354 lines
12 KiB
Plaintext
354 lines
12 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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config SUSPEND
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bool "Suspend to RAM and standby"
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depends on ARCH_SUSPEND_POSSIBLE
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default y
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help
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Allow the system to enter sleep states in which main memory is
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powered and thus its contents are preserved, such as the
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suspend-to-RAM state (e.g. the ACPI S3 state).
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config SUSPEND_FREEZER
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bool "Enable freezer for suspend to RAM/standby" \
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if ARCH_WANTS_FREEZER_CONTROL || BROKEN
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depends on SUSPEND
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default y
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help
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This allows you to turn off the freezer for suspend. If this is
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done, no tasks are frozen for suspend to RAM/standby.
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Turning OFF this setting is NOT recommended! If in doubt, say Y.
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config SUSPEND_SKIP_SYNC
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bool "Skip kernel's sys_sync() on suspend to RAM/standby"
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depends on SUSPEND
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depends on EXPERT
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help
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Skip the kernel sys_sync() before freezing user processes.
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Some systems prefer not to pay this cost on every invocation
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of suspend, or they are content with invoking sync() from
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user-space before invoking suspend. There's a run-time switch
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at '/sys/power/sync_on_suspend' to configure this behaviour.
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This setting changes the default for the run-tim switch. Say Y
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to change the default to disable the kernel sys_sync().
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config HIBERNATE_CALLBACKS
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bool
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config HIBERNATION
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bool "Hibernation (aka 'suspend to disk')"
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depends on SWAP && ARCH_HIBERNATION_POSSIBLE
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select HIBERNATE_CALLBACKS
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select LZO_COMPRESS
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select LZO_DECOMPRESS
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select CRC32
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help
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Enable the suspend to disk (STD) functionality, which is usually
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called "hibernation" in user interfaces. STD checkpoints the
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system and powers it off; and restores that checkpoint on reboot.
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You can suspend your machine with 'echo disk > /sys/power/state'
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after placing resume=/dev/swappartition on the kernel command line
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in your bootloader's configuration file.
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Alternatively, you can use the additional userland tools available
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from <http://suspend.sf.net>.
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In principle it does not require ACPI or APM, although for example
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ACPI will be used for the final steps when it is available. One
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of the reasons to use software suspend is that the firmware hooks
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for suspend states like suspend-to-RAM (STR) often don't work very
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well with Linux.
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It creates an image which is saved in your active swap. Upon the next
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boot, pass the 'resume=/dev/swappartition' argument to the kernel to
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have it detect the saved image, restore memory state from it, and
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continue to run as before. If you do not want the previous state to
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be reloaded, then use the 'noresume' kernel command line argument.
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Note, however, that fsck will be run on your filesystems and you will
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need to run mkswap against the swap partition used for the suspend.
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It also works with swap files to a limited extent (for details see
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<file:Documentation/power/swsusp-and-swap-files.rst>).
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Right now you may boot without resuming and resume later but in the
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meantime you cannot use the swap partition(s)/file(s) involved in
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suspending. Also in this case you must not use the filesystems
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that were mounted before the suspend. In particular, you MUST NOT
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MOUNT any journaled filesystems mounted before the suspend or they
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will get corrupted in a nasty way.
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For more information take a look at <file:Documentation/power/swsusp.rst>.
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config HIBERNATION_SNAPSHOT_DEV
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bool "Userspace snapshot device"
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depends on HIBERNATION
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default y
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help
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Device used by the uswsusp tools.
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Say N if no snapshotting from userspace is needed, this also
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reduces the attack surface of the kernel.
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If in doubt, say Y.
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config PM_STD_PARTITION
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string "Default resume partition"
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depends on HIBERNATION
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default ""
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help
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The default resume partition is the partition that the suspend-
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to-disk implementation will look for a suspended disk image.
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The partition specified here will be different for almost every user.
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It should be a valid swap partition (at least for now) that is turned
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on before suspending.
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The partition specified can be overridden by specifying:
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resume=/dev/<other device>
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which will set the resume partition to the device specified.
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Note there is currently not a way to specify which device to save the
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suspended image to. It will simply pick the first available swap
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device.
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config PM_SLEEP
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def_bool y
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depends on SUSPEND || HIBERNATE_CALLBACKS
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select PM
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select SRCU
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config PM_SLEEP_SMP
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def_bool y
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depends on SMP
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depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
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depends on PM_SLEEP
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select HOTPLUG_CPU
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config PM_SLEEP_SMP_NONZERO_CPU
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def_bool y
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depends on PM_SLEEP_SMP
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depends on ARCH_SUSPEND_NONZERO_CPU
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help
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If an arch can suspend (for suspend, hibernate, kexec, etc) on a
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non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This
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will allow nohz_full mask to include CPU0.
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config PM_AUTOSLEEP
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bool "Opportunistic sleep"
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depends on PM_SLEEP
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help
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Allow the kernel to trigger a system transition into a global sleep
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state automatically whenever there are no active wakeup sources.
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config PM_USERSPACE_AUTOSLEEP
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bool "Userspace opportunistic sleep"
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depends on PM_SLEEP
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help
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Notify kernel of aggressive userspace autosleep power management policy.
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This option changes the behavior of various sleep-sensitive code to deal
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with frequent userspace-initiated transitions into a global sleep state.
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Saying Y here, disables code paths that most users really should keep
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enabled. In particular, only enable this if it is very common to be
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asleep/awake for very short periods of time (<= 2 seconds).
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Only platforms, such as Android, that implement opportunistic sleep from
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a userspace power manager service should enable this option; and not
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other machines. Therefore, you should say N here, unless you are
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extremely certain that this is what you want. The option otherwise has
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bad, undesirable effects, and should not be enabled just for fun.
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config PM_WAKELOCKS
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bool "User space wakeup sources interface"
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depends on PM_SLEEP
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help
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Allow user space to create, activate and deactivate wakeup source
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objects with the help of a sysfs-based interface.
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config PM_WAKELOCKS_LIMIT
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int "Maximum number of user space wakeup sources (0 = no limit)"
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range 0 100000
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default 100
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depends on PM_WAKELOCKS
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config PM_WAKELOCKS_GC
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bool "Garbage collector for user space wakeup sources"
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depends on PM_WAKELOCKS
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default y
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config PM
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bool "Device power management core functionality"
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help
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Enable functionality allowing I/O devices to be put into energy-saving
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(low power) states, for example after a specified period of inactivity
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(autosuspended), and woken up in response to a hardware-generated
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wake-up event or a driver's request.
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Hardware support is generally required for this functionality to work
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and the bus type drivers of the buses the devices are on are
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responsible for the actual handling of device suspend requests and
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wake-up events.
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config PM_DEBUG
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bool "Power Management Debug Support"
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depends on PM
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help
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This option enables various debugging support in the Power Management
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code. This is helpful when debugging and reporting PM bugs, like
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suspend support.
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config PM_ADVANCED_DEBUG
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bool "Extra PM attributes in sysfs for low-level debugging/testing"
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depends on PM_DEBUG
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help
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Add extra sysfs attributes allowing one to access some Power Management
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fields of device objects from user space. If you are not a kernel
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developer interested in debugging/testing Power Management, say "no".
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config PM_TEST_SUSPEND
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bool "Test suspend/resume and wakealarm during bootup"
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depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
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help
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This option will let you suspend your machine during bootup, and
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make it wake up a few seconds later using an RTC wakeup alarm.
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Enable this with a kernel parameter like "test_suspend=mem".
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You probably want to have your system's RTC driver statically
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linked, ensuring that it's available when this test runs.
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config PM_SLEEP_DEBUG
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def_bool y
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depends on PM_DEBUG && PM_SLEEP
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config DPM_WATCHDOG
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bool "Device suspend/resume watchdog"
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depends on PM_DEBUG && PSTORE && EXPERT
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help
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Sets up a watchdog timer to capture drivers that are
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locked up attempting to suspend/resume a device.
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A detected lockup causes system panic with message
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captured in pstore device for inspection in subsequent
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boot session.
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config DPM_WATCHDOG_TIMEOUT
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int "Watchdog timeout in seconds"
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range 1 120
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default 120
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depends on DPM_WATCHDOG
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config PM_TRACE
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bool
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help
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This enables code to save the last PM event point across
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reboot. The architecture needs to support this, x86 for
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example does by saving things in the RTC, see below.
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The architecture specific code must provide the extern
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functions from <linux/resume-trace.h> as well as the
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<asm/resume-trace.h> header with a TRACE_RESUME() macro.
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The way the information is presented is architecture-
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dependent, x86 will print the information during a
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late_initcall.
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config PM_TRACE_RTC
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bool "Suspend/resume event tracing"
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depends on PM_SLEEP_DEBUG
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depends on X86
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select PM_TRACE
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help
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This enables some cheesy code to save the last PM event point in the
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RTC across reboots, so that you can debug a machine that just hangs
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during suspend (or more commonly, during resume).
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To use this debugging feature you should attempt to suspend the
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machine, reboot it and then run
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dmesg -s 1000000 | grep 'hash matches'
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CAUTION: this option will cause your machine's real-time clock to be
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set to an invalid time after a resume.
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config APM_EMULATION
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tristate "Advanced Power Management Emulation"
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depends on SYS_SUPPORTS_APM_EMULATION
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help
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APM is a BIOS specification for saving power using several different
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techniques. This is mostly useful for battery powered laptops with
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APM compliant BIOSes. If you say Y here, the system time will be
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reset after a RESUME operation, the /proc/apm device will provide
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battery status information, and user-space programs will receive
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notification of APM "events" (e.g. battery status change).
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In order to use APM, you will need supporting software. For location
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and more information, read <file:Documentation/power/apm-acpi.rst>
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and the Battery Powered Linux mini-HOWTO, available from
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<http://www.tldp.org/docs.html#howto>.
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This driver does not spin down disk drives (see the hdparm(8)
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manpage ("man 8 hdparm") for that), and it doesn't turn off
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VESA-compliant "green" monitors.
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Generally, if you don't have a battery in your machine, there isn't
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much point in using this driver and you should say N. If you get
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random kernel OOPSes or reboots that don't seem to be related to
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anything, try disabling/enabling this option (or disabling/enabling
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APM in your BIOS).
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config PM_CLK
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def_bool y
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depends on PM && HAVE_CLK
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config PM_GENERIC_DOMAINS
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bool
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depends on PM
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config WQ_POWER_EFFICIENT_DEFAULT
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bool "Enable workqueue power-efficient mode by default"
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depends on PM
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help
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Per-cpu workqueues are generally preferred because they show
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better performance thanks to cache locality; unfortunately,
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per-cpu workqueues tend to be more power hungry than unbound
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workqueues.
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Enabling workqueue.power_efficient kernel parameter makes the
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per-cpu workqueues which were observed to contribute
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significantly to power consumption unbound, leading to measurably
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lower power usage at the cost of small performance overhead.
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This config option determines whether workqueue.power_efficient
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is enabled by default.
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If in doubt, say N.
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config PM_GENERIC_DOMAINS_SLEEP
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def_bool y
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depends on PM_SLEEP && PM_GENERIC_DOMAINS
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config PM_GENERIC_DOMAINS_OF
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def_bool y
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depends on PM_GENERIC_DOMAINS && OF
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config CPU_PM
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bool
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config ENERGY_MODEL
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bool "Energy Model for devices with DVFS (CPUs, GPUs, etc)"
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depends on SMP
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depends on CPU_FREQ
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help
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Several subsystems (thermal and/or the task scheduler for example)
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can leverage information about the energy consumed by devices to
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make smarter decisions. This config option enables the framework
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from which subsystems can access the energy models.
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The exact usage of the energy model is subsystem-dependent.
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If in doubt, say N.
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