kernel/power/Kconfig

   1 config PM
   2         bool "Power Management support"
   3         depends on !IA64_HP_SIM
   4         ---help---
   5           "Power Management" means that parts of your computer are shut
   6           off or put into a power conserving "sleep" mode if they are not
   7           being used.  There are two competing standards for doing this: APM
   8           and ACPI.  If you want to use either one, say Y here and then also
   9           to the requisite support below.
  10
  11           Power Management is most important for battery powered laptop
  12           computers; if you have a laptop, check out the Linux Laptop home
  13           page on the WWW at <http://www.linux-on-laptops.com/> or
  14           Tuxmobil - Linux on Mobile Computers at <http://www.tuxmobil.org/>
  15           and the Battery Powered Linux mini-HOWTO, available from
  16           <http://www.tldp.org/docs.html#howto>.
  17
  18           Note that, even if you say N here, Linux on the x86 architecture
  19           will issue the hlt instruction if nothing is to be done, thereby
  20           sending the processor to sleep and saving power.
  21
  22 config PM_DEBUG
  23         bool "Power Management Debug Support"
  24         depends on PM
  25         ---help---
  26         This option enables various debugging support in the Power Management
  27         code. This is helpful when debugging and reporting PM bugs, like
  28         suspend support.
  29
  30 config PM_ADVANCED_DEBUG
  31         bool "Extra PM attributes in sysfs for low-level debugging/testing"
  32         depends on PM_DEBUG
  33         default n
  34         ---help---
  35         Add extra sysfs attributes allowing one to access some Power Management
  36         fields of device objects from user space.  If you are not a kernel
  37         developer interested in debugging/testing Power Management, say "no".
  38
  39 config PM_VERBOSE
  40         bool "Verbose Power Management debugging"
  41         depends on PM_DEBUG
  42         default n
  43         ---help---
  44         This option enables verbose messages from the Power Management code.
  45
  46 config CAN_PM_TRACE
  47         def_bool y
  48         depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL
  49
  50 config PM_TRACE
  51         bool
  52         help
  53           This enables code to save the last PM event point across
  54           reboot. The architecture needs to support this, x86 for
  55           example does by saving things in the RTC, see below.
  56
  57           The architecture specific code must provide the extern
  58           functions from <linux/resume-trace.h> as well as the
  59           <asm/resume-trace.h> header with a TRACE_RESUME() macro.
  60
  61           The way the information is presented is architecture-
  62           dependent, x86 will print the information during a
  63           late_initcall.
  64
  65 config PM_TRACE_RTC
  66         bool "Suspend/resume event tracing"
  67         depends on CAN_PM_TRACE
  68         depends on X86
  69         select PM_TRACE
  70         default n
  71         ---help---
  72         This enables some cheesy code to save the last PM event point in the
  73         RTC across reboots, so that you can debug a machine that just hangs
  74         during suspend (or more commonly, during resume).
  75
  76         To use this debugging feature you should attempt to suspend the
  77         machine, reboot it and then run
  78
  79                 dmesg -s 1000000 | grep 'hash matches'
  80
  81         CAUTION: this option will cause your machine's real-time clock to be
  82         set to an invalid time after a resume.
  83
  84 config PM_SLEEP_SMP
  85         bool
  86         depends on SMP
  87         depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
  88         depends on PM_SLEEP
  89         select HOTPLUG
  90         select HOTPLUG_CPU
  91         default y
  92
  93 config PM_SLEEP
  94         bool
  95         depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE
  96         default y
  97
  98 config PM_SLEEP_ADVANCED_DEBUG
  99         bool
 100         depends on PM_ADVANCED_DEBUG
 101         default n
 102
 103 config SUSPEND_NVS
 104        bool
 105
 106 config SUSPEND
 107         bool "Suspend to RAM and standby"
 108         depends on PM && ARCH_SUSPEND_POSSIBLE
 109         select SUSPEND_NVS if HAS_IOMEM
 110         default y
 111         ---help---
 112           Allow the system to enter sleep states in which main memory is
 113           powered and thus its contents are preserved, such as the
 114           suspend-to-RAM state (e.g. the ACPI S3 state).
 115
 116 config PM_TEST_SUSPEND
 117         bool "Test suspend/resume and wakealarm during bootup"
 118         depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
 119         ---help---
 120         This option will let you suspend your machine during bootup, and
 121         make it wake up a few seconds later using an RTC wakeup alarm.
 122         Enable this with a kernel parameter like "test_suspend=mem".
 123
 124         You probably want to have your system's RTC driver statically
 125         linked, ensuring that it's available when this test runs.
 126
 127 config SUSPEND_FREEZER
 128         bool "Enable freezer for suspend to RAM/standby" \
 129                 if ARCH_WANTS_FREEZER_CONTROL || BROKEN
 130         depends on SUSPEND
 131         default y
 132         help
 133           This allows you to turn off the freezer for suspend. If this is
 134           done, no tasks are frozen for suspend to RAM/standby.
 135
 136           Turning OFF this setting is NOT recommended! If in doubt, say Y.
 137
 138 config HIBERNATION
 139         bool "Hibernation (aka 'suspend to disk')"
 140         depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
 141         select LZO_COMPRESS
 142         select LZO_DECOMPRESS
 143         select SUSPEND_NVS if HAS_IOMEM
 144         ---help---
 145           Enable the suspend to disk (STD) functionality, which is usually
 146           called "hibernation" in user interfaces.  STD checkpoints the
 147           system and powers it off; and restores that checkpoint on reboot.
 148
 149           You can suspend your machine with 'echo disk > /sys/power/state'
 150           after placing resume=/dev/swappartition on the kernel command line
 151           in your bootloader's configuration file.
 152
 153           Alternatively, you can use the additional userland tools available
 154           from <http://suspend.sf.net>.
 155
 156           In principle it does not require ACPI or APM, although for example
 157           ACPI will be used for the final steps when it is available.  One
 158           of the reasons to use software suspend is that the firmware hooks
 159           for suspend states like suspend-to-RAM (STR) often don't work very
 160           well with Linux.
 161
 162           It creates an image which is saved in your active swap. Upon the next
 163           boot, pass the 'resume=/dev/swappartition' argument to the kernel to
 164           have it detect the saved image, restore memory state from it, and
 165           continue to run as before. If you do not want the previous state to
 166           be reloaded, then use the 'noresume' kernel command line argument.
 167           Note, however, that fsck will be run on your filesystems and you will
 168           need to run mkswap against the swap partition used for the suspend.
 169
 170           It also works with swap files to a limited extent (for details see
 171           <file:Documentation/power/swsusp-and-swap-files.txt>).
 172
 173           Right now you may boot without resuming and resume later but in the
 174           meantime you cannot use the swap partition(s)/file(s) involved in
 175           suspending.  Also in this case you must not use the filesystems
 176           that were mounted before the suspend.  In particular, you MUST NOT
 177           MOUNT any journaled filesystems mounted before the suspend or they
 178           will get corrupted in a nasty way.
 179
 180           For more information take a look at <file:Documentation/power/swsusp.txt>.
 181
 182 config PM_STD_PARTITION
 183         string "Default resume partition"
 184         depends on HIBERNATION
 185         default ""
 186         ---help---
 187           The default resume partition is the partition that the suspend-
 188           to-disk implementation will look for a suspended disk image.
 189
 190           The partition specified here will be different for almost every user.
 191           It should be a valid swap partition (at least for now) that is turned
 192           on before suspending.
 193
 194           The partition specified can be overridden by specifying:
 195
 196                 resume=/dev/<other device>
 197
 198           which will set the resume partition to the device specified.
 199
 200           Note there is currently not a way to specify which device to save the
 201           suspended image to. It will simply pick the first available swap
 202           device.
 203
 204 config APM_EMULATION
 205         tristate "Advanced Power Management Emulation"
 206         depends on PM && SYS_SUPPORTS_APM_EMULATION
 207         help
 208           APM is a BIOS specification for saving power using several different
 209           techniques. This is mostly useful for battery powered laptops with
 210           APM compliant BIOSes. If you say Y here, the system time will be
 211           reset after a RESUME operation, the /proc/apm device will provide
 212           battery status information, and user-space programs will receive
 213           notification of APM "events" (e.g. battery status change).
 214
 215           In order to use APM, you will need supporting software. For location
 216           and more information, read <file:Documentation/power/pm.txt> and the
 217           Battery Powered Linux mini-HOWTO, available from
 218           <http://www.tldp.org/docs.html#howto>.
 219
 220           This driver does not spin down disk drives (see the hdparm(8)
 221           manpage ("man 8 hdparm") for that), and it doesn't turn off
 222           VESA-compliant "green" monitors.
 223
 224           Generally, if you don't have a battery in your machine, there isn't
 225           much point in using this driver and you should say N. If you get
 226           random kernel OOPSes or reboots that don't seem to be related to
 227           anything, try disabling/enabling this option (or disabling/enabling
 228           APM in your BIOS).
 229
 230 config PM_RUNTIME
 231         bool "Run-time PM core functionality"
 232         depends on PM
 233         ---help---
 234           Enable functionality allowing I/O devices to be put into energy-saving
 235           (low power) states at run time (or autosuspended) after a specified
 236           period of inactivity and woken up in response to a hardware-generated
 237           wake-up event or a driver's request.
 238
 239           Hardware support is generally required for this functionality to work
 240           and the bus type drivers of the buses the devices are on are
 241           responsible for the actual handling of the autosuspend requests and
 242           wake-up events.
 243
 244 config PM_OPS
 245         bool
 246         depends on PM_SLEEP || PM_RUNTIME
 247         default y
 248
 249 config ARCH_HAS_OPP
 250         bool
 251
 252 config PM_OPP
 253         bool "Operating Performance Point (OPP) Layer library"
 254         depends on PM
 255         depends on ARCH_HAS_OPP
 256         ---help---
 257           SOCs have a standard set of tuples consisting of frequency and
 258           voltage pairs that the device will support per voltage domain. This
 259           is called Operating Performance Point or OPP. The actual definitions
 260           of OPP varies over silicon within the same family of devices.
 261
 262           OPP layer organizes the data internally using device pointers
 263           representing individual voltage domains and provides SOC
 264           implementations a ready to use framework to manage OPPs.
 265           For more information, read <file:Documentation/power/opp.txt>