xref: /linux/kernel/power/Kconfig (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
1# SPDX-License-Identifier: GPL-2.0-only
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 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
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
95choice
96	prompt "Default compressor"
97	default HIBERNATION_COMP_LZO
98	depends on HIBERNATION
99
100config HIBERNATION_COMP_LZO
101	bool "lzo"
102	depends on CRYPTO_LZO
103
104config HIBERNATION_COMP_LZ4
105	bool "lz4"
106	depends on CRYPTO_LZ4
107
108endchoice
109
110config 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
117config 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
139config PM_SLEEP
140	def_bool y
141	depends on SUSPEND || HIBERNATE_CALLBACKS
142	select PM
143
144config 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
151config 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
160config 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
167config 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
187config 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
194config 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
200config PM_WAKELOCKS_GC
201	bool "Garbage collector for user space wakeup sources"
202	depends on PM_WAKELOCKS
203	default y
204
205config 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
218config 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
226config 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
234config 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
245config PM_SLEEP_DEBUG
246	def_bool y
247	depends on PM_DEBUG && PM_SLEEP
248
249config 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
259config DPM_WATCHDOG_TIMEOUT
260	int "Watchdog timeout in seconds"
261	range 1 120
262	default 120
263	depends on DPM_WATCHDOG
264
265config 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
280config 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
298config 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
324config PM_CLK
325	def_bool y
326	depends on PM && HAVE_CLK
327
328config PM_GENERIC_DOMAINS
329	bool
330	depends on PM
331
332config 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
351config PM_GENERIC_DOMAINS_SLEEP
352	def_bool y
353	depends on PM_SLEEP && PM_GENERIC_DOMAINS
354
355config PM_GENERIC_DOMAINS_OF
356	def_bool y
357	depends on PM_GENERIC_DOMAINS && OF
358
359config CPU_PM
360	bool
361
362config 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