xref: /openbmc/linux/kernel/power/Kconfig (revision 867a0e05)
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 HIBERNATE_CALLBACKS
22	bool
23
24config HIBERNATION
25	bool "Hibernation (aka 'suspend to disk')"
26	depends on SWAP && ARCH_HIBERNATION_POSSIBLE
27	select HIBERNATE_CALLBACKS
28	select LZO_COMPRESS
29	select LZO_DECOMPRESS
30	select CRC32
31	---help---
32	  Enable the suspend to disk (STD) functionality, which is usually
33	  called "hibernation" in user interfaces.  STD checkpoints the
34	  system and powers it off; and restores that checkpoint on reboot.
35
36	  You can suspend your machine with 'echo disk > /sys/power/state'
37	  after placing resume=/dev/swappartition on the kernel command line
38	  in your bootloader's configuration file.
39
40	  Alternatively, you can use the additional userland tools available
41	  from <http://suspend.sf.net>.
42
43	  In principle it does not require ACPI or APM, although for example
44	  ACPI will be used for the final steps when it is available.  One
45	  of the reasons to use software suspend is that the firmware hooks
46	  for suspend states like suspend-to-RAM (STR) often don't work very
47	  well with Linux.
48
49	  It creates an image which is saved in your active swap. Upon the next
50	  boot, pass the 'resume=/dev/swappartition' argument to the kernel to
51	  have it detect the saved image, restore memory state from it, and
52	  continue to run as before. If you do not want the previous state to
53	  be reloaded, then use the 'noresume' kernel command line argument.
54	  Note, however, that fsck will be run on your filesystems and you will
55	  need to run mkswap against the swap partition used for the suspend.
56
57	  It also works with swap files to a limited extent (for details see
58	  <file:Documentation/power/swsusp-and-swap-files.txt>).
59
60	  Right now you may boot without resuming and resume later but in the
61	  meantime you cannot use the swap partition(s)/file(s) involved in
62	  suspending.  Also in this case you must not use the filesystems
63	  that were mounted before the suspend.  In particular, you MUST NOT
64	  MOUNT any journaled filesystems mounted before the suspend or they
65	  will get corrupted in a nasty way.
66
67	  For more information take a look at <file:Documentation/power/swsusp.txt>.
68
69config ARCH_SAVE_PAGE_KEYS
70	bool
71
72config PM_STD_PARTITION
73	string "Default resume partition"
74	depends on HIBERNATION
75	default ""
76	---help---
77	  The default resume partition is the partition that the suspend-
78	  to-disk implementation will look for a suspended disk image.
79
80	  The partition specified here will be different for almost every user.
81	  It should be a valid swap partition (at least for now) that is turned
82	  on before suspending.
83
84	  The partition specified can be overridden by specifying:
85
86		resume=/dev/<other device>
87
88	  which will set the resume partition to the device specified.
89
90	  Note there is currently not a way to specify which device to save the
91	  suspended image to. It will simply pick the first available swap
92	  device.
93
94config PM_SLEEP
95	def_bool y
96	depends on SUSPEND || HIBERNATE_CALLBACKS
97	select PM
98
99config PM_SLEEP_SMP
100	def_bool y
101	depends on SMP
102	depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
103	depends on PM_SLEEP
104	select HOTPLUG_CPU
105
106config PM_AUTOSLEEP
107	bool "Opportunistic sleep"
108	depends on PM_SLEEP
109	default n
110	---help---
111	Allow the kernel to trigger a system transition into a global sleep
112	state automatically whenever there are no active wakeup sources.
113
114config PM_WAKELOCKS
115	bool "User space wakeup sources interface"
116	depends on PM_SLEEP
117	default n
118	---help---
119	Allow user space to create, activate and deactivate wakeup source
120	objects with the help of a sysfs-based interface.
121
122config PM_WAKELOCKS_LIMIT
123	int "Maximum number of user space wakeup sources (0 = no limit)"
124	range 0 100000
125	default 100
126	depends on PM_WAKELOCKS
127
128config PM_WAKELOCKS_GC
129	bool "Garbage collector for user space wakeup sources"
130	depends on PM_WAKELOCKS
131	default y
132
133config PM
134	bool "Device power management core functionality"
135	---help---
136	  Enable functionality allowing I/O devices to be put into energy-saving
137	  (low power) states, for example after a specified period of inactivity
138	  (autosuspended), and woken up in response to a hardware-generated
139	  wake-up event or a driver's request.
140
141	  Hardware support is generally required for this functionality to work
142	  and the bus type drivers of the buses the devices are on are
143	  responsible for the actual handling of device suspend requests and
144	  wake-up events.
145
146config PM_DEBUG
147	bool "Power Management Debug Support"
148	depends on PM
149	---help---
150	This option enables various debugging support in the Power Management
151	code. This is helpful when debugging and reporting PM bugs, like
152	suspend support.
153
154config PM_ADVANCED_DEBUG
155	bool "Extra PM attributes in sysfs for low-level debugging/testing"
156	depends on PM_DEBUG
157	---help---
158	Add extra sysfs attributes allowing one to access some Power Management
159	fields of device objects from user space.  If you are not a kernel
160	developer interested in debugging/testing Power Management, say "no".
161
162config PM_TEST_SUSPEND
163	bool "Test suspend/resume and wakealarm during bootup"
164	depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
165	---help---
166	This option will let you suspend your machine during bootup, and
167	make it wake up a few seconds later using an RTC wakeup alarm.
168	Enable this with a kernel parameter like "test_suspend=mem".
169
170	You probably want to have your system's RTC driver statically
171	linked, ensuring that it's available when this test runs.
172
173config PM_SLEEP_DEBUG
174	def_bool y
175	depends on PM_DEBUG && PM_SLEEP
176
177config DPM_WATCHDOG
178	bool "Device suspend/resume watchdog"
179	depends on PM_DEBUG && PSTORE
180	---help---
181	  Sets up a watchdog timer to capture drivers that are
182	  locked up attempting to suspend/resume a device.
183	  A detected lockup causes system panic with message
184	  captured in pstore device for inspection in subsequent
185	  boot session.
186
187config DPM_WATCHDOG_TIMEOUT
188	int "Watchdog timeout in seconds"
189	range 1 120
190	default 12
191	depends on DPM_WATCHDOG
192
193config PM_TRACE
194	bool
195	help
196	  This enables code to save the last PM event point across
197	  reboot. The architecture needs to support this, x86 for
198	  example does by saving things in the RTC, see below.
199
200	  The architecture specific code must provide the extern
201	  functions from <linux/resume-trace.h> as well as the
202	  <asm/resume-trace.h> header with a TRACE_RESUME() macro.
203
204	  The way the information is presented is architecture-
205	  dependent, x86 will print the information during a
206	  late_initcall.
207
208config PM_TRACE_RTC
209	bool "Suspend/resume event tracing"
210	depends on PM_SLEEP_DEBUG
211	depends on X86
212	select PM_TRACE
213	---help---
214	This enables some cheesy code to save the last PM event point in the
215	RTC across reboots, so that you can debug a machine that just hangs
216	during suspend (or more commonly, during resume).
217
218	To use this debugging feature you should attempt to suspend the
219	machine, reboot it and then run
220
221		dmesg -s 1000000 | grep 'hash matches'
222
223	CAUTION: this option will cause your machine's real-time clock to be
224	set to an invalid time after a resume.
225
226config APM_EMULATION
227	tristate "Advanced Power Management Emulation"
228	depends on PM && SYS_SUPPORTS_APM_EMULATION
229	help
230	  APM is a BIOS specification for saving power using several different
231	  techniques. This is mostly useful for battery powered laptops with
232	  APM compliant BIOSes. If you say Y here, the system time will be
233	  reset after a RESUME operation, the /proc/apm device will provide
234	  battery status information, and user-space programs will receive
235	  notification of APM "events" (e.g. battery status change).
236
237	  In order to use APM, you will need supporting software. For location
238	  and more information, read <file:Documentation/power/apm-acpi.txt>
239	  and the Battery Powered Linux mini-HOWTO, available from
240	  <http://www.tldp.org/docs.html#howto>.
241
242	  This driver does not spin down disk drives (see the hdparm(8)
243	  manpage ("man 8 hdparm") for that), and it doesn't turn off
244	  VESA-compliant "green" monitors.
245
246	  Generally, if you don't have a battery in your machine, there isn't
247	  much point in using this driver and you should say N. If you get
248	  random kernel OOPSes or reboots that don't seem to be related to
249	  anything, try disabling/enabling this option (or disabling/enabling
250	  APM in your BIOS).
251
252config PM_OPP
253	bool
254	---help---
255	  SOCs have a standard set of tuples consisting of frequency and
256	  voltage pairs that the device will support per voltage domain. This
257	  is called Operating Performance Point or OPP. The actual definitions
258	  of OPP varies over silicon within the same family of devices.
259
260	  OPP layer organizes the data internally using device pointers
261	  representing individual voltage domains and provides SOC
262	  implementations a ready to use framework to manage OPPs.
263	  For more information, read <file:Documentation/power/opp.txt>
264
265config PM_CLK
266	def_bool y
267	depends on PM && HAVE_CLK
268
269config PM_GENERIC_DOMAINS
270	bool
271	depends on PM
272
273config WQ_POWER_EFFICIENT_DEFAULT
274	bool "Enable workqueue power-efficient mode by default"
275	depends on PM
276	default n
277	help
278	  Per-cpu workqueues are generally preferred because they show
279	  better performance thanks to cache locality; unfortunately,
280	  per-cpu workqueues tend to be more power hungry than unbound
281	  workqueues.
282
283	  Enabling workqueue.power_efficient kernel parameter makes the
284	  per-cpu workqueues which were observed to contribute
285	  significantly to power consumption unbound, leading to measurably
286	  lower power usage at the cost of small performance overhead.
287
288	  This config option determines whether workqueue.power_efficient
289	  is enabled by default.
290
291	  If in doubt, say N.
292
293config PM_GENERIC_DOMAINS_SLEEP
294	def_bool y
295	depends on PM_SLEEP && PM_GENERIC_DOMAINS
296
297config PM_GENERIC_DOMAINS_OF
298	def_bool y
299	depends on PM_GENERIC_DOMAINS && OF
300
301config CPU_PM
302	bool
303