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.
375