config SUSPEND bool "Suspend to RAM and standby" depends on ARCH_SUSPEND_POSSIBLE select RTC_LIB default y ---help--- Allow the system to enter sleep states in which main memory is powered and thus its contents are preserved, such as the suspend-to-RAM state (e.g. the ACPI S3 state). config SUSPEND_FREEZER bool "Enable freezer for suspend to RAM/standby" \ if ARCH_WANTS_FREEZER_CONTROL || BROKEN depends on SUSPEND default y help This allows you to turn off the freezer for suspend. If this is done, no tasks are frozen for suspend to RAM/standby. Turning OFF this setting is NOT recommended! If in doubt, say Y. config SUSPEND_SKIP_SYNC bool "Skip kernel's sys_sync() on suspend to RAM/standby" depends on SUSPEND depends on EXPERT help Skip the kernel sys_sync() before freezing user processes. Some systems prefer not to pay this cost on every invocation of suspend, or they are content with invoking sync() from user-space before invoking suspend. Say Y if that's your case. config HIBERNATE_CALLBACKS bool config HIBERNATION bool "Hibernation (aka 'suspend to disk')" depends on SWAP && ARCH_HIBERNATION_POSSIBLE select HIBERNATE_CALLBACKS select LZO_COMPRESS select LZO_DECOMPRESS select CRC32 ---help--- Enable the suspend to disk (STD) functionality, which is usually called "hibernation" in user interfaces. STD checkpoints the system and powers it off; and restores that checkpoint on reboot. You can suspend your machine with 'echo disk > /sys/power/state' after placing resume=/dev/swappartition on the kernel command line in your bootloader's configuration file. Alternatively, you can use the additional userland tools available from . In principle it does not require ACPI or APM, although for example ACPI will be used for the final steps when it is available. One of the reasons to use software suspend is that the firmware hooks for suspend states like suspend-to-RAM (STR) often don't work very well with Linux. It creates an image which is saved in your active swap. Upon the next boot, pass the 'resume=/dev/swappartition' argument to the kernel to have it detect the saved image, restore memory state from it, and continue to run as before. If you do not want the previous state to be reloaded, then use the 'noresume' kernel command line argument. Note, however, that fsck will be run on your filesystems and you will need to run mkswap against the swap partition used for the suspend. It also works with swap files to a limited extent (for details see ). Right now you may boot without resuming and resume later but in the meantime you cannot use the swap partition(s)/file(s) involved in suspending. Also in this case you must not use the filesystems that were mounted before the suspend. In particular, you MUST NOT MOUNT any journaled filesystems mounted before the suspend or they will get corrupted in a nasty way. For more information take a look at . config HIBERNATION_IMAGE_REUSE bool "Reuse hibernation image" depends on HIBERNATION ---help--- By default this hibernation image is erased after either a successful or unsuccessful hibernation restore sequeunce. Since filesystem contents on disk are not part of the hibernation image, failure to create a new hibernation image every boot can lead to filesystem corruption. Conversely, if the usecase can guarantee that the filesystem is not ever modified, the same hibernation image can be reused. This prevents creating additional hibernation images unncesarily. For more details, refer to the description of CONFIG_HIBERNATION for booting without resuming. config HIBERNATION_SKIP_CRC bool "Skip LZO image CRC check" default n depends on HIBERNATION ---help--- Some filesystem devices may have hw based integrity checks. In this scenario, repeating the integrity check in software is unnecessary and wasteful. This config option has no effect if uncompressed hibernation images are used. config ARCH_SAVE_PAGE_KEYS bool config PM_STD_PARTITION string "Default resume partition" depends on HIBERNATION default "" ---help--- The default resume partition is the partition that the suspend- to-disk implementation will look for a suspended disk image. The partition specified here will be different for almost every user. It should be a valid swap partition (at least for now) that is turned on before suspending. The partition specified can be overridden by specifying: resume=/dev/ which will set the resume partition to the device specified. Note there is currently not a way to specify which device to save the suspended image to. It will simply pick the first available swap device. config PM_SLEEP def_bool y depends on SUSPEND || HIBERNATE_CALLBACKS select PM select SRCU config PM_SLEEP_SMP def_bool y depends on SMP depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE depends on PM_SLEEP select HOTPLUG_CPU config PM_AUTOSLEEP bool "Opportunistic sleep" depends on PM_SLEEP default n ---help--- Allow the kernel to trigger a system transition into a global sleep state automatically whenever there are no active wakeup sources. config PM_WAKELOCKS bool "User space wakeup sources interface" depends on PM_SLEEP default n ---help--- Allow user space to create, activate and deactivate wakeup source objects with the help of a sysfs-based interface. config PM_WAKELOCKS_LIMIT int "Maximum number of user space wakeup sources (0 = no limit)" range 0 100000 default 100 depends on PM_WAKELOCKS config PM_WAKELOCKS_GC bool "Garbage collector for user space wakeup sources" depends on PM_WAKELOCKS default y config PM bool "Device power management core functionality" ---help--- Enable functionality allowing I/O devices to be put into energy-saving (low power) states, for example after a specified period of inactivity (autosuspended), and woken up in response to a hardware-generated wake-up event or a driver's request. Hardware support is generally required for this functionality to work and the bus type drivers of the buses the devices are on are responsible for the actual handling of device suspend requests and wake-up events. config PM_DEBUG bool "Power Management Debug Support" depends on PM ---help--- This option enables various debugging support in the Power Management code. This is helpful when debugging and reporting PM bugs, like suspend support. config PM_ADVANCED_DEBUG bool "Extra PM attributes in sysfs for low-level debugging/testing" depends on PM_DEBUG ---help--- Add extra sysfs attributes allowing one to access some Power Management fields of device objects from user space. If you are not a kernel developer interested in debugging/testing Power Management, say "no". config PM_TEST_SUSPEND bool "Test suspend/resume and wakealarm during bootup" depends on SUSPEND && PM_DEBUG && RTC_CLASS=y ---help--- This option will let you suspend your machine during bootup, and make it wake up a few seconds later using an RTC wakeup alarm. Enable this with a kernel parameter like "test_suspend=mem". You probably want to have your system's RTC driver statically linked, ensuring that it's available when this test runs. config PM_SLEEP_DEBUG def_bool y depends on PM_DEBUG && PM_SLEEP config DPM_WATCHDOG bool "Device suspend/resume watchdog" depends on PM_DEBUG && PSTORE && EXPERT ---help--- Sets up a watchdog timer to capture drivers that are locked up attempting to suspend/resume a device. A detected lockup causes system panic with message captured in pstore device for inspection in subsequent boot session. config DPM_WATCHDOG_TIMEOUT int "Watchdog timeout in seconds" range 1 120 default 120 depends on DPM_WATCHDOG config PM_TRACE bool help This enables code to save the last PM event point across reboot. The architecture needs to support this, x86 for example does by saving things in the RTC, see below. The architecture specific code must provide the extern functions from as well as the header with a TRACE_RESUME() macro. The way the information is presented is architecture- dependent, x86 will print the information during a late_initcall. config PM_TRACE_RTC bool "Suspend/resume event tracing" depends on PM_SLEEP_DEBUG depends on X86 select PM_TRACE ---help--- This enables some cheesy code to save the last PM event point in the RTC across reboots, so that you can debug a machine that just hangs during suspend (or more commonly, during resume). To use this debugging feature you should attempt to suspend the machine, reboot it and then run dmesg -s 1000000 | grep 'hash matches' CAUTION: this option will cause your machine's real-time clock to be set to an invalid time after a resume. config APM_EMULATION tristate "Advanced Power Management Emulation" depends on SYS_SUPPORTS_APM_EMULATION help APM is a BIOS specification for saving power using several different techniques. This is mostly useful for battery powered laptops with APM compliant BIOSes. If you say Y here, the system time will be reset after a RESUME operation, the /proc/apm device will provide battery status information, and user-space programs will receive notification of APM "events" (e.g. battery status change). In order to use APM, you will need supporting software. For location and more information, read and the Battery Powered Linux mini-HOWTO, available from . This driver does not spin down disk drives (see the hdparm(8) manpage ("man 8 hdparm") for that), and it doesn't turn off VESA-compliant "green" monitors. Generally, if you don't have a battery in your machine, there isn't much point in using this driver and you should say N. If you get random kernel OOPSes or reboots that don't seem to be related to anything, try disabling/enabling this option (or disabling/enabling APM in your BIOS). config PM_OPP bool select SRCU ---help--- SOCs have a standard set of tuples consisting of frequency and voltage pairs that the device will support per voltage domain. This is called Operating Performance Point or OPP. The actual definitions of OPP varies over silicon within the same family of devices. OPP layer organizes the data internally using device pointers representing individual voltage domains and provides SOC implementations a ready to use framework to manage OPPs. For more information, read config PM_CLK def_bool y depends on PM && HAVE_CLK config PM_GENERIC_DOMAINS bool depends on PM config WQ_POWER_EFFICIENT_DEFAULT bool "Enable workqueue power-efficient mode by default" depends on PM default n help Per-cpu workqueues are generally preferred because they show better performance thanks to cache locality; unfortunately, per-cpu workqueues tend to be more power hungry than unbound workqueues. Enabling workqueue.power_efficient kernel parameter makes the per-cpu workqueues which were observed to contribute significantly to power consumption unbound, leading to measurably lower power usage at the cost of small performance overhead. This config option determines whether workqueue.power_efficient is enabled by default. If in doubt, say N. config PM_GENERIC_DOMAINS_SLEEP def_bool y depends on PM_SLEEP && PM_GENERIC_DOMAINS config PM_GENERIC_DOMAINS_OF def_bool y depends on PM_GENERIC_DOMAINS && OF config CPU_PM bool config CPU_FREQ_LIMIT_USERSPACE bool "User space cpufreq limit interface" depends on CPU_FREQ_LIMIT default n help Add sysfs to limit CPU frequency for a userspace program. /sys/power/cpufreq_min_limit /sys/power/cpufreq_max_limit /sys/power/cpufreq_table