summaryrefslogtreecommitdiffstats
path: root/Documentation/kernel-parameters.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/kernel-parameters.txt')
-rw-r--r--Documentation/kernel-parameters.txt160
1 files changed, 151 insertions, 9 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 0a9ae23..932b6e2 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -70,7 +70,6 @@ parameter is applicable:
M68k M68k architecture is enabled.
These options have more detailed description inside of
Documentation/m68k/kernel-options.txt.
- MCA MCA bus support is enabled.
MDA MDA console support is enabled.
MIPS MIPS architecture is enabled.
MOUSE Appropriate mouse support is enabled.
@@ -110,6 +109,7 @@ parameter is applicable:
USB USB support is enabled.
USBHID USB Human Interface Device support is enabled.
V4L Video For Linux support is enabled.
+ VMMIO Driver for memory mapped virtio devices is enabled.
VGA The VGA console has been enabled.
VT Virtual terminal support is enabled.
WDT Watchdog support is enabled.
@@ -335,6 +335,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
requirements as needed. This option
does not override iommu=pt
+ amd_iommu_dump= [HW,X86-64]
+ Enable AMD IOMMU driver option to dump the ACPI table
+ for AMD IOMMU. With this option enabled, AMD IOMMU
+ driver will print ACPI tables for AMD IOMMU during
+ IOMMU initialization.
+
amijoy.map= [HW,JOY] Amiga joystick support
Map of devices attached to JOY0DAT and JOY1DAT
Format: <a>,<b>
@@ -397,8 +403,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
atkbd.softrepeat= [HW]
Use software keyboard repeat
- autotest [IA-64]
-
baycom_epp= [HW,AX25]
Format: <io>,<mode>
@@ -508,6 +512,11 @@ 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
+ memory allocations. For more information, see
+ include/linux/dma-contiguous.h
+
cmo_free_hint= [PPC] Format: { yes | no }
Specify whether pages are marked as being inactive
when they are freed. This is used in CMO environments
@@ -515,6 +524,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
a hypervisor.
Default: yes
+ coherent_pool=nn[KMG] [ARM,KNL]
+ Sets the size of memory pool for coherent, atomic dma
+ allocations if Contiguous Memory Allocator (CMA) is used.
+
code_bytes [X86] How many bytes of object code to print
in an oops report.
Range: 0 - 8192
@@ -610,7 +623,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
time. See Documentation/dynamic-debug-howto.txt for
- details.
+ details. Deprecated, see dyndbg.
debug [KNL] Enable kernel debugging (events log level).
@@ -730,6 +743,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
dscc4.setup= [NET]
+ dyndbg[="val"] [KNL,DYNAMIC_DEBUG]
+ module.dyndbg[="val"]
+ Enable debug messages at boot time. See
+ Documentation/dynamic-debug-howto.txt for details.
+
earlycon= [KNL] Output early console device and options.
uart[8250],io,<addr>[,options]
uart[8250],mmio,<addr>[,options]
@@ -982,6 +1000,20 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
i8k.restricted [HW] Allow controlling fans only if SYS_ADMIN
capability is set.
+ i915.invert_brightness=
+ [DRM] Invert the sense of the variable that is used to
+ set the brightness of the panel backlight. Normally a
+ brightness value of 0 indicates backlight switched off,
+ and the maximum of the brightness value sets the backlight
+ to maximum brightness. If this parameter is set to 0
+ (default) and the machine requires it, or this parameter
+ is set to 1, a brightness value of 0 sets the backlight
+ to maximum brightness, and the maximum of the brightness
+ value switches the backlight off.
+ -1 -- never invert brightness
+ 0 -- machine default
+ 1 -- force brightness inversion
+
icn= [HW,ISDN]
Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
@@ -1424,8 +1456,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
devices can be requested on-demand with the
/dev/loop-control interface.
- mcatest= [IA-64]
-
mce [X86-32] Machine Check Exception
mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
@@ -2160,6 +2190,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
on: Turn realloc on
realloc same as realloc=on
noari do not use PCIe ARI.
+ pcie_scan_all Scan all possible PCIe devices. Otherwise we
+ only look for one device below a PCIe downstream
+ port.
pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
Management.
@@ -2329,18 +2362,100 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
See Documentation/blockdev/ramdisk.txt.
- rcupdate.blimit= [KNL,BOOT]
+ rcutree.blimit= [KNL,BOOT]
Set maximum number of finished RCU callbacks to process
in one batch.
- rcupdate.qhimark= [KNL,BOOT]
+ rcutree.qhimark= [KNL,BOOT]
Set threshold of queued
RCU callbacks over which batch limiting is disabled.
- rcupdate.qlowmark= [KNL,BOOT]
+ rcutree.qlowmark= [KNL,BOOT]
Set threshold of queued RCU callbacks below which
batch limiting is re-enabled.
+ rcutree.rcu_cpu_stall_suppress= [KNL,BOOT]
+ Suppress RCU CPU stall warning messages.
+
+ rcutree.rcu_cpu_stall_timeout= [KNL,BOOT]
+ Set timeout for RCU CPU stall warning messages.
+
+ rcutorture.fqs_duration= [KNL,BOOT]
+ Set duration of force_quiescent_state bursts.
+
+ rcutorture.fqs_holdoff= [KNL,BOOT]
+ Set holdoff time within force_quiescent_state bursts.
+
+ rcutorture.fqs_stutter= [KNL,BOOT]
+ Set wait time between force_quiescent_state bursts.
+
+ rcutorture.irqreader= [KNL,BOOT]
+ Test RCU readers from irq handlers.
+
+ rcutorture.n_barrier_cbs= [KNL,BOOT]
+ Set callbacks/threads for rcu_barrier() testing.
+
+ rcutorture.nfakewriters= [KNL,BOOT]
+ Set number of concurrent RCU writers. These just
+ stress RCU, they don't participate in the actual
+ test, hence the "fake".
+
+ rcutorture.nreaders= [KNL,BOOT]
+ Set number of RCU readers.
+
+ rcutorture.onoff_holdoff= [KNL,BOOT]
+ Set time (s) after boot for CPU-hotplug testing.
+
+ rcutorture.onoff_interval= [KNL,BOOT]
+ Set time (s) between CPU-hotplug operations, or
+ zero to disable CPU-hotplug testing.
+
+ rcutorture.shuffle_interval= [KNL,BOOT]
+ Set task-shuffle interval (s). Shuffling tasks
+ allows some CPUs to go into dyntick-idle mode
+ during the rcutorture test.
+
+ rcutorture.shutdown_secs= [KNL,BOOT]
+ Set time (s) after boot system shutdown. This
+ is useful for hands-off automated testing.
+
+ rcutorture.stall_cpu= [KNL,BOOT]
+ Duration of CPU stall (s) to test RCU CPU stall
+ warnings, zero to disable.
+
+ rcutorture.stall_cpu_holdoff= [KNL,BOOT]
+ Time to wait (s) after boot before inducing stall.
+
+ rcutorture.stat_interval= [KNL,BOOT]
+ Time (s) between statistics printk()s.
+
+ rcutorture.stutter= [KNL,BOOT]
+ Time (s) to stutter testing, for example, specifying
+ five seconds causes the test to run for five seconds,
+ wait for five seconds, and so on. This tests RCU's
+ ability to transition abruptly to and from idle.
+
+ rcutorture.test_boost= [KNL,BOOT]
+ Test RCU priority boosting? 0=no, 1=maybe, 2=yes.
+ "Maybe" means test if the RCU implementation
+ under test support RCU priority boosting.
+
+ rcutorture.test_boost_duration= [KNL,BOOT]
+ Duration (s) of each individual boost test.
+
+ rcutorture.test_boost_interval= [KNL,BOOT]
+ Interval (s) between each boost test.
+
+ rcutorture.test_no_idle_hz= [KNL,BOOT]
+ Test RCU's dyntick-idle handling. See also the
+ rcutorture.shuffle_interval parameter.
+
+ rcutorture.torture_type= [KNL,BOOT]
+ Specify the RCU implementation to test.
+
+ rcutorture.verbose= [KNL,BOOT]
+ Enable additional printk() statements.
+
rdinit= [KNL]
Format: <full_path>
Run specified binary instead of /init from the ramdisk,
@@ -2371,6 +2486,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
resume= [SWSUSP]
Specify the partition device for software suspend
+ Format:
+ {/dev/<dev> | PARTUUID=<uuid> | <int>:<int> | <hex>}
resume_offset= [SWSUSP]
Specify the offset from the beginning of the partition
@@ -2425,6 +2542,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
sched_debug [KNL] Enables verbose scheduler debug messages.
+ skew_tick= [KNL] Offset the periodic timer tick per cpu to mitigate
+ xtime_lock contention on larger systems, and/or RCU lock
+ contention on all systems with CONFIG_MAXSMP set.
+ Format: { "0" | "1" }
+ 0 -- disable. (may be 1 via CONFIG_CMDLINE="skew_tick=1"
+ 1 -- enable.
+ Note: increases power consumption, thus should only be
+ enabled if running jitter sensitive (HPC/RT) workloads.
+
security= [SECURITY] Choose a security module to enable at boot.
If this boot parameter is not specified, only the first
security module asking for security registration will be
@@ -2846,6 +2972,22 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
video= [FB] Frame buffer configuration
See Documentation/fb/modedb.txt.
+ virtio_mmio.device=
+ [VMMIO] Memory mapped virtio (platform) device.
+
+ <size>@<baseaddr>:<irq>[:<id>]
+ where:
+ <size> := size (can use standard suffixes
+ like K, M and G)
+ <baseaddr> := physical base address
+ <irq> := interrupt number (as passed to
+ request_irq())
+ <id> := (optional) platform device id
+ example:
+ virtio_mmio.device=1K@0x100b0000:48:7
+
+ Can be used multiple times for multiple devices.
+
vga= [BOOT,X86-32] Select a particular video mode
See Documentation/x86/boot.txt and
Documentation/svga.txt.