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-rw-r--r--Documentation/kernel-parameters.txt144
1 files changed, 66 insertions, 78 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 343e0f0f84b6..e0f346d201ed 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -100,7 +100,7 @@ parameter is applicable:
100 X86-32 X86-32, aka i386 architecture is enabled. 100 X86-32 X86-32, aka i386 architecture is enabled.
101 X86-64 X86-64 architecture is enabled. 101 X86-64 X86-64 architecture is enabled.
102 More X86-64 boot options can be found in 102 More X86-64 boot options can be found in
103 Documentation/x86_64/boot-options.txt . 103 Documentation/x86/x86_64/boot-options.txt .
104 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64) 104 X86 Either 32bit or 64bit x86 (same as X86-32+X86-64)
105 105
106In addition, the following text indicates that the option: 106In addition, the following text indicates that the option:
@@ -112,10 +112,10 @@ In addition, the following text indicates that the option:
112Parameters denoted with BOOT are actually interpreted by the boot 112Parameters denoted with BOOT are actually interpreted by the boot
113loader, and have no meaning to the kernel directly. 113loader, and have no meaning to the kernel directly.
114Do not modify the syntax of boot loader parameters without extreme 114Do not modify the syntax of boot loader parameters without extreme
115need or coordination with <Documentation/i386/boot.txt>. 115need or coordination with <Documentation/x86/i386/boot.txt>.
116 116
117There are also arch-specific kernel-parameters not documented here. 117There are also arch-specific kernel-parameters not documented here.
118See for example <Documentation/x86_64/boot-options.txt>. 118See for example <Documentation/x86/x86_64/boot-options.txt>.
119 119
120Note that ALL kernel parameters listed below are CASE SENSITIVE, and that 120Note that ALL kernel parameters listed below are CASE SENSITIVE, and that
121a trailing = on the name of any parameter states that that parameter will 121a trailing = on the name of any parameter states that that parameter will
@@ -198,59 +198,42 @@ and is between 256 and 4096 characters. It is defined in the file
198 that require a timer override, but don't have 198 that require a timer override, but don't have
199 HPET 199 HPET
200 200
201 acpi.debug_layer= [HW,ACPI] 201 acpi_backlight= [HW,ACPI]
202 Format: <int> 202 acpi_backlight=vendor
203 Each bit of the <int> indicates an ACPI debug layer, 203 acpi_backlight=video
204 1: enable, 0: disable. It is useful for boot time 204 If set to vendor, prefer vendor specific driver
205 debugging. After system has booted up, it can be set 205 (e.g. thinkpad_acpi, sony_acpi, etc.) instead
206 via /sys/module/acpi/parameters/debug_layer. 206 of the ACPI video.ko driver.
207 CONFIG_ACPI_DEBUG must be enabled for this to produce any output. 207
208 Available bits (add the numbers together) to enable debug output 208 acpi_display_output= [HW,ACPI]
209 for specific parts of the ACPI subsystem: 209 acpi_display_output=vendor
210 0x01 utilities 0x02 hardware 0x04 events 0x08 tables 210 acpi_display_output=video
211 0x10 namespace 0x20 parser 0x40 dispatcher 211 See above.
212 0x80 executer 0x100 resources 0x200 acpica debugger 212
213 0x400 os services 0x800 acpica disassembler. 213 acpi.debug_layer= [HW,ACPI,ACPI_DEBUG]
214 The number can be in decimal or prefixed with 0x in hex. 214 acpi.debug_level= [HW,ACPI,ACPI_DEBUG]
215 Warning: Many of these options can produce a lot of
216 output and make your system unusable. Be very careful.
217
218 acpi.debug_level= [HW,ACPI]
219 Format: <int> 215 Format: <int>
220 Each bit of the <int> indicates an ACPI debug level, 216 CONFIG_ACPI_DEBUG must be enabled to produce any ACPI
221 which corresponds to the level in an ACPI_DEBUG_PRINT 217 debug output. Bits in debug_layer correspond to a
222 statement. After system has booted up, this mask 218 _COMPONENT in an ACPI source file, e.g.,
223 can be set via /sys/module/acpi/parameters/debug_level. 219 #define _COMPONENT ACPI_PCI_COMPONENT
224 220 Bits in debug_level correspond to a level in
225 CONFIG_ACPI_DEBUG must be enabled for this to produce 221 ACPI_DEBUG_PRINT statements, e.g.,
226 any output. The number can be in decimal or prefixed 222 ACPI_DEBUG_PRINT((ACPI_DB_INFO, ...
227 with 0x in hex. Some of these options produce so much 223 See Documentation/acpi/debug.txt for more information
228 output that the system is unusable. 224 about debug layers and levels.
229 225
230 The following global components are defined by the 226 Enable AML "Debug" output, i.e., stores to the Debug
231 ACPI CA: 227 object while interpreting AML:
232 0x01 error 228 acpi.debug_layer=0xffffffff acpi.debug_level=0x2
233 0x02 warn 229 Enable PCI/PCI interrupt routing info messages:
234 0x04 init 230 acpi.debug_layer=0x400000 acpi.debug_level=0x4
235 0x08 debug object 231 Enable all messages related to ACPI hardware:
236 0x10 info 232 acpi.debug_layer=0x2 acpi.debug_level=0xffffffff
237 0x20 init names 233
238 0x40 parse 234 Some values produce so much output that the system is
239 0x80 load 235 unusable. The "log_buf_len" parameter may be useful
240 0x100 dispatch 236 if you need to capture more output.
241 0x200 execute
242 0x400 names
243 0x800 operation region
244 0x1000 bfield
245 0x2000 tables
246 0x4000 values
247 0x8000 objects
248 0x10000 resources
249 0x20000 user requests
250 0x40000 package
251 The number can be in decimal or prefixed with 0x in hex.
252 Warning: Many of these options can produce a lot of
253 output and make your system unusable. Be very careful.
254 237
255 acpi.power_nocheck= [HW,ACPI] 238 acpi.power_nocheck= [HW,ACPI]
256 Format: 1/0 enable/disable the check of power state. 239 Format: 1/0 enable/disable the check of power state.
@@ -311,7 +294,9 @@ and is between 256 and 4096 characters. It is defined in the file
311 Possible values are: 294 Possible values are:
312 isolate - enable device isolation (each device, as far 295 isolate - enable device isolation (each device, as far
313 as possible, will get its own protection 296 as possible, will get its own protection
314 domain) 297 domain) [default]
298 share - put every device behind one IOMMU into the
299 same protection domain
315 fullflush - enable flushing of IO/TLB entries when 300 fullflush - enable flushing of IO/TLB entries when
316 they are unmapped. Otherwise they are 301 they are unmapped. Otherwise they are
317 flushed before they will be reused, which 302 flushed before they will be reused, which
@@ -646,7 +631,7 @@ and is between 256 and 4096 characters. It is defined in the file
646 631
647 digiepca= [HW,SERIAL] 632 digiepca= [HW,SERIAL]
648 See drivers/char/README.epca and 633 See drivers/char/README.epca and
649 Documentation/digiepca.txt. 634 Documentation/serial/digiepca.txt.
650 635
651 disable_mtrr_cleanup [X86] 636 disable_mtrr_cleanup [X86]
652 enable_mtrr_cleanup [X86] 637 enable_mtrr_cleanup [X86]
@@ -757,7 +742,7 @@ and is between 256 and 4096 characters. It is defined in the file
757 See header of drivers/scsi/fdomain.c. 742 See header of drivers/scsi/fdomain.c.
758 743
759 floppy= [HW] 744 floppy= [HW]
760 See Documentation/floppy.txt. 745 See Documentation/blockdev/floppy.txt.
761 746
762 force_pal_cache_flush 747 force_pal_cache_flush
763 [IA-64] Avoid check_sal_cache_flush which may hang on 748 [IA-64] Avoid check_sal_cache_flush which may hang on
@@ -995,13 +980,15 @@ and is between 256 and 4096 characters. It is defined in the file
995 Format: 980 Format:
996 <cpu number>,...,<cpu number> 981 <cpu number>,...,<cpu number>
997 or 982 or
998 <cpu number>-<cpu number> (must be a positive range in ascending order) 983 <cpu number>-<cpu number>
984 (must be a positive range in ascending order)
999 or a mixture 985 or a mixture
1000 <cpu number>,...,<cpu number>-<cpu number> 986 <cpu number>,...,<cpu number>-<cpu number>
987
1001 This option can be used to specify one or more CPUs 988 This option can be used to specify one or more CPUs
1002 to isolate from the general SMP balancing and scheduling 989 to isolate from the general SMP balancing and scheduling
1003 algorithms. The only way to move a process onto or off 990 algorithms. You can move a process onto or off an
1004 an "isolated" CPU is via the CPU affinity syscalls. 991 "isolated" CPU via the CPU affinity syscalls or cpuset.
1005 <cpu number> begins at 0 and the maximum value is 992 <cpu number> begins at 0 and the maximum value is
1006 "number of CPUs in system - 1". 993 "number of CPUs in system - 1".
1007 994
@@ -1116,7 +1103,7 @@ and is between 256 and 4096 characters. It is defined in the file
1116 the same attribute, the last one is used. 1103 the same attribute, the last one is used.
1117 1104
1118 load_ramdisk= [RAM] List of ramdisks to load from floppy 1105 load_ramdisk= [RAM] List of ramdisks to load from floppy
1119 See Documentation/ramdisk.txt. 1106 See Documentation/blockdev/ramdisk.txt.
1120 1107
1121 lockd.nlm_grace_period=P [NFS] Assign grace period. 1108 lockd.nlm_grace_period=P [NFS] Assign grace period.
1122 Format: <integer> 1109 Format: <integer>
@@ -1208,8 +1195,8 @@ and is between 256 and 4096 characters. It is defined in the file
1208 it is equivalent to "nosmp", which also disables 1195 it is equivalent to "nosmp", which also disables
1209 the IO APIC. 1196 the IO APIC.
1210 1197
1211 max_addr=[KMG] [KNL,BOOT,ia64] All physical memory greater than or 1198 max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater than
1212 equal to this physical address is ignored. 1199 or equal to this physical address is ignored.
1213 1200
1214 max_luns= [SCSI] Maximum number of LUNs to probe. 1201 max_luns= [SCSI] Maximum number of LUNs to probe.
1215 Should be between 1 and 2^32-1. 1202 Should be between 1 and 2^32-1.
@@ -1222,7 +1209,7 @@ and is between 256 and 4096 characters. It is defined in the file
1222 1209
1223 mce [X86-32] Machine Check Exception 1210 mce [X86-32] Machine Check Exception
1224 1211
1225 mce=option [X86-64] See Documentation/x86_64/boot-options.txt 1212 mce=option [X86-64] See Documentation/x86/x86_64/boot-options.txt
1226 1213
1227 md= [HW] RAID subsystems devices and level 1214 md= [HW] RAID subsystems devices and level
1228 See Documentation/md.txt. 1215 See Documentation/md.txt.
@@ -1309,6 +1296,9 @@ and is between 256 and 4096 characters. It is defined in the file
1309 1296
1310 mga= [HW,DRM] 1297 mga= [HW,DRM]
1311 1298
1299 min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this
1300 physical address is ignored.
1301
1312 mminit_loglevel= 1302 mminit_loglevel=
1313 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this 1303 [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this
1314 parameter allows control of the logging verbosity for 1304 parameter allows control of the logging verbosity for
@@ -1470,8 +1460,6 @@ and is between 256 and 4096 characters. It is defined in the file
1470 Valid arguments: on, off 1460 Valid arguments: on, off
1471 Default: on 1461 Default: on
1472 1462
1473 noirqbalance [X86-32,SMP,KNL] Disable kernel irq balancing
1474
1475 noirqdebug [X86-32] Disables the code which attempts to detect and 1463 noirqdebug [X86-32] Disables the code which attempts to detect and
1476 disable unhandled interrupt sources. 1464 disable unhandled interrupt sources.
1477 1465
@@ -1613,7 +1601,7 @@ and is between 256 and 4096 characters. It is defined in the file
1613 1601
1614 pcd. [PARIDE] 1602 pcd. [PARIDE]
1615 See header of drivers/block/paride/pcd.c. 1603 See header of drivers/block/paride/pcd.c.
1616 See also Documentation/paride.txt. 1604 See also Documentation/blockdev/paride.txt.
1617 1605
1618 pci=option[,option...] [PCI] various PCI subsystem options: 1606 pci=option[,option...] [PCI] various PCI subsystem options:
1619 off [X86] don't probe for the PCI bus 1607 off [X86] don't probe for the PCI bus
@@ -1714,7 +1702,7 @@ and is between 256 and 4096 characters. It is defined in the file
1714 pcmv= [HW,PCMCIA] BadgePAD 4 1702 pcmv= [HW,PCMCIA] BadgePAD 4
1715 1703
1716 pd. [PARIDE] 1704 pd. [PARIDE]
1717 See Documentation/paride.txt. 1705 See Documentation/blockdev/paride.txt.
1718 1706
1719 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at 1707 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
1720 boot time. 1708 boot time.
@@ -1722,13 +1710,13 @@ and is between 256 and 4096 characters. It is defined in the file
1722 See arch/parisc/kernel/pdc_chassis.c 1710 See arch/parisc/kernel/pdc_chassis.c
1723 1711
1724 pf. [PARIDE] 1712 pf. [PARIDE]
1725 See Documentation/paride.txt. 1713 See Documentation/blockdev/paride.txt.
1726 1714
1727 pg. [PARIDE] 1715 pg. [PARIDE]
1728 See Documentation/paride.txt. 1716 See Documentation/blockdev/paride.txt.
1729 1717
1730 pirq= [SMP,APIC] Manual mp-table setup 1718 pirq= [SMP,APIC] Manual mp-table setup
1731 See Documentation/i386/IO-APIC.txt. 1719 See Documentation/x86/i386/IO-APIC.txt.
1732 1720
1733 plip= [PPT,NET] Parallel port network link 1721 plip= [PPT,NET] Parallel port network link
1734 Format: { parport<nr> | timid | 0 } 1722 Format: { parport<nr> | timid | 0 }
@@ -1795,7 +1783,7 @@ and is between 256 and 4096 characters. It is defined in the file
1795 1783
1796 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk 1784 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
1797 before loading. 1785 before loading.
1798 See Documentation/ramdisk.txt. 1786 See Documentation/blockdev/ramdisk.txt.
1799 1787
1800 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to 1788 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to
1801 probe for; one of (bare|imps|exps|lifebook|any). 1789 probe for; one of (bare|imps|exps|lifebook|any).
@@ -1815,7 +1803,7 @@ and is between 256 and 4096 characters. It is defined in the file
1815 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq> 1803 <io>,<mss_io>,<mss_irq>,<mss_dma>,<mpu_io>,<mpu_irq>
1816 1804
1817 pt. [PARIDE] 1805 pt. [PARIDE]
1818 See Documentation/paride.txt. 1806 See Documentation/blockdev/paride.txt.
1819 1807
1820 pty.legacy_count= 1808 pty.legacy_count=
1821 [KNL] Number of legacy pty's. Overwrites compiled-in 1809 [KNL] Number of legacy pty's. Overwrites compiled-in
@@ -1829,10 +1817,10 @@ and is between 256 and 4096 characters. It is defined in the file
1829 See Documentation/md.txt. 1817 See Documentation/md.txt.
1830 1818
1831 ramdisk_blocksize= [RAM] 1819 ramdisk_blocksize= [RAM]
1832 See Documentation/ramdisk.txt. 1820 See Documentation/blockdev/ramdisk.txt.
1833 1821
1834 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes 1822 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
1835 See Documentation/ramdisk.txt. 1823 See Documentation/blockdev/ramdisk.txt.
1836 1824
1837 rcupdate.blimit= [KNL,BOOT] 1825 rcupdate.blimit= [KNL,BOOT]
1838 Set maximum number of finished RCU callbacks to process 1826 Set maximum number of finished RCU callbacks to process
@@ -2164,7 +2152,7 @@ and is between 256 and 4096 characters. It is defined in the file
2164 See Documentation/sonypi.txt 2152 See Documentation/sonypi.txt
2165 2153
2166 specialix= [HW,SERIAL] Specialix multi-serial port adapter 2154 specialix= [HW,SERIAL] Specialix multi-serial port adapter
2167 See Documentation/specialix.txt. 2155 See Documentation/serial/specialix.txt.
2168 2156
2169 spia_io_base= [HW,MTD] 2157 spia_io_base= [HW,MTD]
2170 spia_fio_base= 2158 spia_fio_base=
@@ -2343,7 +2331,7 @@ and is between 256 and 4096 characters. It is defined in the file
2343 See Documentation/fb/modedb.txt. 2331 See Documentation/fb/modedb.txt.
2344 2332
2345 vga= [BOOT,X86-32] Select a particular video mode 2333 vga= [BOOT,X86-32] Select a particular video mode
2346 See Documentation/i386/boot.txt and 2334 See Documentation/x86/i386/boot.txt and
2347 Documentation/svga.txt. 2335 Documentation/svga.txt.
2348 Use vga=ask for menu. 2336 Use vga=ask for menu.
2349 This is actually a boot loader parameter; the value is 2337 This is actually a boot loader parameter; the value is