2 bool "Power Management support"
3 depends on !IA64_HP_SIM
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.
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>.
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.
23 bool "Power Management Debug Support"
26 This option enables various debugging support in the Power Management
27 code. This is helpful when debugging and reporting PM bugs, like
31 bool "Verbose Power Management debugging"
35 This option enables verbose messages from the Power Management code.
39 depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL
44 This enables code to save the last PM event point across
45 reboot. The architecture needs to support this, x86 for
46 example does by saving things in the RTC, see below.
48 The architecture specific code must provide the extern
49 functions from <linux/resume-trace.h> as well as the
50 <asm/resume-trace.h> header with a TRACE_RESUME() macro.
52 The way the information is presented is architecture-
53 dependent, x86 will print the information during a
57 bool "Suspend/resume event tracing"
58 depends on CAN_PM_TRACE
63 This enables some cheesy code to save the last PM event point in the
64 RTC across reboots, so that you can debug a machine that just hangs
65 during suspend (or more commonly, during resume).
67 To use this debugging feature you should attempt to suspend the
68 machine, reboot it and then run
70 dmesg -s 1000000 | grep 'hash matches'
72 CAUTION: this option will cause your machine's real-time clock to be
73 set to an invalid time after a resume.
78 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
85 depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE
89 bool "Suspend to RAM and standby"
90 depends on PM && ARCH_SUSPEND_POSSIBLE
93 Allow the system to enter sleep states in which main memory is
94 powered and thus its contents are preserved, such as the
95 suspend-to-RAM state (e.g. the ACPI S3 state).
97 config PM_TEST_SUSPEND
98 bool "Test suspend/resume and wakealarm during bootup"
99 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
101 This option will let you suspend your machine during bootup, and
102 make it wake up a few seconds later using an RTC wakeup alarm.
103 Enable this with a kernel parameter like "test_suspend=mem".
105 You probably want to have your system's RTC driver statically
106 linked, ensuring that it's available when this test runs.
108 config SUSPEND_FREEZER
109 bool "Enable freezer for suspend to RAM/standby" \
110 if ARCH_WANTS_FREEZER_CONTROL || BROKEN
114 This allows you to turn off the freezer for suspend. If this is
115 done, no tasks are frozen for suspend to RAM/standby.
117 Turning OFF this setting is NOT recommended! If in doubt, say Y.
119 config HIBERNATION_NVS
125 config HAS_EARLYSUSPEND
130 depends on PM && RTC_CLASS
134 Enable wakelocks. When user space request a sleep state the
135 sleep request will be delayed until no wake locks are held.
138 bool "Wake lock stats"
142 Report wake lock stats in /proc/wakelocks
145 bool "Userspace wake locks"
149 User-space wake lock api. Write "lockname" or "lockname timeout"
150 to /sys/power/wake_lock lock and if needed create a wake lock.
151 Write "lockname" to /sys/power/wake_unlock to unlock a user wake
158 select HAS_EARLYSUSPEND
160 Call early suspend handlers when the user requested sleep state
164 bool "Hibernation (aka 'suspend to disk')"
165 depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
166 select HIBERNATION_NVS if HAS_IOMEM
168 Enable the suspend to disk (STD) functionality, which is usually
169 called "hibernation" in user interfaces. STD checkpoints the
170 system and powers it off; and restores that checkpoint on reboot.
172 You can suspend your machine with 'echo disk > /sys/power/state'
173 after placing resume=/dev/swappartition on the kernel command line
174 in your bootloader's configuration file.
176 Alternatively, you can use the additional userland tools available
177 from <http://suspend.sf.net>.
179 In principle it does not require ACPI or APM, although for example
180 ACPI will be used for the final steps when it is available. One
181 of the reasons to use software suspend is that the firmware hooks
182 for suspend states like suspend-to-RAM (STR) often don't work very
185 It creates an image which is saved in your active swap. Upon the next
186 boot, pass the 'resume=/dev/swappartition' argument to the kernel to
187 have it detect the saved image, restore memory state from it, and
188 continue to run as before. If you do not want the previous state to
189 be reloaded, then use the 'noresume' kernel command line argument.
190 Note, however, that fsck will be run on your filesystems and you will
191 need to run mkswap against the swap partition used for the suspend.
193 It also works with swap files to a limited extent (for details see
194 <file:Documentation/power/swsusp-and-swap-files.txt>).
196 Right now you may boot without resuming and resume later but in the
197 meantime you cannot use the swap partition(s)/file(s) involved in
198 suspending. Also in this case you must not use the filesystems
199 that were mounted before the suspend. In particular, you MUST NOT
200 MOUNT any journaled filesystems mounted before the suspend or they
201 will get corrupted in a nasty way.
203 For more information take a look at <file:Documentation/power/swsusp.txt>.
205 config PM_STD_PARTITION
206 string "Default resume partition"
207 depends on HIBERNATION
210 The default resume partition is the partition that the suspend-
211 to-disk implementation will look for a suspended disk image.
213 The partition specified here will be different for almost every user.
214 It should be a valid swap partition (at least for now) that is turned
215 on before suspending.
217 The partition specified can be overridden by specifying:
219 resume=/dev/<other device>
221 which will set the resume partition to the device specified.
223 Note there is currently not a way to specify which device to save the
224 suspended image to. It will simply pick the first available swap
228 tristate "Advanced Power Management Emulation"
229 depends on PM && SYS_SUPPORTS_APM_EMULATION
231 APM is a BIOS specification for saving power using several different
232 techniques. This is mostly useful for battery powered laptops with
233 APM compliant BIOSes. If you say Y here, the system time will be
234 reset after a RESUME operation, the /proc/apm device will provide
235 battery status information, and user-space programs will receive
236 notification of APM "events" (e.g. battery status change).
238 In order to use APM, you will need supporting software. For location
239 and more information, read <file:Documentation/power/pm.txt> and the
240 Battery Powered Linux mini-HOWTO, available from
241 <http://www.tldp.org/docs.html#howto>.
243 This driver does not spin down disk drives (see the hdparm(8)
244 manpage ("man 8 hdparm") for that), and it doesn't turn off
245 VESA-compliant "green" monitors.
247 Generally, if you don't have a battery in your machine, there isn't
248 much point in using this driver and you should say N. If you get
249 random kernel OOPSes or reboots that don't seem to be related to
250 anything, try disabling/enabling this option (or disabling/enabling
254 bool "Run-time PM core functionality"
257 Enable functionality allowing I/O devices to be put into energy-saving
258 (low power) states at run time (or autosuspended) after a specified
259 period of inactivity and woken up in response to a hardware-generated
260 wake-up event or a driver's request.
262 Hardware support is generally required for this functionality to work
263 and the bus type drivers of the buses the devices are on are
264 responsible for the actual handling of the autosuspend requests and