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 SUSPEND_SKIP_SYNC
  22         bool "Skip kernel's sys_sync() on suspend to RAM/standby"
  23         depends on SUSPEND
  24         depends on EXPERT
  25         help
  26           Skip the kernel sys_sync() before freezing user processes.
  27           Some systems prefer not to pay this cost on every invocation
  28           of suspend, or they are content with invoking sync() from
  29           user-space before invoking suspend.  Say Y if that's your case.
  30
  31 config HIBERNATE_CALLBACKS
  32         bool
  33
  34 config HIBERNATION
  35         bool "Hibernation (aka 'suspend to disk')"
  36         depends on SWAP && ARCH_HIBERNATION_POSSIBLE
  37         select HIBERNATE_CALLBACKS
  38         select LZO_COMPRESS
  39         select LZO_DECOMPRESS
  40         select CRC32
  41         ---help---
  42           Enable the suspend to disk (STD) functionality, which is usually
  43           called "hibernation" in user interfaces.  STD checkpoints the
  44           system and powers it off; and restores that checkpoint on reboot.
  45
  46           You can suspend your machine with 'echo disk > /sys/power/state'
  47           after placing resume=/dev/swappartition on the kernel command line
  48           in your bootloader's configuration file.
  49
  50           Alternatively, you can use the additional userland tools available
  51           from <http://suspend.sf.net>.
  52
  53           In principle it does not require ACPI or APM, although for example
  54           ACPI will be used for the final steps when it is available.  One
  55           of the reasons to use software suspend is that the firmware hooks
  56           for suspend states like suspend-to-RAM (STR) often don't work very
  57           well with Linux.
  58
  59           It creates an image which is saved in your active swap. Upon the next
  60           boot, pass the 'resume=/dev/swappartition' argument to the kernel to
  61           have it detect the saved image, restore memory state from it, and
  62           continue to run as before. If you do not want the previous state to
  63           be reloaded, then use the 'noresume' kernel command line argument.
  64           Note, however, that fsck will be run on your filesystems and you will
  65           need to run mkswap against the swap partition used for the suspend.
  66
  67           It also works with swap files to a limited extent (for details see
  68           <file:Documentation/power/swsusp-and-swap-files.txt>).
  69
  70           Right now you may boot without resuming and resume later but in the
  71           meantime you cannot use the swap partition(s)/file(s) involved in
  72           suspending.  Also in this case you must not use the filesystems
  73           that were mounted before the suspend.  In particular, you MUST NOT
  74           MOUNT any journaled filesystems mounted before the suspend or they
  75           will get corrupted in a nasty way.
  76
  77           For more information take a look at <file:Documentation/power/swsusp.txt>.
  78
  79 config ARCH_SAVE_PAGE_KEYS
  80         bool
  81
  82 config PM_STD_PARTITION
  83         string "Default resume partition"
  84         depends on HIBERNATION
  85         default ""
  86         ---help---
  87           The default resume partition is the partition that the suspend-
  88           to-disk implementation will look for a suspended disk image.
  89
  90           The partition specified here will be different for almost every user.
  91           It should be a valid swap partition (at least for now) that is turned
  92           on before suspending.
  93
  94           The partition specified can be overridden by specifying:
  95
  96                 resume=/dev/<other device>
  97
  98           which will set the resume partition to the device specified.
  99
 100           Note there is currently not a way to specify which device to save the
 101           suspended image to. It will simply pick the first available swap
 102           device.
 103
 104 config PM_SLEEP
 105         def_bool y
 106         depends on SUSPEND || HIBERNATE_CALLBACKS
 107         select PM
 108         select SRCU
 109
 110 config PM_SLEEP_SMP
 111         def_bool y
 112         depends on SMP
 113         depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
 114         depends on PM_SLEEP
 115         select HOTPLUG_CPU
 116
 117 config PM_AUTOSLEEP
 118         bool "Opportunistic sleep"
 119         depends on PM_SLEEP
 120         default n
 121         ---help---
 122         Allow the kernel to trigger a system transition into a global sleep
 123         state automatically whenever there are no active wakeup sources.
 124
 125 config PM_WAKELOCKS
 126         bool "User space wakeup sources interface"
 127         depends on PM_SLEEP
 128         default n
 129         ---help---
 130         Allow user space to create, activate and deactivate wakeup source
 131         objects with the help of a sysfs-based interface.
 132
 133 config PM_WAKELOCKS_LIMIT
 134         int "Maximum number of user space wakeup sources (0 = no limit)"
 135         range 0 100000
 136         default 100
 137         depends on PM_WAKELOCKS
 138
 139 config PM_WAKELOCKS_GC
 140         bool "Garbage collector for user space wakeup sources"
 141         depends on PM_WAKELOCKS
 142         default y
 143
 144 config PM
 145         bool "Device power management core functionality"
 146         ---help---
 147           Enable functionality allowing I/O devices to be put into energy-saving
 148           (low power) states, for example after a specified period of inactivity
 149           (autosuspended), and woken up in response to a hardware-generated
 150           wake-up event or a driver's request.
 151
 152           Hardware support is generally required for this functionality to work
 153           and the bus type drivers of the buses the devices are on are
 154           responsible for the actual handling of device suspend requests and
 155           wake-up events.
 156
 157 config PM_DEBUG
 158         bool "Power Management Debug Support"
 159         depends on PM
 160         ---help---
 161         This option enables various debugging support in the Power Management
 162         code. This is helpful when debugging and reporting PM bugs, like
 163         suspend support.
 164
 165 config PM_ADVANCED_DEBUG
 166         bool "Extra PM attributes in sysfs for low-level debugging/testing"
 167         depends on PM_DEBUG
 168         ---help---
 169         Add extra sysfs attributes allowing one to access some Power Management
 170         fields of device objects from user space.  If you are not a kernel
 171         developer interested in debugging/testing Power Management, say "no".
 172
 173 config PM_TEST_SUSPEND
 174         bool "Test suspend/resume and wakealarm during bootup"
 175         depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
 176         ---help---
 177         This option will let you suspend your machine during bootup, and
 178         make it wake up a few seconds later using an RTC wakeup alarm.
 179         Enable this with a kernel parameter like "test_suspend=mem".
 180
 181         You probably want to have your system's RTC driver statically
 182         linked, ensuring that it's available when this test runs.
 183
 184 config PM_SLEEP_DEBUG
 185         def_bool y
 186         depends on PM_DEBUG && PM_SLEEP
 187
 188 config DPM_WATCHDOG
 189         bool "Device suspend/resume watchdog"
 190         depends on PM_DEBUG && PSTORE && EXPERT
 191         ---help---
 192           Sets up a watchdog timer to capture drivers that are
 193           locked up attempting to suspend/resume a device.
 194           A detected lockup causes system panic with message
 195           captured in pstore device for inspection in subsequent
 196           boot session.
 197
 198 config DPM_WATCHDOG_TIMEOUT
 199         int "Watchdog timeout in seconds"
 200         range 1 120
 201         default 120
 202         depends on DPM_WATCHDOG
 203
 204 config PM_TRACE
 205         bool
 206         help
 207           This enables code to save the last PM event point across
 208           reboot. The architecture needs to support this, x86 for
 209           example does by saving things in the RTC, see below.
 210
 211           The architecture specific code must provide the extern
 212           functions from <linux/resume-trace.h> as well as the
 213           <asm/resume-trace.h> header with a TRACE_RESUME() macro.
 214
 215           The way the information is presented is architecture-
 216           dependent, x86 will print the information during a
 217           late_initcall.
 218
 219 config PM_TRACE_RTC
 220         bool "Suspend/resume event tracing"
 221         depends on PM_SLEEP_DEBUG
 222         depends on X86
 223         select PM_TRACE
 224         ---help---
 225         This enables some cheesy code to save the last PM event point in the
 226         RTC across reboots, so that you can debug a machine that just hangs
 227         during suspend (or more commonly, during resume).
 228
 229         To use this debugging feature you should attempt to suspend the
 230         machine, reboot it and then run
 231
 232                 dmesg -s 1000000 | grep 'hash matches'
 233
 234         CAUTION: this option will cause your machine's real-time clock to be
 235         set to an invalid time after a resume.
 236
 237 config APM_EMULATION
 238         tristate "Advanced Power Management Emulation"
 239         depends on SYS_SUPPORTS_APM_EMULATION
 240         help
 241           APM is a BIOS specification for saving power using several different
 242           techniques. This is mostly useful for battery powered laptops with
 243           APM compliant BIOSes. If you say Y here, the system time will be
 244           reset after a RESUME operation, the /proc/apm device will provide
 245           battery status information, and user-space programs will receive
 246           notification of APM "events" (e.g. battery status change).
 247
 248           In order to use APM, you will need supporting software. For location
 249           and more information, read <file:Documentation/power/apm-acpi.txt>
 250           and the Battery Powered Linux mini-HOWTO, available from
 251           <http://www.tldp.org/docs.html#howto>.
 252
 253           This driver does not spin down disk drives (see the hdparm(8)
 254           manpage ("man 8 hdparm") for that), and it doesn't turn off
 255           VESA-compliant "green" monitors.
 256
 257           Generally, if you don't have a battery in your machine, there isn't
 258           much point in using this driver and you should say N. If you get
 259           random kernel OOPSes or reboots that don't seem to be related to
 260           anything, try disabling/enabling this option (or disabling/enabling
 261           APM in your BIOS).
 262
 263 config PM_OPP
 264         bool
 265         select SRCU
 266         ---help---
 267           SOCs have a standard set of tuples consisting of frequency and
 268           voltage pairs that the device will support per voltage domain. This
 269           is called Operating Performance Point or OPP. The actual definitions
 270           of OPP varies over silicon within the same family of devices.
 271
 272           OPP layer organizes the data internally using device pointers
 273           representing individual voltage domains and provides SOC
 274           implementations a ready to use framework to manage OPPs.
 275           For more information, read <file:Documentation/power/opp.txt>
 276
 277 config PM_CLK
 278         def_bool y
 279         depends on PM && HAVE_CLK
 280
 281 config PM_GENERIC_DOMAINS
 282         bool
 283         depends on PM
 284
 285 config WQ_POWER_EFFICIENT_DEFAULT
 286         bool "Enable workqueue power-efficient mode by default"
 287         depends on PM
 288         default n
 289         help
 290           Per-cpu workqueues are generally preferred because they show
 291           better performance thanks to cache locality; unfortunately,
 292           per-cpu workqueues tend to be more power hungry than unbound
 293           workqueues.
 294
 295           Enabling workqueue.power_efficient kernel parameter makes the
 296           per-cpu workqueues which were observed to contribute
 297           significantly to power consumption unbound, leading to measurably
 298           lower power usage at the cost of small performance overhead.
 299
 300           This config option determines whether workqueue.power_efficient
 301           is enabled by default.
 302
 303           If in doubt, say N.
 304
 305 config PM_GENERIC_DOMAINS_SLEEP
 306         def_bool y
 307         depends on PM_SLEEP && PM_GENERIC_DOMAINS
 308
 309 config PM_GENERIC_DOMAINS_OF
 310         def_bool y
 311         depends on PM_GENERIC_DOMAINS && OF
 312
 313 config CPU_PM
 314         bool