c7276fde27
Update the outdated and inaccurate description of the software suspend in Kconfig. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
165 lines
6.4 KiB
Plaintext
165 lines
6.4 KiB
Plaintext
config PM
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bool "Power Management support"
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depends on !IA64_HP_SIM
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---help---
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"Power Management" means that parts of your computer are shut
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off or put into a power conserving "sleep" mode if they are not
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being used. There are two competing standards for doing this: APM
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and ACPI. If you want to use either one, say Y here and then also
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to the requisite support below.
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Power Management is most important for battery powered laptop
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computers; if you have a laptop, check out the Linux Laptop home
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page on the WWW at <http://www.linux-on-laptops.com/> or
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Tuxmobil - Linux on Mobile Computers at <http://www.tuxmobil.org/>
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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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Note that, even if you say N here, Linux on the x86 architecture
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will issue the hlt instruction if nothing is to be done, thereby
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sending the processor to sleep and saving power.
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config PM_LEGACY
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bool "Legacy Power Management API (DEPRECATED)"
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depends on PM
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default n
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---help---
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Support for pm_register() and friends. This old API is obsoleted
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by the driver model.
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If unsure, say N.
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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 verbose debugging support in the Power Management
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code. This is helpful when debugging and reporting various PM bugs,
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like suspend support.
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config DISABLE_CONSOLE_SUSPEND
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bool "Keep console(s) enabled during suspend/resume (DANGEROUS)"
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depends on PM && PM_DEBUG
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default n
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---help---
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This option turns off the console suspend mechanism that prevents
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debug messages from reaching the console during the suspend/resume
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operations. This may be helpful when debugging device drivers'
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suspend/resume routines, but may itself lead to problems, for example
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if netconsole is used.
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config PM_TRACE
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bool "Suspend/resume event tracing"
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depends on PM && PM_DEBUG && X86_32 && EXPERIMENTAL
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default n
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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 machine,
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then reboot it, 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 PM_SYSFS_DEPRECATED
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bool "Driver model /sys/devices/.../power/state files (DEPRECATED)"
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depends on PM && SYSFS
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default n
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help
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The driver model started out with a sysfs file intended to provide
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a userspace hook for device power management. This feature has never
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worked very well, except for limited testing purposes, and so it will
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be removed. It's not clear that a generic mechanism could really
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handle the wide variability of device power states; any replacements
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are likely to be bus or driver specific.
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config SOFTWARE_SUSPEND
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bool "Software Suspend"
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depends on PM && SWAP && ((X86 && (!SMP || SUSPEND_SMP)) || ((FRV || PPC32) && !SMP))
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---help---
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Enable the suspend to disk (STD) functionality.
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You can suspend your machine with 'echo disk > /sys/power/state'.
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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 if available.
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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 PM_STD_PARTITION
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string "Default resume partition"
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depends on SOFTWARE_SUSPEND
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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 SUSPEND_SMP
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bool
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depends on HOTPLUG_CPU && X86 && PM
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default y
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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/pm.txt> and the
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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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