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Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 272 |
1 files changed, 197 insertions, 75 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 2443f5bb4364..a2d8805c03d5 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -89,6 +89,7 @@ parameter is applicable: SPARC Sparc architecture is enabled. SWSUSP Software suspend (hibernation) is enabled. SUSPEND System suspend states are enabled. + FTRACE Function tracing enabled. TS Appropriate touchscreen support is enabled. USB USB support is enabled. USBHID USB Human Interface Device support is enabled. @@ -100,7 +101,8 @@ parameter is applicable: X86-32 X86-32, aka i386 architecture is enabled. X86-64 X86-64 architecture is enabled. More X86-64 boot options can be found in - Documentation/x86_64/boot-options.txt . + Documentation/x86/x86_64/boot-options.txt . + X86 Either 32bit or 64bit x86 (same as X86-32+X86-64) In addition, the following text indicates that the option: @@ -111,10 +113,10 @@ In addition, the following text indicates that the option: Parameters denoted with BOOT are actually interpreted by the boot loader, and have no meaning to the kernel directly. Do not modify the syntax of boot loader parameters without extreme -need or coordination with <Documentation/i386/boot.txt>. +need or coordination with <Documentation/x86/i386/boot.txt>. There are also arch-specific kernel-parameters not documented here. -See for example <Documentation/x86_64/boot-options.txt>. +See for example <Documentation/x86/x86_64/boot-options.txt>. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that a trailing = on the name of any parameter states that that parameter will @@ -197,40 +199,53 @@ and is between 256 and 4096 characters. It is defined in the file that require a timer override, but don't have HPET - acpi.debug_layer= [HW,ACPI] - Format: <int> - Each bit of the <int> indicates an ACPI debug layer, - 1: enable, 0: disable. It is useful for boot time - debugging. After system has booted up, it can be set - via /sys/module/acpi/parameters/debug_layer. - CONFIG_ACPI_DEBUG must be enabled for this to produce any output. - Available bits (add the numbers together) to enable debug output - for specific parts of the ACPI subsystem: - 0x01 utilities 0x02 hardware 0x04 events 0x08 tables - 0x10 namespace 0x20 parser 0x40 dispatcher - 0x80 executer 0x100 resources 0x200 acpica debugger - 0x400 os services 0x800 acpica disassembler. - The number can be in decimal or prefixed with 0x in hex. - Warning: Many of these options can produce a lot of - output and make your system unusable. Be very careful. - - acpi.debug_level= [HW,ACPI] + acpi_backlight= [HW,ACPI] + acpi_backlight=vendor + acpi_backlight=video + If set to vendor, prefer vendor specific driver + (e.g. thinkpad_acpi, sony_acpi, etc.) instead + of the ACPI video.ko driver. + + acpi_display_output= [HW,ACPI] + acpi_display_output=vendor + acpi_display_output=video + See above. + + acpi.debug_layer= [HW,ACPI,ACPI_DEBUG] + acpi.debug_level= [HW,ACPI,ACPI_DEBUG] Format: <int> - Each bit of the <int> indicates an ACPI debug level, - 1: enable, 0: disable. It is useful for boot time - debugging. After system has booted up, it can be set - via /sys/module/acpi/parameters/debug_level. - CONFIG_ACPI_DEBUG must be enabled for this to produce any output. - Available bits (add the numbers together) to enable different - debug output levels of the ACPI subsystem: - 0x01 error 0x02 warn 0x04 init 0x08 debug object - 0x10 info 0x20 init names 0x40 parse 0x80 load - 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region - 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects - 0x10000 resources 0x20000 user requests 0x40000 package. - The number can be in decimal or prefixed with 0x in hex. - Warning: Many of these options can produce a lot of - output and make your system unusable. Be very careful. + CONFIG_ACPI_DEBUG must be enabled to produce any ACPI + debug output. Bits in debug_layer correspond to a + _COMPONENT in an ACPI source file, e.g., + #define _COMPONENT ACPI_PCI_COMPONENT + Bits in debug_level correspond to a level in + ACPI_DEBUG_PRINT statements, e.g., + ACPI_DEBUG_PRINT((ACPI_DB_INFO, ... + The debug_level mask defaults to "info". See + Documentation/acpi/debug.txt for more information about + debug layers and levels. + + Enable processor driver info messages: + acpi.debug_layer=0x20000000 + Enable PCI/PCI interrupt routing info messages: + acpi.debug_layer=0x400000 + Enable AML "Debug" output, i.e., stores to the Debug + object while interpreting AML: + acpi.debug_layer=0xffffffff acpi.debug_level=0x2 + Enable all messages related to ACPI hardware: + acpi.debug_layer=0x2 acpi.debug_level=0xffffffff + + Some values produce so much output that the system is + unusable. The "log_buf_len" parameter may be useful + if you need to capture more output. + + acpi.power_nocheck= [HW,ACPI] + Format: 1/0 enable/disable the check of power state. + On some bogus BIOS the _PSC object/_STA object of + power resource can't return the correct device power + state. In such case it is unneccessary to check its + power state again in power transition. + 1 : disable the power state check acpi_pm_good [X86-32,X86-64] Override the pmtimer bug detection: force the kernel @@ -283,7 +298,9 @@ and is between 256 and 4096 characters. It is defined in the file Possible values are: isolate - enable device isolation (each device, as far as possible, will get its own protection - domain) + domain) [default] + share - put every device behind one IOMMU into the + same protection domain fullflush - enable flushing of IO/TLB entries when they are unmapped. Otherwise they are flushed before they will be reused, which @@ -618,7 +635,7 @@ and is between 256 and 4096 characters. It is defined in the file digiepca= [HW,SERIAL] See drivers/char/README.epca and - Documentation/digiepca.txt. + Documentation/serial/digiepca.txt. disable_mtrr_cleanup [X86] enable_mtrr_cleanup [X86] @@ -690,7 +707,7 @@ and is between 256 and 4096 characters. It is defined in the file See Documentation/block/as-iosched.txt and Documentation/block/deadline-iosched.txt for details. - elfcorehdr= [X86-32, X86_64] + elfcorehdr= [IA64,PPC,SH,X86-32,X86_64] Specifies physical address of start of kernel core image elf header. Generally kexec loader will pass this option to capture kernel. @@ -729,7 +746,7 @@ and is between 256 and 4096 characters. It is defined in the file See header of drivers/scsi/fdomain.c. floppy= [HW] - See Documentation/floppy.txt. + See Documentation/blockdev/floppy.txt. force_pal_cache_flush [IA-64] Avoid check_sal_cache_flush which may hang on @@ -737,6 +754,14 @@ and is between 256 and 4096 characters. It is defined in the file parameter will force ia64_sal_cache_flush to call ia64_pal_cache_flush instead of SAL_CACHE_FLUSH. + ftrace=[tracer] + [ftrace] will set and start the specified tracer + as early as possible in order to facilitate early + boot debugging. + + ftrace_dump_on_oops + [ftrace] will dump the trace buffers on oops. + gamecon.map[2|3]= [HW,JOY] Multisystem joystick and NES/SNES/PSX pad support via parallel port (up to 5 devices per port) @@ -796,6 +821,12 @@ and is between 256 and 4096 characters. It is defined in the file Defaults to the default architecture's huge page size if not specified. + hlt [BUGS=ARM,SH] + + hvc_iucv= [S390] Number of z/VM IUCV Hypervisor console (HVC) + back-ends. Valid parameters: 0..8 + + i8042.debug [HW] Toggle i8042 debug mode i8042.direct [HW] Put keyboard port into non-translated mode i8042.dumbkbd [HW] Pretend that controller can only read data from keyboard and cannot control its state @@ -964,13 +995,15 @@ and is between 256 and 4096 characters. It is defined in the file Format: <cpu number>,...,<cpu number> or - <cpu number>-<cpu number> (must be a positive range in ascending order) + <cpu number>-<cpu number> + (must be a positive range in ascending order) or a mixture <cpu number>,...,<cpu number>-<cpu number> + 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 - an "isolated" CPU is via the CPU affinity syscalls. + algorithms. You can move a process onto or off an + "isolated" CPU via the CPU affinity syscalls or cpuset. <cpu number> begins at 0 and the maximum value is "number of CPUs in system - 1". @@ -1085,7 +1118,7 @@ and is between 256 and 4096 characters. It is defined in the file the same attribute, the last one is used. load_ramdisk= [RAM] List of ramdisks to load from floppy - See Documentation/ramdisk.txt. + See Documentation/blockdev/ramdisk.txt. lockd.nlm_grace_period=P [NFS] Assign grace period. Format: <integer> @@ -1177,8 +1210,8 @@ and is between 256 and 4096 characters. It is defined in the file it is equivalent to "nosmp", which also disables the IO APIC. - max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or - equal to this physical address is ignored. + max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater than + or equal to this physical address is ignored. max_luns= [SCSI] Maximum number of LUNs to probe. Should be between 1 and 2^32-1. @@ -1191,7 +1224,7 @@ and is between 256 and 4096 characters. It is defined in the file mce [X86-32] Machine Check Exception - mce=option [X86-64] See Documentation/x86_64/boot-options.txt + mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt md= [HW] RAID subsystems devices and level See Documentation/md.txt. @@ -1210,6 +1243,10 @@ and is between 256 and 4096 characters. It is defined in the file mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel memory. + memchunk=nn[KMG] + [KNL,SH] Allow user to override the default size for + per-device physically contiguous DMA buffers. + memmap=exactmap [KNL,X86-32,X86_64] Enable setting of an exact E820 memory map, as specified by the user. Such memmap=exactmap lines can be constructed based on @@ -1274,6 +1311,9 @@ and is between 256 and 4096 characters. It is defined in the file mga= [HW,DRM] + min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this + physical address is ignored. + mminit_loglevel= [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this parameter allows control of the logging verbosity for @@ -1368,7 +1408,20 @@ and is between 256 and 4096 characters. It is defined in the file when a NMI is triggered. Format: [state][,regs][,debounce][,die] - nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels + nmi_watchdog= [KNL,BUGS=X86-32,X86-64] Debugging features for SMP kernels + Format: [panic,][num] + Valid num: 0,1,2 + 0 - turn nmi_watchdog off + 1 - use the IO-APIC timer for the NMI watchdog + 2 - use the local APIC for the NMI watchdog using + a performance counter. Note: This will use one performance + counter and the local APIC's performance vector. + When panic is specified panic when an NMI watchdog timeout occurs. + This is useful when you use a panic=... timeout and need the box + quickly up again. + Instead of 1 and 2 it is possible to use the following + symbolic names: lapic and ioapic + Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic no387 [BUGS=X86-32] Tells the kernel to use the 387 maths emulation library even if a 387 maths coprocessor @@ -1392,6 +1445,8 @@ and is between 256 and 4096 characters. It is defined in the file nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects. + nodsp [SH] Disable hardware DSP at boot time. + noefi [X86-32,X86-64] Disable EFI runtime services support. noexec [IA-64] @@ -1408,18 +1463,24 @@ and is between 256 and 4096 characters. It is defined in the file noexec32=off: disable non-executable mappings read implies executable mappings + nofpu [SH] Disable hardware FPU at boot time. + nofxsr [BUGS=X86-32] Disables x86 floating point extended register save and restore. The kernel will only save legacy floating-point registers on task switch. noclflush [BUGS=X86] Don't use the CLFLUSH instruction - nohlt [BUGS=ARM] + nohlt [BUGS=ARM,SH] no-hlt [BUGS=X86-32] Tells the kernel that the hlt instruction doesn't work correctly and not to use it. + no_file_caps Tells the kernel not to honor file capabilities. The + only way then for a file to be executed with privilege + is to be setuid root or executed by root. + nohalt [IA-64] Tells the kernel not to use the power saving function PAL_HALT_LIGHT when idle. This increases power-consumption. On the positive side, it reduces @@ -1431,8 +1492,6 @@ and is between 256 and 4096 characters. It is defined in the file Valid arguments: on, off Default: on - noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing - noirqdebug [X86-32] Disables the code which attempts to detect and disable unhandled interrupt sources. @@ -1574,10 +1633,10 @@ and is between 256 and 4096 characters. It is defined in the file pcd. [PARIDE] See header of drivers/block/paride/pcd.c. - See also Documentation/paride.txt. + See also Documentation/blockdev/paride.txt. pci=option[,option...] [PCI] various PCI subsystem options: - off [X86-32] don't probe for the PCI bus + off [X86] don't probe for the PCI bus bios [X86-32] force use of PCI BIOS, don't access the hardware directly. Use this if your machine has a non-standard PCI host bridge. @@ -1585,9 +1644,9 @@ and is between 256 and 4096 characters. It is defined in the file hardware access methods are allowed. Use this if you experience crashes upon bootup and you suspect they are caused by the BIOS. - conf1 [X86-32] Force use of PCI Configuration + conf1 [X86] Force use of PCI Configuration Mechanism 1. - conf2 [X86-32] Force use of PCI Configuration + conf2 [X86] Force use of PCI Configuration Mechanism 2. noaer [PCIE] If the PCIEAER kernel config parameter is enabled, this kernel boot option can be used to @@ -1599,6 +1658,17 @@ and is between 256 and 4096 characters. It is defined in the file 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. + noioapicquirk [APIC] Disable all boot interrupt quirks. + Safety option to keep boot IRQs enabled. This + should never be necessary. + ioapicreroute [APIC] Enable rerouting of boot IRQs to the + primary IO-APIC for bridges that cannot disable + boot IRQs. This fixes a source of spurious IRQs + when the system masks IRQs. + noioapicreroute [APIC] Disable workaround that uses the + boot IRQ equivalent of an IRQ that connects to + a chipset where boot IRQs cannot be disabled. + The opposite of ioapicreroute. biosirq [X86-32] Use PCI BIOS calls to get the interrupt routing table. These calls are known to be buggy on several machines and they hang the machine @@ -1607,37 +1677,37 @@ and is between 256 and 4096 characters. It is defined in the file this option if the kernel is unable to allocate IRQs or discover secondary PCI buses on your motherboard. - rom [X86-32] Assign address space to expansion ROMs. + rom [X86] Assign address space to expansion ROMs. Use with caution as certain devices share address decoders between ROMs and other resources. - norom [X86-32,X86_64] Do not assign address space to + norom [X86] Do not assign address space to expansion ROMs that do not already have BIOS assigned address ranges. - irqmask=0xMMMM [X86-32] Set a bit mask of IRQs allowed to be + irqmask=0xMMMM [X86] Set a bit mask of IRQs allowed to be assigned automatically to PCI devices. You can make the kernel exclude IRQs of your ISA cards this way. - pirqaddr=0xAAAAA [X86-32] Specify the physical address + pirqaddr=0xAAAAA [X86] Specify the physical address of the PIRQ table (normally generated by the BIOS) if it is outside the F0000h-100000h range. - lastbus=N [X86-32] Scan all buses thru bus #N. Can be + lastbus=N [X86] Scan all buses thru bus #N. Can be useful if the kernel is unable to find your secondary buses and you want to tell it explicitly which ones they are. - assign-busses [X86-32] Always assign all PCI bus + assign-busses [X86] Always assign all PCI bus numbers ourselves, overriding whatever the firmware may have done. - usepirqmask [X86-32] Honor the possible IRQ mask stored + usepirqmask [X86] Honor the possible IRQ mask stored in the BIOS $PIR table. This is needed on some systems with broken BIOSes, notably some HP Pavilion N5400 and Omnibook XE3 notebooks. This will have no effect if ACPI IRQ routing is enabled. - noacpi [X86-32] Do not use ACPI for IRQ routing + noacpi [X86] Do not use ACPI for IRQ routing or for PCI scanning. - use_crs [X86-32] Use _CRS for PCI resource + use_crs [X86] Use _CRS for PCI resource allocation. routeirq Do IRQ routing for all PCI devices. This is normally done in pci_enable_device(), @@ -1666,10 +1736,16 @@ and is between 256 and 4096 characters. It is defined in the file reserved for the CardBus bridge's memory window. The default value is 64 megabytes. + pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power + Management. + off Disable ASPM. + force Enable ASPM even on devices that claim not to support it. + WARNING: Forcing ASPM on may cause system lockups. + pcmv= [HW,PCMCIA] BadgePAD 4 pd. [PARIDE] - See Documentation/paride.txt. + See Documentation/blockdev/paride.txt. pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at boot time. @@ -1677,13 +1753,13 @@ and is between 256 and 4096 characters. It is defined in the file See arch/parisc/kernel/pdc_chassis.c pf. [PARIDE] - See Documentation/paride.txt. + See Documentation/blockdev/paride.txt. pg. [PARIDE] - See Documentation/paride.txt. + See Documentation/blockdev/paride.txt. pirq= [SMP,APIC] Manual mp-table setup - See Documentation/i386/IO-APIC.txt. + See Documentation/x86/i386/IO-APIC.txt. plip= [PPT,NET] Parallel port network link Format: { parport<nr> | timid | 0 } @@ -1693,6 +1769,10 @@ and is between 256 and 4096 characters. It is defined in the file Override pmtimer IOPort with a hex value. e.g. pmtmr=0x508 + pnp.debug [PNP] + Enable PNP debug messages. This depends on the + CONFIG_PNP_DEBUG_MESSAGES option. + pnpacpi= [ACPI] { off } @@ -1713,6 +1793,11 @@ and is between 256 and 4096 characters. It is defined in the file autoconfiguration. Ranges are in pairs (memory base and size). + dynamic_printk + Enables pr_debug()/dev_dbg() calls if + CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also + be switched on/off via <debugfs>/dynamic_printk/modules + print-fatal-signals= [KNL] debug: print fatal signals print-fatal-signals=1: print segfault info to @@ -1741,7 +1826,7 @@ and is between 256 and 4096 characters. It is defined in the file prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk before loading. - See Documentation/ramdisk.txt. + See Documentation/blockdev/ramdisk.txt. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to probe for; one of (bare|imps|exps|lifebook|any). @@ -1761,7 +1846,7 @@ and is between 256 and 4096 characters. It is defined in the file <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq> pt. [PARIDE] - See Documentation/paride.txt. + See Documentation/blockdev/paride.txt. pty.legacy_count= [KNL] Number of legacy pty's. Overwrites compiled-in @@ -1775,10 +1860,10 @@ and is between 256 and 4096 characters. It is defined in the file See Documentation/md.txt. ramdisk_blocksize= [RAM] - See Documentation/ramdisk.txt. + See Documentation/blockdev/ramdisk.txt. ramdisk_size= [RAM] Sizes of RAM disks in kilobytes - See Documentation/ramdisk.txt. + See Documentation/blockdev/ramdisk.txt. rcupdate.blimit= [KNL,BOOT] Set maximum number of finished RCU callbacks to process @@ -2110,7 +2195,7 @@ and is between 256 and 4096 characters. It is defined in the file See Documentation/sonypi.txt specialix= [HW,SERIAL] Specialix multi-serial port adapter - See Documentation/specialix.txt. + See Documentation/serial/specialix.txt. spia_io_base= [HW,MTD] spia_fio_base= @@ -2123,6 +2208,9 @@ and is between 256 and 4096 characters. It is defined in the file st= [HW,SCSI] SCSI tape parameters (buffers, etc.) See Documentation/scsi/st.txt. + stacktrace [FTRACE] + Enabled the stack tracer on boot up. + sti= [PARISC,HW] Format: <num> Set the STI (builtin display/keyboard on the HP-PARISC @@ -2185,7 +2273,7 @@ and is between 256 and 4096 characters. It is defined in the file thermal.crt= [HW,ACPI] -1: disable all critical trip points in all thermal zones - <degrees C>: lower all critical trip points + <degrees C>: override all critical trip points thermal.nocrt= [HW,ACPI] Set to disable actions on ACPI thermal zone @@ -2207,12 +2295,27 @@ and is between 256 and 4096 characters. It is defined in the file See comment before function dc390_setup() in drivers/scsi/tmscsim.c. + topology= [S390] + Format: {off | on} + Specify if the kernel should make use of the cpu + topology informations if the hardware supports these. + The scheduler will make use of these informations and + e.g. base its process migration decisions on it. + Default is off. + tp720= [HW,PS2] trix= [HW,OSS] MediaTrix AudioTrix Pro Format: <io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq> + tsc= Disable clocksource-must-verify flag for TSC. + Format: <string> + [x86] reliable: mark tsc clocksource as reliable, this + disables clocksource verification at runtime. + Used to enable high-resolution timer mode on older + hardware, and in virtualized environment. + turbografx.map[2|3]= [HW,JOY] TurboGraFX parallel port interface Format: @@ -2247,6 +2350,25 @@ and is between 256 and 4096 characters. It is defined in the file autosuspended. Devices for which the delay is set to a negative value won't be autosuspended at all. + usbcore.usbfs_snoop= + [USB] Set to log all usbfs traffic (default 0 = off). + + usbcore.blinkenlights= + [USB] Set to cycle leds on hubs (default 0 = off). + + usbcore.old_scheme_first= + [USB] Start with the old device initialization + scheme (default 0 = off). + + usbcore.use_both_schemes= + [USB] Try the other device initialization scheme + if the first one fails (default 1 = enabled). + + usbcore.initial_descriptor_timeout= + [USB] Specifies timeout for the initial 64-byte + USB_REQ_GET_DESCRIPTOR request in milliseconds + (default 5000 = 5.0 seconds). + usbhid.mousepoll= [USBHID] The interval which mice are to be polled at. @@ -2270,7 +2392,7 @@ and is between 256 and 4096 characters. It is defined in the file See Documentation/fb/modedb.txt. vga= [BOOT,X86-32] Select a particular video mode - See Documentation/i386/boot.txt and + See Documentation/x86/i386/boot.txt and Documentation/svga.txt. Use vga=ask for menu. This is actually a boot loader parameter; the value is |