xref: /openbmc/linux/kernel/power/Kconfig (revision f3539c12)
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 SUSPEND_SKIP_SYNC
22	bool "Skip kernel's sys_sync() on suspend to RAM/standby"
23	depends on SUSPEND
24	depends on EXPERT
25	help
26	  Skip the kernel sys_sync() before freezing user processes.
27	  Some systems prefer not to pay this cost on every invocation
28	  of suspend, or they are content with invoking sync() from
29	  user-space before invoking suspend.  Say Y if that's your case.
30
31config HIBERNATE_CALLBACKS
32	bool
33
34config HIBERNATION
35	bool "Hibernation (aka 'suspend to disk')"
36	depends on SWAP && ARCH_HIBERNATION_POSSIBLE
37	select HIBERNATE_CALLBACKS
38	select LZO_COMPRESS
39	select LZO_DECOMPRESS
40	select CRC32
41	---help---
42	  Enable the suspend to disk (STD) functionality, which is usually
43	  called "hibernation" in user interfaces.  STD checkpoints the
44	  system and powers it off; and restores that checkpoint on reboot.
45
46	  You can suspend your machine with 'echo disk > /sys/power/state'
47	  after placing resume=/dev/swappartition on the kernel command line
48	  in your bootloader's configuration file.
49
50	  Alternatively, you can use the additional userland tools available
51	  from <http://suspend.sf.net>.
52
53	  In principle it does not require ACPI or APM, although for example
54	  ACPI will be used for the final steps when it is available.  One
55	  of the reasons to use software suspend is that the firmware hooks
56	  for suspend states like suspend-to-RAM (STR) often don't work very
57	  well with Linux.
58
59	  It creates an image which is saved in your active swap. Upon the next
60	  boot, pass the 'resume=/dev/swappartition' argument to the kernel to
61	  have it detect the saved image, restore memory state from it, and
62	  continue to run as before. If you do not want the previous state to
63	  be reloaded, then use the 'noresume' kernel command line argument.
64	  Note, however, that fsck will be run on your filesystems and you will
65	  need to run mkswap against the swap partition used for the suspend.
66
67	  It also works with swap files to a limited extent (for details see
68	  <file:Documentation/power/swsusp-and-swap-files.txt>).
69
70	  Right now you may boot without resuming and resume later but in the
71	  meantime you cannot use the swap partition(s)/file(s) involved in
72	  suspending.  Also in this case you must not use the filesystems
73	  that were mounted before the suspend.  In particular, you MUST NOT
74	  MOUNT any journaled filesystems mounted before the suspend or they
75	  will get corrupted in a nasty way.
76
77	  For more information take a look at <file:Documentation/power/swsusp.txt>.
78
79config ARCH_SAVE_PAGE_KEYS
80	bool
81
82config PM_STD_PARTITION
83	string "Default resume partition"
84	depends on HIBERNATION
85	default ""
86	---help---
87	  The default resume partition is the partition that the suspend-
88	  to-disk implementation will look for a suspended disk image.
89
90	  The partition specified here will be different for almost every user.
91	  It should be a valid swap partition (at least for now) that is turned
92	  on before suspending.
93
94	  The partition specified can be overridden by specifying:
95
96		resume=/dev/<other device>
97
98	  which will set the resume partition to the device specified.
99
100	  Note there is currently not a way to specify which device to save the
101	  suspended image to. It will simply pick the first available swap
102	  device.
103
104config PM_SLEEP
105	def_bool y
106	depends on SUSPEND || HIBERNATE_CALLBACKS
107	select PM
108
109config PM_SLEEP_SMP
110	def_bool y
111	depends on SMP
112	depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
113	depends on PM_SLEEP
114	select HOTPLUG_CPU
115
116config PM_AUTOSLEEP
117	bool "Opportunistic sleep"
118	depends on PM_SLEEP
119	default n
120	---help---
121	Allow the kernel to trigger a system transition into a global sleep
122	state automatically whenever there are no active wakeup sources.
123
124config PM_WAKELOCKS
125	bool "User space wakeup sources interface"
126	depends on PM_SLEEP
127	default n
128	---help---
129	Allow user space to create, activate and deactivate wakeup source
130	objects with the help of a sysfs-based interface.
131
132config PM_WAKELOCKS_LIMIT
133	int "Maximum number of user space wakeup sources (0 = no limit)"
134	range 0 100000
135	default 100
136	depends on PM_WAKELOCKS
137
138config PM_WAKELOCKS_GC
139	bool "Garbage collector for user space wakeup sources"
140	depends on PM_WAKELOCKS
141	default y
142
143config PM
144	bool "Device power management core functionality"
145	---help---
146	  Enable functionality allowing I/O devices to be put into energy-saving
147	  (low power) states, for example after a specified period of inactivity
148	  (autosuspended), and woken up in response to a hardware-generated
149	  wake-up event or a driver's request.
150
151	  Hardware support is generally required for this functionality to work
152	  and the bus type drivers of the buses the devices are on are
153	  responsible for the actual handling of device suspend requests and
154	  wake-up events.
155
156config PM_DEBUG
157	bool "Power Management Debug Support"
158	depends on PM
159	---help---
160	This option enables various debugging support in the Power Management
161	code. This is helpful when debugging and reporting PM bugs, like
162	suspend support.
163
164config PM_ADVANCED_DEBUG
165	bool "Extra PM attributes in sysfs for low-level debugging/testing"
166	depends on PM_DEBUG
167	---help---
168	Add extra sysfs attributes allowing one to access some Power Management
169	fields of device objects from user space.  If you are not a kernel
170	developer interested in debugging/testing Power Management, say "no".
171
172config PM_TEST_SUSPEND
173	bool "Test suspend/resume and wakealarm during bootup"
174	depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
175	---help---
176	This option will let you suspend your machine during bootup, and
177	make it wake up a few seconds later using an RTC wakeup alarm.
178	Enable this with a kernel parameter like "test_suspend=mem".
179
180	You probably want to have your system's RTC driver statically
181	linked, ensuring that it's available when this test runs.
182
183config PM_SLEEP_DEBUG
184	def_bool y
185	depends on PM_DEBUG && PM_SLEEP
186
187config DPM_WATCHDOG
188	bool "Device suspend/resume watchdog"
189	depends on PM_DEBUG && PSTORE
190	---help---
191	  Sets up a watchdog timer to capture drivers that are
192	  locked up attempting to suspend/resume a device.
193	  A detected lockup causes system panic with message
194	  captured in pstore device for inspection in subsequent
195	  boot session.
196
197config DPM_WATCHDOG_TIMEOUT
198	int "Watchdog timeout in seconds"
199	range 1 120
200	default 60
201	depends on DPM_WATCHDOG
202
203config PM_TRACE
204	bool
205	help
206	  This enables code to save the last PM event point across
207	  reboot. The architecture needs to support this, x86 for
208	  example does by saving things in the RTC, see below.
209
210	  The architecture specific code must provide the extern
211	  functions from <linux/resume-trace.h> as well as the
212	  <asm/resume-trace.h> header with a TRACE_RESUME() macro.
213
214	  The way the information is presented is architecture-
215	  dependent, x86 will print the information during a
216	  late_initcall.
217
218config PM_TRACE_RTC
219	bool "Suspend/resume event tracing"
220	depends on PM_SLEEP_DEBUG
221	depends on X86
222	select PM_TRACE
223	---help---
224	This enables some cheesy code to save the last PM event point in the
225	RTC across reboots, so that you can debug a machine that just hangs
226	during suspend (or more commonly, during resume).
227
228	To use this debugging feature you should attempt to suspend the
229	machine, reboot it and then run
230
231		dmesg -s 1000000 | grep 'hash matches'
232
233	CAUTION: this option will cause your machine's real-time clock to be
234	set to an invalid time after a resume.
235
236config APM_EMULATION
237	tristate "Advanced Power Management Emulation"
238	depends on SYS_SUPPORTS_APM_EMULATION
239	help
240	  APM is a BIOS specification for saving power using several different
241	  techniques. This is mostly useful for battery powered laptops with
242	  APM compliant BIOSes. If you say Y here, the system time will be
243	  reset after a RESUME operation, the /proc/apm device will provide
244	  battery status information, and user-space programs will receive
245	  notification of APM "events" (e.g. battery status change).
246
247	  In order to use APM, you will need supporting software. For location
248	  and more information, read <file:Documentation/power/apm-acpi.txt>
249	  and the Battery Powered Linux mini-HOWTO, available from
250	  <http://www.tldp.org/docs.html#howto>.
251
252	  This driver does not spin down disk drives (see the hdparm(8)
253	  manpage ("man 8 hdparm") for that), and it doesn't turn off
254	  VESA-compliant "green" monitors.
255
256	  Generally, if you don't have a battery in your machine, there isn't
257	  much point in using this driver and you should say N. If you get
258	  random kernel OOPSes or reboots that don't seem to be related to
259	  anything, try disabling/enabling this option (or disabling/enabling
260	  APM in your BIOS).
261
262config PM_OPP
263	bool
264	select SRCU
265	---help---
266	  SOCs have a standard set of tuples consisting of frequency and
267	  voltage pairs that the device will support per voltage domain. This
268	  is called Operating Performance Point or OPP. The actual definitions
269	  of OPP varies over silicon within the same family of devices.
270
271	  OPP layer organizes the data internally using device pointers
272	  representing individual voltage domains and provides SOC
273	  implementations a ready to use framework to manage OPPs.
274	  For more information, read <file:Documentation/power/opp.txt>
275
276config PM_CLK
277	def_bool y
278	depends on PM && HAVE_CLK
279
280config PM_GENERIC_DOMAINS
281	bool
282	depends on PM
283
284config WQ_POWER_EFFICIENT_DEFAULT
285	bool "Enable workqueue power-efficient mode by default"
286	depends on PM
287	default n
288	help
289	  Per-cpu workqueues are generally preferred because they show
290	  better performance thanks to cache locality; unfortunately,
291	  per-cpu workqueues tend to be more power hungry than unbound
292	  workqueues.
293
294	  Enabling workqueue.power_efficient kernel parameter makes the
295	  per-cpu workqueues which were observed to contribute
296	  significantly to power consumption unbound, leading to measurably
297	  lower power usage at the cost of small performance overhead.
298
299	  This config option determines whether workqueue.power_efficient
300	  is enabled by default.
301
302	  If in doubt, say N.
303
304config PM_GENERIC_DOMAINS_SLEEP
305	def_bool y
306	depends on PM_SLEEP && PM_GENERIC_DOMAINS
307
308config PM_GENERIC_DOMAINS_OF
309	def_bool y
310	depends on PM_GENERIC_DOMAINS && OF
311
312config CPU_PM
313	bool
314