Root/kernel/power/Kconfig

1config SUSPEND
2    bool "Suspend to RAM and standby"
3    depends on ARCH_SUSPEND_POSSIBLE
4    default y
5    ---help---
6      Allow the system to enter sleep states in which main memory is
7      powered and thus its contents are preserved, such as the
8      suspend-to-RAM state (e.g. the ACPI S3 state).
9
10config SUSPEND_FREEZER
11    bool "Enable freezer for suspend to RAM/standby" \
12        if ARCH_WANTS_FREEZER_CONTROL || BROKEN
13    depends on SUSPEND
14    default y
15    help
16      This allows you to turn off the freezer for suspend. If this is
17      done, no tasks are frozen for suspend to RAM/standby.
18
19      Turning OFF this setting is NOT recommended! If in doubt, say Y.
20
21config HIBERNATE_CALLBACKS
22    bool
23
24config HIBERNATION
25    bool "Hibernation (aka 'suspend to disk')"
26    depends on SWAP && ARCH_HIBERNATION_POSSIBLE
27    select HIBERNATE_CALLBACKS
28    select LZO_COMPRESS
29    select LZO_DECOMPRESS
30    ---help---
31      Enable the suspend to disk (STD) functionality, which is usually
32      called "hibernation" in user interfaces. STD checkpoints the
33      system and powers it off; and restores that checkpoint on reboot.
34
35      You can suspend your machine with 'echo disk > /sys/power/state'
36      after placing resume=/dev/swappartition on the kernel command line
37      in your bootloader's configuration file.
38
39      Alternatively, you can use the additional userland tools available
40      from <http://suspend.sf.net>.
41
42      In principle it does not require ACPI or APM, although for example
43      ACPI will be used for the final steps when it is available. One
44      of the reasons to use software suspend is that the firmware hooks
45      for suspend states like suspend-to-RAM (STR) often don't work very
46      well with Linux.
47
48      It creates an image which is saved in your active swap. Upon the next
49      boot, pass the 'resume=/dev/swappartition' argument to the kernel to
50      have it detect the saved image, restore memory state from it, and
51      continue to run as before. If you do not want the previous state to
52      be reloaded, then use the 'noresume' kernel command line argument.
53      Note, however, that fsck will be run on your filesystems and you will
54      need to run mkswap against the swap partition used for the suspend.
55
56      It also works with swap files to a limited extent (for details see
57      <file:Documentation/power/swsusp-and-swap-files.txt>).
58
59      Right now you may boot without resuming and resume later but in the
60      meantime you cannot use the swap partition(s)/file(s) involved in
61      suspending. Also in this case you must not use the filesystems
62      that were mounted before the suspend. In particular, you MUST NOT
63      MOUNT any journaled filesystems mounted before the suspend or they
64      will get corrupted in a nasty way.
65
66      For more information take a look at <file:Documentation/power/swsusp.txt>.
67
68config PM_STD_PARTITION
69    string "Default resume partition"
70    depends on HIBERNATION
71    default ""
72    ---help---
73      The default resume partition is the partition that the suspend-
74      to-disk implementation will look for a suspended disk image.
75
76      The partition specified here will be different for almost every user.
77      It should be a valid swap partition (at least for now) that is turned
78      on before suspending.
79
80      The partition specified can be overridden by specifying:
81
82        resume=/dev/<other device>
83
84      which will set the resume partition to the device specified.
85
86      Note there is currently not a way to specify which device to save the
87      suspended image to. It will simply pick the first available swap
88      device.
89
90config PM_SLEEP
91    def_bool y
92    depends on SUSPEND || HIBERNATE_CALLBACKS
93
94config PM_SLEEP_SMP
95    def_bool y
96    depends on SMP
97    depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
98    depends on PM_SLEEP
99    select HOTPLUG
100    select HOTPLUG_CPU
101
102config PM_RUNTIME
103    bool "Run-time PM core functionality"
104    depends on !IA64_HP_SIM
105    ---help---
106      Enable functionality allowing I/O devices to be put into energy-saving
107      (low power) states at run time (or autosuspended) after a specified
108      period of inactivity and woken up in response to a hardware-generated
109      wake-up event or a driver's request.
110
111      Hardware support is generally required for this functionality to work
112      and the bus type drivers of the buses the devices are on are
113      responsible for the actual handling of the autosuspend requests and
114      wake-up events.
115
116config PM
117    def_bool y
118    depends on PM_SLEEP || PM_RUNTIME
119
120config PM_DEBUG
121    bool "Power Management Debug Support"
122    depends on PM
123    ---help---
124    This option enables various debugging support in the Power Management
125    code. This is helpful when debugging and reporting PM bugs, like
126    suspend support.
127
128config PM_ADVANCED_DEBUG
129    bool "Extra PM attributes in sysfs for low-level debugging/testing"
130    depends on PM_DEBUG
131    ---help---
132    Add extra sysfs attributes allowing one to access some Power Management
133    fields of device objects from user space. If you are not a kernel
134    developer interested in debugging/testing Power Management, say "no".
135
136config PM_TEST_SUSPEND
137    bool "Test suspend/resume and wakealarm during bootup"
138    depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
139    ---help---
140    This option will let you suspend your machine during bootup, and
141    make it wake up a few seconds later using an RTC wakeup alarm.
142    Enable this with a kernel parameter like "test_suspend=mem".
143
144    You probably want to have your system's RTC driver statically
145    linked, ensuring that it's available when this test runs.
146
147config CAN_PM_TRACE
148    def_bool y
149    depends on PM_DEBUG && PM_SLEEP
150
151config PM_TRACE
152    bool
153    help
154      This enables code to save the last PM event point across
155      reboot. The architecture needs to support this, x86 for
156      example does by saving things in the RTC, see below.
157
158      The architecture specific code must provide the extern
159      functions from <linux/resume-trace.h> as well as the
160      <asm/resume-trace.h> header with a TRACE_RESUME() macro.
161
162      The way the information is presented is architecture-
163      dependent, x86 will print the information during a
164      late_initcall.
165
166config PM_TRACE_RTC
167    bool "Suspend/resume event tracing"
168    depends on CAN_PM_TRACE
169    depends on X86
170    select PM_TRACE
171    ---help---
172    This enables some cheesy code to save the last PM event point in the
173    RTC across reboots, so that you can debug a machine that just hangs
174    during suspend (or more commonly, during resume).
175
176    To use this debugging feature you should attempt to suspend the
177    machine, reboot it and then run
178
179        dmesg -s 1000000 | grep 'hash matches'
180
181    CAUTION: this option will cause your machine's real-time clock to be
182    set to an invalid time after a resume.
183
184config APM_EMULATION
185    tristate "Advanced Power Management Emulation"
186    depends on PM && SYS_SUPPORTS_APM_EMULATION
187    help
188      APM is a BIOS specification for saving power using several different
189      techniques. This is mostly useful for battery powered laptops with
190      APM compliant BIOSes. If you say Y here, the system time will be
191      reset after a RESUME operation, the /proc/apm device will provide
192      battery status information, and user-space programs will receive
193      notification of APM "events" (e.g. battery status change).
194
195      In order to use APM, you will need supporting software. For location
196      and more information, read <file:Documentation/power/pm.txt> and the
197      Battery Powered Linux mini-HOWTO, available from
198      <http://www.tldp.org/docs.html#howto>.
199
200      This driver does not spin down disk drives (see the hdparm(8)
201      manpage ("man 8 hdparm") for that), and it doesn't turn off
202      VESA-compliant "green" monitors.
203
204      Generally, if you don't have a battery in your machine, there isn't
205      much point in using this driver and you should say N. If you get
206      random kernel OOPSes or reboots that don't seem to be related to
207      anything, try disabling/enabling this option (or disabling/enabling
208      APM in your BIOS).
209
210config ARCH_HAS_OPP
211    bool
212
213config PM_OPP
214    bool "Operating Performance Point (OPP) Layer library"
215    depends on ARCH_HAS_OPP
216    ---help---
217      SOCs have a standard set of tuples consisting of frequency and
218      voltage pairs that the device will support per voltage domain. This
219      is called Operating Performance Point or OPP. The actual definitions
220      of OPP varies over silicon within the same family of devices.
221
222      OPP layer organizes the data internally using device pointers
223      representing individual voltage domains and provides SOC
224      implementations a ready to use framework to manage OPPs.
225      For more information, read <file:Documentation/power/opp.txt>
226
227config PM_RUNTIME_CLK
228    def_bool y
229    depends on PM_RUNTIME && HAVE_CLK
230

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