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.
87 depends on SUSPEND_SMP_POSSIBLE || HIBERNATION_SMP_POSSIBLE
94 depends on SUSPEND || HIBERNATION
97 config SUSPEND_UP_POSSIBLE
99 depends on (X86 && !X86_VOYAGER) || PPC || ARM || BLACKFIN || MIPS \
104 config SUSPEND_SMP_POSSIBLE
106 depends on (X86 && !X86_VOYAGER) \
107 || (PPC && (PPC_PSERIES || PPC_PMAC)) || ARM
112 bool "Suspend to RAM and standby"
114 depends on SUSPEND_UP_POSSIBLE || SUSPEND_SMP_POSSIBLE
117 Allow the system to enter sleep states in which main memory is
118 powered and thus its contents are preserved, such as the
119 suspend-to-RAM state (i.e. the ACPI S3 state).
121 config HIBERNATION_UP_POSSIBLE
123 depends on X86 || PPC64_SWSUSP || PPC32
127 config HIBERNATION_SMP_POSSIBLE
129 depends on (X86 && !X86_VOYAGER) || PPC64_SWSUSP
134 bool "Hibernation (aka 'suspend to disk')"
135 depends on PM && SWAP
136 depends on HIBERNATION_UP_POSSIBLE || HIBERNATION_SMP_POSSIBLE
138 Enable the suspend to disk (STD) functionality, which is usually
139 called "hibernation" in user interfaces. STD checkpoints the
140 system and powers it off; and restores that checkpoint on reboot.
142 You can suspend your machine with 'echo disk > /sys/power/state'.
143 Alternatively, you can use the additional userland tools available
144 from <http://suspend.sf.net>.
146 In principle it does not require ACPI or APM, although for example
147 ACPI will be used for the final steps when it is available. One
148 of the reasons to use software suspend is that the firmware hooks
149 for suspend states like suspend-to-RAM (STR) often don't work very
152 It creates an image which is saved in your active swap. Upon the next
153 boot, pass the 'resume=/dev/swappartition' argument to the kernel to
154 have it detect the saved image, restore memory state from it, and
155 continue to run as before. If you do not want the previous state to
156 be reloaded, then use the 'noresume' kernel command line argument.
157 Note, however, that fsck will be run on your filesystems and you will
158 need to run mkswap against the swap partition used for the suspend.
160 It also works with swap files to a limited extent (for details see
161 <file:Documentation/power/swsusp-and-swap-files.txt>).
163 Right now you may boot without resuming and resume later but in the
164 meantime you cannot use the swap partition(s)/file(s) involved in
165 suspending. Also in this case you must not use the filesystems
166 that were mounted before the suspend. In particular, you MUST NOT
167 MOUNT any journaled filesystems mounted before the suspend or they
168 will get corrupted in a nasty way.
170 For more information take a look at <file:Documentation/power/swsusp.txt>.
172 config PM_STD_PARTITION
173 string "Default resume partition"
174 depends on HIBERNATION
177 The default resume partition is the partition that the suspend-
178 to-disk implementation will look for a suspended disk image.
180 The partition specified here will be different for almost every user.
181 It should be a valid swap partition (at least for now) that is turned
182 on before suspending.
184 The partition specified can be overridden by specifying:
186 resume=/dev/<other device>
188 which will set the resume partition to the device specified.
190 Note there is currently not a way to specify which device to save the
191 suspended image to. It will simply pick the first available swap
195 tristate "Advanced Power Management Emulation"
196 depends on PM && SYS_SUPPORTS_APM_EMULATION
198 APM is a BIOS specification for saving power using several different
199 techniques. This is mostly useful for battery powered laptops with
200 APM compliant BIOSes. If you say Y here, the system time will be
201 reset after a RESUME operation, the /proc/apm device will provide
202 battery status information, and user-space programs will receive
203 notification of APM "events" (e.g. battery status change).
205 In order to use APM, you will need supporting software. For location
206 and more information, read <file:Documentation/pm.txt> and the
207 Battery Powered Linux mini-HOWTO, available from
208 <http://www.tldp.org/docs.html#howto>.
210 This driver does not spin down disk drives (see the hdparm(8)
211 manpage ("man 8 hdparm") for that), and it doesn't turn off
212 VESA-compliant "green" monitors.
214 Generally, if you don't have a battery in your machine, there isn't
215 much point in using this driver and you should say N. If you get
216 random kernel OOPSes or reboots that don't seem to be related to
217 anything, try disabling/enabling this option (or disabling/enabling