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 "Legacy Power Management API (DEPRECATED)"
27 Support for pm_register() and friends. This old API is obsoleted
33 bool "Power Management Debug Support"
36 This option enables various debugging support in the Power Management
37 code. This is helpful when debugging and reporting PM bugs, like
41 bool "Verbose Power Management debugging"
45 This option enables verbose messages from the Power Management code.
49 depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL
54 This enables code to save the last PM event point across
55 reboot. The architecture needs to support this, x86 for
56 example does by saving things in the RTC, see below.
58 The architecture specific code must provide the extern
59 functions from <linux/resume-trace.h> as well as the
60 <asm/resume-trace.h> header with a TRACE_RESUME() macro.
62 The way the information is presented is architecture-
63 dependent, x86 will print the information during a
67 bool "Suspend/resume event tracing"
68 depends on CAN_PM_TRACE
73 This enables some cheesy code to save the last PM event point in the
74 RTC across reboots, so that you can debug a machine that just hangs
75 during suspend (or more commonly, during resume).
77 To use this debugging feature you should attempt to suspend the machine,
78 then reboot it, then run
80 dmesg -s 1000000 | grep 'hash matches'
82 CAUTION: this option will cause your machine's real-time clock to be
83 set to an invalid time after a resume.
88 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
95 depends on SUSPEND || HIBERNATION
99 bool "Suspend to RAM and standby"
100 depends on PM && ARCH_SUSPEND_POSSIBLE
103 Allow the system to enter sleep states in which main memory is
104 powered and thus its contents are preserved, such as the
105 suspend-to-RAM state (e.g. the ACPI S3 state).
108 bool "Hibernation (aka 'suspend to disk')"
109 depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
111 Enable the suspend to disk (STD) functionality, which is usually
112 called "hibernation" in user interfaces. STD checkpoints the
113 system and powers it off; and restores that checkpoint on reboot.
115 You can suspend your machine with 'echo disk > /sys/power/state'.
116 Alternatively, you can use the additional userland tools available
117 from <http://suspend.sf.net>.
119 In principle it does not require ACPI or APM, although for example
120 ACPI will be used for the final steps when it is available. One
121 of the reasons to use software suspend is that the firmware hooks
122 for suspend states like suspend-to-RAM (STR) often don't work very
125 It creates an image which is saved in your active swap. Upon the next
126 boot, pass the 'resume=/dev/swappartition' argument to the kernel to
127 have it detect the saved image, restore memory state from it, and
128 continue to run as before. If you do not want the previous state to
129 be reloaded, then use the 'noresume' kernel command line argument.
130 Note, however, that fsck will be run on your filesystems and you will
131 need to run mkswap against the swap partition used for the suspend.
133 It also works with swap files to a limited extent (for details see
134 <file:Documentation/power/swsusp-and-swap-files.txt>).
136 Right now you may boot without resuming and resume later but in the
137 meantime you cannot use the swap partition(s)/file(s) involved in
138 suspending. Also in this case you must not use the filesystems
139 that were mounted before the suspend. In particular, you MUST NOT
140 MOUNT any journaled filesystems mounted before the suspend or they
141 will get corrupted in a nasty way.
143 For more information take a look at <file:Documentation/power/swsusp.txt>.
145 config PM_STD_PARTITION
146 string "Default resume partition"
147 depends on HIBERNATION
150 The default resume partition is the partition that the suspend-
151 to-disk implementation will look for a suspended disk image.
153 The partition specified here will be different for almost every user.
154 It should be a valid swap partition (at least for now) that is turned
155 on before suspending.
157 The partition specified can be overridden by specifying:
159 resume=/dev/<other device>
161 which will set the resume partition to the device specified.
163 Note there is currently not a way to specify which device to save the
164 suspended image to. It will simply pick the first available swap
168 tristate "Advanced Power Management Emulation"
169 depends on PM && SYS_SUPPORTS_APM_EMULATION
171 APM is a BIOS specification for saving power using several different
172 techniques. This is mostly useful for battery powered laptops with
173 APM compliant BIOSes. If you say Y here, the system time will be
174 reset after a RESUME operation, the /proc/apm device will provide
175 battery status information, and user-space programs will receive
176 notification of APM "events" (e.g. battery status change).
178 In order to use APM, you will need supporting software. For location
179 and more information, read <file:Documentation/pm.txt> and the
180 Battery Powered Linux mini-HOWTO, available from
181 <http://www.tldp.org/docs.html#howto>.
183 This driver does not spin down disk drives (see the hdparm(8)
184 manpage ("man 8 hdparm") for that), and it doesn't turn off
185 VESA-compliant "green" monitors.
187 Generally, if you don't have a battery in your machine, there isn't
188 much point in using this driver and you should say N. If you get
189 random kernel OOPSes or reboots that don't seem to be related to
190 anything, try disabling/enabling this option (or disabling/enabling