1 February 2003 Kernel Parameters v2.5.59
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 The text in square brackets at the beginning of the description state the
21 restrictions on the kernel for the said kernel parameter to be valid. The
22 restrictions referred to are that the relevant option is valid if:
24 ACPI ACPI support is enabled.
25 ALSA ALSA sound support is enabled.
26 APIC APIC support is enabled.
27 APM Advanced Power Management support is enabled.
28 AX25 Appropriate AX.25 support is enabled.
29 CD Appropriate CD support is enabled.
30 DEVFS devfs support is enabled.
31 DRM Direct Rendering Management support is enabled.
32 EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
33 EFI EFI Partitioning (GPT) is enabled
34 EIDE EIDE/ATAPI support is enabled.
35 FB The frame buffer device is enabled.
36 HW Appropriate hardware is enabled.
37 IA-32 IA-32 aka i386 architecture is enabled.
38 IA-64 IA-64 architecture is enabled.
39 IOSCHED More than one I/O scheduler is enabled.
40 IP_PNP IP DCHP, BOOTP, or RARP is enabled.
41 ISAPNP ISA PnP code is enabled.
42 ISDN Appropriate ISDN support is enabled.
43 JOY Appropriate joystick support is enabled.
44 LP Printer support is enabled.
45 LOOP Loopback device support is enabled.
46 M68k M68k architecture is enabled.
47 These options have more detailed description inside of
48 Documentation/m68k/kernel-options.txt.
49 MCA MCA bus support is enabled.
50 MDA MDA console support is enabled.
51 MOUSE Appropriate mouse support is enabled.
52 MTD MTD support is enabled.
53 NET Appropriate network support is enabled.
54 NFS Appropriate NFS support is enabled.
55 OSS OSS sound support is enabled.
56 PARIDE The ParIDE subsystem is enabled.
57 PCI PCI bus support is enabled.
58 PCMCIA The PCMCIA subsystem is enabled.
59 PNP Plug & Play support is enabled.
60 PPC PowerPC architecture is enabled.
61 PPT Parallel port support is enabled.
62 PS2 Appropriate PS/2 support is enabled.
63 RAM RAM disk support is enabled.
64 S390 S390 architecture is enabled.
65 SCSI Appropriate SCSI support is enabled.
66 A lot of drivers has their options described inside of
68 SERIAL Serial support is enabled.
69 SMP The kernel is an SMP kernel.
70 SPARC Sparc architecture is enabled.
71 SWSUSP Software suspension is enabled.
72 TS Appropriate touchscreen support is enabled.
73 USB USB support is enabled.
74 V4L Video For Linux support is enabled.
75 VGA The VGA console has been enabled.
76 VT Virtual terminal support is enabled.
77 WDT Watchdog support is enabled.
78 XT IBM PC/XT MFM hard disk support is enabled.
80 In addition, the following text indicates that the option:
82 BUGS= Relates to possible processor bugs on the said processor.
83 KNL Is a kernel start-up parameter.
84 BOOT Is a boot loader parameter.
86 Parameters denoted with BOOT are actually interpreted by the boot
87 loader, and have no meaning to the kernel directly.
88 Do not modify the syntax of boot loader parameters without extreme
89 need or coordination with <Documentation/i386/boot.txt>.
91 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
92 a trailing = on the name of any parameter states that that parameter will
93 be entered as an environment variable, whereas its absence indicates that
94 it will appear as a kernel argument readable via /proc/cmdline by programs
95 running once the system is up.
97 53c7xx= [HW,SCSI] Amiga SCSI controllers
98 See header of drivers/scsi/53c7xx.c.
99 See also Documentation/scsi/ncr53c7xx.txt.
101 acpi= [HW,ACPI] Advanced Configuration and Power Interface
102 Format: { force | off | ht | strict }
103 force -- enable ACPI if default was off
104 off -- disable ACPI if default was on
105 noirq -- do not use ACPI for IRQ routing
106 ht -- run only enough ACPI to enable Hyper Threading
107 strict -- Be less tolerant of platforms that are not
108 strictly ACPI specification compliant.
110 See also Documentation/pm.txt, pci=noacpi
112 acpi_sleep= [HW,ACPI] Sleep options
113 Format: { s3_bios, s3_mode }
114 See Documentation/power/video.txt
116 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
117 Format: { level | edge | high | low }
119 acpi_irq_balance [HW,ACPI] ACPI will balance active IRQs
122 acpi_irq_nobalance [HW,ACPI] ACPI will not move active IRQs (default)
125 acpi_irq_pci= [HW,ACPI] If irq_balance, Clear listed IRQs for use by PCI
126 Format: <irq>,<irq>...
128 acpi_irq_isa= [HW,ACPI] If irq_balance, Mark listed IRQs used by ISA
129 Format: <irq>,<irq>...
131 acpi_osi= [HW,ACPI] empty param disables _OSI
133 acpi_serialize [HW,ACPI] force serialization of AML methods
135 acpi_skip_timer_override [HW,ACPI]
136 Recognize and ignore IRQ0/pin2 Interrupt Override.
137 For broken nForce2 BIOS resulting in XT-PIC timer.
139 acpi_dbg_layer= [HW,ACPI]
141 Each bit of the <int> indicates an acpi debug layer,
142 1: enable, 0: disable. It is useful for boot time
143 debugging. After system has booted up, it can be set
144 via /proc/acpi/debug_layer.
146 acpi_dbg_level= [HW,ACPI]
148 Each bit of the <int> indicates an acpi debug level,
149 1: enable, 0: disable. It is useful for boot time
150 debugging. After system has booted up, it can be set
151 via /proc/acpi/debug_level.
154 Format: <io>,<irq>,<dma>,<dma2>
155 See also Documentation/sound/oss/AD1816.
158 Format: <io>,<irq>,<dma>,<dma2>,<type>
164 See header of drivers/scsi/advansys.c.
166 advwdt= [HW,WDT] Advantech WDT
167 Format: <iostart>,<iostop>
169 aedsp16= [HW,OSS] Audio Excel DSP 16
170 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
171 See also header of sound/oss/aedsp16.c.
174 See Documentation/scsi/aha152x.txt.
177 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
180 See Documentation/scsi/aic7xxx.txt.
183 See Documentation/scsi/aic79xx.txt.
186 Format: <host-scsi-id>,<target-scsi-id>,<max-rate>,<max-offset>
187 See also header of drivers/scsi/AM53C974.c.
189 amijoy.map= [HW,JOY] Amiga joystick support
190 Map of devices attached to JOY0DAT and JOY1DAT
192 See also Documentation/kernel/input/joystick.txt
194 analog.map= [HW,JOY] Analog joystick and gamepad support
195 Specifies type or capabilities of an analog joystick
196 connected to one of 16 gameports
197 Format: <type1>,<type2>,..<type16>
199 apc= [HW,SPARC] Power management functions (SPARCstation-4/5 + deriv.)
201 Disable APC CPU standby support. SPARCstation-Fox does
202 not play well with APC CPU idle - disable it if you have
203 APC and your system crashes randomly.
205 apic= [APIC,i386] Change the output verbosity whilst booting
206 Format: { quiet (default) | verbose | debug }
207 Change the amount of debugging information output
208 when initialising the APIC and IO-APIC components.
210 apm= [APM] Advanced Power Management
211 See header of arch/i386/kernel/apm.c.
216 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
217 Format: <io>,<irq>,<nodeID>
221 atarimouse= [HW,MOUSE] Atari Mouse
223 atascsi= [HW,SCSI] Atari SCSI
225 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess, EzKey
226 and similar keyboards
228 atkbd.reset= [HW] Reset keyboard during initialization
230 atkbd.set= [HW] Select keyboard code set
231 Format: <int> (2 = AT (default) 3 = PS/2)
233 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar keyboards
236 [HW] Use software keyboard repeat
240 awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
241 Format: <io>,<memsize>,<isapnp>
243 aztcd= [HW,CD] Aztech CD268 CDROM driver
244 Format: <io>,0x79 (?)
246 baycom_epp= [HW,AX25]
249 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
251 See header of drivers/net/hamradio/baycom_par.c.
253 baycom_ser_fdx= [HW,AX25] BayCom Serial Port AX.25 Modem (Full Duplex Mode)
254 Format: <io>,<irq>,<mode>[,<baud>]
255 See header of drivers/net/hamradio/baycom_ser_fdx.c.
257 baycom_ser_hdx= [HW,AX25] BayCom Serial Port AX.25 Modem (Half Duplex Mode)
258 Format: <io>,<irq>,<mode>
259 See header of drivers/net/hamradio/baycom_ser_hdx.c.
261 blkmtd_device= [HW,MTD]
267 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
268 bttv.radio= Most important insmod options are available as kernel args too.
269 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
270 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
273 See drivers/scsi/BusLogic.c, comment before function
274 BusLogic_ParseDriverOptions().
276 c101= [NET] Moxa C101 synchronous serial card
278 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
279 Sometimes CPU hardware bugs make them report the cache
280 size incorrectly. The kernel will attempt work arounds
281 to fix known problems, but for some CPUs it is not
282 possible to determine what the correct size should be.
283 This option provides an override for these situations.
286 Format: <io>,<irq>[,PAS]
287 See header of drivers/cdrom/cdu31a.c.
289 chandev= [HW,NET] Generic channel device initialisation
291 clock= [BUGS=IA-32, HW] gettimeofday timesource override.
292 Forces specified timesource (if avaliable) to be used
293 when calculating gettimeofday(). If specicified timesource
294 is not avalible, it defaults to PIT.
295 Format: { pit | tsc | cyclone | pmtmr }
297 hpet= [IA-32,HPET] option to disable HPET and use PIT.
301 Format: { auto | [<io>,][<irq>] }
303 com20020= [HW,NET] ARCnet - COM20020 chipset
304 Format: <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
306 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
309 com90xx= [HW,NET] ARCnet - COM90xx chipset (memory-mapped buffers)
310 Format: <io>[,<irq>[,<memstart>]]
312 condev= [HW,S390] console device
315 console= [KNL] Output console
316 Console device and comm spec (speed, control, parity).
318 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
319 Format: <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
322 Format: { parport<nr> | auto | none }
325 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
330 cs89x0_media= [HW,NET]
331 Format: { rj45 | aui | bnc }
333 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
336 See header of drivers/s390/block/dasd_devmap.c.
338 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
339 (one device per port)
340 Format: <port#>,<type>
341 See also Documentation/input/joystick-parport.txt
343 debug [KNL] Enable kernel debugging (events log level).
346 Format: <area>[,<node>]
347 See also Documentation/networking/decnet.txt.
350 See Documentation/filesystems/devfs/boot-options.
353 Set number of hash buckets for dentry cache.
356 IO parameters + enable/disable command.
358 digiepca= [HW,SERIAL]
359 See drivers/char/README.epca and
360 Documentation/digiepca.txt.
362 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
364 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
366 dmasound= [HW,OSS] Sound subsystem buffers
372 earlyprintk= [x86, x86_64]
374 earlyprintk=serial[,ttySn[,baudrate]]
376 Append ,keep to not disable it when the real console
379 Only vga or serial at a time, not both.
381 Currently only ttyS0 and ttyS1 are supported.
383 Interaction with the standard serial driver is not
386 The VGA output is eventually overwritten by the real
396 Format: {"of[f]" | "sk[ipmbr]"}
397 See comment in arch/i386/boot/edd.S
400 Format: <id>,<membase>,<irq>
402 eisa_irq_edge= [PARISC]
403 See header of drivers/parisc/eisa.c.
406 See comment before function elanfreq_setup() in
407 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
410 Format: {"as"|"cfq"|"deadline"|"noop"}
411 See Documentation/as-iosched.txt for details
414 Format: <lineout>[,<micbias>]
415 See also header of sound/oss/es1370.c.
418 Format: <spdif>,[<nomix>,[<amplifier>]]
419 See also header of sound/oss/es1371.c.
421 ether= [HW,NET] Ethernet cards parameters
422 This option is obsoleted by the "netdev=" option, which
423 has equivalent usage. See its documentation for details.
425 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
429 See header of drivers/scsi/fd_mcs.c.
432 See header of drivers/scsi/fdomain.c.
435 See Documentation/floppy.txt.
437 ftape= [HW] Floppy Tape subsystem debugging options.
438 See Documentation/ftape.txt.
441 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
442 support via parallel port (up to 5 devices per port)
443 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
444 See also Documentation/input/joystick-parport.txt
449 See header of drivers/scsi/gdth.c.
451 gpt [EFI] Forces disk with valid GPT signature but
452 invalid Protective MBR to be treated as GPT.
457 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
460 Format: <io>,<irq>,<dma>,<dma16>
464 hcl= [IA-64] SGI's Hardware Graph compatibility layer
466 hd= [EIDE] (E)IDE hard drive subsystem geometry
467 Format: <cyl>,<head>,<sect>
469 hd?= [HW] (E)IDE subsystem
470 hd?lun= See Documentation/ide.txt.
472 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
473 size of <nn>. This works even on boxes that have no
474 highmem otherwise. This also works to reduce highmem
475 size on bigger boxes.
478 See Documentation/isdn/README.HiSax.
480 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
482 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
484 i8042.direct [HW] Put keyboard port into non-translated mode
485 i8042.dumbkbd [HW] Pretend that controlled can only read data from
486 keyboard and can not control its state
487 (Don't attempt to blink the leds)
488 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
489 i8042.nomux [HW] Don't check presence of an active multiplexing
491 i8042.reset [HW] Reset the controller during init and cleanup
492 i8042.unlock [HW] Unlock (ignore) the keylock
496 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
497 See Documentation/mca.txt.
500 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
502 ide?= [HW] (E)IDE subsystem
503 Config (iomem/irq), tuning or debugging
504 (serialize,reset,no{dma,tune,probe}) or chipset
506 See Documentation/ide.txt.
508 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
509 See Documentation/ide.txt.
512 Format: idle=poll or idle=halt
515 Set number of hash buckets for inode cache.
518 See header of drivers/scsi/in2000.c.
522 Run specified binary instead of /sbin/init as init
525 initcall_debug [KNL] Trace initcalls as they are executed. Useful
526 for working out where the kernel is dying during
529 initrd= [BOOT] Specify the location of the initial ramdisk
531 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
536 io7= [HW] IO7 for Marvel based alpha systems
537 See comment before marvel_specify_io7 in
538 arch/alpha/kernel/core_marvel.c.
541 See Documentation/nfsroot.txt.
543 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
544 See comment before ip2_setup() in drivers/char/ip2.c.
546 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
547 See header of drivers/scsi/ips.c.
550 Format: <RDP>, <reset>, <pci_scan>, <verbosity>
552 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
553 Format: <cpu number>, ..., <cpu number>
554 This option can be used to specify one or more CPUs
555 to isolate from the general SMP balancing and scheduling
556 algorithms. The only way to move a process onto or off
557 an "isolated" CPU is via the CPU affinity syscalls.
559 This option is the preferred way to isolate CPUs. The
560 alternative - manually setting the CPU mask of all tasks
561 in the system can cause problems and suboptimal load
562 balancer performance.
565 Format: <io>,<irq>,<dma>,<setup>
569 js= [HW,JOY] Analog joystick
570 See Documentation/input/joystick.txt.
576 lapic [IA-32,APIC] Enable the local APIC even if BIOS disabled it.
578 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
579 Format: addr:<io>,irq:<irq>
582 See function print_params() in arch/ia64/sn/kernel/llsc4.c.
584 load_ramdisk= [RAM] List of ramdisks to load from floppy
585 See Documentation/ramdisk.txt.
591 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
594 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
595 Format is n, nk, nM. n must be a power of two. The
596 default is set in kernel config.
598 lp=0 [LP] Specify parallel ports to use, e.g,
599 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
600 lp=reset first parallel port). 'lp=0' disables the
601 lp=auto printer driver. 'lp=reset' (which can be
602 specified in addition to the ports) causes
603 attached printers to be reset. Using
604 lp=port1,port2,... specifies the parallel ports
605 to associate lp devices with, starting with
606 lp0. A port specification may be 'none' to skip
607 that lp device, or a parport name such as
608 'parport0'. Specifying 'lp=auto' instead of a
609 port specification list means that device IDs
610 from each port should be examined, to see if
611 an IEEE 1284-compliant printer is attached; if
612 so, the driver will manage that printer.
613 See also header of drivers/char/lp.c.
616 Sets loops_per_jiffy to given constant, thus avoiding
617 time-consuming boot-time autodetection (up to 250 ms per
618 CPU). 0 enables autodetection (default). To determine
619 the correct value for your kernel, boot with normal
620 autodetection and see what value is printed. Note that
621 on SMP systems the preset will be applied to all CPUs,
622 which is likely to cause problems if your CPUs need
623 significantly divergent settings. An incorrect value
624 will cause delays in the kernel to be wrong, leading to
625 unpredictable I/O errors and other breakage. Although
626 unlikely, in the extreme case this might damage your
630 Format: <io>,<irq>,<dma>
633 Format: <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
636 Format: <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
639 Format: <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
644 max_loop= [LOOP] Maximum number of loopback devices that can
648 maxcpus= [SMP] Maximum number of processors that an SMP kernel
651 max_scsi_luns= [SCSI]
653 max_scsi_report_luns=
654 [SCSI] Maximum number of LUNs received
655 Should be between 1 and 16384.
657 mca-pentium [BUGS=IA-32]
662 Format: <port>,<irq>,<mitsumi_bug_93_wait>
666 mce [IA-32] Machine Check Exception
668 md= [HW] RAID subsystems devices and level
669 See Documentation/md.txt.
672 Format: <first>,<last>
673 Specifies range of consoles to be captured by the MDA.
675 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
676 Amount of memory to be used when the kernel is not able
677 to see the whole system memory or for test.
679 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
682 memmap=exactmap [KNL,IA-32] Enable setting of an exact
683 E820 memory map, as specified by the user.
684 Such memmap=exactmap lines can be constructed based on
685 BIOS output or other requirements. See the memmap=nn@ss
688 memmap=nn[KMG]@ss[KMG]
689 [KNL] Force usage of a specific region of memory
690 Region of memory to be used, from ss to ss+nn.
692 memmap=nn[KMG]#ss[KMG]
693 [KNL,ACPI] Mark specific memory as ACPI data.
694 Region of memory to be used, from ss to ss+nn.
696 memmap=nn[KMG]$ss[KMG]
697 [KNL,ACPI] Mark specific memory as reserved.
698 Region of memory to be used, from ss to ss+nn.
700 meye= [HW] Set MotionEye Camera parameters
701 See Documentation/video4linux/meye.txt.
706 [MOUSE] Maximum time between finger touching and
707 leaving touchpad surface for touch to be considered
708 a tap and be reported as a left button click (for
709 touchpads working in absolute mode only).
711 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
712 reporting absolute coordinates, such as tablets
713 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
714 reporting absolute coordinates, such as tablets
720 Format: <name>,<region-number>,<size>,<offset>
723 Format: <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
726 See drivers/mtd/cmdline.c.
728 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
731 See header of drivers/scsi/NCR_D700.c.
737 ncr53c400a= [HW,SCSI]
739 ncr53c406a= [HW,SCSI]
743 netdev= [NET] Network devices parameters
744 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
745 Note that mem_start is often overloaded to mean
746 something different and driver-specific.
749 See Documentation/nfsroot.txt.
751 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
752 See Documentation/nfsroot.txt.
754 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
756 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
757 emulation library even if a 387 maths coprocessor
762 noapic [SMP,APIC] Tells the kernel not to make use of any
763 APIC that may be present on the system.
765 noasync [HW,M68K] Disables async and sync negotiation for
768 nobats [PPC] Do not use BATs for mapping kernel lowmem
769 on "Classic" PPC cores.
773 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
778 noexec=on: enable non-executable mappings (default)
779 noexec=off: disable nn-executable mappings
783 nohighio [BUGS=IA-32] Disable highmem block I/O.
787 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
788 instruction doesn't work correctly and not to
791 noirqdebug [IA-32] Disables the code which attempts to detect and
792 disable unhandled interrupt sources.
794 noisapnp [ISAPNP] Disables ISA PnP code.
796 noinitrd [RAM] Tells the kernel not to load any configured
801 nolapic [IA-32,APIC] Do not enable or use the local APIC.
803 noltlbs [PPC] Do not use large page/tlb entries for kernel
804 lowmem mapping on PPC40x.
806 nomce [IA-32] Machine Check Exception
808 noresidual [PPC] Don't use residual data on PReP machines.
810 noresume [SWSUSP] Disables resume and restore original swap space.
812 no-scroll [VGA] Disables scrollback.
813 This is required for the Braillex ib80-piezo Braille
814 reader made by F.H. Papenmeier (Germany).
818 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
820 nosync [HW,M68K] Disables sync negotiation for all devices.
822 notsc [BUGS=IA-32] Disable Time Stamp Counter
824 nousb [USB] Disable the USB subsystem
832 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
835 Format: <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
838 Use timer interrupt instead of performance counters
843 osst= [HW,SCSI] SCSI Tape Driver
844 Format: <buffer_size>,<write_threshold>
845 See also Documentation/scsi/st.txt.
847 panic= [KNL] Kernel behaviour on panic
850 parport=0 [HW,PPT] Specify parallel ports. 0 disables.
851 parport=auto Use 'auto' to force the driver to use
852 parport=0xBBB[,IRQ[,DMA]] any IRQ/DMA settings detected (the
853 default is to ignore detected IRQ/DMA
854 settings because of possible
855 conflicts). You can specify the base
856 address, IRQ, and DMA settings; IRQ and
857 DMA should be numbers, or 'auto' (for
858 using detected settings on that
859 particular port), or 'nofifo' (to avoid
860 using a FIFO even if it is detected).
861 Parallel ports are assigned in the
862 order they are specified on the command
863 line, starting with parport0.
866 Format: <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
869 See header of drivers/scsi/pas16.c.
874 See header of drivers/block/paride/pcd.c.
875 See also Documentation/paride.txt.
877 pci=option[,option...] [PCI] various PCI subsystem options:
878 off [IA-32] don't probe for the PCI bus
879 bios [IA-32] force use of PCI BIOS, don't access
880 the hardware directly. Use this if your machine
881 has a non-standard PCI host bridge.
882 nobios [IA-32] disallow use of PCI BIOS, only direct
883 hardware access methods are allowed. Use this
884 if you experience crashes upon bootup and you
885 suspect they are caused by the BIOS.
886 conf1 [IA-32] Force use of PCI Configuration Mechanism 1.
887 conf2 [IA-32] Force use of PCI Configuration Mechanism 2.
888 nosort [IA-32] Don't sort PCI devices according to
889 order given by the PCI BIOS. This sorting is done
890 to get a device order compatible with older kernels.
891 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
892 routing table. These calls are known to be buggy
893 on several machines and they hang the machine when used,
894 but on other computers it's the only way to get the
895 interrupt routing table. Try this option if the kernel
896 is unable to allocate IRQs or discover secondary PCI
897 buses on your motherboard.
898 rom [IA-32] Assign address space to expansion ROMs.
899 Use with caution as certain devices share address
900 decoders between ROMs and other resources.
901 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be assigned
902 automatically to PCI devices. You can make the kernel
903 exclude IRQs of your ISA cards this way.
904 lastbus=N [IA-32] Scan all buses till bus #N. Can be useful
905 if the kernel is unable to find your secondary buses
906 and you want to tell it explicitly which ones they are.
907 assign-busses [IA-32] Always assign all PCI bus
908 numbers ourselves, overriding
909 whatever the firmware may have
911 usepirqmask [IA-32] Honor the possible IRQ mask
912 stored in the BIOS $PIR table. This is
913 needed on some systems with broken
914 BIOSes, notably some HP Pavilion N5400
915 and Omnibook XE3 notebooks. This will
916 have no effect if ACPI IRQ routing is
918 noacpi [IA-32] Do not use ACPI for IRQ routing
921 firmware [ARM] Do not re-enumerate the bus but
922 instead just use the configuration
923 from the bootloader. This is currently
924 used on IXP2000 systems where the
925 bus has to be configured a certain way
928 pcmv= [HW,PCMCIA] BadgePAD 4
931 See Documentation/paride.txt.
934 See Documentation/paride.txt.
937 See Documentation/paride.txt.
939 pirq= [SMP,APIC] Manual mp-table setup
940 See Documentation/i386/IO-APIC.txt.
942 plip= [PPT,NET] Parallel port network link
943 Format: { parport<nr> | timid | 0 }
944 See also Documentation/parport.txt.
947 { on | off | curr | res | no-curr | no-res }
950 [ISAPNP] Exclude IRQs for the autoconfiguration
953 [ISAPNP] Exclude DMAs for the autoconfiguration
955 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
956 Ranges are in pairs (I/O port base and size).
959 [ISAPNP] Exclude memory regions for the autoconfiguration
960 Ranges are in pairs (memory base and size).
962 profile= [KNL] Enable kernel profiling via /proc/profile
963 { schedule | <number> }
964 (param: schedule - profile schedule points}
965 (param: profile step/bucket size as a power of 2 for
966 statistical time based profiling)
968 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
970 See Documentation/ramdisk.txt.
972 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
973 probe for (bare|imps|exps).
974 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
977 [HW,MOUSE] Try to reset the device after so many bad packets
980 [HW,MOUSE] Set desired mouse resolution, in dpi.
982 [HW,MOUSE] Controls Logitech smartscroll autorepeat,
983 0 = disabled, 1 = enabled (default).
985 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
986 Format: <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
989 See Documentation/paride.txt.
991 quiet= [KNL] Disable log messages
996 See Documentation/md.txt.
998 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
999 See Documentation/ramdisk.txt.
1003 See Documentation/ramdisk.txt.
1005 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1006 New name for the ramdisk parameter.
1007 See Documentation/ramdisk.txt.
1009 ramdisk_start= [RAM] Starting block of RAM disk image (so you can
1010 place it after the kernel image on a boot floppy).
1011 See Documentation/ramdisk.txt.
1013 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1014 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1015 See arch/*/kernel/reboot.c.
1017 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1019 resume= [SWSUSP] Specify the partition device for software suspension
1021 rhash_entries= [KNL,NET]
1022 Set number of hash buckets for route cache
1024 riscom8= [HW,SERIAL]
1025 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1027 ro [KNL] Mount root device read-only on boot
1029 root= [KNL] Root filesystem
1031 rootflags= [KNL] Set root filesystem mount option string
1033 rootfstype= [KNL] Set root filesystem type
1035 rw [KNL] Mount root device read-write on boot
1037 S [KNL] Run init in single mode
1040 See drivers/net/irda/sa1100_ir.c.
1043 Format: <io>,<irq>,<dma>,<dma2>
1045 sbni= [NET] Granch SBNI12 leased line adapter
1047 sbpcd= [HW,CD] Soundblaster CD adapter
1049 See a comment before function sbpcd_setup() in
1050 drivers/cdrom/sbpcd.c.
1052 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1053 Format: <io>[,<timeout>[,<isapnp>]]
1055 scsi_debug_*= [SCSI]
1056 See drivers/scsi/scsi_debug.c.
1058 scsi_default_dev_flags=
1059 [SCSI] SCSI default device flags
1062 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1063 Format: <vendor>:<model>:<flags>
1064 (flags are integer value)
1066 scsi_logging= [SCSI]
1070 serialnumber [BUGS=IA-32]
1072 sf16fm= [HW] SF16FMI radio driver for Linux
1075 sg_def_reserved_size=
1079 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1082 Maximal number of shapers.
1085 See header of drivers/scsi/sim710.c.
1091 Format: <io>,<irq>,<dma>
1092 See header of drivers/cdrom/sjcd.c.
1097 Format: <io1>[,<io2>[,...,<io8>]]
1099 snd-ad1816a= [HW,ALSA]
1101 snd-ad1848= [HW,ALSA]
1103 snd-ali5451= [HW,ALSA]
1105 snd-als100= [HW,ALSA]
1107 snd-als4000= [HW,ALSA]
1109 snd-azt2320= [HW,ALSA]
1111 snd-cmi8330= [HW,ALSA]
1113 snd-cmipci= [HW,ALSA]
1115 snd-cs4231= [HW,ALSA]
1117 snd-cs4232= [HW,ALSA]
1119 snd-cs4236= [HW,ALSA]
1121 snd-cs4281= [HW,ALSA]
1123 snd-cs46xx= [HW,ALSA]
1125 snd-dt019x= [HW,ALSA]
1127 snd-dummy= [HW,ALSA]
1129 snd-emu10k1= [HW,ALSA]
1131 snd-ens1370= [HW,ALSA]
1133 snd-ens1371= [HW,ALSA]
1135 snd-es968= [HW,ALSA]
1137 snd-es1688= [HW,ALSA]
1139 snd-es18xx= [HW,ALSA]
1141 snd-es1938= [HW,ALSA]
1143 snd-es1968= [HW,ALSA]
1145 snd-fm801= [HW,ALSA]
1147 snd-gusclassic= [HW,ALSA]
1149 snd-gusextreme= [HW,ALSA]
1151 snd-gusmax= [HW,ALSA]
1155 snd-ice1712= [HW,ALSA]
1157 snd-intel8x0= [HW,ALSA]
1159 snd-interwave= [HW,ALSA]
1164 snd-korg1212= [HW,ALSA]
1166 snd-maestro3= [HW,ALSA]
1168 snd-mpu401= [HW,ALSA]
1170 snd-mtpav= [HW,ALSA]
1172 snd-nm256= [HW,ALSA]
1174 snd-opl3sa2= [HW,ALSA]
1182 snd-opti93x= [HW,ALSA]
1186 snd-rme32= [HW,ALSA]
1188 snd-rme96= [HW,ALSA]
1190 snd-rme9652= [HW,ALSA]
1196 snd-sbawe= [HW,ALSA]
1198 snd-serial= [HW,ALSA]
1200 snd-sgalaxy= [HW,ALSA]
1202 snd-sonicvibes= [HW,ALSA]
1207 snd-sun-cs4231= [HW,ALSA]
1209 snd-trident= [HW,ALSA]
1211 snd-usb-audio= [HW,ALSA,USB]
1213 snd-via82xx= [HW,ALSA]
1215 snd-virmidi= [HW,ALSA]
1217 snd-wavefront= [HW,ALSA]
1219 snd-ymfpci= [HW,ALSA]
1221 sonicvibes= [HW,OSS]
1225 Format: <io>[,<irq>]
1227 sonypi= [HW] Sony Programmable I/O Control Device driver
1228 Format: <minor>,<verbose>,<fnkeyinit>,<camera>,<compat>,<nojogdial>
1230 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1231 See Documentation/specialix.txt.
1233 speedstep_coppermine=
1234 [HW,IA-32] Take CPU in your notebook as SpeedStep-capable
1235 See comment before function speedstep_setup() in
1236 arch/i386/kernel/cpu/cpufreq/speedstep.c.
1238 spia_io_base= [HW,MTD]
1244 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1246 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1247 See Documentation/scsi/st.txt.
1250 See header of drivers/scsi/seagate.c.
1254 Set the STI (builtin display/keyboard on the HP-PARISC
1255 machines) console (graphic card) which should be used
1256 as the initial boot-console.
1257 See also comment in drivers/video/console/sticore.c.
1260 See comment in drivers/video/console/sticore.c.
1263 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1265 stram_swap= [HW,M68k]
1267 swiotlb= [IA-64] Number of I/O TLB slabs
1271 sym53c416= [HW,SCSI]
1272 See header of drivers/scsi/sym53c416.c.
1274 sym53c8xx= [HW,SCSI]
1275 See Documentation/scsi/ncr53c8xx.txt.
1278 See header of drivers/scsi/t128.c.
1282 thash_entries= [KNL,NET]
1283 Set number of hash buckets for TCP connection
1286 See header of drivers/char/tipar.c.
1288 tiusb= [HW,USB] Texas Instruments' USB GraphLink (aka SilverLink)
1292 See header of drivers/scsi/seagate.c.
1295 See comment before function dc390_setup() in
1296 drivers/scsi/tmscsim.c.
1300 trix= [HW,OSS] MediaTrix AudioTrix Pro
1301 Format: <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1303 tsdev.xres= [TS] Horizontal screen resolution.
1304 tsdev.yres= [TS] Vertical screen resolution.
1306 turbografx.map[2|3]=
1307 [HW,JOY] TurboGraFX parallel port interface
1308 Format: <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1309 See also Documentation/input/joystick-parport.txt
1311 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1312 See header of drivers/scsi/u14-34f.c.
1320 video= [FB] Frame buffer configuration
1321 See Documentation/fb/modedb.txt.
1323 vga= [BOOT,IA-32] Select a particular video mode
1324 See Documentation/i386/boot.txt and Documentation/svga.txt.
1325 Use vga=ask for menu.
1326 This is actually a boot loader parameter; the value is
1327 passed to the kernel using a special protocol.
1329 vmalloc=nn[KMG] [KNL,BOOT] forces the vmalloc area to have an exact
1330 size of <nn>. This can be used to increase the
1331 minimum size (128MB on x86). It can also be used to
1332 decrease the size and leave more room for directly
1339 waveartist= [HW,OSS]
1340 Format: <io>,<irq>,<dma>,<dma2>
1343 See header of drivers/scsi/wd33c93.c.
1346 See header of drivers/scsi/wd7000.c.
1349 See Documentation/watchdog/watchdog.txt.
1351 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1352 xd_geo= See header of drivers/block/xd.c.
1354 xirc2ps_cs= [NET,PCMCIA]
1355 Format: <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1361 The last known update (for 2.4.0) - the changelog was not kept before.
1362 2000-06-?? Mr. Unknown
1364 Update for 2.5.49, description for most of the options introduced,
1365 references to other documentation (C files, READMEs, ..), added S390,
1366 PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
1368 2002-11-24 Petr Baudis <pasky@ucw.cz>
1369 Randy Dunlap <randy.dunlap@verizon.net>
1373 Add documentation for ALSA options.
1374 Add more DRM drivers.