kernel/power/Kconfig

   1 config SUSPEND
   2         bool "Suspend to RAM and standby"
   3         depends on ARCH_SUSPEND_POSSIBLE
   4         default y
   5         ---help---
   6           Allow the system to enter sleep states in which main memory is
   7           powered and thus its contents are preserved, such as the
   8           suspend-to-RAM state (e.g. the ACPI S3 state).
   9
  10 config SUSPEND_FREEZER
  11         bool "Enable freezer for suspend to RAM/standby" \
  12                 if ARCH_WANTS_FREEZER_CONTROL || BROKEN
  13         depends on SUSPEND
  14         default y
  15         help
  16           This allows you to turn off the freezer for suspend. If this is
  17           done, no tasks are frozen for suspend to RAM/standby.
  18
  19           Turning OFF this setting is NOT recommended! If in doubt, say Y.
  20
  21 config SUSPEND_SKIP_SYNC
  22         bool "Skip kernel's sys_sync() on suspend to RAM/standby"
  23         depends on SUSPEND
  24         depends on EXPERT
  25         help
  26           Skip the kernel sys_sync() before freezing user processes.
  27           Some systems prefer not to pay this cost on every invocation
  28           of suspend, or they are content with invoking sync() from
  29           user-space before invoking suspend.  Say Y if that's your case.
  30
  31 config HIBERNATE_CALLBACKS
  32         bool
  33
  34 config HIBERNATION
  35         bool "Hibernation (aka 'suspend to disk')"
  36         depends on SWAP && ARCH_HIBERNATION_POSSIBLE
  37         select HIBERNATE_CALLBACKS
  38         select LZO_COMPRESS
  39         select LZO_DECOMPRESS
  40         select CRC32
  41         ---help---
  42           Enable the suspend to disk (STD) functionality, which is usually
  43           called "hibernation" in user interfaces.  STD checkpoints the
  44           system and powers it off; and restores that checkpoint on reboot.
  45
  46           You can suspend your machine with 'echo disk > /sys/power/state'
  47           after placing resume=/dev/swappartition on the kernel command line
  48           in your bootloader's configuration file.
  49
  50           Alternatively, you can use the additional userland tools available
  51           from <http://suspend.sf.net>.
  52
  53           In principle it does not require ACPI or APM, although for example
  54           ACPI will be used for the final steps when it is available.  One
  55           of the reasons to use software suspend is that the firmware hooks
  56           for suspend states like suspend-to-RAM (STR) often don't work very
  57           well with Linux.
  58
  59           It creates an image which is saved in your active swap. Upon the next
  60           boot, pass the 'resume=/dev/swappartition' argument to the kernel to
  61           have it detect the saved image, restore memory state from it, and
  62           continue to run as before. If you do not want the previous state to
  63           be reloaded, then use the 'noresume' kernel command line argument.
  64           Note, however, that fsck will be run on your filesystems and you will
  65           need to run mkswap against the swap partition used for the suspend.
  66
  67           It also works with swap files to a limited extent (for details see
  68           <file:Documentation/power/swsusp-and-swap-files.rst>).
  69
  70           Right now you may boot without resuming and resume later but in the
  71           meantime you cannot use the swap partition(s)/file(s) involved in
  72           suspending.  Also in this case you must not use the filesystems
  73           that were mounted before the suspend.  In particular, you MUST NOT
  74           MOUNT any journaled filesystems mounted before the suspend or they
  75           will get corrupted in a nasty way.
  76
  77           For more information take a look at <file:Documentation/power/swsusp.rst>.
  78
  79 config ARCH_SAVE_PAGE_KEYS
  80         bool
  81
  82 config PM_STD_PARTITION
  83         string "Default resume partition"
  84         depends on HIBERNATION
  85         default ""
  86         ---help---
  87           The default resume partition is the partition that the suspend-
  88           to-disk implementation will look for a suspended disk image.
  89
  90           The partition specified here will be different for almost every user.
  91           It should be a valid swap partition (at least for now) that is turned
  92           on before suspending.
  93
  94           The partition specified can be overridden by specifying:
  95
  96                 resume=/dev/<other device>
  97
  98           which will set the resume partition to the device specified.
  99
 100           Note there is currently not a way to specify which device to save the
 101           suspended image to. It will simply pick the first available swap
 102           device.
 103
 104 config PM_SLEEP
 105         def_bool y
 106         depends on SUSPEND || HIBERNATE_CALLBACKS
 107         select PM
 108         select SRCU
 109
 110 config PM_SLEEP_SMP
 111         def_bool y
 112         depends on SMP
 113         depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
 114         depends on PM_SLEEP
 115         select HOTPLUG_CPU
 116
 117 config PM_SLEEP_SMP_NONZERO_CPU
 118         def_bool y
 119         depends on PM_SLEEP_SMP
 120         depends on ARCH_SUSPEND_NONZERO_CPU
 121         ---help---
 122         If an arch can suspend (for suspend, hibernate, kexec, etc) on a
 123         non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This
 124         will allow nohz_full mask to include CPU0.
 125
 126 config PM_AUTOSLEEP
 127         bool "Opportunistic sleep"
 128         depends on PM_SLEEP
 129         default n
 130         ---help---
 131         Allow the kernel to trigger a system transition into a global sleep
 132         state automatically whenever there are no active wakeup sources.
 133
 134 config PM_WAKELOCKS
 135         bool "User space wakeup sources interface"
 136         depends on PM_SLEEP
 137         default n
 138         ---help---
 139         Allow user space to create, activate and deactivate wakeup source
 140         objects with the help of a sysfs-based interface.
 141
 142 config PM_WAKELOCKS_LIMIT
 143         int "Maximum number of user space wakeup sources (0 = no limit)"
 144         range 0 100000
 145         default 100
 146         depends on PM_WAKELOCKS
 147
 148 config PM_WAKELOCKS_GC
 149         bool "Garbage collector for user space wakeup sources"
 150         depends on PM_WAKELOCKS
 151         default y
 152
 153 config PM
 154         bool "Device power management core functionality"
 155         ---help---
 156           Enable functionality allowing I/O devices to be put into energy-saving
 157           (low power) states, for example after a specified period of inactivity
 158           (autosuspended), and woken up in response to a hardware-generated
 159           wake-up event or a driver's request.
 160
 161           Hardware support is generally required for this functionality to work
 162           and the bus type drivers of the buses the devices are on are
 163           responsible for the actual handling of device suspend requests and
 164           wake-up events.
 165
 166 config PM_DEBUG
 167         bool "Power Management Debug Support"
 168         depends on PM
 169         ---help---
 170         This option enables various debugging support in the Power Management
 171         code. This is helpful when debugging and reporting PM bugs, like
 172         suspend support.
 173
 174 config PM_ADVANCED_DEBUG
 175         bool "Extra PM attributes in sysfs for low-level debugging/testing"
 176         depends on PM_DEBUG
 177         ---help---
 178         Add extra sysfs attributes allowing one to access some Power Management
 179         fields of device objects from user space.  If you are not a kernel
 180         developer interested in debugging/testing Power Management, say "no".
 181
 182 config PM_TEST_SUSPEND
 183         bool "Test suspend/resume and wakealarm during bootup"
 184         depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
 185         ---help---
 186         This option will let you suspend your machine during bootup, and
 187         make it wake up a few seconds later using an RTC wakeup alarm.
 188         Enable this with a kernel parameter like "test_suspend=mem".
 189
 190         You probably want to have your system's RTC driver statically
 191         linked, ensuring that it's available when this test runs.
 192
 193 config PM_SLEEP_DEBUG
 194         def_bool y
 195         depends on PM_DEBUG && PM_SLEEP
 196
 197 config DPM_WATCHDOG
 198         bool "Device suspend/resume watchdog"
 199         depends on PM_DEBUG && PSTORE && EXPERT
 200         ---help---
 201           Sets up a watchdog timer to capture drivers that are
 202           locked up attempting to suspend/resume a device.
 203           A detected lockup causes system panic with message
 204           captured in pstore device for inspection in subsequent
 205           boot session.
 206
 207 config DPM_WATCHDOG_TIMEOUT
 208         int "Watchdog timeout in seconds"
 209         range 1 120
 210         default 120
 211         depends on DPM_WATCHDOG
 212
 213 config PM_TRACE
 214         bool
 215         help
 216           This enables code to save the last PM event point across
 217           reboot. The architecture needs to support this, x86 for
 218           example does by saving things in the RTC, see below.
 219
 220           The architecture specific code must provide the extern
 221           functions from <linux/resume-trace.h> as well as the
 222           <asm/resume-trace.h> header with a TRACE_RESUME() macro.
 223
 224           The way the information is presented is architecture-
 225           dependent, x86 will print the information during a
 226           late_initcall.
 227
 228 config PM_TRACE_RTC
 229         bool "Suspend/resume event tracing"
 230         depends on PM_SLEEP_DEBUG
 231         depends on X86
 232         select PM_TRACE
 233         ---help---
 234         This enables some cheesy code to save the last PM event point in the
 235         RTC across reboots, so that you can debug a machine that just hangs
 236         during suspend (or more commonly, during resume).
 237
 238         To use this debugging feature you should attempt to suspend the
 239         machine, reboot it and then run
 240
 241                 dmesg -s 1000000 | grep 'hash matches'
 242
 243         CAUTION: this option will cause your machine's real-time clock to be
 244         set to an invalid time after a resume.
 245
 246 config APM_EMULATION
 247         tristate "Advanced Power Management Emulation"
 248         depends on SYS_SUPPORTS_APM_EMULATION
 249         help
 250           APM is a BIOS specification for saving power using several different
 251           techniques. This is mostly useful for battery powered laptops with
 252           APM compliant BIOSes. If you say Y here, the system time will be
 253           reset after a RESUME operation, the /proc/apm device will provide
 254           battery status information, and user-space programs will receive
 255           notification of APM "events" (e.g. battery status change).
 256
 257           In order to use APM, you will need supporting software. For location
 258           and more information, read <file:Documentation/power/apm-acpi.rst>
 259           and the Battery Powered Linux mini-HOWTO, available from
 260           <http://www.tldp.org/docs.html#howto>.
 261
 262           This driver does not spin down disk drives (see the hdparm(8)
 263           manpage ("man 8 hdparm") for that), and it doesn't turn off
 264           VESA-compliant "green" monitors.
 265
 266           Generally, if you don't have a battery in your machine, there isn't
 267           much point in using this driver and you should say N. If you get
 268           random kernel OOPSes or reboots that don't seem to be related to
 269           anything, try disabling/enabling this option (or disabling/enabling
 270           APM in your BIOS).
 271
 272 config PM_CLK
 273         def_bool y
 274         depends on PM && HAVE_CLK
 275
 276 config PM_GENERIC_DOMAINS
 277         bool
 278         depends on PM
 279
 280 config WQ_POWER_EFFICIENT_DEFAULT
 281         bool "Enable workqueue power-efficient mode by default"
 282         depends on PM
 283         default n
 284         help
 285           Per-cpu workqueues are generally preferred because they show
 286           better performance thanks to cache locality; unfortunately,
 287           per-cpu workqueues tend to be more power hungry than unbound
 288           workqueues.
 289
 290           Enabling workqueue.power_efficient kernel parameter makes the
 291           per-cpu workqueues which were observed to contribute
 292           significantly to power consumption unbound, leading to measurably
 293           lower power usage at the cost of small performance overhead.
 294
 295           This config option determines whether workqueue.power_efficient
 296           is enabled by default.
 297
 298           If in doubt, say N.
 299
 300 config PM_GENERIC_DOMAINS_SLEEP
 301         def_bool y
 302         depends on PM_SLEEP && PM_GENERIC_DOMAINS
 303
 304 config PM_GENERIC_DOMAINS_OF
 305         def_bool y
 306         depends on PM_GENERIC_DOMAINS && OF
 307
 308 config CPU_PM
 309         bool
 310
 311 config ENERGY_MODEL
 312         bool "Energy Model for CPUs"
 313         depends on SMP
 314         depends on CPU_FREQ
 315         default n
 316         help
 317           Several subsystems (thermal and/or the task scheduler for example)
 318           can leverage information about the energy consumed by CPUs to make
 319           smarter decisions. This config option enables the framework from
 320           which subsystems can access the energy models.
 321
 322           The exact usage of the energy model is subsystem-dependent.
 323
 324           If in doubt, say N.