| kernel-parameters.txt (e27a24210aa17b8a0cd462865130fe73afd7e001) | kernel-parameters.txt (2f5947dfcaecb99f2dd559156eecbeb7b95e4c02) |
|---|---|
| 1 acpi= [HW,ACPI,X86,ARM64] 2 Advanced Configuration and Power Interface 3 Format: { force | on | off | strict | noirq | rsdt | 4 copy_dsdt } 5 force -- enable ACPI if default was off 6 on -- enable ACPI but allow fallback to DT [arm64] 7 off -- disable ACPI if default was on 8 noirq -- do not use ACPI for IRQ routing 9 strict -- Be less tolerant of platforms that are not 10 strictly ACPI specification compliant. 11 rsdt -- prefer RSDT over (default) XSDT 12 copy_dsdt -- copy DSDT to memory 13 For ARM64, ONLY "acpi=off", "acpi=on" or "acpi=force" 14 are available 15 | 1 acpi= [HW,ACPI,X86,ARM64] 2 Advanced Configuration and Power Interface 3 Format: { force | on | off | strict | noirq | rsdt | 4 copy_dsdt } 5 force -- enable ACPI if default was off 6 on -- enable ACPI but allow fallback to DT [arm64] 7 off -- disable ACPI if default was on 8 noirq -- do not use ACPI for IRQ routing 9 strict -- Be less tolerant of platforms that are not 10 strictly ACPI specification compliant. 11 rsdt -- prefer RSDT over (default) XSDT 12 copy_dsdt -- copy DSDT to memory 13 For ARM64, ONLY "acpi=off", "acpi=on" or "acpi=force" 14 are available 15 |
| 16 See also Documentation/power/runtime_pm.rst, pci=noacpi | 16 See also Documentation/power/runtime_pm.txt, pci=noacpi |
| 17 18 acpi_apic_instance= [ACPI, IOAPIC] 19 Format: <int> 20 2: use 2nd APIC table, if available 21 1,0: use 1st APIC table 22 default: 0 23 24 acpi_backlight= [HW,ACPI] --- 193 unchanged lines hidden (view full) --- 218 219 acpi_skip_timer_override [HW,ACPI] 220 Recognize and ignore IRQ0/pin2 Interrupt Override. 221 For broken nForce2 BIOS resulting in XT-PIC timer. 222 223 acpi_sleep= [HW,ACPI] Sleep options 224 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, 225 old_ordering, nonvs, sci_force_enable, nobl } | 17 18 acpi_apic_instance= [ACPI, IOAPIC] 19 Format: <int> 20 2: use 2nd APIC table, if available 21 1,0: use 1st APIC table 22 default: 0 23 24 acpi_backlight= [HW,ACPI] --- 193 unchanged lines hidden (view full) --- 218 219 acpi_skip_timer_override [HW,ACPI] 220 Recognize and ignore IRQ0/pin2 Interrupt Override. 221 For broken nForce2 BIOS resulting in XT-PIC timer. 222 223 acpi_sleep= [HW,ACPI] Sleep options 224 Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, 225 old_ordering, nonvs, sci_force_enable, nobl } |
| 226 See Documentation/power/video.rst for information on | 226 See Documentation/power/video.txt for information on |
| 227 s3_bios and s3_mode. 228 s3_beep is for debugging; it makes the PC's speaker beep 229 as soon as the kernel's real-mode entry point is called. 230 s4_nohwsig prevents ACPI hardware signature from being 231 used during resume from hibernation. 232 old_ordering causes the ACPI 1.0 ordering of the _PTS 233 control method, with respect to putting devices into 234 low power states, to be enforced (the ACPI 2.0 ordering --- 190 unchanged lines hidden (view full) --- 425 426 baycom_ser_hdx= [HW,AX25] 427 BayCom Serial Port AX.25 Modem (Half Duplex Mode) 428 Format: <io>,<irq>,<mode> 429 See header of drivers/net/hamradio/baycom_ser_hdx.c. 430 431 blkdevparts= Manual partition parsing of block device(s) for 432 embedded devices based on command line input. | 227 s3_bios and s3_mode. 228 s3_beep is for debugging; it makes the PC's speaker beep 229 as soon as the kernel's real-mode entry point is called. 230 s4_nohwsig prevents ACPI hardware signature from being 231 used during resume from hibernation. 232 old_ordering causes the ACPI 1.0 ordering of the _PTS 233 control method, with respect to putting devices into 234 low power states, to be enforced (the ACPI 2.0 ordering --- 190 unchanged lines hidden (view full) --- 425 426 baycom_ser_hdx= [HW,AX25] 427 BayCom Serial Port AX.25 Modem (Half Duplex Mode) 428 Format: <io>,<irq>,<mode> 429 See header of drivers/net/hamradio/baycom_ser_hdx.c. 430 431 blkdevparts= Manual partition parsing of block device(s) for 432 embedded devices based on command line input. |
| 433 See Documentation/block/cmdline-partition.rst | 433 See Documentation/block/cmdline-partition.txt |
| 434 435 boot_delay= Milliseconds to delay each printk during boot. 436 Values larger than 10 seconds (10000) are changed to 437 no delay (0). 438 Format: integer 439 440 bootmem_debug [KNL] Enable bootmem allocator debug messages. 441 --- 261 unchanged lines hidden (view full) --- 703 [KNL] Using kexec, Linux can switch to a 'crash kernel' 704 upon panic. This parameter reserves the physical 705 memory region [offset, offset + size] for that kernel 706 image. If '@offset' is omitted, then a suitable offset 707 is selected automatically. 708 [KNL, x86_64] select a region under 4G first, and 709 fall back to reserve region above 4G when '@offset' 710 hasn't been specified. | 434 435 boot_delay= Milliseconds to delay each printk during boot. 436 Values larger than 10 seconds (10000) are changed to 437 no delay (0). 438 Format: integer 439 440 bootmem_debug [KNL] Enable bootmem allocator debug messages. 441 --- 261 unchanged lines hidden (view full) --- 703 [KNL] Using kexec, Linux can switch to a 'crash kernel' 704 upon panic. This parameter reserves the physical 705 memory region [offset, offset + size] for that kernel 706 image. If '@offset' is omitted, then a suitable offset 707 is selected automatically. 708 [KNL, x86_64] select a region under 4G first, and 709 fall back to reserve region above 4G when '@offset' 710 hasn't been specified. |
| 711 See Documentation/admin-guide/kdump/kdump.rst for further details. | 711 See Documentation/kdump/kdump.rst for further details. |
| 712 713 crashkernel=range1:size1[,range2:size2,...][@offset] 714 [KNL] Same as above, but depends on the memory 715 in the running system. The syntax of range is 716 start-[end] where start and end are both 717 a memory unit (amount[KMG]). See also | 712 713 crashkernel=range1:size1[,range2:size2,...][@offset] 714 [KNL] Same as above, but depends on the memory 715 in the running system. The syntax of range is 716 start-[end] where start and end are both 717 a memory unit (amount[KMG]). See also |
| 718 Documentation/admin-guide/kdump/kdump.rst for an example. | 718 Documentation/kdump/kdump.rst for an example. |
| 719 720 crashkernel=size[KMG],high 721 [KNL, x86_64] range could be above 4G. Allow kernel 722 to allocate physical memory region from top, so could 723 be above 4G if system have more than 4G ram installed. 724 Otherwise memory region will be allocated below 4G, if 725 available. 726 It will be ignored if crashkernel=X is specified. --- 198 unchanged lines hidden (view full) --- 925 panels may send no or incorrect EDID data sets. 926 This parameter allows to specify an EDID data sets 927 in the /lib/firmware directory that are used instead. 928 Generic built-in EDID data sets are used, if one of 929 edid/1024x768.bin, edid/1280x1024.bin, 930 edid/1680x1050.bin, or edid/1920x1080.bin is given 931 and no file with the same name exists. Details and 932 instructions how to build your own EDID data are | 719 720 crashkernel=size[KMG],high 721 [KNL, x86_64] range could be above 4G. Allow kernel 722 to allocate physical memory region from top, so could 723 be above 4G if system have more than 4G ram installed. 724 Otherwise memory region will be allocated below 4G, if 725 available. 726 It will be ignored if crashkernel=X is specified. --- 198 unchanged lines hidden (view full) --- 925 panels may send no or incorrect EDID data sets. 926 This parameter allows to specify an EDID data sets 927 in the /lib/firmware directory that are used instead. 928 Generic built-in EDID data sets are used, if one of 929 edid/1024x768.bin, edid/1280x1024.bin, 930 edid/1680x1050.bin, or edid/1920x1080.bin is given 931 and no file with the same name exists. Details and 932 instructions how to build your own EDID data are |
| 933 available in Documentation/driver-api/edid.rst. An EDID | 933 available in Documentation/EDID/howto.rst. An EDID |
| 934 data set will only be used for a particular connector, 935 if its name and a colon are prepended to the EDID 936 name. Each connector may use a unique EDID data 937 set by separating the files with a comma. An EDID 938 data set with no connector name will be used for 939 any connectors not explicitly specified. 940 941 dscc4.setup= [NET] --- 252 unchanged lines hidden (view full) --- 1194 See header of drivers/parisc/eisa.c. 1195 1196 elanfreq= [X86-32] 1197 See comment before function elanfreq_setup() in 1198 arch/x86/kernel/cpu/cpufreq/elanfreq.c. 1199 1200 elevator= [IOSCHED] 1201 Format: { "mq-deadline" | "kyber" | "bfq" } | 934 data set will only be used for a particular connector, 935 if its name and a colon are prepended to the EDID 936 name. Each connector may use a unique EDID data 937 set by separating the files with a comma. An EDID 938 data set with no connector name will be used for 939 any connectors not explicitly specified. 940 941 dscc4.setup= [NET] --- 252 unchanged lines hidden (view full) --- 1194 See header of drivers/parisc/eisa.c. 1195 1196 elanfreq= [X86-32] 1197 See comment before function elanfreq_setup() in 1198 arch/x86/kernel/cpu/cpufreq/elanfreq.c. 1199 1200 elevator= [IOSCHED] 1201 Format: { "mq-deadline" | "kyber" | "bfq" } |
| 1202 See Documentation/block/deadline-iosched.rst, 1203 Documentation/block/kyber-iosched.rst and 1204 Documentation/block/bfq-iosched.rst for details. | 1202 See Documentation/block/deadline-iosched.txt, 1203 Documentation/block/kyber-iosched.txt and 1204 Documentation/block/bfq-iosched.txt for details. |
| 1205 1206 elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390] 1207 Specifies physical address of start of kernel core 1208 image elf header and optionally the size. Generally 1209 kexec loader will pass this option to capture kernel. | 1205 1206 elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390] 1207 Specifies physical address of start of kernel core 1208 image elf header and optionally the size. Generally 1209 kexec loader will pass this option to capture kernel. |
| 1210 See Documentation/admin-guide/kdump/kdump.rst for details. | 1210 See Documentation/kdump/kdump.rst for details. |
| 1211 1212 enable_mtrr_cleanup [X86] 1213 The kernel tries to adjust MTRR layout from continuous 1214 to discrete, to make X server driver able to add WB 1215 entry later. This parameter enables that. 1216 1217 enable_timer_pin_1 [X86] 1218 Enable PIN 1 of APIC timer --- 25 unchanged lines hidden (view full) --- 1244 failslab= 1245 fail_page_alloc= 1246 fail_make_request=[KNL] 1247 General fault injection mechanism. 1248 Format: <interval>,<probability>,<space>,<times> 1249 See also Documentation/fault-injection/. 1250 1251 floppy= [HW] | 1211 1212 enable_mtrr_cleanup [X86] 1213 The kernel tries to adjust MTRR layout from continuous 1214 to discrete, to make X server driver able to add WB 1215 entry later. This parameter enables that. 1216 1217 enable_timer_pin_1 [X86] 1218 Enable PIN 1 of APIC timer --- 25 unchanged lines hidden (view full) --- 1244 failslab= 1245 fail_page_alloc= 1246 fail_make_request=[KNL] 1247 General fault injection mechanism. 1248 Format: <interval>,<probability>,<space>,<times> 1249 See also Documentation/fault-injection/. 1250 1251 floppy= [HW] |
| 1252 See Documentation/admin-guide/blockdev/floppy.rst. | 1252 See Documentation/blockdev/floppy.txt. |
| 1253 1254 force_pal_cache_flush 1255 [IA-64] Avoid check_sal_cache_flush which may hang on 1256 buggy SAL_CACHE_FLUSH implementations. Using this 1257 parameter will force ia64_sal_cache_flush to call 1258 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH. 1259 1260 forcepae [X86-32] --- 745 unchanged lines hidden (view full) --- 2006 Ethernet adapter MAC address. 2007 2008 kmemleak= [KNL] Boot-time kmemleak enable/disable 2009 Valid arguments: on, off 2010 Default: on 2011 Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y, 2012 the default is off. 2013 | 1253 1254 force_pal_cache_flush 1255 [IA-64] Avoid check_sal_cache_flush which may hang on 1256 buggy SAL_CACHE_FLUSH implementations. Using this 1257 parameter will force ia64_sal_cache_flush to call 1258 ia64_pal_cache_flush instead of SAL_CACHE_FLUSH. 1259 1260 forcepae [X86-32] --- 745 unchanged lines hidden (view full) --- 2006 Ethernet adapter MAC address. 2007 2008 kmemleak= [KNL] Boot-time kmemleak enable/disable 2009 Valid arguments: on, off 2010 Default: on 2011 Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y, 2012 the default is off. 2013 |
| 2014 kprobe_event=[probe-list] 2015 [FTRACE] Add kprobe events and enable at boot time. 2016 The probe-list is a semicolon delimited list of probe 2017 definitions. Each definition is same as kprobe_events 2018 interface, but the parameters are comma delimited. 2019 For example, to add a kprobe event on vfs_read with 2020 arg1 and arg2, add to the command line; 2021 2022 kprobe_event=p,vfs_read,$arg1,$arg2 2023 2024 See also Documentation/trace/kprobetrace.rst "Kernel 2025 Boot Parameter" section. 2026 | |
| 2027 kpti= [ARM64] Control page table isolation of user 2028 and kernel address spaces. 2029 Default: enabled on cores which need mitigation. 2030 0: force disabled 2031 1: force enabled 2032 2033 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs. 2034 Default is 0 (don't ignore, but inject #GP) --- 207 unchanged lines hidden (view full) --- 2242 * disable: Disable this device. 2243 2244 If there are multiple matching configurations changing 2245 the same attribute, the last one is used. 2246 2247 memblock=debug [KNL] Enable memblock debug messages. 2248 2249 load_ramdisk= [RAM] List of ramdisks to load from floppy | 2014 kpti= [ARM64] Control page table isolation of user 2015 and kernel address spaces. 2016 Default: enabled on cores which need mitigation. 2017 0: force disabled 2018 1: force enabled 2019 2020 kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs. 2021 Default is 0 (don't ignore, but inject #GP) --- 207 unchanged lines hidden (view full) --- 2229 * disable: Disable this device. 2230 2231 If there are multiple matching configurations changing 2232 the same attribute, the last one is used. 2233 2234 memblock=debug [KNL] Enable memblock debug messages. 2235 2236 load_ramdisk= [RAM] List of ramdisks to load from floppy |
| 2250 See Documentation/admin-guide/blockdev/ramdisk.rst. | 2237 See Documentation/blockdev/ramdisk.txt. |
| 2251 2252 lockd.nlm_grace_period=P [NFS] Assign grace period. 2253 Format: <integer> 2254 2255 lockd.nlm_tcpport=N [NFS] Assign TCP port. 2256 Format: <integer> 2257 2258 lockd.nlm_timeout=T [NFS] Assign timeout value. --- 281 unchanged lines hidden (view full) --- 2540 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control 2541 Valid arguments: on, off 2542 Default (depends on kernel configuration option): 2543 on (CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=y) 2544 off (CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=n) 2545 mem_encrypt=on: Activate SME 2546 mem_encrypt=off: Do not activate SME 2547 | 2238 2239 lockd.nlm_grace_period=P [NFS] Assign grace period. 2240 Format: <integer> 2241 2242 lockd.nlm_tcpport=N [NFS] Assign TCP port. 2243 Format: <integer> 2244 2245 lockd.nlm_timeout=T [NFS] Assign timeout value. --- 281 unchanged lines hidden (view full) --- 2527 mem_encrypt= [X86-64] AMD Secure Memory Encryption (SME) control 2528 Valid arguments: on, off 2529 Default (depends on kernel configuration option): 2530 on (CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=y) 2531 off (CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=n) 2532 mem_encrypt=on: Activate SME 2533 mem_encrypt=off: Do not activate SME 2534 |
| 2548 Refer to Documentation/virtual/kvm/amd-memory-encryption.rst | 2535 Refer to Documentation/virt/kvm/amd-memory-encryption.rst |
| 2549 for details on when memory encryption can be activated. 2550 2551 mem_sleep_default= [SUSPEND] Default system suspend mode: 2552 s2idle - Suspend-To-Idle 2553 shallow - Power-On Suspend or equivalent (if supported) 2554 deep - Suspend-To-RAM or equivalent (if supported) 2555 See Documentation/admin-guide/pm/sleep-states.rst. 2556 --- 328 unchanged lines hidden (view full) --- 2885 not work reliably with all consoles, but is known 2886 to work with serial and VGA consoles. 2887 To facilitate more flexible debugging, we also add 2888 console_suspend, a printk module parameter to control 2889 it. Users could use console_suspend (usually 2890 /sys/module/printk/parameters/console_suspend) to 2891 turn on/off it dynamically. 2892 | 2536 for details on when memory encryption can be activated. 2537 2538 mem_sleep_default= [SUSPEND] Default system suspend mode: 2539 s2idle - Suspend-To-Idle 2540 shallow - Power-On Suspend or equivalent (if supported) 2541 deep - Suspend-To-RAM or equivalent (if supported) 2542 See Documentation/admin-guide/pm/sleep-states.rst. 2543 --- 328 unchanged lines hidden (view full) --- 2872 not work reliably with all consoles, but is known 2873 to work with serial and VGA consoles. 2874 To facilitate more flexible debugging, we also add 2875 console_suspend, a printk module parameter to control 2876 it. Users could use console_suspend (usually 2877 /sys/module/printk/parameters/console_suspend) to 2878 turn on/off it dynamically. 2879 |
| 2893 novmcoredd [KNL,KDUMP] 2894 Disable device dump. Device dump allows drivers to 2895 append dump data to vmcore so you can collect driver 2896 specified debug info. Drivers can append the data 2897 without any limit and this data is stored in memory, 2898 so this may cause significant memory stress. Disabling 2899 device dump can help save memory but the driver debug 2900 data will be no longer available. This parameter 2901 is only available when CONFIG_PROC_VMCORE_DEVICE_DUMP 2902 is set. 2903 | |
| 2904 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien 2905 caches in the slab allocator. Saves per-node memory, 2906 but will impact performance. 2907 2908 noalign [KNL,ARM] 2909 2910 noaltinstr [S390] Disables alternative instructions patching 2911 (CPU alternatives feature). --- 39 unchanged lines hidden (view full) --- 2951 read implies executable mappings 2952 2953 nofpu [MIPS,SH] Disable hardware FPU at boot time. 2954 2955 nofxsr [BUGS=X86-32] Disables x86 floating point extended 2956 register save and restore. The kernel will only save 2957 legacy floating-point registers on task switch. 2958 | 2880 noaliencache [MM, NUMA, SLAB] Disables the allocation of alien 2881 caches in the slab allocator. Saves per-node memory, 2882 but will impact performance. 2883 2884 noalign [KNL,ARM] 2885 2886 noaltinstr [S390] Disables alternative instructions patching 2887 (CPU alternatives feature). --- 39 unchanged lines hidden (view full) --- 2927 read implies executable mappings 2928 2929 nofpu [MIPS,SH] Disable hardware FPU at boot time. 2930 2931 nofxsr [BUGS=X86-32] Disables x86 floating point extended 2932 register save and restore. The kernel will only save 2933 legacy floating-point registers on task switch. 2934 |
| 2959 nohugeiomap [KNL,x86,PPC] Disable kernel huge I/O mappings. | 2935 nohugeiomap [KNL,x86] Disable kernel huge I/O mappings. |
| 2960 2961 nosmt [KNL,S390] Disable symmetric multithreading (SMT). 2962 Equivalent to smt=1. 2963 2964 [KNL,x86] Disable symmetric multithreading (SMT). 2965 nosmt=force: Force disable SMT, cannot be undone 2966 via the sysfs control file. 2967 --- 195 unchanged lines hidden (view full) --- 3163 nr_uarts= [SERIAL] maximum number of UARTs to be registered. 3164 3165 numa_balancing= [KNL,X86] Enable or disable automatic NUMA balancing. 3166 Allowed values are enable and disable 3167 3168 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA. 3169 'node', 'default' can be specified 3170 This can be set from sysctl after boot. | 2936 2937 nosmt [KNL,S390] Disable symmetric multithreading (SMT). 2938 Equivalent to smt=1. 2939 2940 [KNL,x86] Disable symmetric multithreading (SMT). 2941 nosmt=force: Force disable SMT, cannot be undone 2942 via the sysfs control file. 2943 --- 195 unchanged lines hidden (view full) --- 3139 nr_uarts= [SERIAL] maximum number of UARTs to be registered. 3140 3141 numa_balancing= [KNL,X86] Enable or disable automatic NUMA balancing. 3142 Allowed values are enable and disable 3143 3144 numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA. 3145 'node', 'default' can be specified 3146 This can be set from sysctl after boot. |
| 3171 See Documentation/admin-guide/sysctl/vm.rst for details. | 3147 See Documentation/sysctl/vm.txt for details. |
| 3172 3173 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver. 3174 See Documentation/debugging-via-ohci1394.txt for more 3175 info. 3176 3177 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands 3178 Rather than timing out after 20 ms if an EC 3179 command is not properly ACKed, override the length --- 107 unchanged lines hidden (view full) --- 3287 Halt all CPUs after the first oops has been printed for 3288 the specified number of seconds. This is to be used if 3289 your oopses keep scrolling off the screen. 3290 3291 pcbit= [HW,ISDN] 3292 3293 pcd. [PARIDE] 3294 See header of drivers/block/paride/pcd.c. | 3148 3149 ohci1394_dma=early [HW] enable debugging via the ohci1394 driver. 3150 See Documentation/debugging-via-ohci1394.txt for more 3151 info. 3152 3153 olpc_ec_timeout= [OLPC] ms delay when issuing EC commands 3154 Rather than timing out after 20 ms if an EC 3155 command is not properly ACKed, override the length --- 107 unchanged lines hidden (view full) --- 3263 Halt all CPUs after the first oops has been printed for 3264 the specified number of seconds. This is to be used if 3265 your oopses keep scrolling off the screen. 3266 3267 pcbit= [HW,ISDN] 3268 3269 pcd. [PARIDE] 3270 See header of drivers/block/paride/pcd.c. |
| 3295 See also Documentation/admin-guide/blockdev/paride.rst. | 3271 See also Documentation/blockdev/paride.txt. |
| 3296 3297 pci=option[,option...] [PCI] various PCI subsystem options. 3298 3299 Some options herein operate on a specific device 3300 or a set of devices (<pci_dev>). These are 3301 specified in one of the following formats: 3302 3303 [<domain>:]<bus>:<dev>.<func>[/<dev>.<func>]* --- 227 unchanged lines hidden (view full) --- 3531 pd_ignore_unused 3532 [PM] 3533 Keep all power-domains already enabled by bootloader on, 3534 even if no driver has claimed them. This is useful 3535 for debug and development, but should not be 3536 needed on a platform with proper driver support. 3537 3538 pd. [PARIDE] | 3272 3273 pci=option[,option...] [PCI] various PCI subsystem options. 3274 3275 Some options herein operate on a specific device 3276 or a set of devices (<pci_dev>). These are 3277 specified in one of the following formats: 3278 3279 [<domain>:]<bus>:<dev>.<func>[/<dev>.<func>]* --- 227 unchanged lines hidden (view full) --- 3507 pd_ignore_unused 3508 [PM] 3509 Keep all power-domains already enabled by bootloader on, 3510 even if no driver has claimed them. This is useful 3511 for debug and development, but should not be 3512 needed on a platform with proper driver support. 3513 3514 pd. [PARIDE] |
| 3539 See Documentation/admin-guide/blockdev/paride.rst. | 3515 See Documentation/blockdev/paride.txt. |
| 3540 3541 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at 3542 boot time. 3543 Format: { 0 | 1 } 3544 See arch/parisc/kernel/pdc_chassis.c 3545 3546 percpu_alloc= Select which percpu first chunk allocator to use. 3547 Currently supported values are "embed" and "page". 3548 Archs may support subset or none of the selections. 3549 See comments in mm/percpu.c for details on each 3550 allocator. This parameter is primarily for debugging 3551 and performance comparison. 3552 3553 pf. [PARIDE] | 3516 3517 pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at 3518 boot time. 3519 Format: { 0 | 1 } 3520 See arch/parisc/kernel/pdc_chassis.c 3521 3522 percpu_alloc= Select which percpu first chunk allocator to use. 3523 Currently supported values are "embed" and "page". 3524 Archs may support subset or none of the selections. 3525 See comments in mm/percpu.c for details on each 3526 allocator. This parameter is primarily for debugging 3527 and performance comparison. 3528 3529 pf. [PARIDE] |
| 3554 See Documentation/admin-guide/blockdev/paride.rst. | 3530 See Documentation/blockdev/paride.txt. |
| 3555 3556 pg. [PARIDE] | 3531 3532 pg. [PARIDE] |
| 3557 See Documentation/admin-guide/blockdev/paride.rst. | 3533 See Documentation/blockdev/paride.txt. |
| 3558 3559 pirq= [SMP,APIC] Manual mp-table setup 3560 See Documentation/x86/i386/IO-APIC.rst. 3561 3562 plip= [PPT,NET] Parallel port network link 3563 Format: { parport<nr> | timid | 0 } 3564 See also Documentation/admin-guide/parport.rst. 3565 --- 95 unchanged lines hidden (view full) --- 3661 Param: "sleep" - profile D-state sleeping (millisecs). 3662 Requires CONFIG_SCHEDSTATS 3663 Param: "kvm" - profile VM exits. 3664 Param: <number> - step/bucket size as a power of 2 for 3665 statistical time based profiling. 3666 3667 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk 3668 before loading. | 3534 3535 pirq= [SMP,APIC] Manual mp-table setup 3536 See Documentation/x86/i386/IO-APIC.rst. 3537 3538 plip= [PPT,NET] Parallel port network link 3539 Format: { parport<nr> | timid | 0 } 3540 See also Documentation/admin-guide/parport.rst. 3541 --- 95 unchanged lines hidden (view full) --- 3637 Param: "sleep" - profile D-state sleeping (millisecs). 3638 Requires CONFIG_SCHEDSTATS 3639 Param: "kvm" - profile VM exits. 3640 Param: <number> - step/bucket size as a power of 2 for 3641 statistical time based profiling. 3642 3643 prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk 3644 before loading. |
| 3669 See Documentation/admin-guide/blockdev/ramdisk.rst. | 3645 See Documentation/blockdev/ramdisk.txt. |
| 3670 3671 psi= [KNL] Enable or disable pressure stall information 3672 tracking. 3673 Format: <bool> 3674 3675 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to 3676 probe for; one of (bare|imps|exps|lifebook|any). 3677 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports --- 5 unchanged lines hidden (view full) --- 3683 [HW,MOUSE] Set desired mouse resolution, in dpi. 3684 psmouse.smartscroll= 3685 [HW,MOUSE] Controls Logitech smartscroll autorepeat. 3686 0 = disabled, 1 = enabled (default). 3687 3688 pstore.backend= Specify the name of the pstore backend to use 3689 3690 pt. [PARIDE] | 3646 3647 psi= [KNL] Enable or disable pressure stall information 3648 tracking. 3649 Format: <bool> 3650 3651 psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to 3652 probe for; one of (bare|imps|exps|lifebook|any). 3653 psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports --- 5 unchanged lines hidden (view full) --- 3659 [HW,MOUSE] Set desired mouse resolution, in dpi. 3660 psmouse.smartscroll= 3661 [HW,MOUSE] Controls Logitech smartscroll autorepeat. 3662 0 = disabled, 1 = enabled (default). 3663 3664 pstore.backend= Specify the name of the pstore backend to use 3665 3666 pt. [PARIDE] |
| 3691 See Documentation/admin-guide/blockdev/paride.rst. | 3667 See Documentation/blockdev/paride.txt. |
| 3692 3693 pti= [X86_64] Control Page Table Isolation of user and 3694 kernel address spaces. Disabling this feature 3695 removes hardening, but improves performance of 3696 system calls and interrupts. 3697 3698 on - unconditionally enable 3699 off - unconditionally disable --- 12 unchanged lines hidden (view full) --- 3712 quiet [KNL] Disable most log messages 3713 3714 r128= [HW,DRM] 3715 3716 raid= [HW,RAID] 3717 See Documentation/admin-guide/md.rst. 3718 3719 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes | 3668 3669 pti= [X86_64] Control Page Table Isolation of user and 3670 kernel address spaces. Disabling this feature 3671 removes hardening, but improves performance of 3672 system calls and interrupts. 3673 3674 on - unconditionally enable 3675 off - unconditionally disable --- 12 unchanged lines hidden (view full) --- 3688 quiet [KNL] Disable most log messages 3689 3690 r128= [HW,DRM] 3691 3692 raid= [HW,RAID] 3693 See Documentation/admin-guide/md.rst. 3694 3695 ramdisk_size= [RAM] Sizes of RAM disks in kilobytes |
| 3720 See Documentation/admin-guide/blockdev/ramdisk.rst. | 3696 See Documentation/blockdev/ramdisk.txt. |
| 3721 3722 random.trust_cpu={on,off} 3723 [KNL] Enable or disable trusting the use of the 3724 CPU's random number generator (if available) to 3725 fully seed the kernel's CRNG. Default is controlled 3726 by CONFIG_RANDOM_TRUST_CPU. 3727 3728 ras=option[,option,...] [KNL] RAS-specific options --- 379 unchanged lines hidden (view full) --- 4108 reboot only), 4109 reboot_type is one of bios, acpi, kbd, triple, efi, or pci, 4110 reboot_force is either force or not specified, 4111 reboot_cpu is s[mp]#### with #### being the processor 4112 to be used for rebooting. 4113 4114 relax_domain_level= 4115 [KNL, SMP] Set scheduler's default relax_domain_level. | 3697 3698 random.trust_cpu={on,off} 3699 [KNL] Enable or disable trusting the use of the 3700 CPU's random number generator (if available) to 3701 fully seed the kernel's CRNG. Default is controlled 3702 by CONFIG_RANDOM_TRUST_CPU. 3703 3704 ras=option[,option,...] [KNL] RAS-specific options --- 379 unchanged lines hidden (view full) --- 4084 reboot only), 4085 reboot_type is one of bios, acpi, kbd, triple, efi, or pci, 4086 reboot_force is either force or not specified, 4087 reboot_cpu is s[mp]#### with #### being the processor 4088 to be used for rebooting. 4089 4090 relax_domain_level= 4091 [KNL, SMP] Set scheduler's default relax_domain_level. |
| 4116 See Documentation/admin-guide/cgroup-v1/cpusets.rst. | 4092 See Documentation/cgroup-v1/cpusets.rst. |
| 4117 4118 reserve= [KNL,BUGS] Force kernel to ignore I/O ports or memory 4119 Format: <base1>,<size1>[,<base2>,<size2>,...] 4120 Reserve I/O ports or memory so the kernel won't use 4121 them. If <base> is less than 0x10000, the region 4122 is assumed to be I/O ports; otherwise it is memory. 4123 4124 reservetop= [X86-32] --- 13 unchanged lines hidden (view full) --- 4138 Specify the partition device for software suspend 4139 Format: 4140 {/dev/<dev> | PARTUUID=<uuid> | <int>:<int> | <hex>} 4141 4142 resume_offset= [SWSUSP] 4143 Specify the offset from the beginning of the partition 4144 given by "resume=" at which the swap header is located, 4145 in <PAGE_SIZE> units (needed only for swap files). | 4093 4094 reserve= [KNL,BUGS] Force kernel to ignore I/O ports or memory 4095 Format: <base1>,<size1>[,<base2>,<size2>,...] 4096 Reserve I/O ports or memory so the kernel won't use 4097 them. If <base> is less than 0x10000, the region 4098 is assumed to be I/O ports; otherwise it is memory. 4099 4100 reservetop= [X86-32] --- 13 unchanged lines hidden (view full) --- 4114 Specify the partition device for software suspend 4115 Format: 4116 {/dev/<dev> | PARTUUID=<uuid> | <int>:<int> | <hex>} 4117 4118 resume_offset= [SWSUSP] 4119 Specify the offset from the beginning of the partition 4120 given by "resume=" at which the swap header is located, 4121 in <PAGE_SIZE> units (needed only for swap files). |
| 4146 See Documentation/power/swsusp-and-swap-files.rst | 4122 See Documentation/power/swsusp-and-swap-files.txt |
| 4147 4148 resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to 4149 read the resume files 4150 4151 resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up. 4152 Useful for devices that are detected asynchronously 4153 (e.g. USB and MMC devices). 4154 --- 211 unchanged lines hidden (view full) --- 4366 functionality. 4367 4368 softlockup_all_cpu_backtrace= 4369 [KNL] Should the soft-lockup detector generate 4370 backtraces on all cpus. 4371 Format: <integer> 4372 4373 sonypi.*= [HW] Sony Programmable I/O Control Device driver | 4123 4124 resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to 4125 read the resume files 4126 4127 resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up. 4128 Useful for devices that are detected asynchronously 4129 (e.g. USB and MMC devices). 4130 --- 211 unchanged lines hidden (view full) --- 4342 functionality. 4343 4344 softlockup_all_cpu_backtrace= 4345 [KNL] Should the soft-lockup detector generate 4346 backtraces on all cpus. 4347 Format: <integer> 4348 4349 sonypi.*= [HW] Sony Programmable I/O Control Device driver |
| 4374 See Documentation/admin-guide/laptops/sonypi.rst | 4350 See Documentation/laptops/sonypi.txt |
| 4375 4376 spectre_v2= [X86] Control mitigation of Spectre variant 2 4377 (indirect branch speculation) vulnerability. 4378 The default operation protects the kernel from 4379 user space attacks. 4380 4381 on - unconditionally enable, implies 4382 spectre_v2_user=on --- 235 unchanged lines hidden (view full) --- 4618 Sets the number of seconds to remain in a suspend test 4619 mode before resuming the system (see 4620 /sys/power/pm_test). Only available when CONFIG_PM_DEBUG 4621 is set. Default value is 5. 4622 4623 swapaccount=[0|1] 4624 [KNL] Enable accounting of swap in memory resource 4625 controller if no parameter or 1 is given or disable | 4351 4352 spectre_v2= [X86] Control mitigation of Spectre variant 2 4353 (indirect branch speculation) vulnerability. 4354 The default operation protects the kernel from 4355 user space attacks. 4356 4357 on - unconditionally enable, implies 4358 spectre_v2_user=on --- 235 unchanged lines hidden (view full) --- 4594 Sets the number of seconds to remain in a suspend test 4595 mode before resuming the system (see 4596 /sys/power/pm_test). Only available when CONFIG_PM_DEBUG 4597 is set. Default value is 5. 4598 4599 swapaccount=[0|1] 4600 [KNL] Enable accounting of swap in memory resource 4601 controller if no parameter or 1 is given or disable |
| 4626 it if 0 is given (See Documentation/admin-guide/cgroup-v1/memory.rst) | 4602 it if 0 is given (See Documentation/cgroup-v1/memory.rst) |
| 4627 4628 swiotlb= [ARM,IA-64,PPC,MIPS,X86] 4629 Format: { <int> | force | noforce } 4630 <int> -- Number of I/O TLB slabs 4631 force -- force using of bounce buffers even if they 4632 wouldn't be automatically used by the kernel 4633 noforce -- Never use bounce buffers (for debugging) 4634 --- 58 unchanged lines hidden (view full) --- 4693 Specify global default ACPI thermal zone polling rate 4694 <deci-seconds>: poll all this frequency 4695 0: no polling (default) 4696 4697 threadirqs [KNL] 4698 Force threading of all interrupt handlers except those 4699 marked explicitly IRQF_NO_THREAD. 4700 | 4603 4604 swiotlb= [ARM,IA-64,PPC,MIPS,X86] 4605 Format: { <int> | force | noforce } 4606 <int> -- Number of I/O TLB slabs 4607 force -- force using of bounce buffers even if they 4608 wouldn't be automatically used by the kernel 4609 noforce -- Never use bounce buffers (for debugging) 4610 --- 58 unchanged lines hidden (view full) --- 4669 Specify global default ACPI thermal zone polling rate 4670 <deci-seconds>: poll all this frequency 4671 0: no polling (default) 4672 4673 threadirqs [KNL] 4674 Force threading of all interrupt handlers except those 4675 marked explicitly IRQF_NO_THREAD. 4676 |
| 4677 tmem [KNL,XEN] 4678 Enable the Transcendent memory driver if built-in. 4679 4680 tmem.cleancache=0|1 [KNL, XEN] 4681 Default is on (1). Disable the usage of the cleancache 4682 API to send anonymous pages to the hypervisor. 4683 4684 tmem.frontswap=0|1 [KNL, XEN] 4685 Default is on (1). Disable the usage of the frontswap 4686 API to send swap pages to the hypervisor. If disabled 4687 the selfballooning and selfshrinking are force disabled. 4688 4689 tmem.selfballooning=0|1 [KNL, XEN] 4690 Default is on (1). Disable the driving of swap pages 4691 to the hypervisor. 4692 4693 tmem.selfshrinking=0|1 [KNL, XEN] 4694 Default is on (1). Partial swapoff that immediately 4695 transfers pages from Xen hypervisor back to the 4696 kernel based on different criteria. 4697 |
|
| 4701 topology= [S390] 4702 Format: {off | on} 4703 Specify if the kernel should make use of the cpu 4704 topology information if the hardware supports this. 4705 The scheduler will make use of this information and 4706 e.g. base its process migration decisions on it. 4707 Default is on. 4708 --- 355 unchanged lines hidden (view full) --- 5064 <id> := (optional) platform device id 5065 example: 5066 virtio_mmio.device=1K@0x100b0000:48:7 5067 5068 Can be used multiple times for multiple devices. 5069 5070 vga= [BOOT,X86-32] Select a particular video mode 5071 See Documentation/x86/boot.rst and | 4698 topology= [S390] 4699 Format: {off | on} 4700 Specify if the kernel should make use of the cpu 4701 topology information if the hardware supports this. 4702 The scheduler will make use of this information and 4703 e.g. base its process migration decisions on it. 4704 Default is on. 4705 --- 355 unchanged lines hidden (view full) --- 5061 <id> := (optional) platform device id 5062 example: 5063 virtio_mmio.device=1K@0x100b0000:48:7 5064 5065 Can be used multiple times for multiple devices. 5066 5067 vga= [BOOT,X86-32] Select a particular video mode 5068 See Documentation/x86/boot.rst and |
| 5072 Documentation/admin-guide/svga.rst. | 5069 Documentation/svga.txt. |
| 5073 Use vga=ask for menu. 5074 This is actually a boot loader parameter; the value is 5075 passed to the kernel using a special protocol. 5076 5077 vm_debug[=options] [KNL] Available with CONFIG_DEBUG_VM=y. 5078 May slow down system boot speed, especially when 5079 enabled on systems with a large amount of memory. 5080 All options are enabled by default, and this --- 181 unchanged lines hidden (view full) --- 5262 5263 xen_nopvspin [X86,XEN] 5264 Disables the ticketlock slowpath using Xen PV 5265 optimizations. 5266 5267 xen_nopv [X86] 5268 Disables the PV optimizations forcing the HVM guest to 5269 run as generic HVM guest with no PV drivers. | 5070 Use vga=ask for menu. 5071 This is actually a boot loader parameter; the value is 5072 passed to the kernel using a special protocol. 5073 5074 vm_debug[=options] [KNL] Available with CONFIG_DEBUG_VM=y. 5075 May slow down system boot speed, especially when 5076 enabled on systems with a large amount of memory. 5077 All options are enabled by default, and this --- 181 unchanged lines hidden (view full) --- 5259 5260 xen_nopvspin [X86,XEN] 5261 Disables the ticketlock slowpath using Xen PV 5262 optimizations. 5263 5264 xen_nopv [X86] 5265 Disables the PV optimizations forcing the HVM guest to 5266 run as generic HVM guest with no PV drivers. |
| 5270 This option is obsoleted by the "nopv" option, which 5271 has equivalent effect for XEN platform. | |
| 5272 5273 xen_scrub_pages= [XEN] 5274 Boolean option to control scrubbing pages before giving them back 5275 to Xen, for use by other domains. Can be also changed at runtime 5276 with /sys/devices/system/xen_memory/xen_memory0/scrub_pages. 5277 Default value controlled with CONFIG_XEN_SCRUB_PAGES_DEFAULT. 5278 5279 xen_timer_slop= [X86-64,XEN] 5280 Set the timer slop (in nanoseconds) for the virtual Xen 5281 timers (default is 100000). This adjusts the minimum 5282 delta of virtualized Xen timers, where lower values 5283 improve timer resolution at the expense of processing 5284 more timer interrupts. 5285 | 5267 5268 xen_scrub_pages= [XEN] 5269 Boolean option to control scrubbing pages before giving them back 5270 to Xen, for use by other domains. Can be also changed at runtime 5271 with /sys/devices/system/xen_memory/xen_memory0/scrub_pages. 5272 Default value controlled with CONFIG_XEN_SCRUB_PAGES_DEFAULT. 5273 5274 xen_timer_slop= [X86-64,XEN] 5275 Set the timer slop (in nanoseconds) for the virtual Xen 5276 timers (default is 100000). This adjusts the minimum 5277 delta of virtualized Xen timers, where lower values 5278 improve timer resolution at the expense of processing 5279 more timer interrupts. 5280 |
| 5286 nopv= [X86,XEN,KVM,HYPER_V,VMWARE] 5287 Disables the PV optimizations forcing the guest to run 5288 as generic guest with no PV drivers. Currently support 5289 XEN HVM, KVM, HYPER_V and VMWARE guest. 5290 | |
| 5291 xirc2ps_cs= [NET,PCMCIA] 5292 Format: 5293 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]] 5294 | 5281 xirc2ps_cs= [NET,PCMCIA] 5282 Format: 5283 <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]] 5284 |
| 5295 xive= [PPC] 5296 By default on POWER9 and above, the kernel will 5297 natively use the XIVE interrupt controller. This option 5298 allows the fallback firmware mode to be used: 5299 5300 off Fallback to firmware control of XIVE interrupt 5301 controller on both pseries and powernv 5302 platforms. Only useful on POWER9 and above. 5303 | |
| 5304 xhci-hcd.quirks [USB,KNL] 5305 A hex value specifying bitmask with supplemental xhci 5306 host controller quirks. Meaning of each bit can be 5307 consulted in header drivers/usb/host/xhci.h. | 5285 xhci-hcd.quirks [USB,KNL] 5286 A hex value specifying bitmask with supplemental xhci 5287 host controller quirks. Meaning of each bit can be 5288 consulted in header drivers/usb/host/xhci.h. |