diff options
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 72 |
1 files changed, 62 insertions, 10 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 0edc409f9ede..5abc09a93bc2 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -571,6 +571,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. UART at the specified I/O port or MMIO address, switching to the matching ttyS device later. The options are the same as for ttyS, above. + hvc<n> Use the hypervisor console device <n>. This is for + both Xen and PowerPC hypervisors. If the device connected to the port is not a TTY but a braille device, prepend "brl," before the device type, for instance @@ -608,6 +610,26 @@ bytes respectively. Such letter suffixes can also be entirely omitted. a memory unit (amount[KMG]). See also Documentation/kdump/kdump.txt for an example. + crashkernel=size[KMG],high + [KNL, x86_64] range could be above 4G. Allow kernel + to allocate physical memory region from top, so could + be above 4G if system have more than 4G ram installed. + Otherwise memory region will be allocated below 4G, if + available. + It will be ignored if crashkernel=X is specified. + crashkernel=size[KMG],low + [KNL, x86_64] range under 4G. When crashkernel=X,high + is passed, kernel could allocate physical memory region + above 4G, that cause second kernel crash on system + that require some amount of low memory, e.g. swiotlb + requires at least 64M+32K low memory. Kernel would + try to allocate 72M below 4G automatically. + This one let user to specify own low range under 4G + for second kernel instead. + 0: to disable low allocation. + It will be ignored when crashkernel=X,high is not used + or memory reserved is below 4G. + cs89x0_dma= [HW,NET] Format: <dma> @@ -761,6 +783,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. earlyprintk= [X86,SH,BLACKFIN] earlyprintk=vga + earlyprintk=xen earlyprintk=serial[,ttySn[,baudrate]] earlyprintk=ttySn[,baudrate] earlyprintk=dbgp[debugController#] @@ -778,6 +801,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. The VGA output is eventually overwritten by the real console. + The xen output can only be used by Xen PV guests. + ekgdboc= [X86,KGDB] Allow early kernel console debugging ekgdboc=kbd @@ -787,6 +812,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. edd= [EDD] Format: {"off" | "on" | "skip[mbr]"} + efi_no_storage_paranoia [EFI; X86] + Using this parameter you can use more than 50% of + your efi variable storage. Use this parameter only if + you are really sure that your UEFI does sane gc and + fulfills the spec otherwise your board may brick. + eisa_irq_edge= [PARISC,HW] See header of drivers/parisc/eisa.c. @@ -977,6 +1008,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. If specified, z/VM IUCV HVC accepts connections from listed z/VM user IDs only. + hwthread_map= [METAG] Comma-separated list of Linux cpu id to + hardware thread id mappings. + Format: <cpu>:<hwthread> + keep_bootcon [KNL] Do not unregister boot console at start. This is only useful for debugging when something happens in the window @@ -1046,16 +1081,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Claim all unknown PCI IDE storage controllers. idle= [X86] - Format: idle=poll, idle=mwait, idle=halt, idle=nomwait + Format: idle=poll, idle=halt, idle=nomwait Poll forces a polling idle loop that can slightly improve the performance of waking up a idle CPU, but will use a lot of power and make the system run hot. Not recommended. - idle=mwait: On systems which support MONITOR/MWAIT but - the kernel chose to not use it because it doesn't save - as much power as a normal idle loop, use the - MONITOR/MWAIT idle loop anyways. Performance should be - the same as idle=poll. idle=halt: Halt is forced to be used for CPU idle. In such case C2/C3 won't be used again. idle=nomwait: Disable mwait for CPU C-states @@ -1138,6 +1168,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 0 disables intel_idle and fall back on acpi_idle. 1 to 6 specify maximum depth of C-state. + intel_pstate= [X86] + disable + Do not enable intel_pstate as the default + scaling driver for the supported processors + intremap= [X86-64, Intel-IOMMU] on enable Interrupt Remapping (default) off disable Interrupt Remapping @@ -1893,10 +1928,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. wfi(ARM) instruction doesn't work correctly and not to use it. This is also useful when using JTAG debugger. - 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. @@ -2234,6 +2265,21 @@ bytes respectively. Such letter suffixes can also be entirely omitted. This sorting is done to get a device order compatible with older (<= 2.4) kernels. nobfsort Don't sort PCI devices into breadth-first order. + pcie_bus_tune_off Disable PCIe MPS (Max Payload Size) + tuning and use the BIOS-configured MPS defaults. + pcie_bus_safe Set every device's MPS to the largest value + supported by all devices below the root complex. + pcie_bus_perf Set device MPS to the largest allowable MPS + based on its parent bus. Also set MRRS (Max + Read Request Size) to the largest supported + value (no larger than the MPS that the device + or bus can support) for best performance. + pcie_bus_peer2peer Set every device's MPS to 128B, which + every device is guaranteed to support. This + configuration allows peer-to-peer DMA between + any pair of devices, possibly at the cost of + reduced performance. This also guarantees + that hot-added devices will work. cbiosize=nn[KMG] The fixed amount of bus space which is reserved for the CardBus bridge's IO window. The default value is 256 bytes. @@ -2255,6 +2301,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. the default. off: Turn ECRC off on: Turn ECRC on. + hpiosize=nn[KMG] The fixed amount of bus space which is + reserved for hotplug bridge's IO window. + Default size is 256 bytes. + hpmemsize=nn[KMG] The fixed amount of bus space which is + reserved for hotplug bridge's memory window. + Default size is 2 megabytes. realloc= Enable/disable reallocating PCI bridge resources if allocations done by BIOS are too small to accommodate resources required by all child |