ACPI: acpi_pci_irq_find_prt_entry(): use list_for_each_entry() instead of list_for_each()
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / power / Kconfig
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1config PM
2 bool "Power Management support"
eb7b6b32 3 depends on !IA64_HP_SIM
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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#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
bca73e4b 22config PM_LEGACY
f89bce3d 23 bool "Legacy Power Management API (DEPRECATED)"
bca73e4b 24 depends on PM
f89bce3d 25 default n
bca73e4b 26 ---help---
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27 Support for pm_register() and friends. This old API is obsoleted
28 by the driver model.
bca73e4b 29
f89bce3d 30 If unsure, say N.
bca73e4b 31
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32config PM_DEBUG
33 bool "Power Management Debug Support"
34 depends on PM
35 ---help---
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36 This option enables various debugging support in the Power Management
37 code. This is helpful when debugging and reporting PM bugs, like
38 suspend support.
39
40config PM_VERBOSE
41 bool "Verbose Power Management debugging"
42 depends on PM_DEBUG
43 default n
44 ---help---
45 This option enables verbose messages from the Power Management code.
1da177e4 46
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47config CAN_PM_TRACE
48 def_bool y
49 depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL
50
eb71c87a 51config PM_TRACE
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52 bool
53 help
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.
57
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.
61
62 The way the information is presented is architecture-
63 dependent, x86 will print the information during a
64 late_initcall.
65
66config PM_TRACE_RTC
eb71c87a 67 bool "Suspend/resume event tracing"
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68 depends on CAN_PM_TRACE
69 depends on X86
70 select PM_TRACE
5c31f273 71 default n
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72 ---help---
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).
76
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77 To use this debugging feature you should attempt to suspend the machine,
78 then reboot it, then run
79
80 dmesg -s 1000000 | grep 'hash matches'
81
82 CAUTION: this option will cause your machine's real-time clock to be
83 set to an invalid time after a resume.
84
f3de4be9 85config PM_SLEEP_SMP
296699de 86 bool
801e4062 87 depends on SMP
f4cb5700 88 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
f3de4be9 89 depends on PM_SLEEP
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90 select HOTPLUG_CPU
91 default y
92
93config PM_SLEEP
94 bool
95 depends on SUSPEND || HIBERNATION
96 default y
97
98config SUSPEND
99 bool "Suspend to RAM and standby"
f4cb5700 100 depends on PM && ARCH_SUSPEND_POSSIBLE
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101 default y
102 ---help---
103 Allow the system to enter sleep states in which main memory is
104 powered and thus its contents are preserved, such as the
f4cb5700 105 suspend-to-RAM state (e.g. the ACPI S3 state).
296699de 106
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107config SUSPEND_FREEZER
108 bool "Enable freezer for suspend to RAM/standby" \
109 if ARCH_WANTS_FREEZER_CONTROL || BROKEN
110 depends on SUSPEND
111 default y
112 help
113 This allows you to turn off the freezer for suspend. If this is
114 done, no tasks are frozen for suspend to RAM/standby.
115
116 Turning OFF this setting is NOT recommended! If in doubt, say Y.
117
b0cb1a19 118config HIBERNATION
296699de 119 bool "Hibernation (aka 'suspend to disk')"
801e4062 120 depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
1da177e4 121 ---help---
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122 Enable the suspend to disk (STD) functionality, which is usually
123 called "hibernation" in user interfaces. STD checkpoints the
124 system and powers it off; and restores that checkpoint on reboot.
1da177e4 125
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126 You can suspend your machine with 'echo disk > /sys/power/state'.
127 Alternatively, you can use the additional userland tools available
128 from <http://suspend.sf.net>.
129
130 In principle it does not require ACPI or APM, although for example
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131 ACPI will be used for the final steps when it is available. One
132 of the reasons to use software suspend is that the firmware hooks
133 for suspend states like suspend-to-RAM (STR) often don't work very
134 well with Linux.
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135
136 It creates an image which is saved in your active swap. Upon the next
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137 boot, pass the 'resume=/dev/swappartition' argument to the kernel to
138 have it detect the saved image, restore memory state from it, and
139 continue to run as before. If you do not want the previous state to
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140 be reloaded, then use the 'noresume' kernel command line argument.
141 Note, however, that fsck will be run on your filesystems and you will
142 need to run mkswap against the swap partition used for the suspend.
1da177e4 143
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144 It also works with swap files to a limited extent (for details see
145 <file:Documentation/power/swsusp-and-swap-files.txt>).
1da177e4 146
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147 Right now you may boot without resuming and resume later but in the
148 meantime you cannot use the swap partition(s)/file(s) involved in
149 suspending. Also in this case you must not use the filesystems
150 that were mounted before the suspend. In particular, you MUST NOT
151 MOUNT any journaled filesystems mounted before the suspend or they
152 will get corrupted in a nasty way.
1da177e4 153
c7276fde 154 For more information take a look at <file:Documentation/power/swsusp.txt>.
471b40d0 155
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156config PM_STD_PARTITION
157 string "Default resume partition"
b0cb1a19 158 depends on HIBERNATION
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159 default ""
160 ---help---
161 The default resume partition is the partition that the suspend-
162 to-disk implementation will look for a suspended disk image.
163
164 The partition specified here will be different for almost every user.
165 It should be a valid swap partition (at least for now) that is turned
166 on before suspending.
167
168 The partition specified can be overridden by specifying:
169
170 resume=/dev/<other device>
171
172 which will set the resume partition to the device specified.
173
174 Note there is currently not a way to specify which device to save the
175 suspended image to. It will simply pick the first available swap
176 device.
177
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178config APM_EMULATION
179 tristate "Advanced Power Management Emulation"
180 depends on PM && SYS_SUPPORTS_APM_EMULATION
181 help
182 APM is a BIOS specification for saving power using several different
183 techniques. This is mostly useful for battery powered laptops with
184 APM compliant BIOSes. If you say Y here, the system time will be
185 reset after a RESUME operation, the /proc/apm device will provide
186 battery status information, and user-space programs will receive
187 notification of APM "events" (e.g. battery status change).
188
189 In order to use APM, you will need supporting software. For location
190 and more information, read <file:Documentation/pm.txt> and the
191 Battery Powered Linux mini-HOWTO, available from
192 <http://www.tldp.org/docs.html#howto>.
193
194 This driver does not spin down disk drives (see the hdparm(8)
195 manpage ("man 8 hdparm") for that), and it doesn't turn off
196 VESA-compliant "green" monitors.
197
198 Generally, if you don't have a battery in your machine, there isn't
199 much point in using this driver and you should say N. If you get
200 random kernel OOPSes or reboots that don't seem to be related to
201 anything, try disabling/enabling this option (or disabling/enabling
202 APM in your BIOS).