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Linus Torvalds1da177e2005-04-16 15:20:36 -07001config PM
2 bool "Power Management support"
Len Browneb7b6b32005-08-25 12:08:25 -04003 depends on !IA64_HP_SIM
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 ---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
22config PM_DEBUG
23 bool "Power Management Debug Support"
24 depends on PM
25 ---help---
Ben Collinsa0349822007-07-19 01:47:27 -070026 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
30config PM_VERBOSE
31 bool "Verbose Power Management debugging"
32 depends on PM_DEBUG
33 default n
34 ---help---
35 This option enables verbose messages from the Power Management code.
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
Johannes Berg90dda1c2007-11-19 23:46:16 +010037config CAN_PM_TRACE
38 def_bool y
39 depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL
40
Linus Torvaldseb71c872006-06-24 14:27:42 -070041config PM_TRACE
Johannes Berg90dda1c2007-11-19 23:46:16 +010042 bool
43 help
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.
47
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.
51
52 The way the information is presented is architecture-
53 dependent, x86 will print the information during a
54 late_initcall.
55
56config PM_TRACE_RTC
Linus Torvaldseb71c872006-06-24 14:27:42 -070057 bool "Suspend/resume event tracing"
Johannes Berg90dda1c2007-11-19 23:46:16 +010058 depends on CAN_PM_TRACE
59 depends on X86
60 select PM_TRACE
Andrew Morton5c31f272006-06-27 02:53:26 -070061 default n
Linus Torvaldseb71c872006-06-24 14:27:42 -070062 ---help---
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).
66
Pavel Machek23b168d2008-02-05 19:27:12 +010067 To use this debugging feature you should attempt to suspend the
68 machine, reboot it and then run
Andrew Morton5c31f272006-06-27 02:53:26 -070069
70 dmesg -s 1000000 | grep 'hash matches'
71
72 CAUTION: this option will cause your machine's real-time clock to be
73 set to an invalid time after a resume.
74
Rafael J. Wysockif3de4be2007-08-30 23:56:29 -070075config PM_SLEEP_SMP
Rafael J. Wysocki296699d2007-07-29 23:27:18 +020076 bool
Johannes Berg801e4062007-12-08 02:12:39 +010077 depends on SMP
Johannes Bergf4cb5702007-12-08 02:14:00 +010078 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
Rafael J. Wysockif3de4be2007-08-30 23:56:29 -070079 depends on PM_SLEEP
Rafael J. Wysocki296699d2007-07-29 23:27:18 +020080 select HOTPLUG_CPU
81 default y
82
83config PM_SLEEP
84 bool
85 depends on SUSPEND || HIBERNATION
86 default y
87
88config SUSPEND
89 bool "Suspend to RAM and standby"
Johannes Bergf4cb5702007-12-08 02:14:00 +010090 depends on PM && ARCH_SUSPEND_POSSIBLE
Rafael J. Wysocki296699d2007-07-29 23:27:18 +020091 default y
92 ---help---
93 Allow the system to enter sleep states in which main memory is
94 powered and thus its contents are preserved, such as the
Johannes Bergf4cb5702007-12-08 02:14:00 +010095 suspend-to-RAM state (e.g. the ACPI S3 state).
Rafael J. Wysocki296699d2007-07-29 23:27:18 +020096
Johannes Bergb28f5082008-01-15 23:17:00 -050097config SUSPEND_FREEZER
98 bool "Enable freezer for suspend to RAM/standby" \
99 if ARCH_WANTS_FREEZER_CONTROL || BROKEN
100 depends on SUSPEND
101 default y
102 help
103 This allows you to turn off the freezer for suspend. If this is
104 done, no tasks are frozen for suspend to RAM/standby.
105
106 Turning OFF this setting is NOT recommended! If in doubt, say Y.
107
Rafael J. Wysockib0cb1a12007-07-29 23:24:36 +0200108config HIBERNATION
Rafael J. Wysocki296699d2007-07-29 23:27:18 +0200109 bool "Hibernation (aka 'suspend to disk')"
Johannes Berg801e4062007-12-08 02:12:39 +0100110 depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 ---help---
David Brownella7ee2e52007-05-06 14:50:50 -0700112 Enable the suspend to disk (STD) functionality, which is usually
113 called "hibernation" in user interfaces. STD checkpoints the
114 system and powers it off; and restores that checkpoint on reboot.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115
Pavel Machek23b168d2008-02-05 19:27:12 +0100116 You can suspend your machine with 'echo disk > /sys/power/state'
117 after placing resume=/dev/swappartition on the kernel command line
118 in your bootloader's configuration file.
119
Rafael J. Wysockic7276fd2007-03-06 01:42:24 -0800120 Alternatively, you can use the additional userland tools available
121 from <http://suspend.sf.net>.
122
123 In principle it does not require ACPI or APM, although for example
David Brownella7ee2e52007-05-06 14:50:50 -0700124 ACPI will be used for the final steps when it is available. One
125 of the reasons to use software suspend is that the firmware hooks
126 for suspend states like suspend-to-RAM (STR) often don't work very
127 well with Linux.
Rafael J. Wysockic7276fd2007-03-06 01:42:24 -0800128
129 It creates an image which is saved in your active swap. Upon the next
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 boot, pass the 'resume=/dev/swappartition' argument to the kernel to
131 have it detect the saved image, restore memory state from it, and
132 continue to run as before. If you do not want the previous state to
Rafael J. Wysockic7276fd2007-03-06 01:42:24 -0800133 be reloaded, then use the 'noresume' kernel command line argument.
134 Note, however, that fsck will be run on your filesystems and you will
135 need to run mkswap against the swap partition used for the suspend.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
Rafael J. Wysockic7276fd2007-03-06 01:42:24 -0800137 It also works with swap files to a limited extent (for details see
138 <file:Documentation/power/swsusp-and-swap-files.txt>).
139
140 Right now you may boot without resuming and resume later but in the
141 meantime you cannot use the swap partition(s)/file(s) involved in
142 suspending. Also in this case you must not use the filesystems
143 that were mounted before the suspend. In particular, you MUST NOT
144 MOUNT any journaled filesystems mounted before the suspend or they
145 will get corrupted in a nasty way.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146
147 For more information take a look at <file:Documentation/power/swsusp.txt>.
148
149config PM_STD_PARTITION
150 string "Default resume partition"
Rafael J. Wysockib0cb1a12007-07-29 23:24:36 +0200151 depends on HIBERNATION
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 default ""
153 ---help---
154 The default resume partition is the partition that the suspend-
155 to-disk implementation will look for a suspended disk image.
156
157 The partition specified here will be different for almost every user.
158 It should be a valid swap partition (at least for now) that is turned
159 on before suspending.
160
161 The partition specified can be overridden by specifying:
162
163 resume=/dev/<other device>
164
165 which will set the resume partition to the device specified.
166
167 Note there is currently not a way to specify which device to save the
168 suspended image to. It will simply pick the first available swap
169 device.
170
Ralf Baechle77269422007-02-09 17:08:57 +0000171config APM_EMULATION
172 tristate "Advanced Power Management Emulation"
173 depends on PM && SYS_SUPPORTS_APM_EMULATION
174 help
175 APM is a BIOS specification for saving power using several different
176 techniques. This is mostly useful for battery powered laptops with
177 APM compliant BIOSes. If you say Y here, the system time will be
178 reset after a RESUME operation, the /proc/apm device will provide
179 battery status information, and user-space programs will receive
180 notification of APM "events" (e.g. battery status change).
181
182 In order to use APM, you will need supporting software. For location
Randy Dunlap53471122008-03-12 18:10:51 -0400183 and more information, read <file:Documentation/power/pm.txt> and the
Ralf Baechle77269422007-02-09 17:08:57 +0000184 Battery Powered Linux mini-HOWTO, available from
185 <http://www.tldp.org/docs.html#howto>.
186
187 This driver does not spin down disk drives (see the hdparm(8)
188 manpage ("man 8 hdparm") for that), and it doesn't turn off
189 VESA-compliant "green" monitors.
190
191 Generally, if you don't have a battery in your machine, there isn't
192 much point in using this driver and you should say N. If you get
193 random kernel OOPSes or reboots that don't seem to be related to
194 anything, try disabling/enabling this option (or disabling/enabling
195 APM in your BIOS).