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 LZO_COMPRESS 43 select LZO_DECOMPRESS 44 select CRC32 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 95config PM_STD_PARTITION 96 string "Default resume partition" 97 depends on HIBERNATION 98 default "" 99 help 100 The default resume partition is the partition that the suspend- 101 to-disk implementation will look for a suspended disk image. 102 103 The partition specified here will be different for almost every user. 104 It should be a valid swap partition (at least for now) that is turned 105 on before suspending. 106 107 The partition specified can be overridden by specifying: 108 109 resume=/dev/<other device> 110 111 which will set the resume partition to the device specified. 112 113 Note there is currently not a way to specify which device to save the 114 suspended image to. It will simply pick the first available swap 115 device. 116 117config PM_SLEEP 118 def_bool y 119 depends on SUSPEND || HIBERNATE_CALLBACKS 120 select PM 121 122config PM_SLEEP_SMP 123 def_bool y 124 depends on SMP 125 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE 126 depends on PM_SLEEP 127 select HOTPLUG_CPU 128 129config PM_SLEEP_SMP_NONZERO_CPU 130 def_bool y 131 depends on PM_SLEEP_SMP 132 depends on ARCH_SUSPEND_NONZERO_CPU 133 help 134 If an arch can suspend (for suspend, hibernate, kexec, etc) on a 135 non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This 136 will allow nohz_full mask to include CPU0. 137 138config PM_AUTOSLEEP 139 bool "Opportunistic sleep" 140 depends on PM_SLEEP 141 help 142 Allow the kernel to trigger a system transition into a global sleep 143 state automatically whenever there are no active wakeup sources. 144 145config PM_USERSPACE_AUTOSLEEP 146 bool "Userspace opportunistic sleep" 147 depends on PM_SLEEP 148 help 149 Notify kernel of aggressive userspace autosleep power management policy. 150 151 This option changes the behavior of various sleep-sensitive code to deal 152 with frequent userspace-initiated transitions into a global sleep state. 153 154 Saying Y here, disables code paths that most users really should keep 155 enabled. In particular, only enable this if it is very common to be 156 asleep/awake for very short periods of time (<= 2 seconds). 157 158 Only platforms, such as Android, that implement opportunistic sleep from 159 a userspace power manager service should enable this option; and not 160 other machines. Therefore, you should say N here, unless you are 161 extremely certain that this is what you want. The option otherwise has 162 bad, undesirable effects, and should not be enabled just for fun. 163 164 165config PM_WAKELOCKS 166 bool "User space wakeup sources interface" 167 depends on PM_SLEEP 168 help 169 Allow user space to create, activate and deactivate wakeup source 170 objects with the help of a sysfs-based interface. 171 172config PM_WAKELOCKS_LIMIT 173 int "Maximum number of user space wakeup sources (0 = no limit)" 174 range 0 100000 175 default 100 176 depends on PM_WAKELOCKS 177 178config PM_WAKELOCKS_GC 179 bool "Garbage collector for user space wakeup sources" 180 depends on PM_WAKELOCKS 181 default y 182 183config PM 184 bool "Device power management core functionality" 185 help 186 Enable functionality allowing I/O devices to be put into energy-saving 187 (low power) states, for example after a specified period of inactivity 188 (autosuspended), and woken up in response to a hardware-generated 189 wake-up event or a driver's request. 190 191 Hardware support is generally required for this functionality to work 192 and the bus type drivers of the buses the devices are on are 193 responsible for the actual handling of device suspend requests and 194 wake-up events. 195 196config PM_DEBUG 197 bool "Power Management Debug Support" 198 depends on PM 199 help 200 This option enables various debugging support in the Power Management 201 code. This is helpful when debugging and reporting PM bugs, like 202 suspend support. 203 204config PM_ADVANCED_DEBUG 205 bool "Extra PM attributes in sysfs for low-level debugging/testing" 206 depends on PM_DEBUG 207 help 208 Add extra sysfs attributes allowing one to access some Power Management 209 fields of device objects from user space. If you are not a kernel 210 developer interested in debugging/testing Power Management, say "no". 211 212config PM_TEST_SUSPEND 213 bool "Test suspend/resume and wakealarm during bootup" 214 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 215 help 216 This option will let you suspend your machine during bootup, and 217 make it wake up a few seconds later using an RTC wakeup alarm. 218 Enable this with a kernel parameter like "test_suspend=mem". 219 220 You probably want to have your system's RTC driver statically 221 linked, ensuring that it's available when this test runs. 222 223config PM_SLEEP_DEBUG 224 def_bool y 225 depends on PM_DEBUG && PM_SLEEP 226 227config DPM_WATCHDOG 228 bool "Device suspend/resume watchdog" 229 depends on PM_DEBUG && PSTORE && EXPERT 230 help 231 Sets up a watchdog timer to capture drivers that are 232 locked up attempting to suspend/resume a device. 233 A detected lockup causes system panic with message 234 captured in pstore device for inspection in subsequent 235 boot session. 236 237config DPM_WATCHDOG_TIMEOUT 238 int "Watchdog timeout in seconds" 239 range 1 120 240 default 120 241 depends on DPM_WATCHDOG 242 243config PM_TRACE 244 bool 245 help 246 This enables code to save the last PM event point across 247 reboot. The architecture needs to support this, x86 for 248 example does by saving things in the RTC, see below. 249 250 The architecture specific code must provide the extern 251 functions from <linux/resume-trace.h> as well as the 252 <asm/resume-trace.h> header with a TRACE_RESUME() macro. 253 254 The way the information is presented is architecture- 255 dependent, x86 will print the information during a 256 late_initcall. 257 258config PM_TRACE_RTC 259 bool "Suspend/resume event tracing" 260 depends on PM_SLEEP_DEBUG 261 depends on X86 262 select PM_TRACE 263 help 264 This enables some cheesy code to save the last PM event point in the 265 RTC across reboots, so that you can debug a machine that just hangs 266 during suspend (or more commonly, during resume). 267 268 To use this debugging feature you should attempt to suspend the 269 machine, reboot it and then run 270 271 dmesg -s 1000000 | grep 'hash matches' 272 273 CAUTION: this option will cause your machine's real-time clock to be 274 set to an invalid time after a resume. 275 276config APM_EMULATION 277 tristate "Advanced Power Management Emulation" 278 depends on SYS_SUPPORTS_APM_EMULATION 279 help 280 APM is a BIOS specification for saving power using several different 281 techniques. This is mostly useful for battery powered laptops with 282 APM compliant BIOSes. If you say Y here, the system time will be 283 reset after a RESUME operation, the /proc/apm device will provide 284 battery status information, and user-space programs will receive 285 notification of APM "events" (e.g. battery status change). 286 287 In order to use APM, you will need supporting software. For location 288 and more information, read <file:Documentation/power/apm-acpi.rst> 289 and the Battery Powered Linux mini-HOWTO, available from 290 <http://www.tldp.org/docs.html#howto>. 291 292 This driver does not spin down disk drives (see the hdparm(8) 293 manpage ("man 8 hdparm") for that), and it doesn't turn off 294 VESA-compliant "green" monitors. 295 296 Generally, if you don't have a battery in your machine, there isn't 297 much point in using this driver and you should say N. If you get 298 random kernel OOPSes or reboots that don't seem to be related to 299 anything, try disabling/enabling this option (or disabling/enabling 300 APM in your BIOS). 301 302config PM_CLK 303 def_bool y 304 depends on PM && HAVE_CLK 305 306config PM_GENERIC_DOMAINS 307 bool 308 depends on PM 309 310config WQ_POWER_EFFICIENT_DEFAULT 311 bool "Enable workqueue power-efficient mode by default" 312 depends on PM 313 help 314 Per-cpu workqueues are generally preferred because they show 315 better performance thanks to cache locality; unfortunately, 316 per-cpu workqueues tend to be more power hungry than unbound 317 workqueues. 318 319 Enabling workqueue.power_efficient kernel parameter makes the 320 per-cpu workqueues which were observed to contribute 321 significantly to power consumption unbound, leading to measurably 322 lower power usage at the cost of small performance overhead. 323 324 This config option determines whether workqueue.power_efficient 325 is enabled by default. 326 327 If in doubt, say N. 328 329config PM_GENERIC_DOMAINS_SLEEP 330 def_bool y 331 depends on PM_SLEEP && PM_GENERIC_DOMAINS 332 333config PM_GENERIC_DOMAINS_OF 334 def_bool y 335 depends on PM_GENERIC_DOMAINS && OF 336 337config CPU_PM 338 bool 339 340config ENERGY_MODEL 341 bool "Energy Model for devices with DVFS (CPUs, GPUs, etc)" 342 depends on SMP 343 depends on CPU_FREQ 344 help 345 Several subsystems (thermal and/or the task scheduler for example) 346 can leverage information about the energy consumed by devices to 347 make smarter decisions. This config option enables the framework 348 from which subsystems can access the energy models. 349 350 The exact usage of the energy model is subsystem-dependent. 351 352 If in doubt, say N. 353