1 # SPDX-License-Identifier: GPL-2.0-only
2 config 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
11 config 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
22 config 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
35 config HIBERNATE_CALLBACKS
36 bool
37
38 config HIBERNATION
39 bool "Hibernation (aka 'suspend to disk')"
40 depends on SWAP && ARCH_HIBERNATION_POSSIBLE
41 select HIBERNATE_CALLBACKS
42 select CRC32
43 select CRYPTO
44 select CRYPTO_LZO
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
83 config 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
95 choice
96 prompt "Default compressor"
97 default HIBERNATION_COMP_LZO
98 depends on HIBERNATION
99
100 config HIBERNATION_COMP_LZO
101 bool "lzo"
102 depends on CRYPTO_LZO
103
104 config HIBERNATION_COMP_LZ4
105 bool "lz4"
106 depends on CRYPTO_LZ4
107
108 endchoice
109
110 config HIBERNATION_DEF_COMP
111 string
112 default "lzo" if HIBERNATION_COMP_LZO
113 default "lz4" if HIBERNATION_COMP_LZ4
114 help
115 Default compressor to be used for hibernation.
116
117 config PM_STD_PARTITION
118 string "Default resume partition"
119 depends on HIBERNATION
120 default ""
121 help
122 The default resume partition is the partition that the suspend-
123 to-disk implementation will look for a suspended disk image.
124
125 The partition specified here will be different for almost every user.
126 It should be a valid swap partition (at least for now) that is turned
127 on before suspending.
128
129 The partition specified can be overridden by specifying:
130
131 resume=/dev/<other device>
132
133 which will set the resume partition to the device specified.
134
135 Note there is currently not a way to specify which device to save the
136 suspended image to. It will simply pick the first available swap
137 device.
138
139 config PM_SLEEP
140 def_bool y
141 depends on SUSPEND || HIBERNATE_CALLBACKS
142 select PM
143
144 config PM_SLEEP_SMP
145 def_bool y
146 depends on SMP
147 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
148 depends on PM_SLEEP
149 select HOTPLUG_CPU
150
151 config PM_SLEEP_SMP_NONZERO_CPU
152 def_bool y
153 depends on PM_SLEEP_SMP
154 depends on ARCH_SUSPEND_NONZERO_CPU
155 help
156 If an arch can suspend (for suspend, hibernate, kexec, etc) on a
157 non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This
158 will allow nohz_full mask to include CPU0.
159
160 config PM_AUTOSLEEP
161 bool "Opportunistic sleep"
162 depends on PM_SLEEP
163 help
164 Allow the kernel to trigger a system transition into a global sleep
165 state automatically whenever there are no active wakeup sources.
166
167 config PM_USERSPACE_AUTOSLEEP
168 bool "Userspace opportunistic sleep"
169 depends on PM_SLEEP
170 help
171 Notify kernel of aggressive userspace autosleep power management policy.
172
173 This option changes the behavior of various sleep-sensitive code to deal
174 with frequent userspace-initiated transitions into a global sleep state.
175
176 Saying Y here, disables code paths that most users really should keep
177 enabled. In particular, only enable this if it is very common to be
178 asleep/awake for very short periods of time (<= 2 seconds).
179
180 Only platforms, such as Android, that implement opportunistic sleep from
181 a userspace power manager service should enable this option; and not
182 other machines. Therefore, you should say N here, unless you are
183 extremely certain that this is what you want. The option otherwise has
184 bad, undesirable effects, and should not be enabled just for fun.
185
186
187 config PM_WAKELOCKS
188 bool "User space wakeup sources interface"
189 depends on PM_SLEEP
190 help
191 Allow user space to create, activate and deactivate wakeup source
192 objects with the help of a sysfs-based interface.
193
194 config PM_WAKELOCKS_LIMIT
195 int "Maximum number of user space wakeup sources (0 = no limit)"
196 range 0 100000
197 default 100
198 depends on PM_WAKELOCKS
199
200 config PM_WAKELOCKS_GC
201 bool "Garbage collector for user space wakeup sources"
202 depends on PM_WAKELOCKS
203 default y
204
205 config PM
206 bool "Device power management core functionality"
207 help
208 Enable functionality allowing I/O devices to be put into energy-saving
209 (low power) states, for example after a specified period of inactivity
210 (autosuspended), and woken up in response to a hardware-generated
211 wake-up event or a driver's request.
212
213 Hardware support is generally required for this functionality to work
214 and the bus type drivers of the buses the devices are on are
215 responsible for the actual handling of device suspend requests and
216 wake-up events.
217
218 config PM_DEBUG
219 bool "Power Management Debug Support"
220 depends on PM
221 help
222 This option enables various debugging support in the Power Management
223 code. This is helpful when debugging and reporting PM bugs, like
224 suspend support.
225
226 config PM_ADVANCED_DEBUG
227 bool "Extra PM attributes in sysfs for low-level debugging/testing"
228 depends on PM_DEBUG
229 help
230 Add extra sysfs attributes allowing one to access some Power Management
231 fields of device objects from user space. If you are not a kernel
232 developer interested in debugging/testing Power Management, say "no".
233
234 config PM_TEST_SUSPEND
235 bool "Test suspend/resume and wakealarm during bootup"
236 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
237 help
238 This option will let you suspend your machine during bootup, and
239 make it wake up a few seconds later using an RTC wakeup alarm.
240 Enable this with a kernel parameter like "test_suspend=mem".
241
242 You probably want to have your system's RTC driver statically
243 linked, ensuring that it's available when this test runs.
244
245 config PM_SLEEP_DEBUG
246 def_bool y
247 depends on PM_DEBUG && PM_SLEEP
248
249 config DPM_WATCHDOG
250 bool "Device suspend/resume watchdog"
251 depends on PM_DEBUG && PSTORE && EXPERT
252 help
253 Sets up a watchdog timer to capture drivers that are
254 locked up attempting to suspend/resume a device.
255 A detected lockup causes system panic with message
256 captured in pstore device for inspection in subsequent
257 boot session.
258
259 config DPM_WATCHDOG_TIMEOUT
260 int "Watchdog timeout in seconds"
261 range 1 120
262 default 120
263 depends on DPM_WATCHDOG
264
265 config PM_TRACE
266 bool
267 help
268 This enables code to save the last PM event point across
269 reboot. The architecture needs to support this, x86 for
270 example does by saving things in the RTC, see below.
271
272 The architecture specific code must provide the extern
273 functions from <linux/resume-trace.h> as well as the
274 <asm/resume-trace.h> header with a TRACE_RESUME() macro.
275
276 The way the information is presented is architecture-
277 dependent, x86 will print the information during a
278 late_initcall.
279
280 config PM_TRACE_RTC
281 bool "Suspend/resume event tracing"
282 depends on PM_SLEEP_DEBUG
283 depends on X86
284 select PM_TRACE
285 help
286 This enables some cheesy code to save the last PM event point in the
287 RTC across reboots, so that you can debug a machine that just hangs
288 during suspend (or more commonly, during resume).
289
290 To use this debugging feature you should attempt to suspend the
291 machine, reboot it and then run
292
293 dmesg -s 1000000 | grep 'hash matches'
294
295 CAUTION: this option will cause your machine's real-time clock to be
296 set to an invalid time after a resume.
297
298 config APM_EMULATION
299 tristate "Advanced Power Management Emulation"
300 depends on SYS_SUPPORTS_APM_EMULATION
301 help
302 APM is a BIOS specification for saving power using several different
303 techniques. This is mostly useful for battery powered laptops with
304 APM compliant BIOSes. If you say Y here, the system time will be
305 reset after a RESUME operation, the /proc/apm device will provide
306 battery status information, and user-space programs will receive
307 notification of APM "events" (e.g. battery status change).
308
309 In order to use APM, you will need supporting software. For location
310 and more information, read <file:Documentation/power/apm-acpi.rst>
311 and the Battery Powered Linux mini-HOWTO, available from
312 <http://www.tldp.org/docs.html#howto>.
313
314 This driver does not spin down disk drives (see the hdparm(8)
315 manpage ("man 8 hdparm") for that), and it doesn't turn off
316 VESA-compliant "green" monitors.
317
318 Generally, if you don't have a battery in your machine, there isn't
319 much point in using this driver and you should say N. If you get
320 random kernel OOPSes or reboots that don't seem to be related to
321 anything, try disabling/enabling this option (or disabling/enabling
322 APM in your BIOS).
323
324 config PM_CLK
325 def_bool y
326 depends on PM && HAVE_CLK
327
328 config PM_GENERIC_DOMAINS
329 bool
330 depends on PM
331
332 config WQ_POWER_EFFICIENT_DEFAULT
333 bool "Enable workqueue power-efficient mode by default"
334 depends on PM
335 help
336 Per-cpu workqueues are generally preferred because they show
337 better performance thanks to cache locality; unfortunately,
338 per-cpu workqueues tend to be more power hungry than unbound
339 workqueues.
340
341 Enabling workqueue.power_efficient kernel parameter makes the
342 per-cpu workqueues which were observed to contribute
343 significantly to power consumption unbound, leading to measurably
344 lower power usage at the cost of small performance overhead.
345
346 This config option determines whether workqueue.power_efficient
347 is enabled by default.
348
349 If in doubt, say N.
350
351 config PM_GENERIC_DOMAINS_SLEEP
352 def_bool y
353 depends on PM_SLEEP && PM_GENERIC_DOMAINS
354
355 config PM_GENERIC_DOMAINS_OF
356 def_bool y
357 depends on PM_GENERIC_DOMAINS && OF
358
359 config CPU_PM
360 bool
361
362 config ENERGY_MODEL
363 bool "Energy Model for devices with DVFS (CPUs, GPUs, etc)"
364 depends on SMP
365 depends on CPU_FREQ
366 help
367 Several subsystems (thermal and/or the task scheduler for example)
368 can leverage information about the energy consumed by devices to
369 make smarter decisions. This config option enables the framework
370 from which subsystems can access the energy models.
371
372 The exact usage of the energy model is subsystem-dependent.
373
374 If in doubt, say N.
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