1 July 2000 Kernel Parameters v2.4.0
4 The following is a consolidated list of the kernel parameters as implemented
5 by the __setup() macro and sorted into English Dictionary order (defined
6 as ignoring all punctuation and sorting digits before letters in a case
7 insensitive manner), and with descriptions where known.
9 The text in square brackets at the beginning of the description state the
10 restrictions on the kernel for the said kernel parameter to be valid. The
11 restrictions referred to are that the relevant option is valid if:
13 ACPI ACPI support is enabled.
14 APIC APIC support is enabled.
15 APM Advanced Power Management support is enabled.
16 AX25 Appropriate AX.25 support is enabled.
17 CD Appropriate CD support is enabled.
18 DEVFS devfs support is enabled.
19 DRM Direct Rendering Management support is enabled.
20 EIDE EIDE/ATAPI support is enabled.
21 FB The frame buffer device is enabled.
22 HW Appropriate hardware is enabled.
23 IA-32 IA-32 aka i386 architecture is enabled.
24 IA-64 IA-64 architecture is enabled.
25 ISDN Appropriate ISDN support is enabled.
26 JOY Appropriate joystick support is enabled.
27 LP Printer support is enabled.
28 LOOP Loopback device support is enabled.
29 M68k M68k architecture is enabled.
30 MCA MCA bus support is enabled.
31 MDA MDA console support is enabled.
32 MOUSE Appropriate mouse support is enabled.
33 NET Appropriate network support is enabled.
34 NFS Appropriate NFS support is enabled.
35 PARIDE The ParIDE subsystem is enabled.
36 PCI PCI bus support is enabled.
37 PCMCIA The PCMCIA subsystem is enabled.
38 PNP Plug & Play support is enabled.
39 PPT Parallel port support is enabled.
40 PS2 Appropriate PS/2 support is enabled.
41 RAM RAM disk support is enabled.
42 SCSI Appropriate SCSI support is enabled.
43 SERIAL Serial support is enabled.
44 SMP The kernel is an SMP kernel.
45 SOUND Appropriate sound system support is enabled.
46 VGA The VGA console has been enabled.
47 VT Virtual terminal support is enabled.
48 XT IBM PC/XT MFM hard disk support is enabled.
50 In addition, the following text indicates that the option:
52 BUGS= Relates to possible processor bugs on the said processor.
53 KNL Is a kernel start-up parameter.
54 BOOT Is a boot loader parameter.
56 Parameters denoted with BOOT are actually interpreted by the boot
57 loader, and have no meaning to the kernel directly.
59 Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
60 a trailing = on the name of any parameter states that that parameter will
61 be entered as an environment variable, whereas its absence indicates that
62 it will appear as a kernel argument readable via /proc/cmdline by programs
63 running once the system is up.
65 53c7xx= [HW,SCSI] Amiga SCSI controllers.
67 acpi= [HW,ACPI] Advanced Configuration and Power Interface
73 adb_buttons= [HW,MOUSE]
89 amijoy= [HW,JOY] Amiga joystick support
91 apm= [APM] Advanced Power Management.
99 atarimouse= [HW,MOUSE] Atari Mouse.
101 atascsi= [HW,SCSI] Atari SCSI.
105 aztcd= [HW,CD] Aztec CD driver.
107 baycom_epp= [HW,AX25]
109 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem.
111 baycom_ser_fdx= [HW,AX25] BayCom Serial Port AX.25 Modem in Full
114 baycom_ser_hdx= [HW,AX25] BayCom Serial Port AX.25 Modem in Half
117 bmouse= [HW,MOUSE,PS2] Bus mouse.
135 console= [KNL] output console + comm spec (speed, control,
146 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter.
156 debug [KNL] Enable kernel debugging (events log level).
162 digi= [HW,SERIAL] io parameters + enable/disable command.
164 digiepca= [HW,SERIAL]
166 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA
169 dmasound= [HW,SOUND] (sound subsystem buffers).
185 ether= [HW,NET] Ethernet cards parameters (iomem, irq,
194 ftape= [HW] Floppy Tape subsystem debugging options.
212 hd= [EIDE] (E)IDE hard drive subsystem geometry
213 (Cyl/heads/sectors) or tune parameters.
221 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter.
225 ide?= [HW] (E)IDE subsystem : config (iomem/irq), tuning or
226 debugging (serialize,reset,no{dma,tune,probe}) or
227 chipset specific parameters.
229 idebus= [HW] (E)IDE subsystem : VLB/PCI bus speed.
237 initrd= [BOOT] Specify the location of the initial ramdisk.
245 js= [HW,JOY] Analog joystick
249 keep_initrd [HW, ARM]
251 load_ramdisk= [RAM] List of ramdisks to load from floppy.
253 logi_busmouse= [HW, MOUSE]
255 lp=0 [LP] Specify parallel ports to use, e.g,
256 lp=port[,port...] lp=none,parport0 (lp0 not configured, lp1 uses
257 lp=reset first parallel port). 'lp=0' disables the
258 lp=auto printer driver. 'lp=reset' (which can be
259 specified in addition to the ports) causes
260 attached printers to be reset. Using
261 lp=port1,port2,... specifies the parallel ports
262 to associate lp devices with, starting with
263 lp0. A port specification may be 'none' to skip
264 that lp device, or a parport name such as
265 'parport0'. Specifying 'lp=auto' instead of a
266 port specification list means that device IDs
267 from each port should be examined, to see if
268 an IEEE 1284-compliant printer is attached; if
269 so, the driver will manage that printer.
281 max_loop=[0-255] [LOOP] Set the maximum number of loopback devices
284 maxcpus= [SMP] States the maximum number of processors that
285 an SMP kernel should make use of.
287 max_scsi_luns= [SCSI]
289 mca-pentium [BUGS=ix86]
295 md= [HW] RAID subsystems devices and level.
303 mem=nn[KMG] [KNL,BOOT] force use of a specific amount of
304 memory; to be used when the kernel is not able
305 to see the whole system memory or for test.
313 msmouse= [HW,MOUSE] Microsoft Mouse.
319 ncr53c400a= [HW,SCSI]
321 ncr53c406a= [HW,SCSI]
329 nfsroot= [NFS] nfs root filesystem for disk-less boxes.
331 nmi_watchdog= [KNL,BUGS=ix86] debugging features for SMP kernels.
333 no387 [BUGS=ix86] Tells the kernel to use the 387 maths
334 emulation library even if a 387 maths coprocessor
339 noapic [SMP,APIC] Tells the kernel not to make use of any
340 APIC that may be present on the system.
342 noasync [HW, M68K] Disables async and sync negotiation for
347 nodisconnect [HW,SCSI, M68K] Disables SCSI disconnects.
353 noinitrd [RAM] Tells the kernel not to load any configured
360 nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
362 nosync [HW, M68K] Disables sync negotiation for all devices.
364 notsc [BUGS=ix86] Disable Time Stamp Counter
376 panic= [KNL] kernel behaviour on panic.
378 parport=0 [HW,PPT] Specify parallel ports. 0 disables.
379 parport=auto Use 'auto' to force the driver to use
380 parport=0xBBB[,IRQ[,DMA]] any IRQ/DMA settings detected (the
381 default is to ignore detected IRQ/DMA
382 settings because of possible
383 conflicts). You can specify the base
384 address, IRQ, and DMA settings; IRQ and
385 DMA should be numbers, or 'auto' (for
386 using detected settings on that
387 particular port), or 'nofifo' (to avoid
388 using a FIFO even if it is detected).
389 Parallel ports are assigned in the
390 order they are specified on the command
391 line, starting with parport0.
401 pci=option[,option...] [PCI] various PCI subsystem options:
402 off [IA-32] don't probe for the PCI bus
403 bios [IA-32] force use of PCI BIOS, don't access
404 the hardware directly. Use this if your machine
405 has a non-standard PCI host bridge.
406 nobios [IA-32] disallow use of PCI BIOS, only direct
407 hardware access methods are allowed. Use this
408 if you experience crashes upon bootup and you
409 suspect they are caused by the BIOS.
410 conf1 [IA-32] Force use of PCI Configuration Mechanism 1.
411 conf2 [IA-32] Force use of PCI Configuration Mechanism 2.
412 nosort [IA-32] Don't sort PCI devices according to
413 order given by the PCI BIOS. This sorting is done
414 to get a device order compatible with older kernels.
415 biosirq [IA-32] Use PCI BIOS calls to get the interrupt
416 routing table. These calls are known to be buggy
417 on several machines and they hang the machine when used,
418 but on other computers it's the only way to get the
419 interrupt routing table. Try this option if the kernel
420 is unable to allocate IRQs or discover secondary PCI
421 buses on your motherboard.
422 rom [IA-32] Assign address space to expansion ROMs.
423 Use with caution as certain devices share address
424 decoders between ROMs and other resources.
425 irqmask=0xMMMM [IA-32] Set a bit mask of IRQs allowed to be assigned
426 automatically to PCI devices. You can make the kernel
427 exclude IRQs of your ISA cards this way.
428 lastbus=N [IA-32] Scan all buses till bus #N. Can be useful
429 if the kernel is unable to find your secondary buses
430 and you want to tell it explicitly which ones they are.
438 pirq= [SMP,APIC] mp-table.
440 plip= [PPT,NET] Parallel port network link.
442 profile= [KNL] enable kernel profiling via /proc/profile
445 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
452 quiet= [KNL] Disable log messages.
458 ramdisk= [RAM] Sizes of RAM disks in kilobytes [deprecated].
463 ramdisk_size= [RAM] New name for the ramdisk parameter.
465 ramdisk_start= [RAM] Starting block of RAM disk image (so you can
466 place it after the kernel image on a boot floppy).
470 reserve= [KNL,BUGS] force the kernel to ignore some iomem area.
474 ro [KNL] Mount root device read-only on boot.
476 root= [KNL] root filesystem.
478 rw [KNL] Mount root device read-write on boot.
480 S [KNL] run init in single mode.
484 sbpcd= [HW,CD] Soundblaster CD adapter.
490 sg_def_reserved_size=
501 sonicvibes= [HW,SOUND]
507 soundmodem= [HW,AX25,SOUND] Use sound card as packet radio modem.
509 specialix= [HW,SERIAL] Specialix multi-serial port adapter.
513 st= [HW,SCSI] SCSI tape parameters (buffers, etc.).
551 video= [FB] frame buffer configuration.
553 vga= [BOOT] on ix386, select a particular video mode
554 (use vga=ask for menu). This is actually a
555 boot loader parameter; the value is passed to
556 the kernel using a special protocol. See
557 linux/Documentation/i386/boot.txt for information.
563 waveartist= [HW,SOUND]
571 xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks.