- Kernel Parameters
+February 2003 Kernel Parameters v2.5.59
~~~~~~~~~~~~~~~~~
The following is a consolidated list of the kernel parameters as implemented
usbcore.blinkenlights=1
-This document may not be entirely up to date and comprehensive. The command
-"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
-module. Loadable modules, after being loaded into the running kernel, also
-reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
-parameters may be changed at runtime by the command
-"echo -n ${value} > /sys/module/${modulename}/parameters/${parm}".
-
-The parameters listed below are only valid if certain kernel build options were
-enabled and if respective hardware is present. The text in square brackets at
-the beginning of each description states the restrictions within which a
-parameter is applicable:
+The text in square brackets at the beginning of the description states the
+restrictions on the kernel for the said kernel parameter to be valid. The
+restrictions referred to are that the relevant option is valid if:
ACPI ACPI support is enabled.
ALSA ALSA sound support is enabled.
APM Advanced Power Management support is enabled.
AX25 Appropriate AX.25 support is enabled.
CD Appropriate CD support is enabled.
+ DEVFS devfs support is enabled.
DRM Direct Rendering Management support is enabled.
EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
EFI EFI Partitioning (GPT) is enabled
MCA MCA bus support is enabled.
MDA MDA console support is enabled.
MOUSE Appropriate mouse support is enabled.
- MSI Message Signaled Interrupts (PCI).
MTD MTD support is enabled.
NET Appropriate network support is enabled.
NUMA NUMA support is enabled.
- GENERIC_TIME The generic timeofday code is enabled.
NFS Appropriate NFS support is enabled.
OSS OSS sound support is enabled.
PARIDE The ParIDE subsystem is enabled.
acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA
Format: <irq>,<irq>...
- acpi_os_name= [HW,ACPI] Tell ACPI BIOS the name of the OS
- Format: To spoof as Windows 98: ="Microsoft Windows"
-
acpi_osi= [HW,ACPI] empty param disables _OSI
acpi_serialize [HW,ACPI] force serialization of AML methods
override platform specific driver.
See also Documentation/acpi-hotkey.txt.
- acpi_pm_good [IA-32,X86-64]
- Override the pmtimer bug detection: force the kernel
- to assume that this machine's pmtimer latches its value
- and always returns good values.
-
enable_timer_pin_1 [i386,x86-64]
Enable PIN 1 of APIC timer
Can be useful to work around chipset bugs
Value can be changed at runtime via
/selinux/checkreqprot.
- clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
- [Deprecated]
- Forces specified clocksource (if avaliable) to be used
- when calculating gettimeofday(). If specified
- clocksource is not avalible, it defaults to PIT.
+ clock= [BUGS=IA-32,HW] gettimeofday timesource override.
+ Forces specified timesource (if avaliable) to be used
+ when calculating gettimeofday(). If specicified
+ timesource is not avalible, it defaults to PIT.
Format: { pit | tsc | cyclone | pmtmr }
disable_8254_timer
tty<n> Use the virtual console device <n>.
ttyS<n>[,options]
- ttyUSB0[,options]
Use the specified serial port. The options are of
- the form "bbbbpnf", where "bbbb" is the baud rate,
- "p" is parity ("n", "o", or "e"), "n" is number of
- bits, and "f" is flow control ("r" for RTS or
- omit it). Default is "9600n8".
+ the form "bbbbpn", where "bbbb" is the baud rate,
+ "p" is parity ("n", "o", or "e"), and "n" is bits.
+ Default is "9600n8".
- See Documentation/serial-console.txt for more
- information. See
- Documentation/networking/netconsole.txt for an
- alternative.
+ See also Documentation/serial-console.txt.
uart,io,<addr>[,options]
uart,mmio,<addr>[,options]
debug [KNL] Enable kernel debugging (events log level).
- debug_locks_verbose=
- [KNL] verbose self-tests
- Format=<0|1>
- Print debugging info while doing the locking API
- self-tests.
- We default to 0 (no extra messages), setting it to
- 1 will print _a lot_ more information - normally
- only useful to kernel developers.
-
decnet= [HW,NET]
Format: <area>[,<node>]
See also Documentation/networking/decnet.txt.
+ devfs= [DEVFS]
+ See Documentation/filesystems/devfs/boot-options.
+
dhash_entries= [KNL]
Set number of hash buckets for dentry cache.
ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
See header of drivers/scsi/ips.c.
- ports= [IP_VS_FTP] IPVS ftp helper module
- Default is 21.
- Up to 8 (IP_VS_APP_MAX_PORTS) ports
- may be specified.
- Format: <port>,<port>....
-
irqfixup [HW]
When an interrupt is not handled search all handlers
for it. Intended to get systems with badly broken
nocache [ARM]
- nodelayacct [KNL] Disable per-task delay accounting
-
nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
noexec [IA-64]
noexec=on: enable non-executable mappings (default)
noexec=off: disable nn-executable mappings
- nofxsr [BUGS=IA-32] Disables x86 floating point extended
- register save and restore. The kernel will only save
- legacy floating-point registers on task switch.
+ nofxsr [BUGS=IA-32]
nohlt [BUGS=ARM]
noltlbs [PPC] Do not use large page/tlb entries for kernel
lowmem mapping on PPC40x.
- nomca [IA-64] Disable machine check abort handling
-
nomce [IA-32] Machine Check Exception
+ nomca [IA-64] Disable machine check abort handling
+
noresidual [PPC] Don't use residual data on PReP machines.
noresume [SWSUSP] Disables resume and restores original swap
nosbagart [IA-64]
- nosep [BUGS=IA-32] Disables x86 SYSENTER/SYSEXIT support.
-
nosmp [SMP] Tells an SMP kernel to act as a UP kernel.
nosync [HW,M68K] Disables sync negotiation for all devices.
pas16= [HW,SCSI]
See header of drivers/scsi/pas16.c.
- pause_on_oops=
- Halt all CPUs after the first oops has been printed for
- the specified number of seconds. This is to be used if
- your oopses keep scrolling off the screen.
-
pcbit= [HW,ISDN]
pcd. [PARIDE]
Mechanism 2.
nommconf [IA-32,X86_64] Disable use of MMCONFIG for PCI
Configuration
- nomsi [MSI] If the PCI_MSI kernel config parameter is
- enabled, this kernel boot option can be used to
- disable the use of MSI interrupts system-wide.
nosort [IA-32] Don't sort PCI devices according to
order given by the PCI BIOS. This sorting is
done to get a device order compatible with
If enabled at boot time, /selinux/disable can be used
later to disable prior to initial policy load.
- selinux_compat_net =
- [SELINUX] Set initial selinux_compat_net flag value.
- Format: { "0" | "1" }
- 0 -- use new secmark-based packet controls
- 1 -- use legacy packet controls
- Default value is 0 (preferred).
- Value can be changed at runtime via
- /selinux/compat_net.
-
serialnumber [BUGS=IA-32]
sg_def_reserved_size= [SCSI]
time Show timing data prefixed to each printk message line
- clocksource= [GENERIC_TIME] Override the default clocksource
- Override the default clocksource and use the clocksource
- with the name specified.
-
tipar.timeout= [HW,PPT]
Set communications timeout in tenths of a second
(default 15).
usbhid.mousepoll=
[USBHID] The interval which mice are to be polled at.
- vdso= [IA-32]
- vdso=1: enable VDSO (default)
- vdso=0: disable VDSO mapping
-
video= [FB] Frame buffer configuration
See Documentation/fb/modedb.txt.
decrease the size and leave more room for directly
mapped kernel RAM.
- vmhalt= [KNL,S390] Perform z/VM CP command after system halt.
- Format: <command>
-
- vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic.
- Format: <command>
+ vmhalt= [KNL,S390]
- vmpoff= [KNL,S390] Perform z/VM CP command after power off.
- Format: <command>
+ vmpoff= [KNL,S390]
waveartist= [HW,OSS]
Format: <io>,<irq>,<dma>,<dma2>
______________________________________________________________________
+Changelog:
+
+2000-06-?? Mr. Unknown
+ The last known update (for 2.4.0) - the changelog was not kept before.
+
+2002-11-24 Petr Baudis <pasky@ucw.cz>
+ Randy Dunlap <randy.dunlap@verizon.net>
+ Update for 2.5.49, description for most of the options introduced,
+ references to other documentation (C files, READMEs, ..), added S390,
+ PPC, SPARC, MTD, ALSA and OSS category. Minor corrections and
+ reformatting.
+
+2005-10-19 Randy Dunlap <rdunlap@xenotime.net>
+ Lots of typos, whitespace, some reformatting.
TODO:
git://git.onelab.eu / linux-2.6.git / blobdiff