1
2config SUSPEND
3 bool "Suspend to RAM and standby"
4 depends on ARCH_SUSPEND_POSSIBLE
5 default y
6 help
7 Allow the system to enter sleep states in which main memory is
8 powered and thus its contents are preserved, such as the
9 suspend-to-RAM state (e.g. the ACPI S3 state).
10
11config SUSPEND_FREEZER
12 bool "Enable freezer for suspend to RAM/standby" \
13 if ARCH_WANTS_FREEZER_CONTROL || BROKEN
14 depends on SUSPEND
15 default y
16 help
17 This allows you to turn off the freezer for suspend. If this is
18 done, no tasks are frozen for suspend to RAM/standby.
19
20 Turning OFF this setting is NOT recommended! If in doubt, say Y.
21
22config SUSPEND_SKIP_SYNC
23 bool "Skip kernel's sys_sync() on suspend to RAM/standby"
24 depends on SUSPEND
25 depends on EXPERT
26 help
27 Skip the kernel sys_sync() before freezing user processes.
28 Some systems prefer not to pay this cost on every invocation
29 of suspend, or they are content with invoking sync() from
30 user-space before invoking suspend. There's a run-time switch
31 at '/sys/power/sync_on_suspend' to configure this behaviour.
32 This setting changes the default for the run-tim switch. Say Y
33 to change the default to disable the kernel sys_sync().
34
35config HIBERNATE_CALLBACKS
36 bool
37
38config HIBERNATION
39 bool "Hibernation (aka 'suspend to disk')"
40 depends on SWAP && ARCH_HIBERNATION_POSSIBLE
41 select HIBERNATE_CALLBACKS
42 select LZO_COMPRESS
43 select LZO_DECOMPRESS
44 select CRC32
45 help
46 Enable the suspend to disk (STD) functionality, which is usually
47 called "hibernation" in user interfaces. STD checkpoints the
48 system and powers it off; and restores that checkpoint on reboot.
49
50 You can suspend your machine with 'echo disk > /sys/power/state'
51 after placing resume=/dev/swappartition on the kernel command line
52 in your bootloader's configuration file.
53
54 Alternatively, you can use the additional userland tools available
55 from <http://suspend.sf.net>.
56
57 In principle it does not require ACPI or APM, although for example
58 ACPI will be used for the final steps when it is available. One
59 of the reasons to use software suspend is that the firmware hooks
60 for suspend states like suspend-to-RAM (STR) often don't work very
61 well with Linux.
62
63 It creates an image which is saved in your active swap. Upon the next
64 boot, pass the 'resume=/dev/swappartition' argument to the kernel to
65 have it detect the saved image, restore memory state from it, and
66 continue to run as before. If you do not want the previous state to
67 be reloaded, then use the 'noresume' kernel command line argument.
68 Note, however, that fsck will be run on your filesystems and you will
69 need to run mkswap against the swap partition used for the suspend.
70
71 It also works with swap files to a limited extent (for details see
72 <file:Documentation/power/swsusp-and-swap-files.rst>).
73
74 Right now you may boot without resuming and resume later but in the
75 meantime you cannot use the swap partition(s)/file(s) involved in
76 suspending. Also in this case you must not use the filesystems
77 that were mounted before the suspend. In particular, you MUST NOT
78 MOUNT any journaled filesystems mounted before the suspend or they
79 will get corrupted in a nasty way.
80
81 For more information take a look at <file:Documentation/power/swsusp.rst>.
82
83config HIBERNATION_SNAPSHOT_DEV
84 bool "Userspace snapshot device"
85 depends on HIBERNATION
86 default y
87 help
88 Device used by the uswsusp tools.
89
90 Say N if no snapshotting from userspace is needed, this also
91 reduces the attack surface of the kernel.
92
93 If in doubt, say Y.
94
95config PM_STD_PARTITION
96 string "Default resume partition"
97 depends on HIBERNATION
98 default ""
99 help
100 The default resume partition is the partition that the suspend-
101 to-disk implementation will look for a suspended disk image.
102
103 The partition specified here will be different for almost every user.
104 It should be a valid swap partition (at least for now) that is turned
105 on before suspending.
106
107 The partition specified can be overridden by specifying:
108
109 resume=/dev/<other device>
110
111 which will set the resume partition to the device specified.
112
113 Note there is currently not a way to specify which device to save the
114 suspended image to. It will simply pick the first available swap
115 device.
116
117config PM_SLEEP
118 def_bool y
119 depends on SUSPEND || HIBERNATE_CALLBACKS
120 select PM
121 select SRCU
122
123config PM_SLEEP_SMP
124 def_bool y
125 depends on SMP
126 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
127 depends on PM_SLEEP
128 select HOTPLUG_CPU
129
130config PM_SLEEP_SMP_NONZERO_CPU
131 def_bool y
132 depends on PM_SLEEP_SMP
133 depends on ARCH_SUSPEND_NONZERO_CPU
134 help
135 If an arch can suspend (for suspend, hibernate, kexec, etc) on a
136 non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This
137 will allow nohz_full mask to include CPU0.
138
139config PM_AUTOSLEEP
140 bool "Opportunistic sleep"
141 depends on PM_SLEEP
142 help
143 Allow the kernel to trigger a system transition into a global sleep
144 state automatically whenever there are no active wakeup sources.
145
146config PM_WAKELOCKS
147 bool "User space wakeup sources interface"
148 depends on PM_SLEEP
149 help
150 Allow user space to create, activate and deactivate wakeup source
151 objects with the help of a sysfs-based interface.
152
153config PM_WAKELOCKS_LIMIT
154 int "Maximum number of user space wakeup sources (0 = no limit)"
155 range 0 100000
156 default 100
157 depends on PM_WAKELOCKS
158
159config PM_WAKELOCKS_GC
160 bool "Garbage collector for user space wakeup sources"
161 depends on PM_WAKELOCKS
162 default y
163
164config PM
165 bool "Device power management core functionality"
166 help
167 Enable functionality allowing I/O devices to be put into energy-saving
168 (low power) states, for example after a specified period of inactivity
169 (autosuspended), and woken up in response to a hardware-generated
170 wake-up event or a driver's request.
171
172 Hardware support is generally required for this functionality to work
173 and the bus type drivers of the buses the devices are on are
174 responsible for the actual handling of device suspend requests and
175 wake-up events.
176
177config PM_DEBUG
178 bool "Power Management Debug Support"
179 depends on PM
180 help
181 This option enables various debugging support in the Power Management
182 code. This is helpful when debugging and reporting PM bugs, like
183 suspend support.
184
185config PM_ADVANCED_DEBUG
186 bool "Extra PM attributes in sysfs for low-level debugging/testing"
187 depends on PM_DEBUG
188 help
189 Add extra sysfs attributes allowing one to access some Power Management
190 fields of device objects from user space. If you are not a kernel
191 developer interested in debugging/testing Power Management, say "no".
192
193config PM_TEST_SUSPEND
194 bool "Test suspend/resume and wakealarm during bootup"
195 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
196 help
197 This option will let you suspend your machine during bootup, and
198 make it wake up a few seconds later using an RTC wakeup alarm.
199 Enable this with a kernel parameter like "test_suspend=mem".
200
201 You probably want to have your system's RTC driver statically
202 linked, ensuring that it's available when this test runs.
203
204config PM_SLEEP_DEBUG
205 def_bool y
206 depends on PM_DEBUG && PM_SLEEP
207
208config DPM_WATCHDOG
209 bool "Device suspend/resume watchdog"
210 depends on PM_DEBUG && PSTORE && EXPERT
211 help
212 Sets up a watchdog timer to capture drivers that are
213 locked up attempting to suspend/resume a device.
214 A detected lockup causes system panic with message
215 captured in pstore device for inspection in subsequent
216 boot session.
217
218config DPM_WATCHDOG_TIMEOUT
219 int "Watchdog timeout in seconds"
220 range 1 120
221 default 120
222 depends on DPM_WATCHDOG
223
224config PM_TRACE
225 bool
226 help
227 This enables code to save the last PM event point across
228 reboot. The architecture needs to support this, x86 for
229 example does by saving things in the RTC, see below.
230
231 The architecture specific code must provide the extern
232 functions from <linux/resume-trace.h> as well as the
233 <asm/resume-trace.h> header with a TRACE_RESUME() macro.
234
235 The way the information is presented is architecture-
236 dependent, x86 will print the information during a
237 late_initcall.
238
239config PM_TRACE_RTC
240 bool "Suspend/resume event tracing"
241 depends on PM_SLEEP_DEBUG
242 depends on X86
243 select PM_TRACE
244 help
245 This enables some cheesy code to save the last PM event point in the
246 RTC across reboots, so that you can debug a machine that just hangs
247 during suspend (or more commonly, during resume).
248
249 To use this debugging feature you should attempt to suspend the
250 machine, reboot it and then run
251
252 dmesg -s 1000000 | grep 'hash matches'
253
254 CAUTION: this option will cause your machine's real-time clock to be
255 set to an invalid time after a resume.
256
257config APM_EMULATION
258 tristate "Advanced Power Management Emulation"
259 depends on SYS_SUPPORTS_APM_EMULATION
260 help
261 APM is a BIOS specification for saving power using several different
262 techniques. This is mostly useful for battery powered laptops with
263 APM compliant BIOSes. If you say Y here, the system time will be
264 reset after a RESUME operation, the /proc/apm device will provide
265 battery status information, and user-space programs will receive
266 notification of APM "events" (e.g. battery status change).
267
268 In order to use APM, you will need supporting software. For location
269 and more information, read <file:Documentation/power/apm-acpi.rst>
270 and the Battery Powered Linux mini-HOWTO, available from
271 <http://www.tldp.org/docs.html#howto>.
272
273 This driver does not spin down disk drives (see the hdparm(8)
274 manpage ("man 8 hdparm") for that), and it doesn't turn off
275 VESA-compliant "green" monitors.
276
277 Generally, if you don't have a battery in your machine, there isn't
278 much point in using this driver and you should say N. If you get
279 random kernel OOPSes or reboots that don't seem to be related to
280 anything, try disabling/enabling this option (or disabling/enabling
281 APM in your BIOS).
282
283config PM_CLK
284 def_bool y
285 depends on PM && HAVE_CLK
286
287config PM_GENERIC_DOMAINS
288 bool
289 depends on PM
290
291config WQ_POWER_EFFICIENT_DEFAULT
292 bool "Enable workqueue power-efficient mode by default"
293 depends on PM
294 help
295 Per-cpu workqueues are generally preferred because they show
296 better performance thanks to cache locality; unfortunately,
297 per-cpu workqueues tend to be more power hungry than unbound
298 workqueues.
299
300 Enabling workqueue.power_efficient kernel parameter makes the
301 per-cpu workqueues which were observed to contribute
302 significantly to power consumption unbound, leading to measurably
303 lower power usage at the cost of small performance overhead.
304
305 This config option determines whether workqueue.power_efficient
306 is enabled by default.
307
308 If in doubt, say N.
309
310config PM_GENERIC_DOMAINS_SLEEP
311 def_bool y
312 depends on PM_SLEEP && PM_GENERIC_DOMAINS
313
314config PM_GENERIC_DOMAINS_OF
315 def_bool y
316 depends on PM_GENERIC_DOMAINS && OF
317
318config CPU_PM
319 bool
320
321config ENERGY_MODEL
322 bool "Energy Model for devices with DVFS (CPUs, GPUs, etc)"
323 depends on SMP
324 depends on CPU_FREQ
325 help
326 Several subsystems (thermal and/or the task scheduler for example)
327 can leverage information about the energy consumed by devices to
328 make smarter decisions. This config option enables the framework
329 from which subsystems can access the energy models.
330
331 The exact usage of the energy model is subsystem-dependent.
332
333 If in doubt, say N.
334
