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-rw-r--r--Documentation/kernel-parameters.txt139
1 files changed, 79 insertions, 60 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 53ba7c7d82b..e0f346d201e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -100,7 +100,7 @@ parameter is applicable:
X86-32 X86-32, aka i386 architecture is enabled.
X86-64 X86-64 architecture is enabled.
More X86-64 boot options can be found in
- Documentation/x86_64/boot-options.txt .
+ Documentation/x86/x86_64/boot-options.txt .
X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
In addition, the following text indicates that the option:
@@ -112,10 +112,10 @@ In addition, the following text indicates that the option:
Parameters denoted with BOOT are actually interpreted by the boot
loader, and have no meaning to the kernel directly.
Do not modify the syntax of boot loader parameters without extreme
-need or coordination with <Documentation/i386/boot.txt>.
+need or coordination with <Documentation/x86/i386/boot.txt>.
There are also arch-specific kernel-parameters not documented here.
-See for example <Documentation/x86_64/boot-options.txt>.
+See for example <Documentation/x86/x86_64/boot-options.txt>.
Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
a trailing = on the name of any parameter states that that parameter will
@@ -198,40 +198,50 @@ and is between 256 and 4096 characters. It is defined in the file
that require a timer override, but don't have
HPET
- acpi.debug_layer= [HW,ACPI]
- Format: <int>
- Each bit of the <int> indicates an ACPI debug layer,
- 1: enable, 0: disable. It is useful for boot time
- debugging. After system has booted up, it can be set
- via /sys/module/acpi/parameters/debug_layer.
- CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
- Available bits (add the numbers together) to enable debug output
- for specific parts of the ACPI subsystem:
- 0x01 utilities 0x02 hardware 0x04 events 0x08 tables
- 0x10 namespace 0x20 parser 0x40 dispatcher
- 0x80 executer 0x100 resources 0x200 acpica debugger
- 0x400 os services 0x800 acpica disassembler.
- The number can be in decimal or prefixed with 0x in hex.
- Warning: Many of these options can produce a lot of
- output and make your system unusable. Be very careful.
-
- acpi.debug_level= [HW,ACPI]
+ acpi_backlight= [HW,ACPI]
+ acpi_backlight=vendor
+ acpi_backlight=video
+ If set to vendor, prefer vendor specific driver
+ (e.g. thinkpad_acpi, sony_acpi, etc.) instead
+ of the ACPI video.ko driver.
+
+ acpi_display_output= [HW,ACPI]
+ acpi_display_output=vendor
+ acpi_display_output=video
+ See above.
+
+ acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
+ acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
Format: <int>
- Each bit of the <int> indicates an ACPI debug level,
- 1: enable, 0: disable. It is useful for boot time
- debugging. After system has booted up, it can be set
- via /sys/module/acpi/parameters/debug_level.
- CONFIG_ACPI_DEBUG must be enabled for this to produce any output.
- Available bits (add the numbers together) to enable different
- debug output levels of the ACPI subsystem:
- 0x01 error 0x02 warn 0x04 init 0x08 debug object
- 0x10 info 0x20 init names 0x40 parse 0x80 load
- 0x100 dispatch 0x200 execute 0x400 names 0x800 operation region
- 0x1000 bfield 0x2000 tables 0x4000 values 0x8000 objects
- 0x10000 resources 0x20000 user requests 0x40000 package.
- The number can be in decimal or prefixed with 0x in hex.
- Warning: Many of these options can produce a lot of
- output and make your system unusable. Be very careful.
+ CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
+ debug output. Bits in debug_layer correspond to a
+ _COMPONENT in an ACPI source file, e.g.,
+ #define _COMPONENT ACPI_PCI_COMPONENT
+ Bits in debug_level correspond to a level in
+ ACPI_DEBUG_PRINT statements, e.g.,
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
+ See Documentation/acpi/debug.txt for more information
+ about debug layers and levels.
+
+ Enable AML "Debug" output, i.e., stores to the Debug
+ object while interpreting AML:
+ acpi.debug_layer=0xffffffff acpi.debug_level=0x2
+ Enable PCI/PCI interrupt routing info messages:
+ acpi.debug_layer=0x400000 acpi.debug_level=0x4
+ Enable all messages related to ACPI hardware:
+ acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
+
+ Some values produce so much output that the system is
+ unusable. The "log_buf_len" parameter may be useful
+ if you need to capture more output.
+
+ acpi.power_nocheck= [HW,ACPI]
+ Format: 1/0 enable/disable the check of power state.
+ On some bogus BIOS the _PSC object/_STA object of
+ power resource can't return the correct device power
+ state. In such case it is unneccessary to check its
+ power state again in power transition.
+ 1 : disable the power state check
acpi_pm_good [X86-32,X86-64]
Override the pmtimer bug detection: force the kernel
@@ -284,7 +294,9 @@ and is between 256 and 4096 characters. It is defined in the file
Possible values are:
isolate - enable device isolation (each device, as far
as possible, will get its own protection
- domain)
+ domain) [default]
+ share - put every device behind one IOMMU into the
+ same protection domain
fullflush - enable flushing of IO/TLB entries when
they are unmapped. Otherwise they are
flushed before they will be reused, which
@@ -619,7 +631,7 @@ and is between 256 and 4096 characters. It is defined in the file
digiepca= [HW,SERIAL]
See drivers/char/README.epca and
- Documentation/digiepca.txt.
+ Documentation/serial/digiepca.txt.
disable_mtrr_cleanup [X86]
enable_mtrr_cleanup [X86]
@@ -730,7 +742,7 @@ and is between 256 and 4096 characters. It is defined in the file
See header of drivers/scsi/fdomain.c.
floppy= [HW]
- See Documentation/floppy.txt.
+ See Documentation/blockdev/floppy.txt.
force_pal_cache_flush
[IA-64] Avoid check_sal_cache_flush which may hang on
@@ -968,13 +980,15 @@ and is between 256 and 4096 characters. It is defined in the file
Format:
<cpu number>,...,<cpu number>
or
- <cpu number>-<cpu number> (must be a positive range in ascending order)
+ <cpu number>-<cpu number>
+ (must be a positive range in ascending order)
or a mixture
<cpu number>,...,<cpu number>-<cpu number>
+
This option can be used to specify one or more CPUs
to isolate from the general SMP balancing and scheduling
- algorithms. The only way to move a process onto or off
- an "isolated" CPU is via the CPU affinity syscalls.
+ algorithms. You can move a process onto or off an
+ "isolated" CPU via the CPU affinity syscalls or cpuset.
<cpu number> begins at 0 and the maximum value is
"number of CPUs in system - 1".
@@ -1089,7 +1103,7 @@ and is between 256 and 4096 characters. It is defined in the file
the same attribute, the last one is used.
load_ramdisk= [RAM] List of ramdisks to load from floppy
- See Documentation/ramdisk.txt.
+ See Documentation/blockdev/ramdisk.txt.
lockd.nlm_grace_period=P [NFS] Assign grace period.
Format: <integer>
@@ -1181,8 +1195,8 @@ and is between 256 and 4096 characters. It is defined in the file
it is equivalent to "nosmp", which also disables
the IO APIC.
- max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or
- equal to this physical address is ignored.
+ max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater than
+ or equal to this physical address is ignored.
max_luns= [SCSI] Maximum number of LUNs to probe.
Should be between 1 and 2^32-1.
@@ -1195,7 +1209,7 @@ and is between 256 and 4096 characters. It is defined in the file
mce [X86-32] Machine Check Exception
- mce=option [X86-64] See Documentation/x86_64/boot-options.txt
+ mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
md= [HW] RAID subsystems devices and level
See Documentation/md.txt.
@@ -1282,6 +1296,9 @@ and is between 256 and 4096 characters. It is defined in the file
mga= [HW,DRM]
+ min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
+ physical address is ignored.
+
mminit_loglevel=
[KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
parameter allows control of the logging verbosity for
@@ -1443,8 +1460,6 @@ and is between 256 and 4096 characters. It is defined in the file
Valid arguments: on, off
Default: on
- noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
-
noirqdebug [X86-32] Disables the code which attempts to detect and
disable unhandled interrupt sources.
@@ -1586,7 +1601,7 @@ and is between 256 and 4096 characters. It is defined in the file
pcd. [PARIDE]
See header of drivers/block/paride/pcd.c.
- See also Documentation/paride.txt.
+ See also Documentation/blockdev/paride.txt.
pci=option[,option...] [PCI] various PCI subsystem options:
off [X86] don't probe for the PCI bus
@@ -1687,7 +1702,7 @@ and is between 256 and 4096 characters. It is defined in the file
pcmv= [HW,PCMCIA] BadgePAD 4
pd. [PARIDE]
- See Documentation/paride.txt.
+ See Documentation/blockdev/paride.txt.
pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
boot time.
@@ -1695,13 +1710,13 @@ and is between 256 and 4096 characters. It is defined in the file
See arch/parisc/kernel/pdc_chassis.c
pf. [PARIDE]
- See Documentation/paride.txt.
+ See Documentation/blockdev/paride.txt.
pg. [PARIDE]
- See Documentation/paride.txt.
+ See Documentation/blockdev/paride.txt.
pirq= [SMP,APIC] Manual mp-table setup
- See Documentation/i386/IO-APIC.txt.
+ See Documentation/x86/i386/IO-APIC.txt.
plip= [PPT,NET] Parallel port network link
Format: { parport<nr> | timid | 0 }
@@ -1711,6 +1726,10 @@ and is between 256 and 4096 characters. It is defined in the file
Override pmtimer IOPort with a hex value.
e.g. pmtmr=0x508
+ pnp.debug [PNP]
+ Enable PNP debug messages. This depends on the
+ CONFIG_PNP_DEBUG_MESSAGES option.
+
pnpacpi= [ACPI]
{ off }
@@ -1764,7 +1783,7 @@ and is between 256 and 4096 characters. It is defined in the file
prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
before loading.
- See Documentation/ramdisk.txt.
+ See Documentation/blockdev/ramdisk.txt.
psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
probe for; one of (bare|imps|exps|lifebook|any).
@@ -1784,7 +1803,7 @@ and is between 256 and 4096 characters. It is defined in the file
<io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
pt. [PARIDE]
- See Documentation/paride.txt.
+ See Documentation/blockdev/paride.txt.
pty.legacy_count=
[KNL] Number of legacy pty's. Overwrites compiled-in
@@ -1798,10 +1817,10 @@ and is between 256 and 4096 characters. It is defined in the file
See Documentation/md.txt.
ramdisk_blocksize= [RAM]
- See Documentation/ramdisk.txt.
+ See Documentation/blockdev/ramdisk.txt.
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
- See Documentation/ramdisk.txt.
+ See Documentation/blockdev/ramdisk.txt.
rcupdate.blimit= [KNL,BOOT]
Set maximum number of finished RCU callbacks to process
@@ -2133,7 +2152,7 @@ and is between 256 and 4096 characters. It is defined in the file
See Documentation/sonypi.txt
specialix= [HW,SERIAL] Specialix multi-serial port adapter
- See Documentation/specialix.txt.
+ See Documentation/serial/specialix.txt.
spia_io_base= [HW,MTD]
spia_fio_base=
@@ -2208,7 +2227,7 @@ and is between 256 and 4096 characters. It is defined in the file
thermal.crt= [HW,ACPI]
-1: disable all critical trip points in all thermal zones
- <degrees C>: lower all critical trip points
+ <degrees C>: override all critical trip points
thermal.nocrt= [HW,ACPI]
Set to disable actions on ACPI thermal zone
@@ -2312,7 +2331,7 @@ and is between 256 and 4096 characters. It is defined in the file
See Documentation/fb/modedb.txt.
vga= [BOOT,X86-32] Select a particular video mode
- See Documentation/i386/boot.txt and
+ See Documentation/x86/i386/boot.txt and
Documentation/svga.txt.
Use vga=ask for menu.
This is actually a boot loader parameter; the value is
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-07 12:37:56 +0000