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![Pranith Kumar](/assets/img/avatar_default.png)
SRCU is not necessary to be compiled by default in all cases. For tinification efforts not compiling SRCU unless necessary is desirable. The current patch tries to make compiling SRCU optional by introducing a new Kconfig option CONFIG_SRCU which is selected when any of the components making use of SRCU are selected. If we do not select CONFIG_SRCU, srcu.o will not be compiled at all. text data bss dec hex filename 2007 0 0 2007 7d7 kernel/rcu/srcu.o Size of arch/powerpc/boot/zImage changes from text data bss dec hex filename 831552 64180 23944 919676 e087c arch/powerpc/boot/zImage : before 829504 64180 23952 917636 e0084 arch/powerpc/boot/zImage : after so the savings are about ~2000 bytes. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com> CC: Josh Triplett <josh@joshtriplett.org> CC: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: resolve conflict due to removal of arch/ia64/kvm/Kconfig. ]
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303 lines
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Text
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 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.txt>).
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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.txt>.
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config ARCH_SAVE_PAGE_KEYS
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bool
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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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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_AUTOSLEEP
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bool "Opportunistic sleep"
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depends on PM_SLEEP
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default n
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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_WAKELOCKS
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bool "User space wakeup sources interface"
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depends on PM_SLEEP
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default n
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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
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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 12
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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 PM && 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.txt>
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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_OPP
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bool
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select SRCU
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---help---
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SOCs have a standard set of tuples consisting of frequency and
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voltage pairs that the device will support per voltage domain. This
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is called Operating Performance Point or OPP. The actual definitions
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of OPP varies over silicon within the same family of devices.
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OPP layer organizes the data internally using device pointers
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representing individual voltage domains and provides SOC
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implementations a ready to use framework to manage OPPs.
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For more information, read <file:Documentation/power/opp.txt>
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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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default n
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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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