diff options
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 59 |
1 files changed, 42 insertions, 17 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index af55e13ace8f..6eaa9cdb7094 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 @@ -630,8 +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 @@ -1309,6 +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 @@ -2354,6 +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#> |
