diff options
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 135 |
1 files changed, 121 insertions, 14 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 6e3b18a8afc6..479eeaf44024 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -235,10 +235,61 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Format: To spoof as Windows 98: ="Microsoft Windows" acpi_osi= [HW,ACPI] Modify list of supported OS interface strings - acpi_osi="string1" # add string1 -- only one string - acpi_osi="!string2" # remove built-in string2 + acpi_osi="string1" # add string1 + acpi_osi="!string2" # remove string2 + acpi_osi=!* # remove all strings + acpi_osi=! # disable all built-in OS vendor + strings acpi_osi= # disable all strings + 'acpi_osi=!' can be used in combination with single or + multiple 'acpi_osi="string1"' to support specific OS + vendor string(s). Note that such command can only + affect the default state of the OS vendor strings, thus + it cannot affect the default state of the feature group + strings and the current state of the OS vendor strings, + specifying it multiple times through kernel command line + is meaningless. This command is useful when one do not + care about the state of the feature group strings which + should be controlled by the OSPM. + Examples: + 1. 'acpi_osi=! acpi_osi="Windows 2000"' is equivalent + to 'acpi_osi="Windows 2000" acpi_osi=!', they all + can make '_OSI("Windows 2000")' TRUE. + + 'acpi_osi=' cannot be used in combination with other + 'acpi_osi=' command lines, the _OSI method will not + exist in the ACPI namespace. NOTE that such command can + only affect the _OSI support state, thus specifying it + multiple times through kernel command line is also + meaningless. + Examples: + 1. 'acpi_osi=' can make 'CondRefOf(_OSI, Local1)' + FALSE. + + 'acpi_osi=!*' can be used in combination with single or + multiple 'acpi_osi="string1"' to support specific + string(s). Note that such command can affect the + current state of both the OS vendor strings and the + feature group strings, thus specifying it multiple times + through kernel command line is meaningful. But it may + still not able to affect the final state of a string if + there are quirks related to this string. This command + is useful when one want to control the state of the + feature group strings to debug BIOS issues related to + the OSPM features. + Examples: + 1. 'acpi_osi="Module Device" acpi_osi=!*' can make + '_OSI("Module Device")' FALSE. + 2. 'acpi_osi=!* acpi_osi="Module Device"' can make + '_OSI("Module Device")' TRUE. + 3. 'acpi_osi=! acpi_osi=!* acpi_osi="Windows 2000"' is + equivalent to + 'acpi_osi=!* acpi_osi=! acpi_osi="Windows 2000"' + and + 'acpi_osi=!* acpi_osi="Windows 2000" acpi_osi=!', + they all will make '_OSI("Windows 2000")' TRUE. + acpi_pm_good [X86] Override the pmtimer bug detection: force the kernel to assume that this machine's pmtimer latches its value @@ -1129,11 +1180,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. The builtin appraise policy appraises all files owned by uid=0. - ima_audit= [IMA] - Format: { "0" | "1" } - 0 -- integrity auditing messages. (Default) - 1 -- enable informational integrity auditing messages. - ima_hash= [IMA] Format: { "sha1" | "md5" } default: "sha1" @@ -1158,6 +1204,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver Format: <irq> + int_pln_enable [x86] Enable power limit notification interrupt + + integrity_audit=[IMA] + Format: { "0" | "1" } + 0 -- basic integrity auditing messages. (Default) + 1 -- additional integrity auditing messages. + intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option on Enable intel iommu driver. @@ -1456,6 +1509,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. * dump_id: dump IDENTIFY data. + * atapi_dmadir: Enable ATAPI DMADIR bridge support + If there are multiple matching configurations changing the same attribute, the last one is used. @@ -2677,9 +2732,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Run specified binary instead of /init from the ramdisk, used for early userspace startup. See initrd. - reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode - Format: <reboot_mode>[,<reboot_mode2>[,...]] - See arch/*/kernel/reboot.c or arch/*/kernel/process.c + reboot= [KNL] + Format (x86 or x86_64): + [w[arm] | c[old] | h[ard] | s[oft] | g[pio]] \ + [[,]s[mp]#### \ + [[,]b[ios] | a[cpi] | k[bd] | t[riple] | e[fi] | p[ci]] \ + [[,]f[orce] + Where reboot_mode is one of warm (soft) or cold (hard) or gpio, + reboot_type is one of bios, acpi, kbd, triple, efi, or pci, + reboot_force is either force or not specified, + reboot_cpu is s[mp]#### with #### being the processor + to be used for rebooting. relax_domain_level= [KNL, SMP] Set scheduler's default relax_domain_level. @@ -2941,7 +3004,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. improve throughput, but will also increase the amount of memory reserved for use by the client. - swapaccount[=0|1] + swapaccount=[0|1] [KNL] Enable accounting of swap in memory resource controller if no parameter or 1 is given or disable it if 0 is given (See Documentation/cgroups/memory.txt) @@ -3069,6 +3132,19 @@ bytes respectively. Such letter suffixes can also be entirely omitted. See also Documentation/trace/ftrace.txt "trace options" section. + traceoff_on_warning + [FTRACE] enable this option to disable tracing when a + warning is hit. This turns off "tracing_on". Tracing can + be enabled again by echoing '1' into the "tracing_on" + file located in /sys/kernel/debug/tracing/ + + This option is useful, as it disables the trace before + the WARNING dump is called, which prevents the trace to + be filled with content caused by the warning output. + + This option can also be set at run time via the sysctl + option: kernel/traceoff_on_warning + transparent_hugepage= [KNL] Format: [always|madvise|never] @@ -3229,6 +3305,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted. video= [FB] Frame buffer configuration See Documentation/fb/modedb.txt. + video.brightness_switch_enabled= [0,1] + If set to 1, on receiving an ACPI notify event + generated by hotkey, video driver will adjust brightness + level and then send out the event to user space through + the allocated input device; If set to 0, video driver + will only send out the event without touching backlight + brightness level. + default: 1 + virtio_mmio.device= [VMMIO] Memory mapped virtio (platform) device. @@ -3288,6 +3373,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. them quite hard to use for exploits but might break your system. + vt.color= [VT] Default text color. + Format: 0xYX, X = foreground, Y = background. + Default: 0x07 = light gray on black. + vt.cur_default= [VT] Default cursor shape. Format: 0xCCBBAA, where AA, BB, and CC are the same as the parameters of the <Esc>[?A;B;Cc escape sequence; @@ -3327,6 +3416,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. overridden by individual drivers. 0 will hide cursors, 1 will display them. + vt.italic= [VT] Default color for italic text; 0-15. + Default: 2 = green. + + vt.underline= [VT] Default color for underlined text; 0-15. + Default: 3 = cyan. + watchdog timers [HW,WDT] For information on watchdog timers, see Documentation/watchdog/watchdog-parameters.txt or other driver-specific files in the @@ -3341,6 +3436,21 @@ bytes respectively. Such letter suffixes can also be entirely omitted. that this also can be controlled per-workqueue for workqueues visible under /sys/bus/workqueue/. + workqueue.power_efficient + Per-cpu workqueues are generally preferred because + they show better performance thanks to cache + locality; unfortunately, per-cpu workqueues tend to + be more power hungry than unbound workqueues. + + Enabling this makes the per-cpu workqueues which + were observed to contribute significantly to power + consumption unbound, leading to measurably lower + power usage at the cost of small performance + overhead. + + The default value of this parameter is determined by + the config option CONFIG_WQ_POWER_EFFICIENT_DEFAULT. + x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of default x2apic cluster mode on platforms supporting x2apic. @@ -3351,9 +3461,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. plus one apbt timer for broadcast timer. x86_mrst_timer=apbt_only | lapic_and_apbt - xd= [HW,XT] Original XT pre-IDE (RLL encoded) disks. - xd_geo= See header of drivers/block/xd.c. - xen_emul_unplug= [HW,X86,XEN] Unplug Xen emulated devices Format: [unplug0,][unplug1] |