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 states 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 DHCP, 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 MSI Message Signaled Interrupts (PCI).
53 MTD MTD support is enabled.
54 NET Appropriate network support is enabled.
55 NUMA NUMA support is enabled.
56 NFS Appropriate NFS support is enabled.
57 OSS OSS sound support is enabled.
58 PARIDE The ParIDE subsystem is enabled.
59 PARISC The PA-RISC architecture is enabled.
60 PCI PCI bus support is enabled.
61 PCMCIA The PCMCIA subsystem is enabled.
62 PNP Plug & Play support is enabled.
63 PPC PowerPC architecture is enabled.
64 PPT Parallel port support is enabled.
65 PS2 Appropriate PS/2 support is enabled.
66 RAM RAM disk support is enabled.
67 S390 S390 architecture is enabled.
68 SCSI Appropriate SCSI support is enabled.
69 A lot of drivers has their options described inside of
71 SELINUX SELinux support is enabled.
72 SERIAL Serial support is enabled.
73 SMP The kernel is an SMP kernel.
74 SPARC Sparc architecture is enabled.
75 SWSUSP Software suspend is enabled.
76 TS Appropriate touchscreen support is enabled.
77 USB USB support is enabled.
78 USBHID USB Human Interface Device support is enabled.
79 V4L Video For Linux support is enabled.
80 VGA The VGA console has been enabled.
81 VT Virtual terminal support is enabled.
82 WDT Watchdog support is enabled.
83 XT IBM PC/XT MFM hard disk support is enabled.
84 X86-64 X86-64 architecture is enabled.
85 More X86-64 boot options can be found in
86 Documentation/x86_64/boot-options.txt .
88 In addition, the following text indicates that the option:
90 BUGS= Relates to possible processor bugs on the said processor.
91 KNL Is a kernel start-up parameter.
92 BOOT Is a boot loader parameter.
94 Parameters denoted with BOOT are actually interpreted by the boot
95 loader, and have no meaning to the kernel directly.
96 Do not modify the syntax of boot loader parameters without extreme
97 need or coordination with <Documentation/i386/boot.txt>.
99 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
100 a trailing = on the name of any parameter states that that parameter will
101 be entered as an environment variable, whereas its absence indicates that
102 it will appear as a kernel argument readable via /proc/cmdline by programs
103 running once the system is up.
105 53c7xx= [HW,SCSI] Amiga SCSI controllers
106 See header of drivers/scsi/53c7xx.c.
107 See also Documentation/scsi/ncr53c7xx.txt.
109 acpi= [HW,ACPI] Advanced Configuration and Power Interface
110 Format: { force | off | ht | strict | noirq }
111 force -- enable ACPI if default was off
112 off -- disable ACPI if default was on
113 noirq -- do not use ACPI for IRQ routing
114 ht -- run only enough ACPI to enable Hyper Threading
115 strict -- Be less tolerant of platforms that are not
116 strictly ACPI specification compliant.
118 See also Documentation/pm.txt, pci=noacpi
120 acpi_sleep= [HW,ACPI] Sleep options
121 Format: { s3_bios, s3_mode }
122 See Documentation/power/video.txt
124 acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
125 Format: { level | edge | high | low }
127 acpi_irq_balance [HW,ACPI]
128 ACPI will balance active IRQs
131 acpi_irq_nobalance [HW,ACPI]
132 ACPI will not move active IRQs (default)
135 acpi_irq_pci= [HW,ACPI] If irq_balance, clear listed IRQs for
137 Format: <irq>,<irq>...
139 acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
140 Format: <irq>,<irq>...
142 acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
143 Format: To spoof as Windows 98: ="Microsoft Windows"
145 acpi_osi= [HW,ACPI] empty param disables _OSI
147 acpi_serialize [HW,ACPI] force serialization of AML methods
149 acpi_skip_timer_override [HW,ACPI]
150 Recognize and ignore IRQ0/pin2 Interrupt Override.
151 For broken nForce2 BIOS resulting in XT-PIC timer.
153 acpi_dbg_layer= [HW,ACPI]
155 Each bit of the <int> indicates an ACPI debug layer,
156 1: enable, 0: disable. It is useful for boot time
157 debugging. After system has booted up, it can be set
158 via /proc/acpi/debug_layer.
160 acpi_dbg_level= [HW,ACPI]
162 Each bit of the <int> indicates an ACPI debug level,
163 1: enable, 0: disable. It is useful for boot time
164 debugging. After system has booted up, it can be set
165 via /proc/acpi/debug_level.
167 acpi_fake_ecdt [HW,ACPI] Workaround failure due to BIOS lacking ECDT
169 acpi_generic_hotkey [HW,ACPI]
170 Allow consolidated generic hotkey driver to
171 override platform specific driver.
172 See also Documentation/acpi-hotkey.txt.
174 enable_timer_pin_1 [i386,x86-64]
175 Enable PIN 1 of APIC timer
176 Can be useful to work around chipset bugs
177 (in particular on some ATI chipsets).
178 The kernel tries to set a reasonable default.
180 disable_timer_pin_1 [i386,x86-64]
181 Disable PIN 1 of APIC timer
182 Can be useful to work around chipset bugs.
185 Format: <io>,<irq>,<dma>,<dma2>
186 See also Documentation/sound/oss/AD1816.
189 Format: <io>,<irq>,<dma>,<dma2>,<type>
195 See header of drivers/scsi/advansys.c.
197 advwdt= [HW,WDT] Advantech WDT
198 Format: <iostart>,<iostop>
200 aedsp16= [HW,OSS] Audio Excel DSP 16
201 Format: <io>,<irq>,<dma>,<mss_io>,<mpu_io>,<mpu_irq>
202 See also header of sound/oss/aedsp16.c.
205 See Documentation/scsi/aha152x.txt.
208 Format: <portbase>[,<buson>,<busoff>[,<dmaspeed>]]
211 See Documentation/scsi/aic7xxx.txt.
214 See Documentation/scsi/aic79xx.txt.
216 amijoy.map= [HW,JOY] Amiga joystick support
217 Map of devices attached to JOY0DAT and JOY1DAT
219 See also Documentation/kernel/input/joystick.txt
221 analog.map= [HW,JOY] Analog joystick and gamepad support
222 Specifies type or capabilities of an analog joystick
223 connected to one of 16 gameports
224 Format: <type1>,<type2>,..<type16>
227 Power management functions (SPARCstation-4/5 + deriv.)
229 Disable APC CPU standby support. SPARCstation-Fox does
230 not play well with APC CPU idle - disable it if you have
231 APC and your system crashes randomly.
233 apic= [APIC,i386] Change the output verbosity whilst booting
234 Format: { quiet (default) | verbose | debug }
235 Change the amount of debugging information output
236 when initialising the APIC and IO-APIC components.
238 apm= [APM] Advanced Power Management
239 See header of arch/i386/kernel/apm.c.
244 arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards
245 Format: <io>,<irq>,<nodeID>
249 atarimouse= [HW,MOUSE] Atari Mouse
251 atascsi= [HW,SCSI] Atari SCSI
253 atkbd.extra= [HW] Enable extra LEDs and keys on IBM RapidAccess,
254 EzKey and similar keyboards
256 atkbd.reset= [HW] Reset keyboard during initialization
258 atkbd.set= [HW] Select keyboard code set
259 Format: <int> (2 = AT (default), 3 = PS/2)
261 atkbd.scroll= [HW] Enable scroll wheel on MS Office and similar
264 atkbd.softraw= [HW] Choose between synthetic and real raw mode
265 Format: <bool> (0 = real, 1 = synthetic (default))
267 atkbd.softrepeat= [HW]
268 Use software keyboard repeat
272 awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth
273 Format: <io>,<memsize>,<isapnp>
275 aztcd= [HW,CD] Aztech CD268 CDROM driver
276 Format: <io>,0x79 (?)
278 baycom_epp= [HW,AX25]
281 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem
283 See header of drivers/net/hamradio/baycom_par.c.
285 baycom_ser_fdx= [HW,AX25]
286 BayCom Serial Port AX.25 Modem (Full Duplex Mode)
287 Format: <io>,<irq>,<mode>[,<baud>]
288 See header of drivers/net/hamradio/baycom_ser_fdx.c.
290 baycom_ser_hdx= [HW,AX25]
291 BayCom Serial Port AX.25 Modem (Half Duplex Mode)
292 Format: <io>,<irq>,<mode>
293 See header of drivers/net/hamradio/baycom_ser_hdx.c.
295 blkmtd_device= [HW,MTD]
301 bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards)
302 bttv.radio= Most important insmod options are available as
304 bttv.pll= See Documentation/video4linux/bttv/Insmod-options
305 bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
308 See drivers/scsi/BusLogic.c, comment before function
309 BusLogic_ParseDriverOptions().
311 c101= [NET] Moxa C101 synchronous serial card
313 cachesize= [BUGS=IA-32] Override level 2 CPU cache size detection.
314 Sometimes CPU hardware bugs make them report the cache
315 size incorrectly. The kernel will attempt work arounds
316 to fix known problems, but for some CPUs it is not
317 possible to determine what the correct size should be.
318 This option provides an override for these situations.
321 Format: <io>,<irq>[,PAS]
322 See header of drivers/cdrom/cdu31a.c.
324 chandev= [HW,NET] Generic channel device initialisation
326 checkreqprot [SELINUX] Set initial checkreqprot flag value.
327 Format: { "0" | "1" }
328 See security/selinux/Kconfig help text.
329 0 -- check protection applied by kernel (includes
330 any implied execute protection).
331 1 -- check protection requested by application.
332 Default value is set via a kernel config option.
333 Value can be changed at runtime via
334 /selinux/checkreqprot.
336 clock= [BUGS=IA-32,HW] gettimeofday timesource override.
337 Forces specified timesource (if avaliable) to be used
338 when calculating gettimeofday(). If specicified
339 timesource is not avalible, it defaults to PIT.
340 Format: { pit | tsc | cyclone | pmtmr }
344 [IA32/X86_64] Disable/Enable interrupt 0 timer routing
345 over the 8254 in addition to over the IO-APIC. The
346 kernel tries to set a sensible default.
348 hpet= [IA-32,HPET] option to disable HPET and use PIT.
352 Format: { auto | [<io>,][<irq>] }
354 com20020= [HW,NET] ARCnet - COM20020 chipset
356 <io>[,<irq>[,<nodeID>[,<backplane>[,<ckp>[,<timeout>]]]]]
358 com90io= [HW,NET] ARCnet - COM90xx chipset (IO-mapped buffers)
362 ARCnet - COM90xx chipset (memory-mapped buffers)
363 Format: <io>[,<irq>[,<memstart>]]
365 condev= [HW,S390] console device
368 console= [KNL] Output console device and options.
370 tty<n> Use the virtual console device <n>.
374 Use the specified serial port. The options are of
375 the form "bbbbpnf", where "bbbb" is the baud rate,
376 "p" is parity ("n", "o", or "e"), "n" is number of
377 bits, and "f" is flow control ("r" for RTS or
378 omit it). Default is "9600n8".
380 See Documentation/serial-console.txt for more
382 Documentation/networking/netconsole.txt for an
385 uart,io,<addr>[,options]
386 uart,mmio,<addr>[,options]
387 Start an early, polled-mode console on the 8250/16550
388 UART at the specified I/O port or MMIO address,
389 switching to the matching ttyS device later. The
390 options are the same as for ttyS, above.
392 cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
394 <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
397 Format: { parport<nr> | auto | none }
399 crashkernel=nn[KMG]@ss[KMG]
400 [KNL] Reserve a chunk of physical memory to
401 hold a kernel to switch to with kexec on panic.
404 Format: <io>,<irq>,<dma>,<dma2>,<mpuio>,<mpuirq>
409 cs89x0_media= [HW,NET]
410 Format: { rj45 | aui | bnc }
412 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
415 See header of drivers/s390/block/dasd_devmap.c.
417 db9.dev[2|3]= [HW,JOY] Multisystem joystick support via parallel port
418 (one device per port)
419 Format: <port#>,<type>
420 See also Documentation/input/joystick-parport.txt
422 debug [KNL] Enable kernel debugging (events log level).
425 Format: <area>[,<node>]
426 See also Documentation/networking/decnet.txt.
429 See Documentation/filesystems/devfs/boot-options.
432 Set number of hash buckets for dentry cache.
435 IO parameters + enable/disable command.
437 digiepca= [HW,SERIAL]
438 See drivers/char/README.epca and
439 Documentation/digiepca.txt.
441 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
443 Format: <io_dev0>[,<io_dev1>[,..<io_dev32>]]
445 dmasound= [HW,OSS] Sound subsystem buffers
451 earlyprintk= [IA-32,X86-64]
453 earlyprintk=serial[,ttySn[,baudrate]]
455 Append ",keep" to not disable it when the real console
458 Only vga or serial at a time, not both.
460 Currently only ttyS0 and ttyS1 are supported.
462 Interaction with the standard serial driver is not
465 The VGA output is eventually overwritten by the real
470 ec_intr= [HW,ACPI] ACPI Embedded Controller interrupt mode
473 non-0: interrupt mode (default)
480 Format: {"of[f]" | "sk[ipmbr]"}
481 See comment in arch/i386/boot/edd.S
484 Format: <id>,<membase>,<irq>
486 eisa_irq_edge= [PARISC,HW]
487 See header of drivers/parisc/eisa.c.
490 See comment before function elanfreq_setup() in
491 arch/i386/kernel/cpu/cpufreq/elanfreq.c.
494 Format: {"anticipatory" | "cfq" | "deadline" | "noop"}
495 See Documentation/block/as-iosched.txt and
496 Documentation/block/deadline-iosched.txt for details.
498 elfcorehdr= [IA-32, X86_64]
499 Specifies physical address of start of kernel core
500 image elf header. Generally kexec loader will
501 pass this option to capture kernel.
502 See Documentation/kdump/kdump.txt for details.
504 enforcing [SELINUX] Set initial enforcing status.
506 See security/selinux/Kconfig help text.
507 0 -- permissive (log only, no denials).
508 1 -- enforcing (deny and log).
510 Value can be changed at runtime via /selinux/enforce.
513 Format: <lineout>[,<micbias>]
514 See also header of sound/oss/es1370.c.
517 Format: <spdif>,[<nomix>,[<amplifier>]]
518 See also header of sound/oss/es1371.c.
520 ether= [HW,NET] Ethernet cards parameters
521 This option is obsoleted by the "netdev=" option, which
522 has equivalent usage. See its documentation for details.
524 eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
528 See header of drivers/scsi/fd_mcs.c.
531 See header of drivers/scsi/fdomain.c.
534 See Documentation/floppy.txt.
536 ftape= [HW] Floppy Tape subsystem debugging options.
537 See Documentation/ftape.txt.
540 [HW,JOY] Multisystem joystick and NES/SNES/PSX pad
541 support via parallel port (up to 5 devices per port)
542 Format: <port#>,<pad1>,<pad2>,<pad3>,<pad4>,<pad5>
543 See also Documentation/input/joystick-parport.txt
548 See header of drivers/scsi/gdth.c.
550 gpt [EFI] Forces disk with valid GPT signature but
551 invalid Protective MBR to be treated as GPT.
556 gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller
559 Format: <io>,<irq>,<dma>,<dma16>
563 hashdist= [KNL,NUMA] Large hashes allocated during boot
564 are distributed across NUMA nodes. Defaults on
565 for IA-64, off otherwise.
566 Format: 0 | 1 (for off | on)
568 hcl= [IA-64] SGI's Hardware Graph compatibility layer
570 hd= [EIDE] (E)IDE hard drive subsystem geometry
571 Format: <cyl>,<head>,<sect>
573 hd?= [HW] (E)IDE subsystem
574 hd?lun= See Documentation/ide.txt.
576 highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact
577 size of <nn>. This works even on boxes that have no
578 highmem otherwise. This also works to reduce highmem
579 size on bigger boxes.
582 See Documentation/isdn/README.HiSax.
584 hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages.
586 noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing
588 i8042.direct [HW] Put keyboard port into non-translated mode
589 i8042.dumbkbd [HW] Pretend that controlled can only read data from
590 keyboard and can not control its state
591 (Don't attempt to blink the leds)
592 i8042.noaux [HW] Don't check for auxiliary (== mouse) port
593 i8042.nokbd [HW] Don't check/create keyboard port
594 i8042.nomux [HW] Don't check presence of an active multiplexing
596 i8042.nopnp [HW] Don't use ACPIPnP / PnPBIOS to discover KBD/AUX
599 [HW] Frequency with which keyboard LEDs should blink
600 when kernel panics (default is 0.5 sec)
601 i8042.reset [HW] Reset the controller during init and cleanup
602 i8042.unlock [HW] Unlock (ignore) the keylock
606 i8k.ignore_dmi [HW] Continue probing hardware even if DMI data
607 indicates that the driver is running on unsupported
609 i8k.force [HW] Activate i8k driver even if SMM BIOS signature
610 does not match list of supported models.
612 [HW] Report power status in /proc/i8k
613 (disabled by default)
614 i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
617 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter
618 See Documentation/mca.txt.
621 Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
623 ide= [HW] (E)IDE subsystem
624 Format: ide=nodma or ide=doubler or ide=reverse
625 See Documentation/ide.txt.
627 ide?= [HW] (E)IDE subsystem
628 Format: ide?=noprobe or chipset specific parameters.
629 See Documentation/ide.txt.
631 idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed
632 See Documentation/ide.txt.
635 Format: idle=poll or idle=halt
638 Set number of hash buckets for inode cache.
641 See header of drivers/scsi/in2000.c.
645 Run specified binary instead of /sbin/init as init
648 initcall_debug [KNL] Trace initcalls as they are executed. Useful
649 for working out where the kernel is dying during
652 initrd= [BOOT] Specify the location of the initial ramdisk
654 inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver
657 combined_mode= [HW] control which driver uses IDE ports in combined
658 mode: legacy IDE driver, libata, or both
659 (in the libata case, libata.atapi_enabled=1 may be
660 useful as well). Note that using the ide or libata
661 options may affect your device naming (e.g. by
662 changing hdc to sdb).
663 Format: combined (default), ide, or libata
667 io7= [HW] IO7 for Marvel based alpha systems
668 See comment before marvel_specify_io7 in
669 arch/alpha/kernel/core_marvel.c.
672 See Documentation/nfsroot.txt.
674 ip2= [HW] Set IO/IRQ pairs for up to 4 IntelliPort boards
675 See comment before ip2_setup() in drivers/char/ip2.c.
677 ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
678 See header of drivers/scsi/ips.c.
681 When an interrupt is not handled search all handlers
682 for it. Intended to get systems with badly broken
686 When an interrupt is not handled search all handlers
687 for it. Also check all handlers each timer
688 interrupt. Intended to get systems with badly broken
692 Format: <RDP>,<reset>,<pci_scan>,<verbosity>
694 isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
695 Format: <cpu number>,...,<cpu number>
696 This option can be used to specify one or more CPUs
697 to isolate from the general SMP balancing and scheduling
698 algorithms. The only way to move a process onto or off
699 an "isolated" CPU is via the CPU affinity syscalls.
700 <cpu number> begins at 0 and the maximum value is
701 "number of CPUs in system - 1".
703 This option is the preferred way to isolate CPUs. The
704 alternative -- manually setting the CPU mask of all
705 tasks in the system -- can cause problems and
706 suboptimal load balancer performance.
709 Format: <io>,<irq>,<dma>,<setup>
713 js= [HW,JOY] Analog joystick
714 See Documentation/input/joystick.txt.
718 kstack=N [IA-32,X86-64] Print N words from the kernel stack
723 lapic [IA-32,APIC] Enable the local APIC even if BIOS
726 lasi= [HW,SCSI] PARISC LASI driver for the 53c700 chip
727 Format: addr:<io>,irq:<irq>
729 llsc*= [IA64] See function print_params() in
730 arch/ia64/sn/kernel/llsc4.c.
732 load_ramdisk= [RAM] List of ramdisks to load from floppy
733 See Documentation/ramdisk.txt.
735 lockd.nlm_grace_period=P [NFS] Assign grace period.
738 lockd.nlm_tcpport=N [NFS] Assign TCP port.
741 lockd.nlm_timeout=T [NFS] Assign timeout value.
744 lockd.nlm_udpport=M [NFS] Assign UDP port.
747 logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
750 loglevel= All Kernel Messages with a loglevel smaller than the
751 console loglevel will be printed to the console. It can
752 also be changed with klogd or other programs. The
753 loglevels are defined as follows:
755 0 (KERN_EMERG) system is unusable
756 1 (KERN_ALERT) action must be taken immediately
757 2 (KERN_CRIT) critical conditions
758 3 (KERN_ERR) error conditions
759 4 (KERN_WARNING) warning conditions
760 5 (KERN_NOTICE) normal but significant condition
761 6 (KERN_INFO) informational
762 7 (KERN_DEBUG) debug-level messages
764 log_buf_len=n Sets the size of the printk ring buffer, in bytes.
765 Format: { n | nk | nM }
766 n must be a power of two. The default size
767 is set in the kernel config file.
769 lp=0 [LP] Specify parallel ports to use, e.g,
770 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
771 lp=reset first parallel port). 'lp=0' disables the
772 lp=auto printer driver. 'lp=reset' (which can be
773 specified in addition to the ports) causes
774 attached printers to be reset. Using
775 lp=port1,port2,... specifies the parallel ports
776 to associate lp devices with, starting with
777 lp0. A port specification may be 'none' to skip
778 that lp device, or a parport name such as
779 'parport0'. Specifying 'lp=auto' instead of a
780 port specification list means that device IDs
781 from each port should be examined, to see if
782 an IEEE 1284-compliant printer is attached; if
783 so, the driver will manage that printer.
784 See also header of drivers/char/lp.c.
787 Sets loops_per_jiffy to given constant, thus avoiding
788 time-consuming boot-time autodetection (up to 250 ms per
789 CPU). 0 enables autodetection (default). To determine
790 the correct value for your kernel, boot with normal
791 autodetection and see what value is printed. Note that
792 on SMP systems the preset will be applied to all CPUs,
793 which is likely to cause problems if your CPUs need
794 significantly divergent settings. An incorrect value
795 will cause delays in the kernel to be wrong, leading to
796 unpredictable I/O errors and other breakage. Although
797 unlikely, in the extreme case this might damage your
801 Format: <io>,<irq>,<dma>
803 mac5380= [HW,SCSI] Format:
804 <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
806 mac53c9x= [HW,SCSI] Format:
807 <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
809 machvec= [IA64] Force the use of a particular machine-vector
810 (machvec) in a generic kernel.
811 Example: machvec=hpzx1_swiotlb
813 mad16= [HW,OSS] Format:
814 <io>,<irq>,<dma>,<dma16>,<mpu_io>,<mpu_irq>,<joystick>
819 max_loop= [LOOP] Maximum number of loopback devices that can
823 maxcpus= [SMP] Maximum number of processors that an SMP kernel
826 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
827 equal to this physical address is ignored.
829 max_luns= [SCSI] Maximum number of LUNs to probe.
830 Should be between 1 and 2^32-1.
833 [SCSI] Maximum number of LUNs received.
834 Should be between 1 and 16384.
836 mca-pentium [BUGS=IA-32]
841 Format: <port>,<irq>,<mitsumi_bug_93_wait>
845 mce [IA-32] Machine Check Exception
847 md= [HW] RAID subsystems devices and level
848 See Documentation/md.txt.
851 Format: <first>,<last>
852 Specifies range of consoles to be captured by the MDA.
854 mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
855 Amount of memory to be used when the kernel is not able
856 to see the whole system memory or for test.
857 [IA-32] Use together with memmap= to avoid physical
858 address space collisions. Without memmap= PCI devices
859 could be placed at addresses belonging to unused RAM.
861 mem=nopentium [BUGS=IA-32] Disable usage of 4MB pages for kernel
864 memmap=exactmap [KNL,IA-32,X86_64] Enable setting of an exact
865 E820 memory map, as specified by the user.
866 Such memmap=exactmap lines can be constructed based on
867 BIOS output or other requirements. See the memmap=nn@ss
870 memmap=nn[KMG]@ss[KMG]
871 [KNL] Force usage of a specific region of memory
872 Region of memory to be used, from ss to ss+nn.
874 memmap=nn[KMG]#ss[KMG]
875 [KNL,ACPI] Mark specific memory as ACPI data.
876 Region of memory to be used, from ss to ss+nn.
878 memmap=nn[KMG]$ss[KMG]
879 [KNL,ACPI] Mark specific memory as reserved.
880 Region of memory to be used, from ss to ss+nn.
882 meye.*= [HW] Set MotionEye Camera parameters
883 See Documentation/video4linux/meye.txt.
888 [KNL,SMP] debug: override scheduler migration costs
889 Format: <level-1-usecs>,<level-2-usecs>,...
890 This debugging option can be used to override the
891 default scheduler migration cost matrix. The numbers
892 are indexed by 'CPU domain distance'.
893 E.g. migration_cost=1000,2000,3000 on an SMT NUMA
894 box will set up an intra-core migration cost of
895 1 msec, an inter-core migration cost of 2 msecs,
896 and an inter-node migration cost of 3 msecs.
898 WARNING: using the wrong values here can break
899 scheduler performance, so it's only for scheduler
900 development purposes, not production environments.
903 [KNL,SMP] migration cost auto-detect verbosity
905 If a system's migration matrix reported at bootup
906 seems erroneous then this option can be used to
907 increase verbosity of the detection process.
908 We default to 0 (no extra messages), 1 will print
909 some more information, and 2 will be really
910 verbose (probably only useful if you also have a
911 serial console attached to the system).
914 [KNL,SMP] multiply/divide migration costs by a factor
916 This debug option can be used to proportionally
917 increase or decrease the auto-detected migration
918 costs for all entries of the migration matrix.
919 E.g. migration_factor=150 will increase migration
920 costs by 50%. (and thus the scheduler will be less
921 eager migrating cache-hot tasks)
922 migration_factor=80 will decrease migration costs
923 by 20%. (thus the scheduler will be more eager to
926 WARNING: using the wrong values here can break
927 scheduler performance, so it's only for scheduler
928 development purposes, not production environments.
931 [MOUSE] Maximum time between finger touching and
932 leaving touchpad surface for touch to be considered
933 a tap and be reported as a left button click (for
934 touchpads working in absolute mode only).
936 mousedev.xres= [MOUSE] Horizontal screen resolution, used for devices
937 reporting absolute coordinates, such as tablets
938 mousedev.yres= [MOUSE] Vertical screen resolution, used for devices
939 reporting absolute coordinates, such as tablets
945 Format: <name>,<region-number>,<size>,<offset>
947 MTD_Region= [MTD] Format:
948 <name>,<region-number>[,<base>,<size>,<buswidth>,<altbuswidth>]
951 See drivers/mtd/cmdline.c.
953 mtouchusb.raw_coordinates=
954 [HW] Make the MicroTouch USB driver use raw coordinates
955 ('y', default) or cooked coordinates ('n')
957 n2= [NET] SDL Inc. RISCom/N2 synchronous serial card
960 See header of drivers/scsi/NCR_D700.c.
966 ncr53c400a= [HW,SCSI]
968 ncr53c406a= [HW,SCSI]
972 netdev= [NET] Network devices parameters
973 Format: <irq>,<io>,<mem_start>,<mem_end>,<name>
974 Note that mem_start is often overloaded to mean
975 something different and driver-specific.
976 This usage is only documented in each driver source
980 See Documentation/nfsroot.txt.
982 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
983 See Documentation/nfsroot.txt.
985 nfs.callback_tcpport=
986 [NFS] set the TCP port on which the NFSv4 callback
987 channel should listen.
989 nfs.idmap_cache_timeout=
990 [NFS] set the maximum lifetime for idmapper cache
993 nmi_watchdog= [KNL,BUGS=IA-32] Debugging features for SMP kernels
995 no387 [BUGS=IA-32] Tells the kernel to use the 387 maths
996 emulation library even if a 387 maths coprocessor
1001 noapic [SMP,APIC] Tells the kernel to not make use of any
1002 IOAPICs that may be present in the system.
1004 noasync [HW,M68K] Disables async and sync negotiation for
1007 nobats [PPC] Do not use BATs for mapping kernel lowmem
1008 on "Classic" PPC cores.
1012 nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
1016 noexec [IA-32,X86-64]
1017 noexec=on: enable non-executable mappings (default)
1018 noexec=off: disable nn-executable mappings
1020 nofxsr [BUGS=IA-32] Disables x86 floating point extended
1021 register save and restore. The kernel will only save
1022 legacy floating-point registers on task switch.
1026 no-hlt [BUGS=IA-32] Tells the kernel that the hlt
1027 instruction doesn't work correctly and not to
1030 nohalt [IA-64] Tells the kernel not to use the power saving
1031 function PAL_HALT_LIGHT when idle. This increases
1032 power-consumption. On the positive side, it reduces
1033 interrupt wake-up latency, which may improve performance
1034 in certain environments such as networked servers or
1037 noirqdebug [IA-32] Disables the code which attempts to detect and
1038 disable unhandled interrupt sources.
1040 noisapnp [ISAPNP] Disables ISA PnP code.
1042 noinitrd [RAM] Tells the kernel not to load any configured
1047 nolapic [IA-32,APIC] Do not enable or use the local APIC.
1049 noltlbs [PPC] Do not use large page/tlb entries for kernel
1050 lowmem mapping on PPC40x.
1052 nomce [IA-32] Machine Check Exception
1054 nomca [IA-64] Disable machine check abort handling
1056 noresidual [PPC] Don't use residual data on PReP machines.
1058 noresume [SWSUSP] Disables resume and restores original swap
1061 no-scroll [VGA] Disables scrollback.
1062 This is required for the Braillex ib80-piezo Braille
1063 reader made by F.H. Papenmeier (Germany).
1067 nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
1069 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
1071 nosync [HW,M68K] Disables sync negotiation for all devices.
1073 notsc [BUGS=IA-32] Disable Time Stamp Counter
1075 nousb [USB] Disable the USB subsystem
1079 nr_uarts= [SERIAL] maximum number of UARTs to be registered.
1085 Format: <io>,<irq>,<dma>,<dma2>,<mpu_io>,<mpu_irq>
1087 opl3sa2= [HW,OSS] Format:
1088 <io>,<irq>,<dma>,<dma2>,<mss_io>,<mpu_io>,<ymode>,<loopback>[,<isapnp>,<multiple]
1090 oprofile.timer= [HW]
1091 Use timer interrupt instead of performance counters
1096 osst= [HW,SCSI] SCSI Tape Driver
1097 Format: <buffer_size>,<write_threshold>
1098 See also Documentation/scsi/st.txt.
1100 panic= [KNL] Kernel behaviour on panic
1103 parkbd.port= [HW] Parallel port number the keyboard adapter is
1104 connected to, default is 0.
1106 parkbd.mode= [HW] Parallel port keyboard adapter mode of operation,
1107 0 for XT, 1 for AT (default is AT).
1110 parport= [HW,PPT] Specify parallel ports. 0 disables.
1111 Format: { 0 | auto | 0xBBB[,IRQ[,DMA]] }
1112 Use 'auto' to force the driver to use any
1113 IRQ/DMA settings detected (the default is to
1114 ignore detected IRQ/DMA settings because of
1115 possible conflicts). You can specify the base
1116 address, IRQ, and DMA settings; IRQ and DMA
1117 should be numbers, or 'auto' (for using detected
1118 settings on that particular port), or 'nofifo'
1119 (to avoid using a FIFO even if it is detected).
1120 Parallel ports are assigned in the order they
1121 are specified on the command line, starting
1124 parport_init_mode= [HW,PPT]
1125 Configure VIA parallel port to operate in
1126 a specific mode. This is necessary on Pegasos
1127 computer where firmware has no options for setting
1128 up parallel port mode and sets it to spp.
1129 Currently this function knows 686a and 8231 chips.
1130 Format: [spp|ps2|epp|ecp|ecpepp]
1132 pas2= [HW,OSS] Format:
1133 <io>,<irq>,<dma>,<dma16>,<sb_io>,<sb_irq>,<sb_dma>,<sb_dma16>
1136 See header of drivers/scsi/pas16.c.
1139 Halt all CPUs after the first oops has been printed for
1140 the specified number of seconds. This is to be used if
1141 your oopses keep scrolling off the screen.
1146 See header of drivers/block/paride/pcd.c.
1147 See also Documentation/paride.txt.
1149 pci=option[,option...] [PCI] various PCI subsystem options:
1150 off [IA-32] don't probe for the PCI bus
1151 bios [IA-32] force use of PCI BIOS, don't access
1152 the hardware directly. Use this if your machine
1153 has a non-standard PCI host bridge.
1154 nobios [IA-32] disallow use of PCI BIOS, only direct
1155 hardware access methods are allowed. Use this
1156 if you experience crashes upon bootup and you
1157 suspect they are caused by the BIOS.
1158 conf1 [IA-32] Force use of PCI Configuration
1160 conf2 [IA-32] Force use of PCI Configuration
1162 nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
1164 nomsi [MSI] If the PCI_MSI kernel config parameter is
1165 enabled, this kernel boot option can be used to
1166 disable the use of MSI interrupts system-wide.
1167 nosort [IA-32] Don't sort PCI devices according to
1168 order given by the PCI BIOS. This sorting is
1169 done to get a device order compatible with
1171 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
1172 routing table. These calls are known to be buggy
1173 on several machines and they hang the machine
1174 when used, but on other computers it's the only
1175 way to get the interrupt routing table. Try
1176 this option if the kernel is unable to allocate
1177 IRQs or discover secondary PCI buses on your
1179 rom [IA-32] Assign address space to expansion ROMs.
1180 Use with caution as certain devices share
1181 address decoders between ROMs and other
1183 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be
1184 assigned automatically to PCI devices. You can
1185 make the kernel exclude IRQs of your ISA cards
1187 pirqaddr=0xAAAAA [IA-32] Specify the physical address
1188 of the PIRQ table (normally generated
1189 by the BIOS) if it is outside the
1190 F0000h-100000h range.
1191 lastbus=N [IA-32] Scan all buses thru bus #N. Can be
1192 useful if the kernel is unable to find your
1193 secondary buses and you want to tell it
1194 explicitly which ones they are.
1195 assign-busses [IA-32] Always assign all PCI bus
1196 numbers ourselves, overriding
1197 whatever the firmware may have done.
1198 usepirqmask [IA-32] Honor the possible IRQ mask stored
1199 in the BIOS $PIR table. This is needed on
1200 some systems with broken BIOSes, notably
1201 some HP Pavilion N5400 and Omnibook XE3
1202 notebooks. This will have no effect if ACPI
1203 IRQ routing is enabled.
1204 noacpi [IA-32] Do not use ACPI for IRQ routing
1205 or for PCI scanning.
1206 routeirq Do IRQ routing for all PCI devices.
1207 This is normally done in pci_enable_device(),
1208 so this option is a temporary workaround
1209 for broken drivers that don't call it.
1210 firmware [ARM] Do not re-enumerate the bus but instead
1211 just use the configuration from the
1212 bootloader. This is currently used on
1213 IXP2000 systems where the bus has to be
1214 configured a certain way for adjunct CPUs.
1216 pcmv= [HW,PCMCIA] BadgePAD 4
1219 See Documentation/paride.txt.
1221 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1224 See arch/parisc/kernel/pdc_chassis.c
1227 See Documentation/paride.txt.
1230 See Documentation/paride.txt.
1232 pirq= [SMP,APIC] Manual mp-table setup
1233 See Documentation/i386/IO-APIC.txt.
1235 plip= [PPT,NET] Parallel port network link
1236 Format: { parport<nr> | timid | 0 }
1237 See also Documentation/parport.txt.
1243 { on | off | curr | res | no-curr | no-res }
1246 [ISAPNP] Exclude IRQs for the autoconfiguration
1249 [ISAPNP] Exclude DMAs for the autoconfiguration
1251 pnp_reserve_io= [ISAPNP] Exclude I/O ports for the autoconfiguration
1252 Ranges are in pairs (I/O port base and size).
1255 [ISAPNP] Exclude memory regions for the
1257 Ranges are in pairs (memory base and size).
1259 profile= [KNL] Enable kernel profiling via /proc/profile
1260 Format: [schedule,]<number>
1261 Param: "schedule" - profile schedule points.
1262 Param: <number> - step/bucket size as a power of 2 for
1263 statistical time based profiling.
1265 processor.max_cstate= [HW,ACPI]
1266 Limit processor to maximum C-state
1267 max_cstate=9 overrides any DMI blacklist limit.
1269 processor.nocst [HW,ACPI]
1270 Ignore the _CST method to determine C-states,
1271 instead using the legacy FADT method
1273 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1275 See Documentation/ramdisk.txt.
1277 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1278 probe for; one of (bare|imps|exps|lifebook|any).
1279 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports
1281 psmouse.resetafter= [HW,MOUSE]
1282 Try to reset the device after so many bad packets
1285 [HW,MOUSE] Set desired mouse resolution, in dpi.
1286 psmouse.smartscroll=
1287 [HW,MOUSE] Controls Logitech smartscroll autorepeat.
1288 0 = disabled, 1 = enabled (default).
1290 pss= [HW,OSS] Personal Sound System (ECHO ESC614)
1292 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1295 See Documentation/paride.txt.
1297 quiet= [KNL] Disable log messages
1302 See Documentation/md.txt.
1304 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated]
1305 See Documentation/ramdisk.txt.
1307 ramdisk_blocksize= [RAM]
1308 See Documentation/ramdisk.txt.
1310 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1311 New name for the ramdisk parameter.
1312 See Documentation/ramdisk.txt.
1314 rcu.blimit= [KNL,BOOT] Set maximum number of finished
1315 RCU callbacks to process in one batch.
1317 rcu.qhimark= [KNL,BOOT] Set threshold of queued
1318 RCU callbacks over which batch limiting is disabled.
1320 rcu.qlowmark= [KNL,BOOT] Set threshold of queued
1321 RCU callbacks below which batch limiting is re-enabled.
1323 rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional
1324 RCU callbacks to queued before forcing reschedule
1329 Run specified binary instead of /init from the ramdisk,
1330 used for early userspace startup. See initrd.
1332 reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
1333 Format: <reboot_mode>[,<reboot_mode2>[,...]]
1334 See arch/*/kernel/reboot.c.
1336 reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
1339 Specify the partition device for software suspend
1341 rhash_entries= [KNL,NET]
1342 Set number of hash buckets for route cache
1344 riscom8= [HW,SERIAL]
1345 Format: <io_board1>[,<io_board2>[,...<io_boardN>]]
1347 ro [KNL] Mount root device read-only on boot
1349 root= [KNL] Root filesystem
1351 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
1352 mount the root filesystem
1354 rootflags= [KNL] Set root filesystem mount option string
1356 rootfstype= [KNL] Set root filesystem type
1358 rw [KNL] Mount root device read-write on boot
1360 S [KNL] Run init in single mode
1363 See drivers/net/irda/sa1100_ir.c.
1366 Format: <io>,<irq>,<dma>,<dma2>
1368 sbni= [NET] Granch SBNI12 leased line adapter
1370 sbpcd= [HW,CD] Soundblaster CD adapter
1372 See a comment before function sbpcd_setup() in
1373 drivers/cdrom/sbpcd.c.
1375 sc1200wdt= [HW,WDT] SC1200 WDT (watchdog) driver
1376 Format: <io>[,<timeout>[,<isapnp>]]
1378 scsi_debug_*= [SCSI]
1379 See drivers/scsi/scsi_debug.c.
1381 scsi_default_dev_flags=
1382 [SCSI] SCSI default device flags
1385 scsi_dev_flags= [SCSI] Black/white list entry for vendor and model
1386 Format: <vendor>:<model>:<flags>
1387 (flags are integer value)
1389 scsi_logging= [SCSI]
1391 selinux [SELINUX] Disable or enable SELinux at boot time.
1392 Format: { "0" | "1" }
1393 See security/selinux/Kconfig help text.
1396 Default value is set via kernel config option.
1397 If enabled at boot time, /selinux/disable can be used
1398 later to disable prior to initial policy load.
1400 serialnumber [BUGS=IA-32]
1402 sg_def_reserved_size= [SCSI]
1405 Format: <io>,<irq>,<dma>,<dma2>,<sgbase>
1408 Maximal number of shapers.
1411 See header of drivers/scsi/sim710.c.
1417 Format: <io>,<irq>,<dma>
1418 See header of drivers/cdrom/sjcd.c.
1423 Format: <io1>[,<io2>[,...,<io8>]]
1425 snd-ad1816a= [HW,ALSA]
1427 snd-ad1848= [HW,ALSA]
1429 snd-ali5451= [HW,ALSA]
1431 snd-als100= [HW,ALSA]
1433 snd-als4000= [HW,ALSA]
1435 snd-azt2320= [HW,ALSA]
1437 snd-cmi8330= [HW,ALSA]
1439 snd-cmipci= [HW,ALSA]
1441 snd-cs4231= [HW,ALSA]
1443 snd-cs4232= [HW,ALSA]
1445 snd-cs4236= [HW,ALSA]
1447 snd-cs4281= [HW,ALSA]
1449 snd-cs46xx= [HW,ALSA]
1451 snd-dt019x= [HW,ALSA]
1453 snd-dummy= [HW,ALSA]
1455 snd-emu10k1= [HW,ALSA]
1457 snd-ens1370= [HW,ALSA]
1459 snd-ens1371= [HW,ALSA]
1461 snd-es968= [HW,ALSA]
1463 snd-es1688= [HW,ALSA]
1465 snd-es18xx= [HW,ALSA]
1467 snd-es1938= [HW,ALSA]
1469 snd-es1968= [HW,ALSA]
1471 snd-fm801= [HW,ALSA]
1473 snd-gusclassic= [HW,ALSA]
1475 snd-gusextreme= [HW,ALSA]
1477 snd-gusmax= [HW,ALSA]
1481 snd-ice1712= [HW,ALSA]
1483 snd-intel8x0= [HW,ALSA]
1485 snd-interwave= [HW,ALSA]
1490 snd-korg1212= [HW,ALSA]
1492 snd-maestro3= [HW,ALSA]
1494 snd-mpu401= [HW,ALSA]
1496 snd-mtpav= [HW,ALSA]
1498 snd-nm256= [HW,ALSA]
1500 snd-opl3sa2= [HW,ALSA]
1508 snd-opti93x= [HW,ALSA]
1512 snd-rme32= [HW,ALSA]
1514 snd-rme96= [HW,ALSA]
1516 snd-rme9652= [HW,ALSA]
1522 snd-sbawe= [HW,ALSA]
1524 snd-serial= [HW,ALSA]
1526 snd-sgalaxy= [HW,ALSA]
1528 snd-sonicvibes= [HW,ALSA]
1533 snd-sun-cs4231= [HW,ALSA]
1535 snd-trident= [HW,ALSA]
1537 snd-usb-audio= [HW,ALSA,USB]
1539 snd-via82xx= [HW,ALSA]
1541 snd-virmidi= [HW,ALSA]
1543 snd-wavefront= [HW,ALSA]
1545 snd-ymfpci= [HW,ALSA]
1547 sonicvibes= [HW,OSS]
1551 Format: <io>[,<irq>]
1553 sonypi.*= [HW] Sony Programmable I/O Control Device driver
1554 See Documentation/sonypi.txt
1556 specialix= [HW,SERIAL] Specialix multi-serial port adapter
1557 See Documentation/specialix.txt.
1559 spia_io_base= [HW,MTD]
1565 Format: <io>,<irq>,<dma>,<mpu_io>,<mpu_irq>
1567 st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
1568 See Documentation/scsi/st.txt.
1571 See header of drivers/scsi/seagate.c.
1575 Set the STI (builtin display/keyboard on the HP-PARISC
1576 machines) console (graphic card) which should be used
1577 as the initial boot-console.
1578 See also comment in drivers/video/console/sticore.c.
1581 See comment in drivers/video/console/sticore.c.
1584 Format: bpp:<bpp1>[:<bpp2>[:<bpp3>...]]
1586 swiotlb= [IA-64] Number of I/O TLB slabs
1590 sym53c416= [HW,SCSI]
1591 See header of drivers/scsi/sym53c416.c.
1594 See header of drivers/scsi/t128.c.
1598 thash_entries= [KNL,NET]
1599 Set number of hash buckets for TCP connection
1601 time Show timing data prefixed to each printk message line
1603 tipar.timeout= [HW,PPT]
1604 Set communications timeout in tenths of a second
1607 tipar.delay= [HW,PPT]
1608 Set inter-bit delay in microseconds (default 10).
1611 See header of drivers/scsi/seagate.c.
1614 See comment before function dc390_setup() in
1615 drivers/scsi/tmscsim.c.
1619 trix= [HW,OSS] MediaTrix AudioTrix Pro
1621 <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
1623 tsdev.xres= [TS] Horizontal screen resolution.
1624 tsdev.yres= [TS] Vertical screen resolution.
1626 turbografx.map[2|3]= [HW,JOY]
1627 TurboGraFX parallel port interface
1629 <port#>,<js1>,<js2>,<js3>,<js4>,<js5>,<js6>,<js7>
1630 See also Documentation/input/joystick-parport.txt
1632 u14-34f= [HW,SCSI] UltraStor 14F/34F SCSI host adapter
1633 See header of drivers/scsi/u14-34f.c.
1642 [USBHID] The interval which mice are to be polled at.
1644 video= [FB] Frame buffer configuration
1645 See Documentation/fb/modedb.txt.
1647 vga= [BOOT,IA-32] Select a particular video mode
1648 See Documentation/i386/boot.txt and
1649 Documentation/svga.txt.
1650 Use vga=ask for menu.
1651 This is actually a boot loader parameter; the value is
1652 passed to the kernel using a special protocol.
1654 vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact
1655 size of <nn>. This can be used to increase the
1656 minimum size (128MB on x86). It can also be used to
1657 decrease the size and leave more room for directly
1664 waveartist= [HW,OSS]
1665 Format: <io>,<irq>,<dma>,<dma2>
1668 See header of drivers/scsi/wd33c93.c.
1671 See header of drivers/scsi/wd7000.c.
1674 See Documentation/watchdog/watchdog.txt.
1676 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.
1677 xd_geo= See header of drivers/block/xd.c.
1679 xirc2ps_cs= [NET,PCMCIA]
1681 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
1683 norandmaps Don't use address space randomization
1684 Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
1687 ______________________________________________________________________
1690 2000-06-?? Mr. Unknown
1691 The last known update (for 2.4.0) - the changelog was not kept before.
1693 2002-11-24 Petr Baudis <pasky@ucw.cz>
1694 Randy Dunlap <randy.dunlap@verizon.net>
1695 Update for 2.5.49, description for most of the options introduced,
1696 references to other documentation (C files, READMEs, ..), added S390,
1697 PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
1700 2005-10-19 Randy Dunlap <rdunlap@xenotime.net>
1701 Lots of typos, whitespace, some reformatting.
1705 Add documentation for ALSA options.
1706 Add more DRM drivers.