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 (DEPRECATED)"
  24         depends on PM
  25         default n
  26         ---help---
  27            Support for pm_register() and friends.  This old API is obsoleted
  28            by the driver model.
  29
  30            If unsure, say N.
  31
  32 config PM_DEBUG
  33         bool "Power Management Debug Support"
  34         depends on PM
  35         ---help---
  36         This option enables verbose debugging support in the Power Management
  37         code. This is helpful when debugging and reporting various PM bugs,
  38         like suspend support.
  39
  40 config DISABLE_CONSOLE_SUSPEND
  41         bool "Keep console(s) enabled during suspend/resume (DANGEROUS)"
  42         depends on PM && PM_DEBUG
  43         default n
  44         ---help---
  45         This option turns off the console suspend mechanism that prevents
  46         debug messages from reaching the console during the suspend/resume
  47         operations.  This may be helpful when debugging device drivers'
  48         suspend/resume routines, but may itself lead to problems, for example
  49         if netconsole is used.
  50
  51 config PM_TRACE
  52         bool "Suspend/resume event tracing"
  53         depends on PM && PM_DEBUG && X86_32 && EXPERIMENTAL
  54         default n
  55         ---help---
  56         This enables some cheesy code to save the last PM event point in the
  57         RTC across reboots, so that you can debug a machine that just hangs
  58         during suspend (or more commonly, during resume).
  59
  60         To use this debugging feature you should attempt to suspend the machine,
  61         then reboot it, then run
  62
  63                 dmesg -s 1000000 | grep 'hash matches'
  64
  65         CAUTION: this option will cause your machine's real-time clock to be
  66         set to an invalid time after a resume.
  67
  68 config PM_SYSFS_DEPRECATED
  69         bool "Driver model /sys/devices/.../power/state files (DEPRECATED)"
  70         depends on PM && SYSFS
  71         default n
  72         help
  73           The driver model started out with a sysfs file intended to provide
  74           a userspace hook for device power management.  This feature has never
  75           worked very well, except for limited testing purposes, and so it will
  76           be removed.   It's not clear that a generic mechanism could really
  77           handle the wide variability of device power states; any replacements
  78           are likely to be bus or driver specific.
  79
  80 config SOFTWARE_SUSPEND
  81         bool "Software Suspend"
  82         depends on PM && SWAP && ((X86 && (!SMP || SUSPEND_SMP)) || ((FRV || PPC32) && !SMP))
  83         ---help---
  84           Enable the possibility of suspending the machine.
  85           It doesn't need ACPI or APM.
  86           You may suspend your machine by 'swsusp' or 'shutdown -z <time>'
  87           (patch for sysvinit needed).
  88
  89           It creates an image which is saved in your active swap. Upon next
  90           boot, pass the 'resume=/dev/swappartition' argument to the kernel to
  91           have it detect the saved image, restore memory state from it, and
  92           continue to run as before. If you do not want the previous state to
  93           be reloaded, then use the 'noresume' kernel argument. However, note
  94           that your partitions will be fsck'd and you must re-mkswap your swap
  95           partitions. It does not work with swap files.
  96
  97           Right now you may boot without resuming and then later resume but
  98           in meantime you cannot use those swap partitions/files which were
  99           involved in suspending. Also in this case there is a risk that buffers
 100           on disk won't match with saved ones.
 101
 102           For more information take a look at <file:Documentation/power/swsusp.txt>.
 103
 104           (For now, swsusp is incompatible with PAE aka HIGHMEM_64G on i386.
 105           we need identity mapping for resume to work, and that is trivial
 106           to get with 4MB pages, but less than trivial on PAE).
 107
 108 config PM_STD_PARTITION
 109         string "Default resume partition"
 110         depends on SOFTWARE_SUSPEND
 111         default ""
 112         ---help---
 113           The default resume partition is the partition that the suspend-
 114           to-disk implementation will look for a suspended disk image.
 115
 116           The partition specified here will be different for almost every user.
 117           It should be a valid swap partition (at least for now) that is turned
 118           on before suspending.
 119
 120           The partition specified can be overridden by specifying:
 121
 122                 resume=/dev/<other device>
 123
 124           which will set the resume partition to the device specified.
 125
 126           Note there is currently not a way to specify which device to save the
 127           suspended image to. It will simply pick the first available swap
 128           device.
 129
 130 config SUSPEND_SMP
 131         bool
 132         depends on HOTPLUG_CPU && X86 && PM
 133         default y
 134
 135 config APM_EMULATION
 136         tristate "Advanced Power Management Emulation"
 137         depends on PM && SYS_SUPPORTS_APM_EMULATION
 138         help
 139           APM is a BIOS specification for saving power using several different
 140           techniques. This is mostly useful for battery powered laptops with
 141           APM compliant BIOSes. If you say Y here, the system time will be
 142           reset after a RESUME operation, the /proc/apm device will provide
 143           battery status information, and user-space programs will receive
 144           notification of APM "events" (e.g. battery status change).
 145
 146           In order to use APM, you will need supporting software. For location
 147           and more information, read <file:Documentation/pm.txt> and the
 148           Battery Powered Linux mini-HOWTO, available from
 149           <http://www.tldp.org/docs.html#howto>.
 150
 151           This driver does not spin down disk drives (see the hdparm(8)
 152           manpage ("man 8 hdparm") for that), and it doesn't turn off
 153           VESA-compliant "green" monitors.
 154
 155           Generally, if you don't have a battery in your machine, there isn't
 156           much point in using this driver and you should say N. If you get
 157           random kernel OOPSes or reboots that don't seem to be related to
 158           anything, try disabling/enabling this option (or disabling/enabling
 159           APM in your BIOS).