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Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 94 |
1 files changed, 74 insertions, 20 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 30a8ad0dae5..6eaa9cdb709 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1,27 +1,37 @@ Kernel Parameters ~~~~~~~~~~~~~~~~~ -The following is a consolidated list of the kernel parameters as implemented -(mostly) by the __setup() macro and sorted into English Dictionary order -(defined as ignoring all punctuation and sorting digits before letters in a -case insensitive manner), and with descriptions where known. - -Module parameters for loadable modules are specified only as the -parameter name with optional '=' and value as appropriate, such as: - - modprobe usbcore blinkenlights=1 - -Module parameters for modules that are built into the kernel image -are specified on the kernel command line with the module name plus -'.' plus parameter name, with '=' and value if appropriate, such as: - - usbcore.blinkenlights=1 +The following is a consolidated list of the kernel parameters as +implemented by the __setup(), core_param() and module_param() macros +and sorted into English Dictionary order (defined as ignoring all +punctuation and sorting digits before letters in a case insensitive +manner), and with descriptions where known. + +The kernel parses parameters from the kernel command line up to "--"; +if it doesn't recognize a parameter and it doesn't contain a '.', the +parameter gets passed to init: parameters with '=' go into init's +environment, others are passed as command line arguments to init. +Everything after "--" is passed as an argument to init. + +Module parameters can be specified in two ways: via the kernel command +line with a module name prefix, or via modprobe, e.g.: + + (kernel command line) usbcore.blinkenlights=1 + (modprobe command line) modprobe usbcore blinkenlights=1 + +Parameters for modules which are built into the kernel need to be +specified on the kernel command line. modprobe looks through the +kernel command line (/proc/cmdline) and collects module parameters +when it loads a module, so the kernel command line can be used for +loadable modules too. Hyphens (dashes) and underscores are equivalent in parameter names, so log_buf_len=1M print-fatal-signals=1 can also be entered as log-buf-len=1M print_fatal_signals=1 +Double-quotes can be used to protect spaces in values, e.g.: + param="spaces in here" 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 @@ -214,6 +224,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. unusable. The "log_buf_len" parameter may be useful if you need to capture more output. + acpi_force_table_verification [HW,ACPI] + Enable table checksum verification during early stage. + By default, this is disabled due to x86 early mapping + size limitation. + acpi_irq_balance [HW,ACPI] ACPI will balance active IRQs default in APIC mode @@ -237,7 +252,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted. This feature is enabled by default. This option allows to turn off the feature. - acpi_no_auto_ssdt [HW,ACPI] Disable automatic loading of SSDT + acpi_no_static_ssdt [HW,ACPI] + Disable installation of static SSDTs at early boot time + By default, SSDTs contained in the RSDT/XSDT will be + installed automatically and they will appear under + /sys/firmware/acpi/tables. + This option turns off this feature. + Note that specifying this option does not affect + dynamic table installation which will install SSDT + tables to /sys/firmware/acpi/tables/dynamic. acpica_no_return_repair [HW, ACPI] Disable AML predefined validation mechanism @@ -617,8 +640,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Also note the kernel might malfunction if you disable some critical bits. - cma=nn[MG] [ARM,KNL] - Sets the size of kernel global memory area for contiguous + cma=nn[MG]@[start[MG][-end[MG]]] + [ARM,X86,KNL] + Sets the size of kernel global memory area for + contiguous memory allocations and optionally the + placement constraint by the physical address range of memory allocations. For more information, see include/linux/dma-contiguous.h @@ -883,6 +909,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. which are not unmapped. earlycon= [KNL] Output early console device and options. + uart[8250],io,<addr>[,options] uart[8250],mmio,<addr>[,options] uart[8250],mmio32,<addr>[,options] @@ -892,7 +919,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted. (mmio) or 32-bit (mmio32). The options are the same as for ttyS, above. - earlyprintk= [X86,SH,BLACKFIN,ARM] + pl011,<addr> + Start an early, polled-mode console on a pl011 serial + port at the specified address. The pl011 serial port + must already be setup and configured. Options are not + yet supported. + + smh Use ARM semihosting calls for early console. + + earlyprintk= [X86,SH,BLACKFIN,ARM,M68k] earlyprintk=vga earlyprintk=efi earlyprintk=xen @@ -1287,6 +1322,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. for working out where the kernel is dying during startup. + initcall_blacklist= [KNL] Do not execute a comma-separated list of + initcall functions. Useful for debugging built-in + modules and initcalls. + initrd= [BOOT] Specify the location of the initial ramdisk inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver @@ -2332,6 +2371,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted. timeout < 0: reboot immediately Format: <timeout> + crash_kexec_post_notifiers + Run kdump after running panic-notifiers and dumping + kmsg. This only for the users who doubt kdump always + succeeds in any situation. + Note that this also increases risks of kdump failure, + because some panic notifiers can make the crashed + kernel more unstable. + parkbd.port= [HW] Parallel port number the keyboard adapter is connected to, default is 0. Format: <parport#> @@ -2889,6 +2936,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. [KNL, SMP] Set scheduler's default relax_domain_level. See Documentation/cgroups/cpusets.txt. + relative_sleep_states= + [SUSPEND] Use sleep state labeling where the deepest + state available other than hibernation is always "mem". + Format: { "0" | "1" } + 0 -- Traditional sleep state labels. + 1 -- Relative sleep state labels. + reserve= [KNL,BUGS] Force the kernel to ignore some iomem area reservetop= [X86-32] @@ -3461,7 +3515,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. the allocated input device; If set to 0, video driver will only send out the event without touching backlight brightness level. - default: 1 + default: 0 virtio_mmio.device= [VMMIO] Memory mapped virtio (platform) device. |