kernel/power/Kconfig

   1 config PM
   2         bool "Power Management support"
   3         depends on !IA64_HP_SIM
   4         ---help---
   5           "Power Management" means that parts of your computer are shut
   6           off or put into a power conserving "sleep" mode if they are not
   7           being used.  There are two competing standards for doing this: APM
   8           and ACPI.  If you want to use either one, say Y here and then also
   9           to the requisite support below.
  10
  11           Power Management is most important for battery powered laptop
  12           computers; if you have a laptop, check out the Linux Laptop home
  13           page on the WWW at <http://www.linux-on-laptops.com/> or
  14           Tuxmobil - Linux on Mobile Computers at <http://www.tuxmobil.org/>
  15           and the Battery Powered Linux mini-HOWTO, available from
  16           <http://www.tldp.org/docs.html#howto>.
  17
  18           Note that, even if you say N here, Linux on the x86 architecture
  19           will issue the hlt instruction if nothing is to be done, thereby
  20           sending the processor to sleep and saving power.
  21
  22 config PM_LEGACY
  23         bool "Legacy Power Management API"
  24         depends on PM
  25         default y
  26         ---help---
  27            Support for pm_register() and friends.
  28
  29            If unsure, say Y.
  30
  31 config PM_DEBUG
  32         bool "Power Management Debug Support"
  33         depends on PM
  34         ---help---
  35         This option enables verbose debugging support in the Power Management
  36         code. This is helpful when debugging and reporting various PM bugs,
  37         like suspend support.
  38
  39 config PM_TRACE
  40         bool "Suspend/resume event tracing"
  41         depends on PM && PM_DEBUG && X86_32 && EXPERIMENTAL
  42         default n
  43         ---help---
  44         This enables some cheesy code to save the last PM event point in the
  45         RTC across reboots, so that you can debug a machine that just hangs
  46         during suspend (or more commonly, during resume).
  47
  48         To use this debugging feature you should attempt to suspend the machine,
  49         then reboot it, then run
  50
  51                 dmesg -s 1000000 | grep 'hash matches'
  52
  53         CAUTION: this option will cause your machine's real-time clock to be
  54         set to an invalid time after a resume.
  55
  56
  57 config SOFTWARE_SUSPEND
  58         bool "Software Suspend"
  59         depends on PM && SWAP && (X86 && (!SMP || SUSPEND_SMP)) || ((FRV || PPC32) && !SMP)
  60         ---help---
  61           Enable the possibility of suspending the machine.
  62           It doesn't need ACPI or APM.
  63           You may suspend your machine by 'swsusp' or 'shutdown -z <time>'
  64           (patch for sysvinit needed).
  65
  66           It creates an image which is saved in your active swap. Upon next
  67           boot, pass the 'resume=/dev/swappartition' argument to the kernel to
  68           have it detect the saved image, restore memory state from it, and
  69           continue to run as before. If you do not want the previous state to
  70           be reloaded, then use the 'noresume' kernel argument. However, note
  71           that your partitions will be fsck'd and you must re-mkswap your swap
  72           partitions. It does not work with swap files.
  73
  74           Right now you may boot without resuming and then later resume but
  75           in meantime you cannot use those swap partitions/files which were
  76           involved in suspending. Also in this case there is a risk that buffers
  77           on disk won't match with saved ones.
  78
  79           For more information take a look at <file:Documentation/power/swsusp.txt>.
  80
  81 config PM_STD_PARTITION
  82         string "Default resume partition"
  83         depends on SOFTWARE_SUSPEND
  84         default ""
  85         ---help---
  86           The default resume partition is the partition that the suspend-
  87           to-disk implementation will look for a suspended disk image.
  88
  89           The partition specified here will be different for almost every user.
  90           It should be a valid swap partition (at least for now) that is turned
  91           on before suspending.
  92
  93           The partition specified can be overridden by specifying:
  94
  95                 resume=/dev/<other device>
  96
  97           which will set the resume partition to the device specified.
  98
  99           Note there is currently not a way to specify which device to save the
 100           suspended image to. It will simply pick the first available swap
 101           device.
 102
 103 config SWSUSP_ENCRYPT
 104         bool "Encrypt suspend image"
 105         depends on SOFTWARE_SUSPEND && CRYPTO=y && (CRYPTO_AES=y || CRYPTO_AES_586=y || CRYPTO_AES_X86_64=y)
 106         default ""
 107         ---help---
 108           To prevent data gathering from swap after resume you can encrypt
 109           the suspend image with a temporary key that is deleted on
 110           resume.
 111
 112           Note that the temporary key is stored unencrypted on disk while the
 113           system is suspended.
 114
 115 config SUSPEND_SMP
 116         bool
 117         depends on HOTPLUG_CPU && X86 && PM
 118         default y