1config 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
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---
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
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.
36
37config CAN_PM_TRACE
38 def_bool y
39 depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL
40
41config PM_TRACE
42 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
57 bool "Suspend/resume event tracing"
58 depends on CAN_PM_TRACE
59 depends on X86
60 select PM_TRACE
61 default n
62 ---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
67 To use this debugging feature you should attempt to suspend the
68 machine, reboot it and then run
69
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
75config PM_SLEEP_SMP
76 bool
77 depends on SMP
78 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
79 depends on PM_SLEEP
80 select HOTPLUG_CPU
81 default y
82
83config PM_SLEEP
84 bool
85 depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE
86 default y
87
88config SUSPEND
89 bool "Suspend to RAM and standby"
90 depends on PM && ARCH_SUSPEND_POSSIBLE
91 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
95 suspend-to-RAM state (e.g. the ACPI S3 state).
96
97config PM_TEST_SUSPEND
98 bool "Test suspend/resume and wakealarm during bootup"
99 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
100 ---help---
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".
104
105 You probably want to have your system's RTC driver statically
106 linked, ensuring that it's available when this test runs.
107
108config SUSPEND_FREEZER
109 bool "Enable freezer for suspend to RAM/standby" \
110 if ARCH_WANTS_FREEZER_CONTROL || BROKEN
111 depends on SUSPEND
112 default y
113 help
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.
116
117 Turning OFF this setting is NOT recommended! If in doubt, say Y.
118
119config HIBERNATION_NVS
120 bool
121
122config HIBERNATION
123 bool "Hibernation (aka 'suspend to disk')"
124 depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
125 select HIBERNATION_NVS if HAS_IOMEM
126 ---help---
127 Enable the suspend to disk (STD) functionality, which is usually
128 called "hibernation" in user interfaces. STD checkpoints the
129 system and powers it off; and restores that checkpoint on reboot.
130
131 You can suspend your machine with 'echo disk > /sys/power/state'
132 after placing resume=/dev/swappartition on the kernel command line
133 in your bootloader's configuration file.
134
135 Alternatively, you can use the additional userland tools available
136 from <http://suspend.sf.net>.
137
138 In principle it does not require ACPI or APM, although for example
139 ACPI will be used for the final steps when it is available. One
140 of the reasons to use software suspend is that the firmware hooks
141 for suspend states like suspend-to-RAM (STR) often don't work very
142 well with Linux.
143
144 It creates an image which is saved in your active swap. Upon the next
145 boot, pass the 'resume=/dev/swappartition' argument to the kernel to
146 have it detect the saved image, restore memory state from it, and
147 continue to run as before. If you do not want the previous state to
148 be reloaded, then use the 'noresume' kernel command line argument.
149 Note, however, that fsck will be run on your filesystems and you will
150 need to run mkswap against the swap partition used for the suspend.
151
152 It also works with swap files to a limited extent (for details see
153 <file:Documentation/power/swsusp-and-swap-files.txt>).
154
155 Right now you may boot without resuming and resume later but in the
156 meantime you cannot use the swap partition(s)/file(s) involved in
157 suspending. Also in this case you must not use the filesystems
158 that were mounted before the suspend. In particular, you MUST NOT
159 MOUNT any journaled filesystems mounted before the suspend or they
160 will get corrupted in a nasty way.
161
162 For more information take a look at <file:Documentation/power/swsusp.txt>.
163
164config PM_STD_PARTITION
165 string "Default resume partition"
166 depends on HIBERNATION
167 default ""
168 ---help---
169 The default resume partition is the partition that the suspend-
170 to-disk implementation will look for a suspended disk image.
171
172 The partition specified here will be different for almost every user.
173 It should be a valid swap partition (at least for now) that is turned
174 on before suspending.
175
176 The partition specified can be overridden by specifying:
177
178 resume=/dev/<other device>
179
180 which will set the resume partition to the device specified.
181
182 Note there is currently not a way to specify which device to save the
183 suspended image to. It will simply pick the first available swap
184 device.
185
186config APM_EMULATION
187 tristate "Advanced Power Management Emulation"
188 depends on PM && SYS_SUPPORTS_APM_EMULATION
189 help
190 APM is a BIOS specification for saving power using several different
191 techniques. This is mostly useful for battery powered laptops with
192 APM compliant BIOSes. If you say Y here, the system time will be
193 reset after a RESUME operation, the /proc/apm device will provide
194 battery status information, and user-space programs will receive
195 notification of APM "events" (e.g. battery status change).
196
197 In order to use APM, you will need supporting software. For location
198 and more information, read <file:Documentation/power/pm.txt> and the
199 Battery Powered Linux mini-HOWTO, available from
200 <http://www.tldp.org/docs.html#howto>.
201
202 This driver does not spin down disk drives (see the hdparm(8)
203 manpage ("man 8 hdparm") for that), and it doesn't turn off
204 VESA-compliant "green" monitors.
205
206 Generally, if you don't have a battery in your machine, there isn't
207 much point in using this driver and you should say N. If you get
208 random kernel OOPSes or reboots that don't seem to be related to
209 anything, try disabling/enabling this option (or disabling/enabling
210 APM in your BIOS).
211
212config PM_RUNTIME
213 bool "Run-time PM core functionality"
214 depends on PM
215 ---help---
216 Enable functionality allowing I/O devices to be put into energy-saving
217 (low power) states at run time (or autosuspended) after a specified
218 period of inactivity and woken up in response to a hardware-generated
219 wake-up event or a driver's request.
220
221 Hardware support is generally required for this functionality to work
222 and the bus type drivers of the buses the devices are on are
223 responsible for the actual handling of the autosuspend requests and
224 wake-up events.
225
