xref: /openbmc/linux/kernel/power/Kconfig (revision 9c1f8594)
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	---help---
31	  Enable the suspend to disk (STD) functionality, which is usually
32	  called "hibernation" in user interfaces.  STD checkpoints the
33	  system and powers it off; and restores that checkpoint on reboot.
34
35	  You can suspend your machine with 'echo disk > /sys/power/state'
36	  after placing resume=/dev/swappartition on the kernel command line
37	  in your bootloader's configuration file.
38
39	  Alternatively, you can use the additional userland tools available
40	  from <http://suspend.sf.net>.
41
42	  In principle it does not require ACPI or APM, although for example
43	  ACPI will be used for the final steps when it is available.  One
44	  of the reasons to use software suspend is that the firmware hooks
45	  for suspend states like suspend-to-RAM (STR) often don't work very
46	  well with Linux.
47
48	  It creates an image which is saved in your active swap. Upon the next
49	  boot, pass the 'resume=/dev/swappartition' argument to the kernel to
50	  have it detect the saved image, restore memory state from it, and
51	  continue to run as before. If you do not want the previous state to
52	  be reloaded, then use the 'noresume' kernel command line argument.
53	  Note, however, that fsck will be run on your filesystems and you will
54	  need to run mkswap against the swap partition used for the suspend.
55
56	  It also works with swap files to a limited extent (for details see
57	  <file:Documentation/power/swsusp-and-swap-files.txt>).
58
59	  Right now you may boot without resuming and resume later but in the
60	  meantime you cannot use the swap partition(s)/file(s) involved in
61	  suspending.  Also in this case you must not use the filesystems
62	  that were mounted before the suspend.  In particular, you MUST NOT
63	  MOUNT any journaled filesystems mounted before the suspend or they
64	  will get corrupted in a nasty way.
65
66	  For more information take a look at <file:Documentation/power/swsusp.txt>.
67
68config PM_STD_PARTITION
69	string "Default resume partition"
70	depends on HIBERNATION
71	default ""
72	---help---
73	  The default resume partition is the partition that the suspend-
74	  to-disk implementation will look for a suspended disk image.
75
76	  The partition specified here will be different for almost every user.
77	  It should be a valid swap partition (at least for now) that is turned
78	  on before suspending.
79
80	  The partition specified can be overridden by specifying:
81
82		resume=/dev/<other device>
83
84	  which will set the resume partition to the device specified.
85
86	  Note there is currently not a way to specify which device to save the
87	  suspended image to. It will simply pick the first available swap
88	  device.
89
90config PM_SLEEP
91	def_bool y
92	depends on SUSPEND || HIBERNATE_CALLBACKS
93
94config PM_SLEEP_SMP
95	def_bool y
96	depends on SMP
97	depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE
98	depends on PM_SLEEP
99	select HOTPLUG
100	select HOTPLUG_CPU
101
102config PM_RUNTIME
103	bool "Run-time PM core functionality"
104	depends on !IA64_HP_SIM
105	---help---
106	  Enable functionality allowing I/O devices to be put into energy-saving
107	  (low power) states at run time (or autosuspended) after a specified
108	  period of inactivity and woken up in response to a hardware-generated
109	  wake-up event or a driver's request.
110
111	  Hardware support is generally required for this functionality to work
112	  and the bus type drivers of the buses the devices are on are
113	  responsible for the actual handling of the autosuspend requests and
114	  wake-up events.
115
116config PM
117	def_bool y
118	depends on PM_SLEEP || PM_RUNTIME
119
120config PM_DEBUG
121	bool "Power Management Debug Support"
122	depends on PM
123	---help---
124	This option enables various debugging support in the Power Management
125	code. This is helpful when debugging and reporting PM bugs, like
126	suspend support.
127
128config PM_ADVANCED_DEBUG
129	bool "Extra PM attributes in sysfs for low-level debugging/testing"
130	depends on PM_DEBUG
131	---help---
132	Add extra sysfs attributes allowing one to access some Power Management
133	fields of device objects from user space.  If you are not a kernel
134	developer interested in debugging/testing Power Management, say "no".
135
136config PM_TEST_SUSPEND
137	bool "Test suspend/resume and wakealarm during bootup"
138	depends on SUSPEND && PM_DEBUG && RTC_CLASS=y
139	---help---
140	This option will let you suspend your machine during bootup, and
141	make it wake up a few seconds later using an RTC wakeup alarm.
142	Enable this with a kernel parameter like "test_suspend=mem".
143
144	You probably want to have your system's RTC driver statically
145	linked, ensuring that it's available when this test runs.
146
147config CAN_PM_TRACE
148	def_bool y
149	depends on PM_DEBUG && PM_SLEEP
150
151config PM_TRACE
152	bool
153	help
154	  This enables code to save the last PM event point across
155	  reboot. The architecture needs to support this, x86 for
156	  example does by saving things in the RTC, see below.
157
158	  The architecture specific code must provide the extern
159	  functions from <linux/resume-trace.h> as well as the
160	  <asm/resume-trace.h> header with a TRACE_RESUME() macro.
161
162	  The way the information is presented is architecture-
163	  dependent, x86 will print the information during a
164	  late_initcall.
165
166config PM_TRACE_RTC
167	bool "Suspend/resume event tracing"
168	depends on CAN_PM_TRACE
169	depends on X86
170	select PM_TRACE
171	---help---
172	This enables some cheesy code to save the last PM event point in the
173	RTC across reboots, so that you can debug a machine that just hangs
174	during suspend (or more commonly, during resume).
175
176	To use this debugging feature you should attempt to suspend the
177	machine, reboot it and then run
178
179		dmesg -s 1000000 | grep 'hash matches'
180
181	CAUTION: this option will cause your machine's real-time clock to be
182	set to an invalid time after a resume.
183
184config APM_EMULATION
185	tristate "Advanced Power Management Emulation"
186	depends on PM && SYS_SUPPORTS_APM_EMULATION
187	help
188	  APM is a BIOS specification for saving power using several different
189	  techniques. This is mostly useful for battery powered laptops with
190	  APM compliant BIOSes. If you say Y here, the system time will be
191	  reset after a RESUME operation, the /proc/apm device will provide
192	  battery status information, and user-space programs will receive
193	  notification of APM "events" (e.g. battery status change).
194
195	  In order to use APM, you will need supporting software. For location
196	  and more information, read <file:Documentation/power/apm-acpi.txt>
197	  and the Battery Powered Linux mini-HOWTO, available from
198	  <http://www.tldp.org/docs.html#howto>.
199
200	  This driver does not spin down disk drives (see the hdparm(8)
201	  manpage ("man 8 hdparm") for that), and it doesn't turn off
202	  VESA-compliant "green" monitors.
203
204	  Generally, if you don't have a battery in your machine, there isn't
205	  much point in using this driver and you should say N. If you get
206	  random kernel OOPSes or reboots that don't seem to be related to
207	  anything, try disabling/enabling this option (or disabling/enabling
208	  APM in your BIOS).
209
210config ARCH_HAS_OPP
211	bool
212
213config PM_OPP
214	bool "Operating Performance Point (OPP) Layer library"
215	depends on ARCH_HAS_OPP
216	---help---
217	  SOCs have a standard set of tuples consisting of frequency and
218	  voltage pairs that the device will support per voltage domain. This
219	  is called Operating Performance Point or OPP. The actual definitions
220	  of OPP varies over silicon within the same family of devices.
221
222	  OPP layer organizes the data internally using device pointers
223	  representing individual voltage domains and provides SOC
224	  implementations a ready to use framework to manage OPPs.
225	  For more information, read <file:Documentation/power/opp.txt>
226
227config PM_CLK
228	def_bool y
229	depends on PM && HAVE_CLK
230
231config PM_GENERIC_DOMAINS
232	bool
233	depends on PM
234
235config PM_GENERIC_DOMAINS_RUNTIME
236	def_bool y
237	depends on PM_RUNTIME && PM_GENERIC_DOMAINS
238