0001 # SPDX-License-Identifier: GPL-2.0-only
0002 config SUSPEND
0003 bool "Suspend to RAM and standby"
0004 depends on ARCH_SUSPEND_POSSIBLE
0005 default y
0006 help
0007 Allow the system to enter sleep states in which main memory is
0008 powered and thus its contents are preserved, such as the
0009 suspend-to-RAM state (e.g. the ACPI S3 state).
0010
0011 config SUSPEND_FREEZER
0012 bool "Enable freezer for suspend to RAM/standby" \
0013 if ARCH_WANTS_FREEZER_CONTROL || BROKEN
0014 depends on SUSPEND
0015 default y
0016 help
0017 This allows you to turn off the freezer for suspend. If this is
0018 done, no tasks are frozen for suspend to RAM/standby.
0019
0020 Turning OFF this setting is NOT recommended! If in doubt, say Y.
0021
0022 config SUSPEND_SKIP_SYNC
0023 bool "Skip kernel's sys_sync() on suspend to RAM/standby"
0024 depends on SUSPEND
0025 depends on EXPERT
0026 help
0027 Skip the kernel sys_sync() before freezing user processes.
0028 Some systems prefer not to pay this cost on every invocation
0029 of suspend, or they are content with invoking sync() from
0030 user-space before invoking suspend. There's a run-time switch
0031 at '/sys/power/sync_on_suspend' to configure this behaviour.
0032 This setting changes the default for the run-tim switch. Say Y
0033 to change the default to disable the kernel sys_sync().
0034
0035 config HIBERNATE_CALLBACKS
0036 bool
0037
0038 config HIBERNATION
0039 bool "Hibernation (aka 'suspend to disk')"
0040 depends on SWAP && ARCH_HIBERNATION_POSSIBLE
0041 select HIBERNATE_CALLBACKS
0042 select LZO_COMPRESS
0043 select LZO_DECOMPRESS
0044 select CRC32
0045 help
0046 Enable the suspend to disk (STD) functionality, which is usually
0047 called "hibernation" in user interfaces. STD checkpoints the
0048 system and powers it off; and restores that checkpoint on reboot.
0049
0050 You can suspend your machine with 'echo disk > /sys/power/state'
0051 after placing resume=/dev/swappartition on the kernel command line
0052 in your bootloader's configuration file.
0053
0054 Alternatively, you can use the additional userland tools available
0055 from <http://suspend.sf.net>.
0056
0057 In principle it does not require ACPI or APM, although for example
0058 ACPI will be used for the final steps when it is available. One
0059 of the reasons to use software suspend is that the firmware hooks
0060 for suspend states like suspend-to-RAM (STR) often don't work very
0061 well with Linux.
0062
0063 It creates an image which is saved in your active swap. Upon the next
0064 boot, pass the 'resume=/dev/swappartition' argument to the kernel to
0065 have it detect the saved image, restore memory state from it, and
0066 continue to run as before. If you do not want the previous state to
0067 be reloaded, then use the 'noresume' kernel command line argument.
0068 Note, however, that fsck will be run on your filesystems and you will
0069 need to run mkswap against the swap partition used for the suspend.
0070
0071 It also works with swap files to a limited extent (for details see
0072 <file:Documentation/power/swsusp-and-swap-files.rst>).
0073
0074 Right now you may boot without resuming and resume later but in the
0075 meantime you cannot use the swap partition(s)/file(s) involved in
0076 suspending. Also in this case you must not use the filesystems
0077 that were mounted before the suspend. In particular, you MUST NOT
0078 MOUNT any journaled filesystems mounted before the suspend or they
0079 will get corrupted in a nasty way.
0080
0081 For more information take a look at <file:Documentation/power/swsusp.rst>.
0082
0083 config HIBERNATION_SNAPSHOT_DEV
0084 bool "Userspace snapshot device"
0085 depends on HIBERNATION
0086 default y
0087 help
0088 Device used by the uswsusp tools.
0089
0090 Say N if no snapshotting from userspace is needed, this also
0091 reduces the attack surface of the kernel.
0092
0093 If in doubt, say Y.
0094
0095 config PM_STD_PARTITION
0096 string "Default resume partition"
0097 depends on HIBERNATION
0098 default ""
0099 help
0100 The default resume partition is the partition that the suspend-
0101 to-disk implementation will look for a suspended disk image.
0102
0103 The partition specified here will be different for almost every user.
0104 It should be a valid swap partition (at least for now) that is turned
0105 on before suspending.
0106
0107 The partition specified can be overridden by specifying:
0108
0109 resume=/dev/<other device>
0110
0111 which will set the resume partition to the device specified.
0112
0113 Note there is currently not a way to specify which device to save the
0114 suspended image to. It will simply pick the first available swap
0115 device.
0116
0117 config PM_SLEEP
0118 def_bool y
0119 depends on SUSPEND || HIBERNATE_CALLBACKS
0120 select PM
0121 select SRCU
0122
0123 config PM_SLEEP_SMP
0124 def_bool y
0125 depends on SMP
0126 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
0127 depends on PM_SLEEP
0128 select HOTPLUG_CPU
0129
0130 config PM_SLEEP_SMP_NONZERO_CPU
0131 def_bool y
0132 depends on PM_SLEEP_SMP
0133 depends on ARCH_SUSPEND_NONZERO_CPU
0134 help
0135 If an arch can suspend (for suspend, hibernate, kexec, etc) on a
0136 non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This
0137 will allow nohz_full mask to include CPU0.
0138
0139 config PM_AUTOSLEEP
0140 bool "Opportunistic sleep"
0141 depends on PM_SLEEP
0142 help
0143 Allow the kernel to trigger a system transition into a global sleep
0144 state automatically whenever there are no active wakeup sources.
0145
0146 config PM_USERSPACE_AUTOSLEEP
0147 bool "Userspace opportunistic sleep"
0148 depends on PM_SLEEP
0149 help
0150 Notify kernel of aggressive userspace autosleep power management policy.
0151
0152 This option changes the behavior of various sleep-sensitive code to deal
0153 with frequent userspace-initiated transitions into a global sleep state.
0154
0155 Saying Y here, disables code paths that most users really should keep
0156 enabled. In particular, only enable this if it is very common to be
0157 asleep/awake for very short periods of time (<= 2 seconds).
0158
0159 Only platforms, such as Android, that implement opportunistic sleep from
0160 a userspace power manager service should enable this option; and not
0161 other machines. Therefore, you should say N here, unless you are
0162 extremely certain that this is what you want. The option otherwise has
0163 bad, undesirable effects, and should not be enabled just for fun.
0164
0165
0166 config PM_WAKELOCKS
0167 bool "User space wakeup sources interface"
0168 depends on PM_SLEEP
0169 help
0170 Allow user space to create, activate and deactivate wakeup source
0171 objects with the help of a sysfs-based interface.
0172
0173 config PM_WAKELOCKS_LIMIT
0174 int "Maximum number of user space wakeup sources (0 = no limit)"
0175 range 0 100000
0176 default 100
0177 depends on PM_WAKELOCKS
0178
0179 config PM_WAKELOCKS_GC
0180 bool "Garbage collector for user space wakeup sources"
0181 depends on PM_WAKELOCKS
0182 default y
0183
0184 config PM
0185 bool "Device power management core functionality"
0186 help
0187 Enable functionality allowing I/O devices to be put into energy-saving
0188 (low power) states, for example after a specified period of inactivity
0189 (autosuspended), and woken up in response to a hardware-generated
0190 wake-up event or a driver's request.
0191
0192 Hardware support is generally required for this functionality to work
0193 and the bus type drivers of the buses the devices are on are
0194 responsible for the actual handling of device suspend requests and
0195 wake-up events.
0196
0197 config PM_DEBUG
0198 bool "Power Management Debug Support"
0199 depends on PM
0200 help
0201 This option enables various debugging support in the Power Management
0202 code. This is helpful when debugging and reporting PM bugs, like
0203 suspend support.
0204
0205 config PM_ADVANCED_DEBUG
0206 bool "Extra PM attributes in sysfs for low-level debugging/testing"
0207 depends on PM_DEBUG
0208 help
0209 Add extra sysfs attributes allowing one to access some Power Management
0210 fields of device objects from user space. If you are not a kernel
0211 developer interested in debugging/testing Power Management, say "no".
0212
0213 config PM_TEST_SUSPEND
0214 bool "Test suspend/resume and wakealarm during bootup"
0215 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
0216 help
0217 This option will let you suspend your machine during bootup, and
0218 make it wake up a few seconds later using an RTC wakeup alarm.
0219 Enable this with a kernel parameter like "test_suspend=mem".
0220
0221 You probably want to have your system's RTC driver statically
0222 linked, ensuring that it's available when this test runs.
0223
0224 config PM_SLEEP_DEBUG
0225 def_bool y
0226 depends on PM_DEBUG && PM_SLEEP
0227
0228 config DPM_WATCHDOG
0229 bool "Device suspend/resume watchdog"
0230 depends on PM_DEBUG && PSTORE && EXPERT
0231 help
0232 Sets up a watchdog timer to capture drivers that are
0233 locked up attempting to suspend/resume a device.
0234 A detected lockup causes system panic with message
0235 captured in pstore device for inspection in subsequent
0236 boot session.
0237
0238 config DPM_WATCHDOG_TIMEOUT
0239 int "Watchdog timeout in seconds"
0240 range 1 120
0241 default 120
0242 depends on DPM_WATCHDOG
0243
0244 config PM_TRACE
0245 bool
0246 help
0247 This enables code to save the last PM event point across
0248 reboot. The architecture needs to support this, x86 for
0249 example does by saving things in the RTC, see below.
0250
0251 The architecture specific code must provide the extern
0252 functions from <linux/resume-trace.h> as well as the
0253 <asm/resume-trace.h> header with a TRACE_RESUME() macro.
0254
0255 The way the information is presented is architecture-
0256 dependent, x86 will print the information during a
0257 late_initcall.
0258
0259 config PM_TRACE_RTC
0260 bool "Suspend/resume event tracing"
0261 depends on PM_SLEEP_DEBUG
0262 depends on X86
0263 select PM_TRACE
0264 help
0265 This enables some cheesy code to save the last PM event point in the
0266 RTC across reboots, so that you can debug a machine that just hangs
0267 during suspend (or more commonly, during resume).
0268
0269 To use this debugging feature you should attempt to suspend the
0270 machine, reboot it and then run
0271
0272 dmesg -s 1000000 | grep 'hash matches'
0273
0274 CAUTION: this option will cause your machine's real-time clock to be
0275 set to an invalid time after a resume.
0276
0277 config APM_EMULATION
0278 tristate "Advanced Power Management Emulation"
0279 depends on SYS_SUPPORTS_APM_EMULATION
0280 help
0281 APM is a BIOS specification for saving power using several different
0282 techniques. This is mostly useful for battery powered laptops with
0283 APM compliant BIOSes. If you say Y here, the system time will be
0284 reset after a RESUME operation, the /proc/apm device will provide
0285 battery status information, and user-space programs will receive
0286 notification of APM "events" (e.g. battery status change).
0287
0288 In order to use APM, you will need supporting software. For location
0289 and more information, read <file:Documentation/power/apm-acpi.rst>
0290 and the Battery Powered Linux mini-HOWTO, available from
0291 <http://www.tldp.org/docs.html#howto>.
0292
0293 This driver does not spin down disk drives (see the hdparm(8)
0294 manpage ("man 8 hdparm") for that), and it doesn't turn off
0295 VESA-compliant "green" monitors.
0296
0297 Generally, if you don't have a battery in your machine, there isn't
0298 much point in using this driver and you should say N. If you get
0299 random kernel OOPSes or reboots that don't seem to be related to
0300 anything, try disabling/enabling this option (or disabling/enabling
0301 APM in your BIOS).
0302
0303 config PM_CLK
0304 def_bool y
0305 depends on PM && HAVE_CLK
0306
0307 config PM_GENERIC_DOMAINS
0308 bool
0309 depends on PM
0310
0311 config WQ_POWER_EFFICIENT_DEFAULT
0312 bool "Enable workqueue power-efficient mode by default"
0313 depends on PM
0314 help
0315 Per-cpu workqueues are generally preferred because they show
0316 better performance thanks to cache locality; unfortunately,
0317 per-cpu workqueues tend to be more power hungry than unbound
0318 workqueues.
0319
0320 Enabling workqueue.power_efficient kernel parameter makes the
0321 per-cpu workqueues which were observed to contribute
0322 significantly to power consumption unbound, leading to measurably
0323 lower power usage at the cost of small performance overhead.
0324
0325 This config option determines whether workqueue.power_efficient
0326 is enabled by default.
0327
0328 If in doubt, say N.
0329
0330 config PM_GENERIC_DOMAINS_SLEEP
0331 def_bool y
0332 depends on PM_SLEEP && PM_GENERIC_DOMAINS
0333
0334 config PM_GENERIC_DOMAINS_OF
0335 def_bool y
0336 depends on PM_GENERIC_DOMAINS && OF
0337
0338 config CPU_PM
0339 bool
0340
0341 config ENERGY_MODEL
0342 bool "Energy Model for devices with DVFS (CPUs, GPUs, etc)"
0343 depends on SMP
0344 depends on CPU_FREQ
0345 help
0346 Several subsystems (thermal and/or the task scheduler for example)
0347 can leverage information about the energy consumed by devices to
0348 make smarter decisions. This config option enables the framework
0349 from which subsystems can access the energy models.
0350
0351 The exact usage of the energy model is subsystem-dependent.
0352
0353 If in doubt, say N.
