kernel/power/Kconfig - linux - Git at Google


            
            config PM

            
            	bool "Power Management support"

            
            	depends on !IA64_HP_SIM

            
            	---help---

            
            	  "Power Management" means that parts of your computer are shut

            
            	  off or put into a power conserving "sleep" mode if they are not

            
            	  being used.  There are two competing standards for doing this: APM

            
            	  and ACPI.  If you want to use either one, say Y here and then also

            
            	  to the requisite support below.


            	  Power Management is most important for battery powered laptop

            
            	  computers; if you have a laptop, check out the Linux Laptop home

            
            	  page on the WWW at <http://www.linux-on-laptops.com/> or

            
            	  Tuxmobil - Linux on Mobile Computers at <http://www.tuxmobil.org/>

            
            	  and the Battery Powered Linux mini-HOWTO, available from

            
            	  <http://www.tldp.org/docs.html#howto>.


            	  Note that, even if you say N here, Linux on the x86 architecture

            
            	  will issue the hlt instruction if nothing is to be done, thereby

            
            	  sending the processor to sleep and saving power.


            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_VERBOSE

            
            	bool "Verbose Power Management debugging"

            
            	depends on PM_DEBUG

            
            	default n

            
            	---help---

            
            	This option enables verbose messages from the Power Management code.


            config CAN_PM_TRACE

            
            	def_bool y

            
            	depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL


            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 <linux/resume-trace.h> as well as the

            
            	  <asm/resume-trace.h> 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 CAN_PM_TRACE

            
            	depends on X86

            
            	select PM_TRACE

            
            	default n

            
            	---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 PM_SLEEP_SMP

            
            	bool

            
            	depends on SMP

            
            	depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE

            
            	depends on PM_SLEEP

            
            	select HOTPLUG_CPU

            
            	default y


            config PM_SLEEP

            
            	bool

            
            	depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE

            
            	default y


            config SUSPEND

            
            	bool "Suspend to RAM and standby"

            
            	depends on PM && ARCH_SUSPEND_POSSIBLE

            
            	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 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 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 HIBERNATION_NVS

            
            	bool


            config HIBERNATION

            
            	bool "Hibernation (aka 'suspend to disk')"

            
            	depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE

            
            	select HIBERNATION_NVS if HAS_IOMEM

            
            	---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 <http://suspend.sf.net>.


            	  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

            
            	  <file:Documentation/power/swsusp-and-swap-files.txt>).


            	  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 <file:Documentation/power/swsusp.txt>.


            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/<other device>


            	  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 APM_EMULATION

            
            	tristate "Advanced Power Management Emulation"

            
            	depends on PM && 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 <file:Documentation/power/pm.txt> and the

            
            	  Battery Powered Linux mini-HOWTO, available from

            
            	  <http://www.tldp.org/docs.html#howto>.


            	  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_RUNTIME

            
            	bool "Run-time PM core functionality"

            
            	depends on PM

            
            	---help---

            
            	  Enable functionality allowing I/O devices to be put into energy-saving

            
            	  (low power) states at run time (or autosuspended) after a specified

            
            	  period of inactivity 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 the autosuspend requests and

            
            	  wake-up events.
	config PM
	bool "Power Management support"
	depends on !IA64_HP_SIM
	---help---
	"Power Management" means that parts of your computer are shut
	off or put into a power conserving "sleep" mode if they are not
	being used. There are two competing standards for doing this: APM
	and ACPI. If you want to use either one, say Y here and then also
	to the requisite support below.

	Power Management is most important for battery powered laptop
	computers; if you have a laptop, check out the Linux Laptop home
	page on the WWW at <http://www.linux-on-laptops.com/> or
	Tuxmobil - Linux on Mobile Computers at <http://www.tuxmobil.org/>
	and the Battery Powered Linux mini-HOWTO, available from
	<http://www.tldp.org/docs.html#howto>.

	Note that, even if you say N here, Linux on the x86 architecture
	will issue the hlt instruction if nothing is to be done, thereby
	sending the processor to sleep and saving power.

	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_VERBOSE
	bool "Verbose Power Management debugging"
	depends on PM_DEBUG
	default n
	---help---
	This option enables verbose messages from the Power Management code.

	config CAN_PM_TRACE
	def_bool y
	depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL

	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 <linux/resume-trace.h> as well as the
	<asm/resume-trace.h> 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 CAN_PM_TRACE
	depends on X86
	select PM_TRACE
	default n
	---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 PM_SLEEP_SMP
	bool
	depends on SMP
	depends on ARCH_SUSPEND_POSSIBLE \|\| ARCH_HIBERNATION_POSSIBLE
	depends on PM_SLEEP
	select HOTPLUG_CPU
	default y

	config PM_SLEEP
	bool
	depends on SUSPEND \|\| HIBERNATION \|\| XEN_SAVE_RESTORE
	default y

	config SUSPEND
	bool "Suspend to RAM and standby"
	depends on PM && ARCH_SUSPEND_POSSIBLE
	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 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 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 HIBERNATION_NVS
	bool

	config HIBERNATION
	bool "Hibernation (aka 'suspend to disk')"
	depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
	select HIBERNATION_NVS if HAS_IOMEM
	---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 <http://suspend.sf.net>.

	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
	<file:Documentation/power/swsusp-and-swap-files.txt>).

	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 <file:Documentation/power/swsusp.txt>.

	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/<other device>

	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 APM_EMULATION
	tristate "Advanced Power Management Emulation"
	depends on PM && 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 <file:Documentation/power/pm.txt> and the
	Battery Powered Linux mini-HOWTO, available from
	<http://www.tldp.org/docs.html#howto>.

	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_RUNTIME
	bool "Run-time PM core functionality"
	depends on PM
	---help---
	Enable functionality allowing I/O devices to be put into energy-saving
	(low power) states at run time (or autosuspended) after a specified
	period of inactivity 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 the autosuspend requests and
	wake-up events.