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 HIBERNATE_CALLBACKS
  22         bool
  23
  24 config HIBERNATION
  25         bool "Hibernation (aka 'suspend to disk')"
  26         depends on SWAP && ARCH_HIBERNATION_POSSIBLE
  27         select HIBERNATE_CALLBACKS
  28         select LZO_COMPRESS
  29         select LZO_DECOMPRESS
  30         select CRC32
  31         ---help---
  32           Enable the suspend to disk (STD) functionality, which is usually
  33           called "hibernation" in user interfaces.  STD checkpoints the
  34           system and powers it off; and restores that checkpoint on reboot.
  35
  36           You can suspend your machine with 'echo disk > /sys/power/state'
  37           after placing resume=/dev/swappartition on the kernel command line
  38           in your bootloader's configuration file.
  39
  40           Alternatively, you can use the additional userland tools available
  41           from <http://suspend.sf.net>.
  42
  43           In principle it does not require ACPI or APM, although for example
  44           ACPI will be used for the final steps when it is available.  One
  45           of the reasons to use software suspend is that the firmware hooks
  46           for suspend states like suspend-to-RAM (STR) often don't work very
  47           well with Linux.
  48
  49           It creates an image which is saved in your active swap. Upon the next
  50           boot, pass the 'resume=/dev/swappartition' argument to the kernel to
  51           have it detect the saved image, restore memory state from it, and
  52           continue to run as before. If you do not want the previous state to
  53           be reloaded, then use the 'noresume' kernel command line argument.
  54           Note, however, that fsck will be run on your filesystems and you will
  55           need to run mkswap against the swap partition used for the suspend.
  56
  57           It also works with swap files to a limited extent (for details see
  58           <file:Documentation/power/swsusp-and-swap-files.txt>).
  59
  60           Right now you may boot without resuming and resume later but in the
  61           meantime you cannot use the swap partition(s)/file(s) involved in
  62           suspending.  Also in this case you must not use the filesystems
  63           that were mounted before the suspend.  In particular, you MUST NOT
  64           MOUNT any journaled filesystems mounted before the suspend or they
  65           will get corrupted in a nasty way.
  66
  67           For more information take a look at <file:Documentation/power/swsusp.txt>.
  68
  69 config ARCH_SAVE_PAGE_KEYS
  70         bool
  71
  72 config PM_STD_PARTITION
  73         string "Default resume partition"
  74         depends on HIBERNATION
  75         default ""
  76         ---help---
  77           The default resume partition is the partition that the suspend-
  78           to-disk implementation will look for a suspended disk image.
  79
  80           The partition specified here will be different for almost every user.
  81           It should be a valid swap partition (at least for now) that is turned
  82           on before suspending.
  83
  84           The partition specified can be overridden by specifying:
  85
  86                 resume=/dev/<other device>
  87
  88           which will set the resume partition to the device specified.
  89
  90           Note there is currently not a way to specify which device to save the
  91           suspended image to. It will simply pick the first available swap
  92           device.
  93
  94 config PM_SLEEP
  95         def_bool y
  96         depends on SUSPEND || HIBERNATE_CALLBACKS
  97
  98 config PM_SLEEP_SMP
  99         def_bool y
 100         depends on SMP
 101         depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
 102         depends on PM_SLEEP
 103         select HOTPLUG_CPU
 104
 105 config PM_AUTOSLEEP
 106         bool "Opportunistic sleep"
 107         depends on PM_SLEEP
 108         default n
 109         ---help---
 110         Allow the kernel to trigger a system transition into a global sleep
 111         state automatically whenever there are no active wakeup sources.
 112
 113 config PM_WAKELOCKS
 114         bool "User space wakeup sources interface"
 115         depends on PM_SLEEP
 116         default n
 117         ---help---
 118         Allow user space to create, activate and deactivate wakeup source
 119         objects with the help of a sysfs-based interface.
 120
 121 config PM_WAKELOCKS_LIMIT
 122         int "Maximum number of user space wakeup sources (0 = no limit)"
 123         range 0 100000
 124         default 100
 125         depends on PM_WAKELOCKS
 126
 127 config PM_WAKELOCKS_GC
 128         bool "Garbage collector for user space wakeup sources"
 129         depends on PM_WAKELOCKS
 130         default y
 131
 132 config PM_RUNTIME
 133         bool "Run-time PM core functionality"
 134         depends on !IA64_HP_SIM
 135         ---help---
 136           Enable functionality allowing I/O devices to be put into energy-saving
 137           (low power) states at run time (or autosuspended) after a specified
 138           period of inactivity and woken up in response to a hardware-generated
 139           wake-up event or a driver's request.
 140
 141           Hardware support is generally required for this functionality to work
 142           and the bus type drivers of the buses the devices are on are
 143           responsible for the actual handling of the autosuspend requests and
 144           wake-up events.
 145
 146 config PM
 147         def_bool y
 148         depends on PM_SLEEP || PM_RUNTIME
 149
 150 config PM_DEBUG
 151         bool "Power Management Debug Support"
 152         depends on PM
 153         ---help---
 154         This option enables various debugging support in the Power Management
 155         code. This is helpful when debugging and reporting PM bugs, like
 156         suspend support.
 157
 158 config PM_ADVANCED_DEBUG
 159         bool "Extra PM attributes in sysfs for low-level debugging/testing"
 160         depends on PM_DEBUG
 161         ---help---
 162         Add extra sysfs attributes allowing one to access some Power Management
 163         fields of device objects from user space.  If you are not a kernel
 164         developer interested in debugging/testing Power Management, say "no".
 165
 166 config PM_TEST_SUSPEND
 167         bool "Test suspend/resume and wakealarm during bootup"
 168         depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
 169         ---help---
 170         This option will let you suspend your machine during bootup, and
 171         make it wake up a few seconds later using an RTC wakeup alarm.
 172         Enable this with a kernel parameter like "test_suspend=mem".
 173
 174         You probably want to have your system's RTC driver statically
 175         linked, ensuring that it's available when this test runs.
 176
 177 config PM_SLEEP_DEBUG
 178         def_bool y
 179         depends on PM_DEBUG && PM_SLEEP
 180
 181 config DPM_WATCHDOG
 182         bool "Device suspend/resume watchdog"
 183         depends on PM_DEBUG && PSTORE
 184         ---help---
 185           Sets up a watchdog timer to capture drivers that are
 186           locked up attempting to suspend/resume a device.
 187           A detected lockup causes system panic with message
 188           captured in pstore device for inspection in subsequent
 189           boot session.
 190
 191 config DPM_WATCHDOG_TIMEOUT
 192         int "Watchdog timeout in seconds"
 193         range 1 120
 194         default 12
 195         depends on DPM_WATCHDOG
 196
 197 config PM_TRACE
 198         bool
 199         help
 200           This enables code to save the last PM event point across
 201           reboot. The architecture needs to support this, x86 for
 202           example does by saving things in the RTC, see below.
 203
 204           The architecture specific code must provide the extern
 205           functions from <linux/resume-trace.h> as well as the
 206           <asm/resume-trace.h> header with a TRACE_RESUME() macro.
 207
 208           The way the information is presented is architecture-
 209           dependent, x86 will print the information during a
 210           late_initcall.
 211
 212 config PM_TRACE_RTC
 213         bool "Suspend/resume event tracing"
 214         depends on PM_SLEEP_DEBUG
 215         depends on X86
 216         select PM_TRACE
 217         ---help---
 218         This enables some cheesy code to save the last PM event point in the
 219         RTC across reboots, so that you can debug a machine that just hangs
 220         during suspend (or more commonly, during resume).
 221
 222         To use this debugging feature you should attempt to suspend the
 223         machine, reboot it and then run
 224
 225                 dmesg -s 1000000 | grep 'hash matches'
 226
 227         CAUTION: this option will cause your machine's real-time clock to be
 228         set to an invalid time after a resume.
 229
 230 config APM_EMULATION
 231         tristate "Advanced Power Management Emulation"
 232         depends on PM && SYS_SUPPORTS_APM_EMULATION
 233         help
 234           APM is a BIOS specification for saving power using several different
 235           techniques. This is mostly useful for battery powered laptops with
 236           APM compliant BIOSes. If you say Y here, the system time will be
 237           reset after a RESUME operation, the /proc/apm device will provide
 238           battery status information, and user-space programs will receive
 239           notification of APM "events" (e.g. battery status change).
 240
 241           In order to use APM, you will need supporting software. For location
 242           and more information, read <file:Documentation/power/apm-acpi.txt>
 243           and the Battery Powered Linux mini-HOWTO, available from
 244           <http://www.tldp.org/docs.html#howto>.
 245
 246           This driver does not spin down disk drives (see the hdparm(8)
 247           manpage ("man 8 hdparm") for that), and it doesn't turn off
 248           VESA-compliant "green" monitors.
 249
 250           Generally, if you don't have a battery in your machine, there isn't
 251           much point in using this driver and you should say N. If you get
 252           random kernel OOPSes or reboots that don't seem to be related to
 253           anything, try disabling/enabling this option (or disabling/enabling
 254           APM in your BIOS).
 255
 256 config PM_OPP
 257         bool
 258         ---help---
 259           SOCs have a standard set of tuples consisting of frequency and
 260           voltage pairs that the device will support per voltage domain. This
 261           is called Operating Performance Point or OPP. The actual definitions
 262           of OPP varies over silicon within the same family of devices.
 263
 264           OPP layer organizes the data internally using device pointers
 265           representing individual voltage domains and provides SOC
 266           implementations a ready to use framework to manage OPPs.
 267           For more information, read <file:Documentation/power/opp.txt>
 268
 269 config PM_CLK
 270         def_bool y
 271         depends on PM && HAVE_CLK
 272
 273 config PM_GENERIC_DOMAINS
 274         bool
 275         depends on PM
 276
 277 config WQ_POWER_EFFICIENT_DEFAULT
 278         bool "Enable workqueue power-efficient mode by default"
 279         depends on PM
 280         default n
 281         help
 282           Per-cpu workqueues are generally preferred because they show
 283           better performance thanks to cache locality; unfortunately,
 284           per-cpu workqueues tend to be more power hungry than unbound
 285           workqueues.
 286
 287           Enabling workqueue.power_efficient kernel parameter makes the
 288           per-cpu workqueues which were observed to contribute
 289           significantly to power consumption unbound, leading to measurably
 290           lower power usage at the cost of small performance overhead.
 291
 292           This config option determines whether workqueue.power_efficient
 293           is enabled by default.
 294
 295           If in doubt, say N.
 296
 297 config PM_GENERIC_DOMAINS_SLEEP
 298         def_bool y
 299         depends on PM_SLEEP && PM_GENERIC_DOMAINS
 300
 301 config PM_GENERIC_DOMAINS_RUNTIME
 302         def_bool y
 303         depends on PM_RUNTIME && PM_GENERIC_DOMAINS
 304
 305 config PM_GENERIC_DOMAINS_OF
 306         def_bool y
 307         depends on PM_GENERIC_DOMAINS && OF
 308
 309 config CPU_PM
 310         bool
 311         depends on SUSPEND || CPU_IDLE