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 select SRCU 122 123config PM_SLEEP_SMP 124 def_bool y 125 depends on SMP 126 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE 127 depends on PM_SLEEP 128 select HOTPLUG_CPU 129 130config PM_SLEEP_SMP_NONZERO_CPU 131 def_bool y 132 depends on PM_SLEEP_SMP 133 depends on ARCH_SUSPEND_NONZERO_CPU 134 help 135 If an arch can suspend (for suspend, hibernate, kexec, etc) on a 136 non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This 137 will allow nohz_full mask to include CPU0. 138 139config PM_AUTOSLEEP 140 bool "Opportunistic sleep" 141 depends on PM_SLEEP 142 help 143 Allow the kernel to trigger a system transition into a global sleep 144 state automatically whenever there are no active wakeup sources. 145 146config PM_USERSPACE_AUTOSLEEP 147 bool "Userspace opportunistic sleep" 148 depends on PM_SLEEP 149 help 150 Notify kernel of aggressive userspace autosleep power management policy. 151 152 This option changes the behavior of various sleep-sensitive code to deal 153 with frequent userspace-initiated transitions into a global sleep state. 154 155 Saying Y here, disables code paths that most users really should keep 156 enabled. In particular, only enable this if it is very common to be 157 asleep/awake for very short periods of time (<= 2 seconds). 158 159 Only platforms, such as Android, that implement opportunistic sleep from 160 a userspace power manager service should enable this option; and not 161 other machines. Therefore, you should say N here, unless you are 162 extremely certain that this is what you want. The option otherwise has 163 bad, undesirable effects, and should not be enabled just for fun. 164 165 166config PM_WAKELOCKS 167 bool "User space wakeup sources interface" 168 depends on PM_SLEEP 169 help 170 Allow user space to create, activate and deactivate wakeup source 171 objects with the help of a sysfs-based interface. 172 173config PM_WAKELOCKS_LIMIT 174 int "Maximum number of user space wakeup sources (0 = no limit)" 175 range 0 100000 176 default 100 177 depends on PM_WAKELOCKS 178 179config PM_WAKELOCKS_GC 180 bool "Garbage collector for user space wakeup sources" 181 depends on PM_WAKELOCKS 182 default y 183 184config PM 185 bool "Device power management core functionality" 186 help 187 Enable functionality allowing I/O devices to be put into energy-saving 188 (low power) states, for example after a specified period of inactivity 189 (autosuspended), and woken up in response to a hardware-generated 190 wake-up event or a driver's request. 191 192 Hardware support is generally required for this functionality to work 193 and the bus type drivers of the buses the devices are on are 194 responsible for the actual handling of device suspend requests and 195 wake-up events. 196 197config PM_DEBUG 198 bool "Power Management Debug Support" 199 depends on PM 200 help 201 This option enables various debugging support in the Power Management 202 code. This is helpful when debugging and reporting PM bugs, like 203 suspend support. 204 205config PM_ADVANCED_DEBUG 206 bool "Extra PM attributes in sysfs for low-level debugging/testing" 207 depends on PM_DEBUG 208 help 209 Add extra sysfs attributes allowing one to access some Power Management 210 fields of device objects from user space. If you are not a kernel 211 developer interested in debugging/testing Power Management, say "no". 212 213config PM_TEST_SUSPEND 214 bool "Test suspend/resume and wakealarm during bootup" 215 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 216 help 217 This option will let you suspend your machine during bootup, and 218 make it wake up a few seconds later using an RTC wakeup alarm. 219 Enable this with a kernel parameter like "test_suspend=mem". 220 221 You probably want to have your system's RTC driver statically 222 linked, ensuring that it's available when this test runs. 223 224config PM_SLEEP_DEBUG 225 def_bool y 226 depends on PM_DEBUG && PM_SLEEP 227 228config DPM_WATCHDOG 229 bool "Device suspend/resume watchdog" 230 depends on PM_DEBUG && PSTORE && EXPERT 231 help 232 Sets up a watchdog timer to capture drivers that are 233 locked up attempting to suspend/resume a device. 234 A detected lockup causes system panic with message 235 captured in pstore device for inspection in subsequent 236 boot session. 237 238config DPM_WATCHDOG_TIMEOUT 239 int "Watchdog timeout in seconds" 240 range 1 120 241 default 120 242 depends on DPM_WATCHDOG 243 244config PM_TRACE 245 bool 246 help 247 This enables code to save the last PM event point across 248 reboot. The architecture needs to support this, x86 for 249 example does by saving things in the RTC, see below. 250 251 The architecture specific code must provide the extern 252 functions from <linux/resume-trace.h> as well as the 253 <asm/resume-trace.h> header with a TRACE_RESUME() macro. 254 255 The way the information is presented is architecture- 256 dependent, x86 will print the information during a 257 late_initcall. 258 259config PM_TRACE_RTC 260 bool "Suspend/resume event tracing" 261 depends on PM_SLEEP_DEBUG 262 depends on X86 263 select PM_TRACE 264 help 265 This enables some cheesy code to save the last PM event point in the 266 RTC across reboots, so that you can debug a machine that just hangs 267 during suspend (or more commonly, during resume). 268 269 To use this debugging feature you should attempt to suspend the 270 machine, reboot it and then run 271 272 dmesg -s 1000000 | grep 'hash matches' 273 274 CAUTION: this option will cause your machine's real-time clock to be 275 set to an invalid time after a resume. 276 277config APM_EMULATION 278 tristate "Advanced Power Management Emulation" 279 depends on SYS_SUPPORTS_APM_EMULATION 280 help 281 APM is a BIOS specification for saving power using several different 282 techniques. This is mostly useful for battery powered laptops with 283 APM compliant BIOSes. If you say Y here, the system time will be 284 reset after a RESUME operation, the /proc/apm device will provide 285 battery status information, and user-space programs will receive 286 notification of APM "events" (e.g. battery status change). 287 288 In order to use APM, you will need supporting software. For location 289 and more information, read <file:Documentation/power/apm-acpi.rst> 290 and the Battery Powered Linux mini-HOWTO, available from 291 <http://www.tldp.org/docs.html#howto>. 292 293 This driver does not spin down disk drives (see the hdparm(8) 294 manpage ("man 8 hdparm") for that), and it doesn't turn off 295 VESA-compliant "green" monitors. 296 297 Generally, if you don't have a battery in your machine, there isn't 298 much point in using this driver and you should say N. If you get 299 random kernel OOPSes or reboots that don't seem to be related to 300 anything, try disabling/enabling this option (or disabling/enabling 301 APM in your BIOS). 302 303config PM_CLK 304 def_bool y 305 depends on PM && HAVE_CLK 306 307config PM_GENERIC_DOMAINS 308 bool 309 depends on PM 310 311config WQ_POWER_EFFICIENT_DEFAULT 312 bool "Enable workqueue power-efficient mode by default" 313 depends on PM 314 help 315 Per-cpu workqueues are generally preferred because they show 316 better performance thanks to cache locality; unfortunately, 317 per-cpu workqueues tend to be more power hungry than unbound 318 workqueues. 319 320 Enabling workqueue.power_efficient kernel parameter makes the 321 per-cpu workqueues which were observed to contribute 322 significantly to power consumption unbound, leading to measurably 323 lower power usage at the cost of small performance overhead. 324 325 This config option determines whether workqueue.power_efficient 326 is enabled by default. 327 328 If in doubt, say N. 329 330config PM_GENERIC_DOMAINS_SLEEP 331 def_bool y 332 depends on PM_SLEEP && PM_GENERIC_DOMAINS 333 334config PM_GENERIC_DOMAINS_OF 335 def_bool y 336 depends on PM_GENERIC_DOMAINS && OF 337 338config CPU_PM 339 bool 340 341config ENERGY_MODEL 342 bool "Energy Model for devices with DVFS (CPUs, GPUs, etc)" 343 depends on SMP 344 depends on CPU_FREQ 345 help 346 Several subsystems (thermal and/or the task scheduler for example) 347 can leverage information about the energy consumed by devices to 348 make smarter decisions. This config option enables the framework 349 from which subsystems can access the energy models. 350 351 The exact usage of the energy model is subsystem-dependent. 352 353 If in doubt, say N. 354