extreme
107 need or coordination with <Documentation/i386/boot.txt>.
109 There are also arch-specific kernel-parameters not documented here.
110 See for example <Documentation/x86_64/boot-options.txt>.
112 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
113 a trailing = on the name of any parameter states that that parameter will
114 be entered as an environment variable, whereas its absence indicates that
115 it will appear as a kernel argument readable via /proc/cmdline by programs
116 running once the system is up.
118 The number of kernel parameters is not limited, but the length of the
119 complete command line (parameters including spaces etc.) is limited to
120 a fixed number of characters. This limit depends on the architecture
121 and is between 256 and 4096 characters. It is defined in the file
122 ./include/asm/setup.h as COMMAND_LINE_SIZE.
125 53c7xx= [HW,SCSI] Amiga SCSI controllers
126 See header of drivers/scsi/53c7xx.c.
127 See also Documentation/scsi/ncr53c7xx.txt.
129 acpi= [HW,ACPI,X86-64,i386]
130 Advanced Configuration and Power Interface
131 Format: { force | off | ht | strict | noirq }
132 force -- enable ACPI if default was off
133 off -- disable ACPI if default was on
134 noirq -- do not use ACPI for IRQ routing
135 ht -- run only enough ACPI to enable Hyper Threading
136 strict -- Be less tolerant of platforms that are not
137 strictly ACPI specification compliant.
139 See also Documentation/pm.txt, pci=noacpi
141 acpi_apic_instance= [ACPI, IOAPIC]
143 2: use 2nd APIC table, if available
144 1,0: use 1st APIC table
147 acpi_sleep= [HW,ACPI] Sleep options
148 Format: { s3_bios, s3_mode }
149 See Documentation/power/video.txt
151 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
152 Format: { level | edge | high | low }
154 acpi_irq_balance [HW,ACPI]
155 ACPI will balance active IRQs
158 acpi_irq_nobalance [HW,ACPI]
159 ACPI will not move active IRQs (default)
162 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
164 Format: <irq>,<irq>...
166 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
167 Format: <irq>,<irq>...
169 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
170 Format: To spoof as Windows 98: ="Microsoft Windows"
172 acpi_osi= [HW,ACPI] empty param disables _OSI
174 acpi_serialize [HW,ACPI] force serialization of AML methods
176 acpi_skip_timer_override [HW,ACPI]
177 Recognize and ignore IRQ0/pin2 Interrupt Override.
178 For broken nForce2 BIOS resulting in XT-PIC timer.
179 acpi_use_timer_override [HW,ACPI}
180 Use timer override. For some broken Nvidia NF5 boards
181 that require a timer override, but don't have
184 acpi_dbg_layer= [HW,ACPI]
186 Each bit of the <int> indicates an ACPI debug layer,
187 1: enable, 0: disable. It is useful for boot time
188 debugging. After system has booted up, it can be set
189 via /proc/acpi/debug_layer.
191 acpi_dbg_level= [HW,ACPI]
193 Each bit of the <int> indicates an ACPI debug level,
194 1: enable, 0: disable. It is useful for boot time
195 debugging. After system has booted up, it can be set
196 via /proc/acpi/debug_level.
198 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
200 acpi_generic_hotkey [HW,ACPI]
201 Allow consolidated generic hotkey driver to
202 override platform specific driver.
203 See also Documentation/acpi-hotkey.txt.
205 acpi_pm_good [IA-32,X86-64]
206 Override the pmtimer bug detection: force the kernel
207 to assume that this machine's pmtimer latches its value
208 and always returns good values.
210 enable_timer_pin_1 [i386,x86-64]
211 Enable PIN 1 of APIC timer
212 Can be useful to work around chipset bugs
213 (in particular on some ATI chipsets).
214 The kernel tries to set a reasonable default.
216 disable_timer_pin_1 [i386,x86-64]
217 Disable PIN 1 of APIC timer
218 Can be useful to work around chipset bugs.
221 Format: <io>,<irq>,<dma>,<dma2>
222 See also Documentation/sound/oss/AD1816.
225 Format: <io>,<irq>,<dma>,<dma2>,<type>
231 See header of drivers/scsi/advansys.c.
233 advwdt= [HW,WDT] Advantech WDT
234 Format: <iostart>,<iostop>
236 aedsp16= [HW,OSS] Audio Excel DSP 16
237 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
238 See also header of sound/oss/aedsp16.c.
241 See Documentation/scsi/aha152x.txt.
244 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
247 See Documentation/scsi/aic7xxx.txt.
250 See Documentation/scsi/aic79xx.txt.
252 amijoy.map= [HW,JOY] Amiga joystick support
253 Map of devices attached to JOY0DAT and JOY1DAT
255 See also Documentation/kernel/input/joystick.txt
257 analog.map= [HW,JOY] Analog joystick and gamepad support
258 Specifies type or capabilities of an analog joystick
259 connected to one of 16 gameports
260 Format: <type1>,<type2>,..<type16>
263 Power management functions (SPARCstation-4/5 + deriv.)
265 Disable APC CPU standby support. SPARCstation-Fox does
266 not play well with APC CPU idle - disable it if you have
267 APC and your system crashes randomly.
269 apic= [APIC,i386] Change the output verbosity whilst booting
270 Format: { quiet (default) | verbose | debug }
271 Change the amount of debugging information output
272 when initialising the APIC and IO-APIC components.
274 apm= [APM] Advanced Power Management
275 See header of arch/i386/kernel/apm.c.
280 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
281 Format: <io>,<irq>,<nodeID>
285 atarimouse= [HW,MOUSE] Atari Mouse
287 atascsi= [HW,SCSI] Atari SCSI
289 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
290 EzKey and similar keyboards
292 atkbd.reset= [HW] Reset keyboard during initialization
294 atkbd.set= [HW] Select keyboard code set
295 Format: <int> (2 = AT (default), 3 = PS/2)
297 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
300 atkbd.softraw= [HW] Choose between synthetic and real raw mode
301 Format: <bool> (0 = real, 1 = synthetic (default))
303 atkbd.softrepeat= [HW]
304 Use software keyboard repeat
308 aztcd= [HW,CD] Aztech CD268 CDROM driver
309 Format: <io>,0x79 (?)
311 baycom_epp= [HW,AX25]
314 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
316 See header of drivers/net/hamradio/baycom_par.c.
318 baycom_ser_fdx= [HW,AX25]
319 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
320 Format: <io>,<irq>,<mode>[,<baud>]
321 See header of drivers/net/hamradio/baycom_ser_fdx.c.
323 baycom_ser_hdx= [HW,AX25]
324 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
325 Format: <io>,<irq>,<mode>
326 See header of drivers/net/hamradio/baycom_ser_hdx.c.
328 blkmtd_device= [HW,MTD]
334 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
335 bttv.radio= Most important insmod options are available as
337 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
338 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
341 See drivers/scsi/BusLogic.c, comment before function
342 BusLogic_ParseDriverOptions().
344 c101= [NET] Moxa C101 synchronous serial card
346 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
347 Sometimes CPU hardware bugs make them report the cache
348 size incorrectly. The kernel will attempt work arounds
349 to fix known problems, but for some CPUs it is not
350 possible to determine what the correct size should be.
351 This option provides an override for these situations.
354 Format: <io>,<irq>[,PAS]
355 See header of drivers/cdrom/cdu31a.c.
357 chandev= [HW,NET] Generic channel device initialisation
359 checkreqprot [SELINUX] Set initial checkreqprot flag value.
360 Format: { "0" | "1" }
361 See security/selinux/Kconfig help text.
362 0 -- check protection applied by kernel (includes
363 any implied execute protection).
364 1 -- check protection requested by application.
365 Default value is set via a kernel config option.
366 Value can be changed at runtime via
367 /selinux/checkreqprot.
369 clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
371 Forces specified clocksource (if available) to be used
372 when calculating gettimeofday(). If specified
373 clocksource is not available, it defaults to PIT.
374 Format: { pit | tsc | cyclone | pmtmr }
376 code_bytes [IA32] How many bytes of object code to print in an
383 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
384 over the 8254 in addition to over the IO-APIC. The
385 kernel tries to set a sensible default.
387 hpet= [IA-32,HPET] option to disable HPET and use PIT.
391 Format: { auto | [<io>,][<irq>] }
393 com20020= [HW,NET] ARCnet - COM20020 chipset
395 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
397 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
401 ARCnet - COM90xx chipset (memory-mapped buffers)
402 Format: <io>[,<irq>[,<memstart>]]
404 condev= [HW,S390] console device
407 console= [KNL] Output console device and options.
409 tty<n> Use the virtual console device <n>.
413 Use the specified serial port. The options are of
414 the form "bbbbpnf", where "bbbb" is the baud rate,
415 "p" is parity ("n", "o", or "e"), "n" is number of
416 bits, and "f" is flow control ("r" for RTS or
417 omit it). Default is "9600n8".
419 See Documentation/serial-console.txt for more
421 Documentation/networking/netconsole.txt for an
424 uart,io,<addr>[,options]
425 uart,mmio,<addr>[,options]
426 Start an early, polled-mode console on the 8250/16550
427 UART at the specified I/O port or MMIO address,
428 switching to the matching ttyS device later. The
429 options are the same as for ttyS, above.
431 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
433 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
436 Format: { parport<nr> | auto | none }
438 crashkernel=nn[KMG]@ss[KMG]
439 [KNL] Reserve a chunk of physical memory to
440 hold a kernel to switch to with kexec on panic.
443 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
448 cs89x0_media= [HW,NET]
449 Format: { rj45 | aui | bnc }
451 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
454 See header of drivers/s390/block/dasd_devmap.c.
456 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
457 (one device per port)
458 Format: <port#>,<type>
459 See also Documentation/input/joystick-parport.txt
461 debug [KNL] Enable kernel debugging (events log level).
464 [KNL] verbose self-tests
466 Print debugging info while doing the locking API
468 We default to 0 (no extra messages), setting it to
469 1 will print _a lot_ more information - normally
470 only useful to kernel developers.
473 Format: <area>[,<node>]
474 See also Documentation/networking/decnet.txt.
477 Set number of hash buckets for dentry cache.
480 IO parameters + enable/disable command.
482 digiepca= [HW,SERIAL]
483 See drivers/char/README.epca and
484 Documentation/digiepca.txt.
486 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
488 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
490 dmasound= [HW,OSS] Sound subsystem buffers
496 earlyprintk= [IA-32,X86-64,SH]
498 earlyprintk=serial[,ttySn[,baudrate]]
500 Append ",keep" to not disable it when the real console
503 Only vga or serial at a time, not both.
505 Currently only ttyS0 and ttyS1 are supported.
507 Interaction with the standard serial driver is not
510 The VGA output is eventually overwritten by the real
515 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
518 non-0: interrupt mode (default)
525 Format: {"of[f]" | "sk[ipmbr]"}
526 See comment in arch/i386/boot/edd.S
529 Format: <id>,<membase>,<irq>
531 eisa_irq_edge= [PARISC,HW]
532 See header of drivers/parisc/eisa.c.
535 See comment before function elanfreq_setup() in
536 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
539 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
540 See Documentation/block/as-iosched.txt and
541 Documentation/block/deadline-iosched.txt for details.
543 elfcorehdr= [IA-32, X86_64]
544 Specifies physical address of start of kernel core
545 image elf header. Generally kexec loader will
546 pass this option to capture kernel.
547 See Documentation/kdump/kdump.txt for details.
549 enforcing [SELINUX] Set initial enforcing status.
551 See security/selinux/Kconfig help text.
552 0 -- permissive (log only, no denials).
553 1 -- enforcing (deny and log).
555 Value can be changed at runtime via /selinux/enforce.
558 Format: <spdif>,[<nomix>,[<amplifier>]]
559 See also header of sound/oss/es1371.c.
561 ether= [HW,NET] Ethernet cards parameters
562 This option is obsoleted by the "netdev=" option, which
563 has equivalent usage. See its documentation for details.
565 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
570 fail_make_request=[KNL]
571 General fault injection mechanism.
572 Format: <interval>,<probability>,<space>,<times>
573 See also /Documentation/fault-injection/.
576 See header of drivers/scsi/fd_mcs.c.
579 See header of drivers/scsi/fdomain.c.
582 See Documentation/floppy.txt.
585 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
586 support via parallel port (up to 5 devices per port)
587 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
588 See also Documentation/input/joystick-parport.txt
593 See header of drivers/scsi/gdth.c.
595 gpt [EFI] Forces disk with valid GPT signature but
596 invalid Protective MBR to be treated as GPT.
603 hashdist= [KNL,NUMA] Large hashes allocated during boot
604 are distributed across NUMA nodes. Defaults on
605 for IA-64, off otherwise.
606 Format: 0 | 1 (for off | on)
608 hcl= [IA-64] SGI's Hardware Graph compatibility layer
610 hd= [EIDE] (E)IDE hard drive subsystem geometry
611 Format: <cyl>,<head>,<sect>
613 hd?= [HW] (E)IDE subsystem
614 hd?lun= See Documentation/ide.txt.
616 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
617 size of <nn>. This works even on boxes that have no
618 highmem otherwise. This also works to reduce highmem
619 size on bigger boxes.
621 highres= [KNL] Enable/disable high resolution timer mode.
622 Valid parameters: "on", "off"
626 See Documentation/isdn/README.HiSax.
628 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
630 i8042.direct [HW] Put keyboard port into non-translated mode
631 i8042.dumbkbd [HW] Pretend that controller can only read data from
632 keyboard and cannot control its state
633 (Don't attempt to blink the leds)
634 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
635 i8042.nokbd [HW] Don't check/create keyboard port
636 i8042.nomux [HW] Don't check presence of an active multiplexing
638 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
641 [HW] Frequency with which keyboard LEDs should blink
642 when kernel panics (default is 0.5 sec)
643 i8042.reset [HW] Reset the controller during init and cleanup
644 i8042.unlock [HW] Unlock (ignore) the keylock
648 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
649 indicates that the driver is running on unsupported
651 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
652 does not match list of supported models.
654 [HW] Report power status in /proc/i8k
655 (disabled by default)
656 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
659 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
660 See Documentation/mca.txt.
663 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
665 ide= [HW] (E)IDE subsystem
666 Format: ide=nodma or ide=doubler or ide=reverse
667 See Documentation/ide.txt.
669 ide?= [HW] (E)IDE subsystem
670 Format: ide?=noprobe or chipset specific parameters.
671 See Documentation/ide.txt.
673 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
674 See Documentation/ide.txt.
677 Format: idle=poll or idle=halt
679 ignore_loglevel [KNL]
680 Ignore loglevel setting - this will print /all/
681 kernel messages to the console. Useful for debugging.
684 Set number of hash buckets for inode cache.
687 See header of drivers/scsi/in2000.c.
691 Run specified binary instead of /sbin/init as init
694 initcall_debug [KNL] Trace initcalls as they are executed. Useful
695 for working out where the kernel is dying during
698 initrd= [BOOT] Specify the location of the initial ramdisk
700 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
703 combined_mode= [HW] control which driver uses IDE ports in combined
704 mode: legacy IDE driver, libata, or both
705 (in the libata case, libata.atapi_enabled=1 may be
706 useful as well). Note that using the ide or libata
707 options may affect your device naming (e.g. by
708 changing hdc to sdb).
709 Format: combined (default), ide, or libata
713 io7= [HW] IO7 for Marvel based alpha systems
714 See comment before marvel_specify_io7 in
715 arch/alpha/kernel/core_marvel.c.
718 See Documentation/nfsroot.txt.
720 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
721 See comment before ip2_setup() in drivers/char/ip2.c.
723 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
724 See header of drivers/scsi/ips.c.
726 ports= [IP_VS_FTP] IPVS ftp helper module
728 Up to 8 (IP_VS_APP_MAX_PORTS) ports
730 Format: <port>,<port>....
733 When an interrupt is not handled search all handlers
734 for it. Intended to get systems with badly broken
738 When an interrupt is not handled search all handlers
739 for it. Also check all handlers each timer
740 interrupt. Intended to get systems with badly broken
744 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
746 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
748 <cpu number>,...,<cpu number>
750 <cpu number>-<cpu number> (must be a positive range in ascending order)
752 <cpu number>,...,<cpu number>-<cpu number>
753 This option can be used to specify one or more CPUs
754 to isolate from the general SMP balancing and scheduling
755 algorithms. The only way to move a process onto or off
756 an "isolated" CPU is via the CPU affinity syscalls.
757 <cpu number> begins at 0 and the maximum value is
758 "number of CPUs in system - 1".
760 This option is the preferred way to isolate CPUs. The
761 alternative -- manually setting the CPU mask of all
762 tasks in the system -- can cause problems and
763 suboptimal load balancer performance.
766 Format: <io>,<irq>,<dma>,<setup>
770 js= [HW,JOY] Analog joystick
771 See Documentation/input/joystick.txt.
775 kstack=N [IA-32,X86-64] Print N words from the kernel stack
780 lapic [IA-32,APIC] Enable the local APIC even if BIOS
783 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
784 Format: addr:<io>,irq:<irq>
786 llsc*= [IA64] See function print_params() in
787 arch/ia64/sn/kernel/llsc4.c.
789 load_ramdisk= [RAM] List of ramdisks to load from floppy
790 See Documentation/ramdisk.txt.
792 lockd.nlm_grace_period=P [NFS] Assign grace period.
795 lockd.nlm_tcpport=N [NFS] Assign TCP port.
798 lockd.nlm_timeout=T [NFS] Assign timeout value.
801 lockd.nlm_udpport=M [NFS] Assign UDP port.
804 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
807 loglevel= All Kernel Messages with a loglevel smaller than the
808 console loglevel will be printed to the console. It can
809 also be changed with klogd or other programs. The
810 loglevels are defined as follows:
812 0 (KERN_EMERG) system is unusable
813 1 (KERN_ALERT) action must be taken immediately
814 2 (KERN_CRIT) critical conditions
815 3 (KERN_ERR) error conditions
816 4 (KERN_WARNING) warning conditions
817 5 (KERN_NOTICE) normal but significant condition
818 6 (KERN_INFO) informational
819 7 (KERN_DEBUG) debug-level messages
821 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
822 Format: { n | nk | nM }
823 n must be a power of two. The default size
824 is set in the kernel config file.
826 lp=0 [LP] Specify parallel ports to use, e.g,
827 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
828 lp=reset first parallel port). 'lp=0' disables the
829 lp=auto printer driver. 'lp=reset' (which can be
830 specified in addition to the ports) causes
831 attached printers to be reset. Using
832 lp=port1,port2,... specifies the parallel ports
833 to associate lp devices with, starting with
834 lp0. A port specification may be 'none' to skip
835 that lp device, or a parport name such as
836 'parport0'. Specifying 'lp=auto' instead of a
837 port specification list means that device IDs
838 from each port should be examined, to see if
839 an IEEE 1284-compliant printer is attached; if
840 so, the driver will manage that printer.
841 See also header of drivers/char/lp.c.
844 Sets loops_per_jiffy to given constant, thus avoiding
845 time-consuming boot-time autodetection (up to 250 ms per
846 CPU). 0 enables autodetection (default). To determine
847 the correct value for your kernel, boot with normal
848 autodetection and see what value is printed. Note that
849 on SMP systems the preset will be applied to all CPUs,
850 which is likely to cause problems if your CPUs need
851 significantly divergent settings. An incorrect value
852 will cause delays in the kernel to be wrong, leading to
853 unpredictable I/O errors and other breakage. Although
854 unlikely, in the extreme case this might damage your
858 Format: <io>,<irq>,<dma>
860 mac5380= [HW,SCSI] Format:
861 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
863 mac53c9x= [HW,SCSI] Format:
864 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
866 machvec= [IA64] Force the use of a particular machine-vector
867 (machvec) in a generic kernel.
868 Example: machvec=hpzx1_swiotlb
870 max_loop= [LOOP] Maximum number of loopback devices that can
874 maxcpus= [SMP] Maximum number of processors that an SMP kernel
876 Using "nosmp" or "maxcpus=0" will disable SMP
877 entirely (the MPS table probe still happens, though).
878 A command-line option of "maxcpus=<NUM>", where <NUM>
879 is an integer greater than 0, limits the maximum number
880 of CPUs activated in SMP mode to <NUM>.
881 Using "maxcpus=1" on an SMP kernel is the trivial
882 case of an SMP kernel with only one CPU.
884 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
885 equal to this physical address is ignored.
887 max_luns= [SCSI] Maximum number of LUNs to probe.
888 Should be between 1 and 2^32-1.
891 [SCSI] Maximum number of LUNs received.
892 Should be between 1 and 16384.
894 mca-pentium [BUGS=IA-32]
899 Format: <port>,<irq>,<mitsumi_bug_93_wait>
903 mce [IA-32] Machine Check Exception
905 md= [HW] RAID subsystems devices and level
906 See Documentation/md.txt.
909 Format: <first>,<last>
910 Specifies range of consoles to be captured by the MDA.
912 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
913 Amount of memory to be used when the kernel is not able
914 to see the whole system memory or for test.
915 [IA-32] Use together with memmap= to avoid physical
916 address space collisions. Without memmap= PCI devices
917 could be placed at addresses belonging to unused RAM.
919 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
922 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
923 E820 memory map, as specified by the user.
924 Such memmap=exactmap lines can be constructed based on
925 BIOS output or other requirements. See the memmap=nn@ss
928 memmap=nn[KMG]@ss[KMG]
929 [KNL] Force usage of a specific region of memory
930 Region of memory to be used, from ss to ss+nn.
932 memmap=nn[KMG]#ss[KMG]
933 [KNL,ACPI] Mark specific memory as ACPI data.
934 Region of memory to be used, from ss to ss+nn.
936 memmap=nn[KMG]$ss[KMG]
937 [KNL,ACPI] Mark specific memory as reserved.
938 Region of memory to be used, from ss to ss+nn.
940 meye.*= [HW] Set MotionEye Camera parameters
941 See Documentation/video4linux/meye.txt.
946 [KNL,SMP] debug: override scheduler migration costs
947 Format: <level-1-usecs>,<level-2-usecs>,...
948 This debugging option can be used to override the
949 default scheduler migration cost matrix. The numbers
950 are indexed by 'CPU domain distance'.
951 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
952 box will set up an intra-core migration cost of
953 1 msec, an inter-core migration cost of 2 msecs,
954 and an inter-node migration cost of 3 msecs.
956 WARNING: using the wrong values here can break
957 scheduler performance, so it's only for scheduler
958 development purposes, not production environments.
961 [KNL,SMP] migration cost auto-detect verbosity
963 If a system's migration matrix reported at bootup
964 seems erroneous then this option can be used to
965 increase verbosity of the detection process.
966 We default to 0 (no extra messages), 1 will print
967 some more information, and 2 will be really
968 verbose (probably only useful if you also have a
969 serial console attached to the system).
972 [KNL,SMP] multiply/divide migration costs by a factor
974 This debug option can be used to proportionally
975 increase or decrease the auto-detected migration
976 costs for all entries of the migration matrix.
977 E.g. migration_factor=150 will increase migration
978 costs by 50%. (and thus the scheduler will be less
979 eager migrating cache-hot tasks)
980 migration_factor=80 will decrease migration costs
981 by 20%. (thus the scheduler will be more eager to
984 WARNING: using the wrong values here can break
985 scheduler performance, so it's only for scheduler
986 development purposes, not production environments.
989 [MOUSE] Maximum time between finger touching and
990 leaving touchpad surface for touch to be considered
991 a tap and be reported as a left button click (for
992 touchpads working in absolute mode only).
994 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
995 reporting absolute coordinates, such as tablets
996 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
997 reporting absolute coordinates, such as tablets
1002 MTD_Partition= [MTD]
1003 Format: <name>,<region-number>,<size>,<offset>
1005 MTD_Region= [MTD] Format:
1006 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
1009 See drivers/mtd/cmdline.c.
1011 mtouchusb.raw_coordinates=
1012 [HW] Make the MicroTouch USB driver use raw coordinates
1013 ('y', default) or cooked coordinates ('n')
1015 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
1018 See header of drivers/scsi/NCR_D700.c.
1022 ncr53c400= [HW,SCSI]
1024 ncr53c400a= [HW,SCSI]
1026 ncr53c406a= [HW,SCSI]
1028 ncr53c8xx= [HW,SCSI]
1030 netdev= [NET] Network devices parameters
1031 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
1032 Note that mem_start is often overloaded to mean
1033 something different and driver-specific.
1034 This usage is only documented in each driver source
1038 See Documentation/nfsroot.txt.
1040 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
1041 See Documentation/nfsroot.txt.
1043 nfs.callback_tcpport=
1044 [NFS] set the TCP port on which the NFSv4 callback
1045 channel should listen.
1047 nfs.idmap_cache_timeout=
1048 [NFS] set the maximum lifetime for idmapper cache
1051 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
1053 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
1054 emulation library even if a 387 maths coprocessor
1057 noacpi [LIBATA] Disables use of ACPI in libata suspend/resume
1061 noaliencache [MM, NUMA] Disables the allcoation of alien caches in
1062 the slab allocator. Saves per-node memory, but will
1063 impact performance on real NUMA hardware.
1067 noapic [SMP,APIC] Tells the kernel to not make use of any
1068 IOAPICs that may be present in the system.
1070 noasync [HW,M68K] Disables async and sync negotiation for
1073 nobats [PPC] Do not use BATs for mapping kernel lowmem
1074 on "Classic" PPC cores.
1078 nodelayacct [KNL] Disable per-task delay accounting
1080 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1084 noexec [IA-32,X86-64]
1085 noexec=on: enable non-executable mappings (default)
1086 noexec=off: disable nn-executable mappings
1088 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1089 register save and restore. The kernel will only save
1090 legacy floating-point registers on task switch.
1094 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1095 instruction doesn't work correctly and not to
1098 nohalt [IA-64] Tells the kernel not to use the power saving
1099 function PAL_HALT_LIGHT when idle. This increases
1100 power-consumption. On the positive side, it reduces
1101 interrupt wake-up latency, which may improve performance
1102 in certain environments such as networked servers or
1105 nohz= [KNL] Boottime enable/disable dynamic ticks
1106 Valid arguments: on, off
1109 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
1111 noirqdebug [IA-32] Disables the code which attempts to detect and
1112 disable unhandled interrupt sources.
1114 no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for
1115 broken timer IRQ sources.
1117 noisapnp [ISAPNP] Disables ISA PnP code.
1119 noinitrd [RAM] Tells the kernel not to load any configured
1124 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1126 noltlbs [PPC] Do not use large page/tlb entries for kernel
1127 lowmem mapping on PPC40x.
1129 nomca [IA-64] Disable machine check abort handling
1131 nomce [IA-32] Machine Check Exception
1133 noresidual [PPC] Don't use residual data on PReP machines.
1135 noresume [SWSUSP] Disables resume and restores original swap
1138 no-scroll [VGA] Disables scrollback.
1139 This is required for the Braillex ib80-piezo Braille
1140 reader made by F.H. Papenmeier (Germany).
1144 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1146 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1148 nosync [HW,M68K] Disables sync negotiation for all devices.
1150 notsc [BUGS=IA-32] Disable Time Stamp Counter
1152 nousb [USB] Disable the USB subsystem
1156 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1161 opl3sa2= [HW,OSS] Format:
1162 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1164 oprofile.timer= [HW]
1165 Use timer interrupt instead of performance counters
1170 osst= [HW,SCSI] SCSI Tape Driver
1171 Format: <buffer_size>,<write_threshold>
1172 See also Documentation/scsi/st.txt.
1174 panic= [KNL] Kernel behaviour on panic
1177 parkbd.port= [HW] Parallel port number the keyboard adapter is
1178 connected to, default is 0.
1180 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1181 0 for XT, 1 for AT (default is AT).
1184 parport= [HW,PPT] Specify parallel ports. 0 disables.
1185 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1186 Use 'auto' to force the driver to use any
1187 IRQ/DMA settings detected (the default is to
1188 ignore detected IRQ/DMA settings because of
1189 possible conflicts). You can specify the base
1190 address, IRQ, and DMA settings; IRQ and DMA
1191 should be numbers, or 'auto' (for using detected
1192 settings on that particular port), or 'nofifo'
1193 (to avoid using a FIFO even if it is detected).
1194 Parallel ports are assigned in the order they
1195 are specified on the command line, starting
1198 parport_init_mode= [HW,PPT]
1199 Configure VIA parallel port to operate in
1200 a specific mode. This is necessary on Pegasos
1201 computer where firmware has no options for setting
1202 up parallel port mode and sets it to spp.
1203 Currently this function knows 686a and 8231 chips.
1204 Format: [spp|ps2|epp|ecp|ecpepp]
1206 pas2= [HW,OSS] Format:
1207 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1210 See header of drivers/scsi/pas16.c.
1213 Halt all CPUs after the first oops has been printed for
1214 the specified number of seconds. This is to be used if
1215 your oopses keep scrolling off the screen.
1220 See header of drivers/block/paride/pcd.c.
1221 See also Documentation/paride.txt.
1223 pci=option[,option...] [PCI] various PCI subsystem options:
1224 off [IA-32] don't probe for the PCI bus
1225 bios [IA-32] force use of PCI BIOS, don't access
1226 the hardware directly. Use this if your machine
1227 has a non-standard PCI host bridge.
1228 nobios [IA-32] disallow use of PCI BIOS, only direct
1229 hardware access methods are allowed. Use this
1230 if you experience crashes upon bootup and you
1231 suspect they are caused by the BIOS.
1232 conf1 [IA-32] Force use of PCI Configuration
1234 conf2 [IA-32] Force use of PCI Configuration
1236 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1238 nomsi [MSI] If the PCI_MSI kernel config parameter is
1239 enabled, this kernel boot option can be used to
1240 disable the use of MSI interrupts system-wide.
1241 nosort [IA-32] Don't sort PCI devices according to
1242 order given by the PCI BIOS. This sorting is
1243 done to get a device order compatible with
1245 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1246 routing table. These calls are known to be buggy
1247 on several machines and they hang the machine
1248 when used, but on other computers it's the only
1249 way to get the interrupt routing table. Try
1250 this option if the kernel is unable to allocate
1251 IRQs or discover secondary PCI buses on your
1253 rom [IA-32] Assign address space to expansion ROMs.
1254 Use with caution as certain devices share
1255 address decoders between ROMs and other
1257 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1258 assigned automatically to PCI devices. You can
1259 make the kernel exclude IRQs of your ISA cards
1261 pirqaddr=0xAAAAA [IA-32] Specify the physical address
1262 of the PIRQ table (normally generated
1263 by the BIOS) if it is outside the
1264 F0000h-100000h range.
1265 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1266 useful if the kernel is unable to find your
1267 secondary buses and you want to tell it
1268 explicitly which ones they are.
1269 assign-busses [IA-32] Always assign all PCI bus
1270 numbers ourselves, overriding
1271 whatever the firmware may have done.
1272 usepirqmask [IA-32] Honor the possible IRQ mask stored
1273 in the BIOS $PIR table. This is needed on
1274 some systems with broken BIOSes, notably
1275 some HP Pavilion N5400 and Omnibook XE3
1276 notebooks. This will have no effect if ACPI
1277 IRQ routing is enabled.
1278 noacpi [IA-32] Do not use ACPI for IRQ routing
1279 or for PCI scanning.
1280 routeirq Do IRQ routing for all PCI devices.
1281 This is normally done in pci_enable_device(),
1282 so this option is a temporary workaround
1283 for broken drivers that don't call it.
1284 firmware [ARM] Do not re-enumerate the bus but instead
1285 just use the configuration from the
1286 bootloader. This is currently used on
1287 IXP2000 systems where the bus has to be
1288 configured a certain way for adjunct CPUs.
1289 noearly [X86] Don't do any early type 1 scanning.
1290 This might help on some broken boards which
1291 machine check when some devices' config space
1292 is read. But various workarounds are disabled
1293 and some IOMMU drivers will not work.
1294 bfsort Sort PCI devices into breadth-first order.
1295 This sorting is done to get a device
1296 order compatible with older (<= 2.4) kernels.
1297 nobfsort Don't sort PCI devices into breadth-first order.
1298 cbiosize=nn[KMG] The fixed amount of bus space which is
1299 reserved for the CardBus bridge's IO window.
1300 The default value is 256 bytes.
1301 cbmemsize=nn[KMG] The fixed amount of bus space which is
1302 reserved for the CardBus bridge's memory
1303 window. The default value is 64 megabytes.
1305 pcmv= [HW,PCMCIA] BadgePAD 4
1308 See Documentation/paride.txt.
1310 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1313 See arch/parisc/kernel/pdc_chassis.c
1316 See Documentation/paride.txt.
1319 See Documentation/paride.txt.
1321 pirq= [SMP,APIC] Manual mp-table setup
1322 See Documentation/i386/IO-APIC.txt.
1324 plip= [PPT,NET] Parallel port network link
1325 Format: { parport<nr> | timid | 0 }
1326 See also Documentation/parport.txt.
1332 { on | off | curr | res | no-curr | no-res }
1335 [ISAPNP] Exclude IRQs for the autoconfiguration
1338 [ISAPNP] Exclude DMAs for the autoconfiguration
1340 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1341 Ranges are in pairs (I/O port base and size).
1344 [ISAPNP] Exclude memory regions for the
1346 Ranges are in pairs (memory base and size).
1348 profile= [KNL] Enable kernel profiling via /proc/profile
1349 Format: [schedule,]<number>
1350 Param: "schedule" - profile schedule points.
1351 Param: <number> - step/bucket size as a power of 2 for
1352 statistical time based profiling.
1353 Param: "sleep" - profile D-state sleeping (millisecs)
1355 processor.max_cstate= [HW,ACPI]
1356 Limit processor to maximum C-state
1357 max_cstate=9 overrides any DMI blacklist limit.
1359 processor.nocst [HW,ACPI]
1360 Ignore the _CST method to determine C-states,
1361 instead using the legacy FADT method
1363 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1365 See Documentation/ramdisk.txt.
1367 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1368 probe for; one of (bare|imps|exps|lifebook|any).
1369 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1371 psmouse.resetafter= [HW,MOUSE]
1372 Try to reset the device after so many bad packets
1375 [HW,MOUSE] Set desired mouse resolution, in dpi.
1376 psmouse.smartscroll=
1377 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1378 0 = disabled, 1 = enabled (default).
1380 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1382 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1385 See Documentation/paride.txt.
1387 quiet [KNL] Disable most log messages
1392 See Documentation/md.txt.
1394 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1395 See Documentation/ramdisk.txt.
1397 ramdisk_blocksize= [RAM]
1398 See Documentation/ramdisk.txt.
1400 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1401 New name for the ramdisk parameter.
1402 See Documentation/ramdisk.txt.
1404 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1405 RCU callbacks to process in one batch.
1407 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1408 RCU callbacks over which batch limiting is disabled.
1410 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1411 RCU callbacks below which batch limiting is re-enabled.
1415 Run specified binary instead of /init from the ramdisk,
1416 used for early userspace startup. See initrd.
1418 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1419 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1420 See arch/*/kernel/reboot.c or arch/*/kernel/process.c
1422 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1426 Reserves a hole at the top of the kernel virtual
1429 reset_devices [KNL] Force drivers to reset the underlying device
1430 during initialization.
1433 Specify the partition device for software suspend
1435 resume_offset= [SWSUSP]
1436 Specify the offset from the beginning of the partition
1437 given by "resume=" at which the swap header is located,
1438 in <PAGE_SIZE> units (needed only for swap files).
1439 See Documentation/power/swsusp-and-swap-files.txt
1441 retain_initrd [RAM] Keep initrd memory after extraction
1443 rhash_entries= [KNL,NET]
1444 Set number of hash buckets for route cache
1446 riscom8= [HW,SERIAL]
1447 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1449 ro [KNL] Mount root device read-only on boot
1451 root= [KNL] Root filesystem
1453 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1454 mount the root filesystem
1456 rootflags= [KNL] Set root filesystem mount option string
1458 rootfstype= [KNL] Set root filesystem type
1460 rw [KNL] Mount root device read-write on boot
1462 S [KNL] Run init in single mode
1465 See drivers/net/irda/sa1100_ir.c.
1468 Format: <io>,<irq>,<dma>,<dma2>
1470 sbni= [NET] Granch SBNI12 leased line adapter
1472 sbpcd= [HW,CD] Soundblaster CD adapter
1474 See a comment before function sbpcd_setup() in
1475 drivers/cdrom/sbpcd.c.
1477 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1478 Format: <io>[,<timeout>[,<isapnp>]]
1480 scsi_debug_*= [SCSI]
1481 See drivers/scsi/scsi_debug.c.
1483 scsi_default_dev_flags=
1484 [SCSI] SCSI default device flags
1487 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1488 Format: <vendor>:<model>:<flags>
1489 (flags are integer value)
1491 scsi_logging= [SCSI]
1493 scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are
1494 discovered. async scans them in kernel threads,
1495 allowing boot to proceed. none ignores them, expecting
1496 user space to do the scan.
1498 selinux [SELINUX] Disable or enable SELinux at boot time.
1499 Format: { "0" | "1" }
1500 See security/selinux/Kconfig help text.
1503 Default value is set via kernel config option.
1504 If enabled at boot time, /selinux/disable can be used
1505 later to disable prior to initial policy load.
1507 selinux_compat_net =
1508 [SELINUX] Set initial selinux_compat_net flag value.
1509 Format: { "0" | "1" }
1510 0 -- use new secmark-based packet controls
1511 1 -- use legacy packet controls
1512 Default value is 0 (preferred).
1513 Value can be changed at runtime via
1514 /selinux/compat_net.
1516 serialnumber [BUGS=IA-32]
1518 sg_def_reserved_size= [SCSI]
1521 Maximal number of shapers.
1524 See header of drivers/scsi/sim710.c.
1530 Format: <io>,<irq>,<dma>
1531 See header of drivers/cdrom/sjcd.c.
1536 Format: <io1>[,<io2>[,...,<io8>]]
1538 snd-ad1816a= [HW,ALSA]
1540 snd-ad1848= [HW,ALSA]
1542 snd-ali5451= [HW,ALSA]
1544 snd-als100= [HW,ALSA]
1546 snd-als4000= [HW,ALSA]
1548 snd-azt2320= [HW,ALSA]
1550 snd-cmi8330= [HW,ALSA]
1552 snd-cmipci= [HW,ALSA]
1554 snd-cs4231= [HW,ALSA]
1556 snd-cs4232= [HW,ALSA]
1558 snd-cs4236= [HW,ALSA]
1560 snd-cs4281= [HW,ALSA]
1562 snd-cs46xx= [HW,ALSA]
1564 snd-dt019x= [HW,ALSA]
1566 snd-dummy= [HW,ALSA]
1568 snd-emu10k1= [HW,ALSA]
1570 snd-ens1370= [HW,ALSA]
1572 snd-ens1371= [HW,ALSA]
1574 snd-es968= [HW,ALSA]
1576 snd-es1688= [HW,ALSA]
1578 snd-es18xx= [HW,ALSA]
1580 snd-es1938= [HW,ALSA]
1582 snd-es1968= [HW,ALSA]
1584 snd-fm801= [HW,ALSA]
1586 snd-gusclassic= [HW,ALSA]
1588 snd-gusextreme= [HW,ALSA]
1590 snd-gusmax= [HW,ALSA]
1594 snd-ice1712= [HW,ALSA]
1596 snd-intel8x0= [HW,ALSA]
1598 snd-interwave= [HW,ALSA]
1603 snd-korg1212= [HW,ALSA]
1605 snd-maestro3= [HW,ALSA]
1607 snd-mpu401= [HW,ALSA]
1609 snd-mtpav= [HW,ALSA]
1611 snd-nm256= [HW,ALSA]
1613 snd-opl3sa2= [HW,ALSA]
1621 snd-opti93x= [HW,ALSA]
1625 snd-rme32= [HW,ALSA]
1627 snd-rme96= [HW,ALSA]
1629 snd-rme9652= [HW,ALSA]
1635 snd-sbawe= [HW,ALSA]
1637 snd-serial= [HW,ALSA]
1639 snd-sgalaxy= [HW,ALSA]
1641 snd-sonicvibes= [HW,ALSA]
1646 snd-sun-cs4231= [HW,ALSA]
1648 snd-trident= [HW,ALSA]
1650 snd-usb-audio= [HW,ALSA,USB]
1652 snd-via82xx= [HW,ALSA]
1654 snd-virmidi= [HW,ALSA]
1656 snd-wavefront= [HW,ALSA]
1658 snd-ymfpci= [HW,ALSA]
1661 Format: <io>[,<irq>]
1663 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1664 See Documentation/sonypi.txt
1666 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1667 See Documentation/specialix.txt.
1669 spia_io_base= [HW,MTD]
1675 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1677 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1678 See Documentation/scsi/st.txt.
1681 See header of drivers/scsi/seagate.c.
1685 Set the STI (builtin display/keyboard on the HP-PARISC
1686 machines) console (graphic card) which should be used
1687 as the initial boot-console.
1688 See also comment in drivers/video/console/sticore.c.
1691 See comment in drivers/video/console/sticore.c.
1694 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1698 Control how the NFS server code allocates CPUs to
1699 service thread pools. Depending on how many NICs
1700 you have and where their interrupts are bound, this
1701 option will affect which CPUs will do NFS serving.
1702 Note: this parameter cannot be changed while the
1703 NFS server is running.
1705 auto the server chooses an appropriate mode
1706 automatically using heuristics
1707 global a single global pool contains all CPUs
1708 percpu one pool for each CPU
1709 pernode one pool for each NUMA node (equivalent
1710 to global on non-NUMA machines)
1712 swiotlb= [IA-64] Number of I/O TLB slabs
1716 sym53c416= [HW,SCSI]
1717 See header of drivers/scsi/sym53c416.c.
1719 sysrq_always_enabled
1721 Ignore sysrq setting - this boot parameter will
1722 neutralize any effect of /proc/sys/kernel/sysrq.
1723 Useful for debugging.
1726 See header of drivers/scsi/t128.c.
1730 thash_entries= [KNL,NET]
1731 Set number of hash buckets for TCP connection
1733 time Show timing data prefixed to each printk message line
1735 clocksource= [GENERIC_TIME] Override the default clocksource
1736 Override the default clocksource and use the clocksource
1737 with the name specified.
1739 tipar.timeout= [HW,PPT]
1740 Set communications timeout in tenths of a second
1743 tipar.delay= [HW,PPT]
1744 Set inter-bit delay in microseconds (default 10).
1747 See header of drivers/scsi/seagate.c.
1750 See comment before function dc390_setup() in
1751 drivers/scsi/tmscsim.c.
1755 trix= [HW,OSS] MediaTrix AudioTrix Pro
1757 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1759 tsdev.xres= [TS] Horizontal screen resolution.
1760 tsdev.yres= [TS] Vertical screen resolution.
1762 turbografx.map[2|3]= [HW,JOY]
1763 TurboGraFX parallel port interface
1765 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1766 See also Documentation/input/joystick-parport.txt
1768 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1769 See header of drivers/scsi/u14-34f.c.
1778 [USB] Ignore overcurrent events (default N).
1779 Some badly-designed motherboards generate lots of
1780 bogus events, for ports that aren't wired to
1781 anything. Set this parameter to avoid log spamming.
1782 Note that genuine overcurrent events won't be
1785 usbcore.autosuspend=
1786 [USB] The autosuspend time delay (in seconds) used
1787 for newly-detected USB devices (default 2). This
1788 is the time required before an idle device will be
1789 autosuspended. Devices for which the delay is set
1790 to 0 won't be autosuspended at all.
1793 [USBHID] The interval which mice are to be polled at.
1796 vdso=1: enable VDSO (default)
1797 vdso=0: disable VDSO mapping
1799 video= [FB] Frame buffer configuration
1800 See Documentation/fb/modedb.txt.
1802 vga= [BOOT,IA-32] Select a particular video mode
1803 See Documentation/i386/boot.txt and
1804 Documentation/svga.txt.
1805 Use vga=ask for menu.
1806 This is actually a boot loader parameter; the value is
1807 passed to the kernel using a special protocol.
1809 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1810 size of <nn>. This can be used to increase the
1811 minimum size (128MB on x86). It can also be used to
1812 decrease the size and leave more room for directly
1815 vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
1818 vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
1821 vmpoff= [KNL,S390] Perform z/VM CP command after power off.
1824 waveartist= [HW,OSS]
1825 Format: <io>,<irq>,<dma>,<dma2>
1828 See header of drivers/scsi/wd33c93.c.
1831 See header of drivers/scsi/wd7000.c.
1834 See Documentation/watchdog/watchdog.txt.
1836 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1837 xd_geo= See header of drivers/block/xd.c.
1839 xirc2ps_cs= [NET,PCMCIA]
1841 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1843 norandmaps Don't use address space randomization
1844 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1846 unwind_debug=N N > 0 will enable dwarf2 unwinder debugging
1847 This is useful to get more information why
1848 you got a "dwarf2 unwinder stuck"
1850 ______________________________________________________________________
1854 Add documentation for ALSA options.
1855 Add more DRM drivers.