kernel/power/Kconfig

   1 config SUSPEND
   2         bool "Suspend to RAM and standby"
   3         depends on ARCH_SUSPEND_POSSIBLE
   4         default y
   5         ---help---
   6           Allow the system to enter sleep states in which main memory is
   7           powered and thus its contents are preserved, such as the
   8           suspend-to-RAM state (e.g. the ACPI S3 state).
   9
  10 config SUSPEND_FREEZER
  11         bool "Enable freezer for suspend to RAM/standby" \
  12                 if ARCH_WANTS_FREEZER_CONTROL || BROKEN
  13         depends on SUSPEND
  14         default y
  15         help
  16           This allows you to turn off the freezer for suspend. If this is
  17           done, no tasks are frozen for suspend to RAM/standby.
  18
  19           Turning OFF this setting is NOT recommended! If in doubt, say Y.
  20
  21 config HIBERNATION
  22         bool "Hibernation (aka 'suspend to disk')"
  23         depends on SWAP && ARCH_HIBERNATION_POSSIBLE
  24         select LZO_COMPRESS
  25         select LZO_DECOMPRESS
  26         ---help---
  27           Enable the suspend to disk (STD) functionality, which is usually
  28           called "hibernation" in user interfaces.  STD checkpoints the
  29           system and powers it off; and restores that checkpoint on reboot.
  30
  31           You can suspend your machine with 'echo disk > /sys/power/state'
  32           after placing resume=/dev/swappartition on the kernel command line
  33           in your bootloader's configuration file.
  34
  35           Alternatively, you can use the additional userland tools available
  36           from <http://suspend.sf.net>.
  37
  38           In principle it does not require ACPI or APM, although for example
  39           ACPI will be used for the final steps when it is available.  One
  40           of the reasons to use software suspend is that the firmware hooks
  41           for suspend states like suspend-to-RAM (STR) often don't work very
  42           well with Linux.
  43
  44           It creates an image which is saved in your active swap. Upon the next
  45           boot, pass the 'resume=/dev/swappartition' argument to the kernel to
  46           have it detect the saved image, restore memory state from it, and
  47           continue to run as before. If you do not want the previous state to
  48           be reloaded, then use the 'noresume' kernel command line argument.
  49           Note, however, that fsck will be run on your filesystems and you will
  50           need to run mkswap against the swap partition used for the suspend.
  51
  52           It also works with swap files to a limited extent (for details see
  53           <file:Documentation/power/swsusp-and-swap-files.txt>).
  54
  55           Right now you may boot without resuming and resume later but in the
  56           meantime you cannot use the swap partition(s)/file(s) involved in
  57           suspending.  Also in this case you must not use the filesystems
  58           that were mounted before the suspend.  In particular, you MUST NOT
  59           MOUNT any journaled filesystems mounted before the suspend or they
  60           will get corrupted in a nasty way.
  61
  62           For more information take a look at <file:Documentation/power/swsusp.txt>.
  63
  64 config PM_STD_PARTITION
  65         string "Default resume partition"
  66         depends on HIBERNATION
  67         default ""
  68         ---help---
  69           The default resume partition is the partition that the suspend-
  70           to-disk implementation will look for a suspended disk image.
  71
  72           The partition specified here will be different for almost every user.
  73           It should be a valid swap partition (at least for now) that is turned
  74           on before suspending.
  75
  76           The partition specified can be overridden by specifying:
  77
  78                 resume=/dev/<other device>
  79
  80           which will set the resume partition to the device specified.
  81
  82           Note there is currently not a way to specify which device to save the
  83           suspended image to. It will simply pick the first available swap
  84           device.
  85
  86 config PM_SLEEP
  87         def_bool y
  88         depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE
  89
  90 config PM_SLEEP_SMP
  91         def_bool y
  92         depends on SMP
  93         depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
  94         depends on PM_SLEEP
  95         select HOTPLUG
  96         select HOTPLUG_CPU
  97
  98 config PM_RUNTIME
  99         bool "Run-time PM core functionality"
 100         depends on !IA64_HP_SIM
 101         ---help---
 102           Enable functionality allowing I/O devices to be put into energy-saving
 103           (low power) states at run time (or autosuspended) after a specified
 104           period of inactivity and woken up in response to a hardware-generated
 105           wake-up event or a driver's request.
 106
 107           Hardware support is generally required for this functionality to work
 108           and the bus type drivers of the buses the devices are on are
 109           responsible for the actual handling of the autosuspend requests and
 110           wake-up events.
 111
 112 config PM
 113         def_bool y
 114         depends on PM_SLEEP || PM_RUNTIME
 115
 116 config PM_DEBUG
 117         bool "Power Management Debug Support"
 118         depends on PM
 119         ---help---
 120         This option enables various debugging support in the Power Management
 121         code. This is helpful when debugging and reporting PM bugs, like
 122         suspend support.
 123
 124 config PM_VERBOSE
 125         bool "Verbose Power Management debugging"
 126         depends on PM_DEBUG
 127         ---help---
 128         This option enables verbose messages from the Power Management code.
 129
 130 config PM_ADVANCED_DEBUG
 131         bool "Extra PM attributes in sysfs for low-level debugging/testing"
 132         depends on PM_DEBUG
 133         ---help---
 134         Add extra sysfs attributes allowing one to access some Power Management
 135         fields of device objects from user space.  If you are not a kernel
 136         developer interested in debugging/testing Power Management, say "no".
 137
 138 config PM_TEST_SUSPEND
 139         bool "Test suspend/resume and wakealarm during bootup"
 140         depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
 141         ---help---
 142         This option will let you suspend your machine during bootup, and
 143         make it wake up a few seconds later using an RTC wakeup alarm.
 144         Enable this with a kernel parameter like "test_suspend=mem".
 145
 146         You probably want to have your system's RTC driver statically
 147         linked, ensuring that it's available when this test runs.
 148
 149 config CAN_PM_TRACE
 150         def_bool y
 151         depends on PM_DEBUG && PM_SLEEP
 152
 153 config PM_TRACE
 154         bool
 155         help
 156           This enables code to save the last PM event point across
 157           reboot. The architecture needs to support this, x86 for
 158           example does by saving things in the RTC, see below.
 159
 160           The architecture specific code must provide the extern
 161           functions from <linux/resume-trace.h> as well as the
 162           <asm/resume-trace.h> header with a TRACE_RESUME() macro.
 163
 164           The way the information is presented is architecture-
 165           dependent, x86 will print the information during a
 166           late_initcall.
 167
 168 config PM_TRACE_RTC
 169         bool "Suspend/resume event tracing"
 170         depends on CAN_PM_TRACE
 171         depends on X86
 172         select PM_TRACE
 173         ---help---
 174         This enables some cheesy code to save the last PM event point in the
 175         RTC across reboots, so that you can debug a machine that just hangs
 176         during suspend (or more commonly, during resume).
 177
 178         To use this debugging feature you should attempt to suspend the
 179         machine, reboot it and then run
 180
 181                 dmesg -s 1000000 | grep 'hash matches'
 182
 183         CAUTION: this option will cause your machine's real-time clock to be
 184         set to an invalid time after a resume.
 185
 186 config APM_EMULATION
 187         tristate "Advanced Power Management Emulation"
 188         depends on PM && SYS_SUPPORTS_APM_EMULATION
 189         help
 190           APM is a BIOS specification for saving power using several different
 191           techniques. This is mostly useful for battery powered laptops with
 192           APM compliant BIOSes. If you say Y here, the system time will be
 193           reset after a RESUME operation, the /proc/apm device will provide
 194           battery status information, and user-space programs will receive
 195           notification of APM "events" (e.g. battery status change).
 196
 197           In order to use APM, you will need supporting software. For location
 198           and more information, read <file:Documentation/power/pm.txt> and the
 199           Battery Powered Linux mini-HOWTO, available from
 200           <http://www.tldp.org/docs.html#howto>.
 201
 202           This driver does not spin down disk drives (see the hdparm(8)
 203           manpage ("man 8 hdparm") for that), and it doesn't turn off
 204           VESA-compliant "green" monitors.
 205
 206           Generally, if you don't have a battery in your machine, there isn't
 207           much point in using this driver and you should say N. If you get
 208           random kernel OOPSes or reboots that don't seem to be related to
 209           anything, try disabling/enabling this option (or disabling/enabling
 210           APM in your BIOS).
 211
 212 config ARCH_HAS_OPP
 213         bool
 214
 215 config PM_OPP
 216         bool "Operating Performance Point (OPP) Layer library"
 217         depends on ARCH_HAS_OPP
 218         ---help---
 219           SOCs have a standard set of tuples consisting of frequency and
 220           voltage pairs that the device will support per voltage domain. This
 221           is called Operating Performance Point or OPP. The actual definitions
 222           of OPP varies over silicon within the same family of devices.
 223
 224           OPP layer organizes the data internally using device pointers
 225           representing individual voltage domains and provides SOC
 226           implementations a ready to use framework to manage OPPs.
 227           For more information, read <file:Documentation/power/opp.txt>