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 CRC32 43 select CRYPTO 44 select CRYPTO_LZO 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 95choice 96 prompt "Default compressor" 97 default HIBERNATION_COMP_LZO 98 depends on HIBERNATION 99 100config HIBERNATION_COMP_LZO 101 bool "lzo" 102 depends on CRYPTO_LZO 103 104endchoice 105 106config HIBERNATION_DEF_COMP 107 string 108 default "lzo" if HIBERNATION_COMP_LZO 109 help 110 Default compressor to be used for hibernation. 111 112config PM_STD_PARTITION 113 string "Default resume partition" 114 depends on HIBERNATION 115 default "" 116 help 117 The default resume partition is the partition that the suspend- 118 to-disk implementation will look for a suspended disk image. 119 120 The partition specified here will be different for almost every user. 121 It should be a valid swap partition (at least for now) that is turned 122 on before suspending. 123 124 The partition specified can be overridden by specifying: 125 126 resume=/dev/<other device> 127 128 which will set the resume partition to the device specified. 129 130 Note there is currently not a way to specify which device to save the 131 suspended image to. It will simply pick the first available swap 132 device. 133 134config PM_SLEEP 135 def_bool y 136 depends on SUSPEND || HIBERNATE_CALLBACKS 137 select PM 138 139config PM_SLEEP_SMP 140 def_bool y 141 depends on SMP 142 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE 143 depends on PM_SLEEP 144 select HOTPLUG_CPU 145 146config PM_SLEEP_SMP_NONZERO_CPU 147 def_bool y 148 depends on PM_SLEEP_SMP 149 depends on ARCH_SUSPEND_NONZERO_CPU 150 help 151 If an arch can suspend (for suspend, hibernate, kexec, etc) on a 152 non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This 153 will allow nohz_full mask to include CPU0. 154 155config PM_AUTOSLEEP 156 bool "Opportunistic sleep" 157 depends on PM_SLEEP 158 help 159 Allow the kernel to trigger a system transition into a global sleep 160 state automatically whenever there are no active wakeup sources. 161 162config PM_USERSPACE_AUTOSLEEP 163 bool "Userspace opportunistic sleep" 164 depends on PM_SLEEP 165 help 166 Notify kernel of aggressive userspace autosleep power management policy. 167 168 This option changes the behavior of various sleep-sensitive code to deal 169 with frequent userspace-initiated transitions into a global sleep state. 170 171 Saying Y here, disables code paths that most users really should keep 172 enabled. In particular, only enable this if it is very common to be 173 asleep/awake for very short periods of time (<= 2 seconds). 174 175 Only platforms, such as Android, that implement opportunistic sleep from 176 a userspace power manager service should enable this option; and not 177 other machines. Therefore, you should say N here, unless you are 178 extremely certain that this is what you want. The option otherwise has 179 bad, undesirable effects, and should not be enabled just for fun. 180 181 182config PM_WAKELOCKS 183 bool "User space wakeup sources interface" 184 depends on PM_SLEEP 185 help 186 Allow user space to create, activate and deactivate wakeup source 187 objects with the help of a sysfs-based interface. 188 189config PM_WAKELOCKS_LIMIT 190 int "Maximum number of user space wakeup sources (0 = no limit)" 191 range 0 100000 192 default 100 193 depends on PM_WAKELOCKS 194 195config PM_WAKELOCKS_GC 196 bool "Garbage collector for user space wakeup sources" 197 depends on PM_WAKELOCKS 198 default y 199 200config PM 201 bool "Device power management core functionality" 202 help 203 Enable functionality allowing I/O devices to be put into energy-saving 204 (low power) states, for example after a specified period of inactivity 205 (autosuspended), and woken up in response to a hardware-generated 206 wake-up event or a driver's request. 207 208 Hardware support is generally required for this functionality to work 209 and the bus type drivers of the buses the devices are on are 210 responsible for the actual handling of device suspend requests and 211 wake-up events. 212 213config PM_DEBUG 214 bool "Power Management Debug Support" 215 depends on PM 216 help 217 This option enables various debugging support in the Power Management 218 code. This is helpful when debugging and reporting PM bugs, like 219 suspend support. 220 221config PM_ADVANCED_DEBUG 222 bool "Extra PM attributes in sysfs for low-level debugging/testing" 223 depends on PM_DEBUG 224 help 225 Add extra sysfs attributes allowing one to access some Power Management 226 fields of device objects from user space. If you are not a kernel 227 developer interested in debugging/testing Power Management, say "no". 228 229config PM_TEST_SUSPEND 230 bool "Test suspend/resume and wakealarm during bootup" 231 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 232 help 233 This option will let you suspend your machine during bootup, and 234 make it wake up a few seconds later using an RTC wakeup alarm. 235 Enable this with a kernel parameter like "test_suspend=mem". 236 237 You probably want to have your system's RTC driver statically 238 linked, ensuring that it's available when this test runs. 239 240config PM_SLEEP_DEBUG 241 def_bool y 242 depends on PM_DEBUG && PM_SLEEP 243 244config DPM_WATCHDOG 245 bool "Device suspend/resume watchdog" 246 depends on PM_DEBUG && PSTORE && EXPERT 247 help 248 Sets up a watchdog timer to capture drivers that are 249 locked up attempting to suspend/resume a device. 250 A detected lockup causes system panic with message 251 captured in pstore device for inspection in subsequent 252 boot session. 253 254config DPM_WATCHDOG_TIMEOUT 255 int "Watchdog timeout in seconds" 256 range 1 120 257 default 120 258 depends on DPM_WATCHDOG 259 260config PM_TRACE 261 bool 262 help 263 This enables code to save the last PM event point across 264 reboot. The architecture needs to support this, x86 for 265 example does by saving things in the RTC, see below. 266 267 The architecture specific code must provide the extern 268 functions from <linux/resume-trace.h> as well as the 269 <asm/resume-trace.h> header with a TRACE_RESUME() macro. 270 271 The way the information is presented is architecture- 272 dependent, x86 will print the information during a 273 late_initcall. 274 275config PM_TRACE_RTC 276 bool "Suspend/resume event tracing" 277 depends on PM_SLEEP_DEBUG 278 depends on X86 279 select PM_TRACE 280 help 281 This enables some cheesy code to save the last PM event point in the 282 RTC across reboots, so that you can debug a machine that just hangs 283 during suspend (or more commonly, during resume). 284 285 To use this debugging feature you should attempt to suspend the 286 machine, reboot it and then run 287 288 dmesg -s 1000000 | grep 'hash matches' 289 290 CAUTION: this option will cause your machine's real-time clock to be 291 set to an invalid time after a resume. 292 293config APM_EMULATION 294 tristate "Advanced Power Management Emulation" 295 depends on SYS_SUPPORTS_APM_EMULATION 296 help 297 APM is a BIOS specification for saving power using several different 298 techniques. This is mostly useful for battery powered laptops with 299 APM compliant BIOSes. If you say Y here, the system time will be 300 reset after a RESUME operation, the /proc/apm device will provide 301 battery status information, and user-space programs will receive 302 notification of APM "events" (e.g. battery status change). 303 304 In order to use APM, you will need supporting software. For location 305 and more information, read <file:Documentation/power/apm-acpi.rst> 306 and the Battery Powered Linux mini-HOWTO, available from 307 <http://www.tldp.org/docs.html#howto>. 308 309 This driver does not spin down disk drives (see the hdparm(8) 310 manpage ("man 8 hdparm") for that), and it doesn't turn off 311 VESA-compliant "green" monitors. 312 313 Generally, if you don't have a battery in your machine, there isn't 314 much point in using this driver and you should say N. If you get 315 random kernel OOPSes or reboots that don't seem to be related to 316 anything, try disabling/enabling this option (or disabling/enabling 317 APM in your BIOS). 318 319config PM_CLK 320 def_bool y 321 depends on PM && HAVE_CLK 322 323config PM_GENERIC_DOMAINS 324 bool 325 depends on PM 326 327config WQ_POWER_EFFICIENT_DEFAULT 328 bool "Enable workqueue power-efficient mode by default" 329 depends on PM 330 help 331 Per-cpu workqueues are generally preferred because they show 332 better performance thanks to cache locality; unfortunately, 333 per-cpu workqueues tend to be more power hungry than unbound 334 workqueues. 335 336 Enabling workqueue.power_efficient kernel parameter makes the 337 per-cpu workqueues which were observed to contribute 338 significantly to power consumption unbound, leading to measurably 339 lower power usage at the cost of small performance overhead. 340 341 This config option determines whether workqueue.power_efficient 342 is enabled by default. 343 344 If in doubt, say N. 345 346config PM_GENERIC_DOMAINS_SLEEP 347 def_bool y 348 depends on PM_SLEEP && PM_GENERIC_DOMAINS 349 350config PM_GENERIC_DOMAINS_OF 351 def_bool y 352 depends on PM_GENERIC_DOMAINS && OF 353 354config CPU_PM 355 bool 356 357config ENERGY_MODEL 358 bool "Energy Model for devices with DVFS (CPUs, GPUs, etc)" 359 depends on SMP 360 depends on CPU_FREQ 361 help 362 Several subsystems (thermal and/or the task scheduler for example) 363 can leverage information about the energy consumed by devices to 364 make smarter decisions. This config option enables the framework 365 from which subsystems can access the energy models. 366 367 The exact usage of the energy model is subsystem-dependent. 368 369 If in doubt, say N. 370