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
 109 config PM_SLEEP_SMP
 110         def_bool y
 111         depends on SMP
 112         depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
 113         depends on PM_SLEEP
 114         select HOTPLUG_CPU
 115
 116 config PM_AUTOSLEEP
 117         bool "Opportunistic sleep"
 118         depends on PM_SLEEP
 119         default n
 120         ---help---
 121         Allow the kernel to trigger a system transition into a global sleep
 122         state automatically whenever there are no active wakeup sources.
 123
 124 config PM_WAKELOCKS
 125         bool "User space wakeup sources interface"
 126         depends on PM_SLEEP
 127         default n
 128         ---help---
 129         Allow user space to create, activate and deactivate wakeup source
 130         objects with the help of a sysfs-based interface.
 131
 132 config PM_WAKELOCKS_LIMIT
 133         int "Maximum number of user space wakeup sources (0 = no limit)"
 134         range 0 100000
 135         default 100
 136         depends on PM_WAKELOCKS
 137
 138 config PM_WAKELOCKS_GC
 139         bool "Garbage collector for user space wakeup sources"
 140         depends on PM_WAKELOCKS
 141         default y
 142
 143 config PM
 144         bool "Device power management core functionality"
 145         ---help---
 146           Enable functionality allowing I/O devices to be put into energy-saving
 147           (low power) states, for example after a specified period of inactivity
 148           (autosuspended), and woken up in response to a hardware-generated
 149           wake-up event or a driver's request.
 150
 151           Hardware support is generally required for this functionality to work
 152           and the bus type drivers of the buses the devices are on are
 153           responsible for the actual handling of device suspend requests and
 154           wake-up events.
 155
 156 config PM_DEBUG
 157         bool "Power Management Debug Support"
 158         depends on PM
 159         ---help---
 160         This option enables various debugging support in the Power Management
 161         code. This is helpful when debugging and reporting PM bugs, like
 162         suspend support.
 163
 164 config PM_ADVANCED_DEBUG
 165         bool "Extra PM attributes in sysfs for low-level debugging/testing"
 166         depends on PM_DEBUG
 167         ---help---
 168         Add extra sysfs attributes allowing one to access some Power Management
 169         fields of device objects from user space.  If you are not a kernel
 170         developer interested in debugging/testing Power Management, say "no".
 171
 172 config PM_TEST_SUSPEND
 173         bool "Test suspend/resume and wakealarm during bootup"
 174         depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
 175         ---help---
 176         This option will let you suspend your machine during bootup, and
 177         make it wake up a few seconds later using an RTC wakeup alarm.
 178         Enable this with a kernel parameter like "test_suspend=mem".
 179
 180         You probably want to have your system's RTC driver statically
 181         linked, ensuring that it's available when this test runs.
 182
 183 config PM_SLEEP_DEBUG
 184         def_bool y
 185         depends on PM_DEBUG && PM_SLEEP
 186
 187 config DPM_WATCHDOG
 188         bool "Device suspend/resume watchdog"
 189         depends on PM_DEBUG && PSTORE && EXPERT
 190         ---help---
 191           Sets up a watchdog timer to capture drivers that are
 192           locked up attempting to suspend/resume a device.
 193           A detected lockup causes system panic with message
 194           captured in pstore device for inspection in subsequent
 195           boot session.
 196
 197 config DPM_WATCHDOG_TIMEOUT
 198         int "Watchdog timeout in seconds"
 199         range 1 120
 200         default 120
 201         depends on DPM_WATCHDOG
 202
 203 config PM_TRACE
 204         bool
 205         help
 206           This enables code to save the last PM event point across
 207           reboot. The architecture needs to support this, x86 for
 208           example does by saving things in the RTC, see below.
 209
 210           The architecture specific code must provide the extern
 211           functions from <linux/resume-trace.h> as well as the
 212           <asm/resume-trace.h> header with a TRACE_RESUME() macro.
 213
 214           The way the information is presented is architecture-
 215           dependent, x86 will print the information during a
 216           late_initcall.
 217
 218 config PM_TRACE_RTC
 219         bool "Suspend/resume event tracing"
 220         depends on PM_SLEEP_DEBUG
 221         depends on X86
 222         select PM_TRACE
 223         ---help---
 224         This enables some cheesy code to save the last PM event point in the
 225         RTC across reboots, so that you can debug a machine that just hangs
 226         during suspend (or more commonly, during resume).
 227
 228         To use this debugging feature you should attempt to suspend the
 229         machine, reboot it and then run
 230
 231                 dmesg -s 1000000 | grep 'hash matches'
 232
 233         CAUTION: this option will cause your machine's real-time clock to be
 234         set to an invalid time after a resume.
 235
 236 config APM_EMULATION
 237         tristate "Advanced Power Management Emulation"
 238         depends on SYS_SUPPORTS_APM_EMULATION
 239         help
 240           APM is a BIOS specification for saving power using several different
 241           techniques. This is mostly useful for battery powered laptops with
 242           APM compliant BIOSes. If you say Y here, the system time will be
 243           reset after a RESUME operation, the /proc/apm device will provide
 244           battery status information, and user-space programs will receive
 245           notification of APM "events" (e.g. battery status change).
 246
 247           In order to use APM, you will need supporting software. For location
 248           and more information, read <file:Documentation/power/apm-acpi.txt>
 249           and the Battery Powered Linux mini-HOWTO, available from
 250           <http://www.tldp.org/docs.html#howto>.
 251
 252           This driver does not spin down disk drives (see the hdparm(8)
 253           manpage ("man 8 hdparm") for that), and it doesn't turn off
 254           VESA-compliant "green" monitors.
 255
 256           Generally, if you don't have a battery in your machine, there isn't
 257           much point in using this driver and you should say N. If you get
 258           random kernel OOPSes or reboots that don't seem to be related to
 259           anything, try disabling/enabling this option (or disabling/enabling
 260           APM in your BIOS).
 261
 262 config PM_CLK
 263         def_bool y
 264         depends on PM && HAVE_CLK
 265
 266 config PM_GENERIC_DOMAINS
 267         bool
 268         depends on PM
 269
 270 config WQ_POWER_EFFICIENT_DEFAULT
 271         bool "Enable workqueue power-efficient mode by default"
 272         depends on PM
 273         default n
 274         help
 275           Per-cpu workqueues are generally preferred because they show
 276           better performance thanks to cache locality; unfortunately,
 277           per-cpu workqueues tend to be more power hungry than unbound
 278           workqueues.
 279
 280           Enabling workqueue.power_efficient kernel parameter makes the
 281           per-cpu workqueues which were observed to contribute
 282           significantly to power consumption unbound, leading to measurably
 283           lower power usage at the cost of small performance overhead.
 284
 285           This config option determines whether workqueue.power_efficient
 286           is enabled by default.
 287
 288           If in doubt, say N.
 289
 290 config PM_GENERIC_DOMAINS_SLEEP
 291         def_bool y
 292         depends on PM_SLEEP && PM_GENERIC_DOMAINS
 293
 294 config PM_GENERIC_DOMAINS_OF
 295         def_bool y
 296         depends on PM_GENERIC_DOMAINS && OF
 297
 298 config CPU_PM
 299         bool