X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=Documentation%2Fkernel-parameters.txt;h=202aad533b4c16e4cd4d8559359c1269dfe32bd6;hb=refs%2Fheads%2Fvserver;hp=fc99075e0af47f0b73a2ae2dfb7d19920c604dea;hpb=64ba3f394c830ec48a1c31b53dcae312c56f1604;p=linux-2.6.git diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index fc99075e0..202aad533 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1,4 +1,4 @@ -February 2003 Kernel Parameters v2.5.59 + Kernel Parameters ~~~~~~~~~~~~~~~~~ The following is a consolidated list of the kernel parameters as implemented @@ -17,9 +17,17 @@ are specified on the kernel command line with the module name plus usbcore.blinkenlights=1 -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: +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: ACPI ACPI support is enabled. ALSA ALSA sound support is enabled. @@ -27,7 +35,6 @@ restrictions referred to are that the relevant option is valid if: 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 @@ -49,9 +56,11 @@ restrictions referred to are that the relevant option is valid if: 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. @@ -101,6 +110,13 @@ be entered as an environment variable, whereas its absence indicates that it will appear as a kernel argument readable via /proc/cmdline by programs running once the system is up. +The number of kernel parameters is not limited, but the length of the +complete command line (parameters including spaces etc.) is limited to +a fixed number of characters. This limit depends on the architecture +and is between 256 and 4096 characters. It is defined in the file +./include/asm/setup.h as COMMAND_LINE_SIZE. + + 53c7xx= [HW,SCSI] Amiga SCSI controllers See header of drivers/scsi/53c7xx.c. See also Documentation/scsi/ncr53c7xx.txt. @@ -138,6 +154,9 @@ running once the system is up. acpi_irq_isa= [HW,ACPI] If irq_balance, mark listed IRQs used by ISA Format: ,... + 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 @@ -145,6 +164,10 @@ running once the system is up. acpi_skip_timer_override [HW,ACPI] Recognize and ignore IRQ0/pin2 Interrupt Override. For broken nForce2 BIOS resulting in XT-PIC timer. + acpi_use_timer_override [HW,ACPI} + Use timer override. For some broken Nvidia NF5 boards + that require a timer override, but don't have + HPET acpi_dbg_layer= [HW,ACPI] Format: @@ -167,6 +190,11 @@ running once the system is up. 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 @@ -265,9 +293,6 @@ running once the system is up. autotest [IA64] - awe= [HW,OSS] AWE32/SB32/AWE64 wave table synth - Format: ,, - aztcd= [HW,CD] Aztech CD268 CDROM driver Format: ,0x79 (?) @@ -329,10 +354,11 @@ running once the system is up. Value can be changed at runtime via /selinux/checkreqprot. - 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. + clock= [BUGS=IA-32, HW] gettimeofday clocksource override. + [Deprecated] + Forces specified clocksource (if available) to be used + when calculating gettimeofday(). If specified + clocksource is not available, it defaults to PIT. Format: { pit | tsc | cyclone | pmtmr } disable_8254_timer @@ -366,12 +392,17 @@ running once the system is up. tty Use the virtual console device . ttyS[,options] + ttyUSB0[,options] Use the specified serial port. The options are of - the form "bbbbpn", where "bbbb" is the baud rate, - "p" is parity ("n", "o", or "e"), and "n" is bits. - Default is "9600n8". + 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". - See also Documentation/serial-console.txt. + See Documentation/serial-console.txt for more + information. See + Documentation/networking/netconsole.txt for an + alternative. uart,io,[,options] uart,mmio,[,options] @@ -412,13 +443,19 @@ running once the system is up. 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: [,] 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. @@ -500,10 +537,6 @@ running once the system is up. Default value is 0. Value can be changed at runtime via /selinux/enforce. - es1370= [HW,OSS] - Format: [,] - See also header of sound/oss/es1370.c. - es1371= [HW,OSS] Format: ,[,[]] See also header of sound/oss/es1371.c. @@ -515,6 +548,13 @@ running once the system is up. eurwdt= [HW,WDT] Eurotech CPU-1220/1410 onboard watchdog. Format: [,] + failslab= + fail_page_alloc= + fail_make_request=[KNL] + General fault injection mechanism. + Format: ,,, + See also /Documentation/fault-injection/. + fd_mcs= [HW,SCSI] See header of drivers/scsi/fd_mcs.c. @@ -524,9 +564,6 @@ running once the system is up. floppy= [HW] See Documentation/floppy.txt. - ftape= [HW] Floppy Tape subsystem debugging options. - See Documentation/ftape.txt. - gamecon.map[2|3]= [HW,JOY] Multisystem joystick and NES/SNES/PSX pad support via parallel port (up to 5 devices per port) @@ -544,11 +581,6 @@ running once the system is up. gscd= [HW,CD] Format: - gt96100eth= [NET] MIPS GT96100 Advanced Communication Controller - - gus= [HW,OSS] - Format: ,,, - gvp11= [HW,SCSI] hashdist= [KNL,NUMA] Large hashes allocated during boot @@ -574,11 +606,9 @@ running once the system is up. hugepages= [HW,IA-32,IA-64] Maximal number of HugeTLB pages. - noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing - i8042.direct [HW] Put keyboard port into non-translated mode - i8042.dumbkbd [HW] Pretend that controlled can only read data from - keyboard and can not control its state + i8042.dumbkbd [HW] Pretend that controller can only read data from + keyboard and cannot control its state (Don't attempt to blink the leds) i8042.noaux [HW] Don't check for auxiliary (== mouse) port i8042.nokbd [HW] Don't check/create keyboard port @@ -625,6 +655,10 @@ running once the system is up. idle= [HW] Format: idle=poll or idle=halt + ignore_loglevel [KNL] + Ignore loglevel setting - this will print /all/ + kernel messages to the console. Useful for debugging. + ihash_entries= [KNL] Set number of hash buckets for inode cache. @@ -668,6 +702,12 @@ running once the system is up. 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: ,.... + irqfixup [HW] When an interrupt is not handled search all handlers for it. Intended to get systems with badly broken @@ -683,7 +723,12 @@ running once the system is up. Format: ,,, isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler. - Format: ,..., + Format: + ,..., + or + - (must be a positive range in ascending order) + or a mixture + ,...,- This option can be used to specify one or more CPUs to isolate from the general SMP balancing and scheduling algorithms. The only way to move a process onto or off @@ -801,12 +846,6 @@ running once the system is up. (machvec) in a generic kernel. Example: machvec=hpzx1_swiotlb - mad16= [HW,OSS] Format: - ,,,,,, - - maui= [HW,OSS] - Format: , - max_loop= [LOOP] Maximum number of loopback devices that can be mounted Format: <1-256> @@ -987,6 +1026,10 @@ running once the system is up. emulation library even if a 387 maths coprocessor is present. + noaliencache [MM, NUMA] Disables the allcoation of alien caches in + the slab allocator. Saves per-node memory, but will + impact performance on real NUMA hardware. + noalign [KNL,ARM] noapic [SMP,APIC] Tells the kernel to not make use of any @@ -1000,6 +1043,8 @@ running once the system is up. nocache [ARM] + nodelayacct [KNL] Disable per-task delay accounting + nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects. noexec [IA-64] @@ -1008,7 +1053,9 @@ running once the system is up. noexec=on: enable non-executable mappings (default) noexec=off: disable nn-executable mappings - nofxsr [BUGS=IA-32] + 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. nohlt [BUGS=ARM] @@ -1023,9 +1070,14 @@ running once the system is up. in certain environments such as networked servers or real-time systems. + noirqbalance [IA-32,SMP,KNL] Disable kernel irq balancing + noirqdebug [IA-32] Disables the code which attempts to detect and disable unhandled interrupt sources. + no_timer_check [IA-32,X86_64,APIC] Disables the code which tests for + broken timer IRQ sources. + noisapnp [ISAPNP] Disables ISA PnP code. noinitrd [RAM] Tells the kernel not to load any configured @@ -1038,10 +1090,10 @@ running once the system is up. noltlbs [PPC] Do not use large page/tlb entries for kernel lowmem mapping on PPC40x. - nomce [IA-32] Machine Check Exception - nomca [IA-64] Disable machine check abort handling + nomce [IA-32] Machine Check Exception + noresidual [PPC] Don't use residual data on PReP machines. noresume [SWSUSP] Disables resume and restores original swap @@ -1053,6 +1105,8 @@ running once the system is up. 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. @@ -1068,9 +1122,6 @@ running once the system is up. opl3= [HW,OSS] Format: - opl3sa= [HW,OSS] - Format: ,,,,, - opl3sa2= [HW,OSS] Format: ,,,,,,,[,, - step/bucket size as a power of 2 for statistical time based profiling. + Param: "sleep" - profile D-state sleeping (millisecs) processor.max_cstate= [HW,ACPI] Limit processor to maximum C-state @@ -1273,7 +1347,7 @@ running once the system is up. pt. [PARIDE] See Documentation/paride.txt. - quiet= [KNL] Disable log messages + quiet [KNL] Disable most log messages r128= [HW,DRM] @@ -1299,10 +1373,6 @@ running once the system is up. rcu.qlowmark= [KNL,BOOT] Set threshold of queued RCU callbacks below which batch limiting is re-enabled. - rcu.rsinterval= [KNL,BOOT,SMP] Set the number of additional - RCU callbacks to queued before forcing reschedule - on all cpus. - rdinit= [KNL] Format: Run specified binary instead of /init from the ramdisk, @@ -1310,13 +1380,27 @@ running once the system is up. reboot= [BUGS=IA-32,BUGS=ARM,BUGS=IA-64] Rebooting mode Format: [,[,...]] - See arch/*/kernel/reboot.c. + See arch/*/kernel/reboot.c or arch/*/kernel/process.c reserve= [KNL,BUGS] Force the kernel to ignore some iomem area + reservetop= [IA-32] + Format: nn[KMG] + Reserves a hole at the top of the kernel virtual + address space. + + reset_devices [KNL] Force drivers to reset the underlying device + during initialization. + resume= [SWSUSP] Specify the partition device for software suspend + resume_offset= [SWSUSP] + Specify the offset from the beginning of the partition + given by "resume=" at which the swap header is located, + in units (needed only for swap files). + See Documentation/power/swsusp-and-swap-files.txt + rhash_entries= [KNL,NET] Set number of hash buckets for route cache @@ -1367,6 +1451,11 @@ running once the system is up. scsi_logging= [SCSI] + scsi_mod.scan= [SCSI] sync (default) scans SCSI busses as they are + discovered. async scans them in kernel threads, + allowing boot to proceed. none ignores them, expecting + user space to do the scan. + selinux [SELINUX] Disable or enable SELinux at boot time. Format: { "0" | "1" } See security/selinux/Kconfig help text. @@ -1376,13 +1465,19 @@ running once the system is up. 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] - sgalaxy= [HW,OSS] - Format: ,,,, - shapers= [NET] Maximal number of shapers. @@ -1523,9 +1618,6 @@ running once the system is up. snd-ymfpci= [HW,ALSA] - sonicvibes= [HW,OSS] - Format: - sonycd535= [HW,CD] Format: [,] @@ -1569,6 +1661,12 @@ running once the system is up. sym53c416= [HW,SCSI] See header of drivers/scsi/sym53c416.c. + sysrq_always_enabled + [KNL] + Ignore sysrq setting - this boot parameter will + neutralize any effect of /proc/sys/kernel/sysrq. + Useful for debugging. + t128= [HW,SCSI] See header of drivers/scsi/t128.c. @@ -1579,6 +1677,10 @@ running once the system is up. 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). @@ -1617,9 +1719,21 @@ running once the system is up. uart6850= [HW,OSS] Format: , + uhci-hcd.ignore_oc= + [USB] Ignore overcurrent events (default N). + Some badly-designed motherboards generate lots of + bogus events, for ports that aren't wired to + anything. Set this parameter to avoid log spamming. + Note that genuine overcurrent events won't be + reported either. + 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. @@ -1636,9 +1750,14 @@ running once the system is up. decrease the size and leave more room for directly mapped kernel RAM. - vmhalt= [KNL,S390] + vmhalt= [KNL,S390] Perform z/VM CP command after system halt. + Format: + + vmpanic= [KNL,S390] Perform z/VM CP command after kernel panic. + Format: - vmpoff= [KNL,S390] + vmpoff= [KNL,S390] Perform z/VM CP command after power off. + Format: waveartist= [HW,OSS] Format: ,,, @@ -1662,22 +1781,11 @@ running once the system is up. norandmaps Don't use address space randomization Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space + unwind_debug=N N > 0 will enable dwarf2 unwinder debugging + This is useful to get more information why + you got a "dwarf2 unwinder stuck" ______________________________________________________________________ -Changelog: - -2000-06-?? Mr. Unknown - The last known update (for 2.4.0) - the changelog was not kept before. - -2002-11-24 Petr Baudis - Randy Dunlap - 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 - Lots of typos, whitespace, some reformatting. TODO: