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_LEGACY

            
            	bool "Legacy Power Management API (DEPRECATED)"

            
            	depends on PM

            
            	default n

            
            	---help---

            
            	   Support for pm_register() and friends.  This old API is obsoleted

            
            	   by the driver model.


            	   If unsure, say N.


            config PM_DEBUG

            
            	bool "Power Management Debug Support"

            
            	depends on PM

            
            	---help---

            
            	This option enables verbose debugging support in the Power Management

            
            	code. This is helpful when debugging and reporting various PM bugs,

            
            	like suspend support.


            config DISABLE_CONSOLE_SUSPEND

            
            	bool "Keep console(s) enabled during suspend/resume (DANGEROUS)"

            
            	depends on PM && PM_DEBUG

            
            	default n

            
            	---help---

            
            	This option turns off the console suspend mechanism that prevents

            
            	debug messages from reaching the console during the suspend/resume

            
            	operations.  This may be helpful when debugging device drivers'

            
            	suspend/resume routines, but may itself lead to problems, for example

            
            	if netconsole is used.


            config PM_TRACE

            
            	bool "Suspend/resume event tracing"

            
            	depends on PM && PM_DEBUG && X86_32 && EXPERIMENTAL

            
            	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,

            
            	then reboot it, 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_SYSFS_DEPRECATED

            
            	bool "Driver model /sys/devices/.../power/state files (DEPRECATED)"

            
            	depends on PM && SYSFS

            
            	default n

            
            	help

            
            	  The driver model started out with a sysfs file intended to provide

            
            	  a userspace hook for device power management.  This feature has never

            
            	  worked very well, except for limited testing purposes, and so it will

            
            	  be removed.   It's not clear that a generic mechanism could really

            
            	  handle the wide variability of device power states; any replacements

            
            	  are likely to be bus or driver specific.


            config SOFTWARE_SUSPEND

            
            	bool "Software Suspend"

            
            	depends on PM && SWAP && ((X86 && (!SMP || SUSPEND_SMP)) || ((FRV || PPC32) && !SMP))

            
            	---help---

            
            	  Enable the possibility of suspending the machine.

            
            	  It doesn't need ACPI or APM.

            
            	  You may suspend your machine by 'swsusp' or 'shutdown -z <time>'

            
            	  (patch for sysvinit needed).


            	  It creates an image which is saved in your active swap. Upon 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 argument. However, note

            
            	  that your partitions will be fsck'd and you must re-mkswap your swap

            
            	  partitions. It does not work with swap files.


            	  Right now you may boot without resuming and then later resume but

            
            	  in meantime you cannot use those swap partitions/files which were

            
            	  involved in suspending. Also in this case there is a risk that buffers

            
            	  on disk won't match with saved ones.


            	  For more information take a look at <file:Documentation/power/swsusp.txt>.


            	  (For now, swsusp is incompatible with PAE aka HIGHMEM_64G on i386.

            
            	  we need identity mapping for resume to work, and that is trivial

            
            	  to get with 4MB pages, but less than trivial on PAE).


            config PM_STD_PARTITION

            
            	string "Default resume partition"

            
            	depends on SOFTWARE_SUSPEND

            
            	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 SUSPEND_SMP

            
            	bool

            
            	depends on HOTPLUG_CPU && X86 && PM

            
            	default y


            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/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
	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_LEGACY
	bool "Legacy Power Management API (DEPRECATED)"
	depends on PM
	default n
	---help---
	Support for pm_register() and friends. This old API is obsoleted
	by the driver model.

	If unsure, say N.

	config PM_DEBUG
	bool "Power Management Debug Support"
	depends on PM
	---help---
	This option enables verbose debugging support in the Power Management
	code. This is helpful when debugging and reporting various PM bugs,
	like suspend support.

	config DISABLE_CONSOLE_SUSPEND
	bool "Keep console(s) enabled during suspend/resume (DANGEROUS)"
	depends on PM && PM_DEBUG
	default n
	---help---
	This option turns off the console suspend mechanism that prevents
	debug messages from reaching the console during the suspend/resume
	operations. This may be helpful when debugging device drivers'
	suspend/resume routines, but may itself lead to problems, for example
	if netconsole is used.

	config PM_TRACE
	bool "Suspend/resume event tracing"
	depends on PM && PM_DEBUG && X86_32 && EXPERIMENTAL
	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,
	then reboot it, 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_SYSFS_DEPRECATED
	bool "Driver model /sys/devices/.../power/state files (DEPRECATED)"
	depends on PM && SYSFS
	default n
	help
	The driver model started out with a sysfs file intended to provide
	a userspace hook for device power management. This feature has never
	worked very well, except for limited testing purposes, and so it will
	be removed. It's not clear that a generic mechanism could really
	handle the wide variability of device power states; any replacements
	are likely to be bus or driver specific.

	config SOFTWARE_SUSPEND
	bool "Software Suspend"
	depends on PM && SWAP && ((X86 && (!SMP \|\| SUSPEND_SMP)) \|\| ((FRV \|\| PPC32) && !SMP))
	---help---
	Enable the possibility of suspending the machine.
	It doesn't need ACPI or APM.
	You may suspend your machine by 'swsusp' or 'shutdown -z <time>'
	(patch for sysvinit needed).

	It creates an image which is saved in your active swap. Upon 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 argument. However, note
	that your partitions will be fsck'd and you must re-mkswap your swap
	partitions. It does not work with swap files.

	Right now you may boot without resuming and then later resume but
	in meantime you cannot use those swap partitions/files which were
	involved in suspending. Also in this case there is a risk that buffers
	on disk won't match with saved ones.

	For more information take a look at <file:Documentation/power/swsusp.txt>.

	(For now, swsusp is incompatible with PAE aka HIGHMEM_64G on i386.
	we need identity mapping for resume to work, and that is trivial
	to get with 4MB pages, but less than trivial on PAE).

	config PM_STD_PARTITION
	string "Default resume partition"
	depends on SOFTWARE_SUSPEND
	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 SUSPEND_SMP
	bool
	depends on HOTPLUG_CPU && X86 && PM
	default y

	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/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).