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         select PM
  98
  99 config PM_SLEEP_SMP
 100         def_bool y
 101         depends on SMP
 102         depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
 103         depends on PM_SLEEP
 104         select HOTPLUG_CPU
 105
 106 config PM_AUTOSLEEP
 107         bool "Opportunistic sleep"
 108         depends on PM_SLEEP
 109         default n
 110         ---help---
 111         Allow the kernel to trigger a system transition into a global sleep
 112         state automatically whenever there are no active wakeup sources.
 113
 114 config PM_WAKELOCKS
 115         bool "User space wakeup sources interface"
 116         depends on PM_SLEEP
 117         default n
 118         ---help---
 119         Allow user space to create, activate and deactivate wakeup source
 120         objects with the help of a sysfs-based interface.
 121
 122 config PM_WAKELOCKS_LIMIT
 123         int "Maximum number of user space wakeup sources (0 = no limit)"
 124         range 0 100000
 125         default 100
 126         depends on PM_WAKELOCKS
 127
 128 config PM_WAKELOCKS_GC
 129         bool "Garbage collector for user space wakeup sources"
 130         depends on PM_WAKELOCKS
 131         default y
 132
 133 config PM
 134         bool "Device power management core functionality"
 135         ---help---
 136           Enable functionality allowing I/O devices to be put into energy-saving
 137           (low power) states, for example after a specified period of inactivity
 138           (autosuspended), 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 device suspend requests and
 144           wake-up events.
 145
 146 config PM_DEBUG
 147         bool "Power Management Debug Support"
 148         depends on PM
 149         ---help---
 150         This option enables various debugging support in the Power Management
 151         code. This is helpful when debugging and reporting PM bugs, like
 152         suspend support.
 153
 154 config PM_ADVANCED_DEBUG
 155         bool "Extra PM attributes in sysfs for low-level debugging/testing"
 156         depends on PM_DEBUG
 157         ---help---
 158         Add extra sysfs attributes allowing one to access some Power Management
 159         fields of device objects from user space.  If you are not a kernel
 160         developer interested in debugging/testing Power Management, say "no".
 161
 162 config PM_TEST_SUSPEND
 163         bool "Test suspend/resume and wakealarm during bootup"
 164         depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
 165         ---help---
 166         This option will let you suspend your machine during bootup, and
 167         make it wake up a few seconds later using an RTC wakeup alarm.
 168         Enable this with a kernel parameter like "test_suspend=mem".
 169
 170         You probably want to have your system's RTC driver statically
 171         linked, ensuring that it's available when this test runs.
 172
 173 config PM_SLEEP_DEBUG
 174         def_bool y
 175         depends on PM_DEBUG && PM_SLEEP
 176
 177 config DPM_WATCHDOG
 178         bool "Device suspend/resume watchdog"
 179         depends on PM_DEBUG && PSTORE
 180         ---help---
 181           Sets up a watchdog timer to capture drivers that are
 182           locked up attempting to suspend/resume a device.
 183           A detected lockup causes system panic with message
 184           captured in pstore device for inspection in subsequent
 185           boot session.
 186
 187 config DPM_WATCHDOG_TIMEOUT
 188         int "Watchdog timeout in seconds"
 189         range 1 120
 190         default 12
 191         depends on DPM_WATCHDOG
 192
 193 config PM_TRACE
 194         bool
 195         help
 196           This enables code to save the last PM event point across
 197           reboot. The architecture needs to support this, x86 for
 198           example does by saving things in the RTC, see below.
 199
 200           The architecture specific code must provide the extern
 201           functions from <linux/resume-trace.h> as well as the
 202           <asm/resume-trace.h> header with a TRACE_RESUME() macro.
 203
 204           The way the information is presented is architecture-
 205           dependent, x86 will print the information during a
 206           late_initcall.
 207
 208 config PM_TRACE_RTC
 209         bool "Suspend/resume event tracing"
 210         depends on PM_SLEEP_DEBUG
 211         depends on X86
 212         select PM_TRACE
 213         ---help---
 214         This enables some cheesy code to save the last PM event point in the
 215         RTC across reboots, so that you can debug a machine that just hangs
 216         during suspend (or more commonly, during resume).
 217
 218         To use this debugging feature you should attempt to suspend the
 219         machine, reboot it and then run
 220
 221                 dmesg -s 1000000 | grep 'hash matches'
 222
 223         CAUTION: this option will cause your machine's real-time clock to be
 224         set to an invalid time after a resume.
 225
 226 config APM_EMULATION
 227         tristate "Advanced Power Management Emulation"
 228         depends on PM && SYS_SUPPORTS_APM_EMULATION
 229         help
 230           APM is a BIOS specification for saving power using several different
 231           techniques. This is mostly useful for battery powered laptops with
 232           APM compliant BIOSes. If you say Y here, the system time will be
 233           reset after a RESUME operation, the /proc/apm device will provide
 234           battery status information, and user-space programs will receive
 235           notification of APM "events" (e.g. battery status change).
 236
 237           In order to use APM, you will need supporting software. For location
 238           and more information, read <file:Documentation/power/apm-acpi.txt>
 239           and the Battery Powered Linux mini-HOWTO, available from
 240           <http://www.tldp.org/docs.html#howto>.
 241
 242           This driver does not spin down disk drives (see the hdparm(8)
 243           manpage ("man 8 hdparm") for that), and it doesn't turn off
 244           VESA-compliant "green" monitors.
 245
 246           Generally, if you don't have a battery in your machine, there isn't
 247           much point in using this driver and you should say N. If you get
 248           random kernel OOPSes or reboots that don't seem to be related to
 249           anything, try disabling/enabling this option (or disabling/enabling
 250           APM in your BIOS).
 251
 252 config PM_OPP
 253         bool
 254         select SRCU
 255         ---help---
 256           SOCs have a standard set of tuples consisting of frequency and
 257           voltage pairs that the device will support per voltage domain. This
 258           is called Operating Performance Point or OPP. The actual definitions
 259           of OPP varies over silicon within the same family of devices.
 260
 261           OPP layer organizes the data internally using device pointers
 262           representing individual voltage domains and provides SOC
 263           implementations a ready to use framework to manage OPPs.
 264           For more information, read <file:Documentation/power/opp.txt>
 265
 266 config PM_CLK
 267         def_bool y
 268         depends on PM && HAVE_CLK
 269
 270 config PM_GENERIC_DOMAINS
 271         bool
 272         depends on PM
 273
 274 config WQ_POWER_EFFICIENT_DEFAULT
 275         bool "Enable workqueue power-efficient mode by default"
 276         depends on PM
 277         default n
 278         help
 279           Per-cpu workqueues are generally preferred because they show
 280           better performance thanks to cache locality; unfortunately,
 281           per-cpu workqueues tend to be more power hungry than unbound
 282           workqueues.
 283
 284           Enabling workqueue.power_efficient kernel parameter makes the
 285           per-cpu workqueues which were observed to contribute
 286           significantly to power consumption unbound, leading to measurably
 287           lower power usage at the cost of small performance overhead.
 288
 289           This config option determines whether workqueue.power_efficient
 290           is enabled by default.
 291
 292           If in doubt, say N.
 293
 294 config PM_GENERIC_DOMAINS_SLEEP
 295         def_bool y
 296         depends on PM_SLEEP && PM_GENERIC_DOMAINS
 297
 298 config PM_GENERIC_DOMAINS_OF
 299         def_bool y
 300         depends on PM_GENERIC_DOMAINS && OF
 301
 302 config CPU_PM
 303         bool