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 104config HIBERNATION_COMP_LZ4 105 bool "lz4" 106 depends on CRYPTO_LZ4 107 108endchoice 109 110config HIBERNATION_DEF_COMP 111 string 112 default "lzo" if HIBERNATION_COMP_LZO 113 default "lz4" if HIBERNATION_COMP_LZ4 114 help 115 Default compressor to be used for hibernation. 116 117config PM_STD_PARTITION 118 string "Default resume partition" 119 depends on HIBERNATION 120 default "" 121 help 122 The default resume partition is the partition that the suspend- 123 to-disk implementation will look for a suspended disk image. 124 125 The partition specified here will be different for almost every user. 126 It should be a valid swap partition (at least for now) that is turned 127 on before suspending. 128 129 The partition specified can be overridden by specifying: 130 131 resume=/dev/<other device> 132 133 which will set the resume partition to the device specified. 134 135 Note there is currently not a way to specify which device to save the 136 suspended image to. It will simply pick the first available swap 137 device. 138 139config PM_SLEEP 140 def_bool y 141 depends on SUSPEND || HIBERNATE_CALLBACKS 142 select PM 143 144config PM_SLEEP_SMP 145 def_bool y 146 depends on SMP 147 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE 148 depends on PM_SLEEP 149 select HOTPLUG_CPU 150 151config PM_SLEEP_SMP_NONZERO_CPU 152 def_bool y 153 depends on PM_SLEEP_SMP 154 depends on ARCH_SUSPEND_NONZERO_CPU 155 help 156 If an arch can suspend (for suspend, hibernate, kexec, etc) on a 157 non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This 158 will allow nohz_full mask to include CPU0. 159 160config PM_AUTOSLEEP 161 bool "Opportunistic sleep" 162 depends on PM_SLEEP 163 help 164 Allow the kernel to trigger a system transition into a global sleep 165 state automatically whenever there are no active wakeup sources. 166 167config PM_USERSPACE_AUTOSLEEP 168 bool "Userspace opportunistic sleep" 169 depends on PM_SLEEP 170 help 171 Notify kernel of aggressive userspace autosleep power management policy. 172 173 This option changes the behavior of various sleep-sensitive code to deal 174 with frequent userspace-initiated transitions into a global sleep state. 175 176 Saying Y here, disables code paths that most users really should keep 177 enabled. In particular, only enable this if it is very common to be 178 asleep/awake for very short periods of time (<= 2 seconds). 179 180 Only platforms, such as Android, that implement opportunistic sleep from 181 a userspace power manager service should enable this option; and not 182 other machines. Therefore, you should say N here, unless you are 183 extremely certain that this is what you want. The option otherwise has 184 bad, undesirable effects, and should not be enabled just for fun. 185 186 187config PM_WAKELOCKS 188 bool "User space wakeup sources interface" 189 depends on PM_SLEEP 190 help 191 Allow user space to create, activate and deactivate wakeup source 192 objects with the help of a sysfs-based interface. 193 194config PM_WAKELOCKS_LIMIT 195 int "Maximum number of user space wakeup sources (0 = no limit)" 196 range 0 100000 197 default 100 198 depends on PM_WAKELOCKS 199 200config PM_WAKELOCKS_GC 201 bool "Garbage collector for user space wakeup sources" 202 depends on PM_WAKELOCKS 203 default y 204 205config PM_QOS_CPU_SYSTEM_WAKEUP 206 bool "User space interface for CPU system wakeup QoS" 207 depends on CPU_IDLE 208 help 209 Enable this to allow user space via the cpu_wakeup_latency file to 210 specify a CPU system wakeup latency limit. 211 212 This may be particularly useful for platforms supporting multiple low 213 power states for CPUs during system-wide suspend and s2idle in 214 particular. 215 216config PM 217 bool "Device power management core functionality" 218 help 219 Enable functionality allowing I/O devices to be put into energy-saving 220 (low power) states, for example after a specified period of inactivity 221 (autosuspended), and woken up in response to a hardware-generated 222 wake-up event or a driver's request. 223 224 Hardware support is generally required for this functionality to work 225 and the bus type drivers of the buses the devices are on are 226 responsible for the actual handling of device suspend requests and 227 wake-up events. 228 229config PM_DEBUG 230 bool "Power Management Debug Support" 231 depends on PM 232 help 233 This option enables various debugging support in the Power Management 234 code. This is helpful when debugging and reporting PM bugs, like 235 suspend support. 236 237config PM_ADVANCED_DEBUG 238 bool "Extra PM attributes in sysfs for low-level debugging/testing" 239 depends on PM_DEBUG 240 help 241 Add extra sysfs attributes allowing one to access some Power Management 242 fields of device objects from user space. If you are not a kernel 243 developer interested in debugging/testing Power Management, say "no". 244 245config PM_TEST_SUSPEND 246 bool "Test suspend/resume and wakealarm during bootup" 247 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 248 help 249 This option will let you suspend your machine during bootup, and 250 make it wake up a few seconds later using an RTC wakeup alarm. 251 Enable this with a kernel parameter like "test_suspend=mem". 252 253 You probably want to have your system's RTC driver statically 254 linked, ensuring that it's available when this test runs. 255 256config PM_SLEEP_DEBUG 257 def_bool y 258 depends on PM_DEBUG && PM_SLEEP 259 260config DPM_WATCHDOG 261 bool "Device suspend/resume watchdog" 262 depends on PM_DEBUG && PSTORE && EXPERT 263 help 264 Sets up a watchdog timer to capture drivers that are 265 locked up attempting to suspend/resume a device. 266 A detected lockup causes system panic with message 267 captured in pstore device for inspection in subsequent 268 boot session. 269 270config DPM_WATCHDOG_TIMEOUT 271 int "Watchdog timeout to panic in seconds" 272 range 1 120 273 default 120 274 depends on DPM_WATCHDOG 275 276config DPM_WATCHDOG_WARNING_TIMEOUT 277 int "Watchdog timeout to warn in seconds" 278 range 1 DPM_WATCHDOG_TIMEOUT 279 default DPM_WATCHDOG_TIMEOUT 280 depends on DPM_WATCHDOG 281 help 282 If the DPM watchdog warning timeout and main timeout are 283 different then a non-fatal warning (with a stack trace of 284 the stuck suspend routine) will be printed when the warning 285 timeout expires. If the suspend routine gets un-stuck 286 before the main timeout expires then no other action is 287 taken. If the routine continues to be stuck and the main 288 timeout expires then an emergency-level message and stack 289 trace will be printed and the system will panic. 290 291 If the warning timeout is equal to the main timeout (the 292 default) then the warning will never happen and the system 293 will jump straight to panic when the main timeout expires. 294 295config PM_TRACE 296 bool 297 help 298 This enables code to save the last PM event point across 299 reboot. The architecture needs to support this, x86 for 300 example does by saving things in the RTC, see below. 301 302 The architecture specific code must provide the extern 303 functions from <linux/resume-trace.h> as well as the 304 <asm/resume-trace.h> header with a TRACE_RESUME() macro. 305 306 The way the information is presented is architecture- 307 dependent, x86 will print the information during a 308 late_initcall. 309 310config PM_TRACE_RTC 311 bool "Suspend/resume event tracing" 312 depends on PM_SLEEP_DEBUG 313 depends on X86 314 select PM_TRACE 315 help 316 This enables some cheesy code to save the last PM event point in the 317 RTC across reboots, so that you can debug a machine that just hangs 318 during suspend (or more commonly, during resume). 319 320 To use this debugging feature you should attempt to suspend the 321 machine, reboot it and then run 322 323 dmesg -s 1000000 | grep 'hash matches' 324 325 CAUTION: this option will cause your machine's real-time clock to be 326 set to an invalid time after a resume. 327 328config APM_EMULATION 329 tristate "Advanced Power Management Emulation" 330 depends on SYS_SUPPORTS_APM_EMULATION 331 help 332 APM is a BIOS specification for saving power using several different 333 techniques. This is mostly useful for battery powered laptops with 334 APM compliant BIOSes. If you say Y here, the system time will be 335 reset after a RESUME operation, the /proc/apm device will provide 336 battery status information, and user-space programs will receive 337 notification of APM "events" (e.g. battery status change). 338 339 In order to use APM, you will need supporting software. For location 340 and more information, read <file:Documentation/power/apm-acpi.rst> 341 and the Battery Powered Linux mini-HOWTO, available from 342 <http://www.tldp.org/docs.html#howto>. 343 344 This driver does not spin down disk drives (see the hdparm(8) 345 manpage ("man 8 hdparm") for that), and it doesn't turn off 346 VESA-compliant "green" monitors. 347 348 Generally, if you don't have a battery in your machine, there isn't 349 much point in using this driver and you should say N. If you get 350 random kernel OOPSes or reboots that don't seem to be related to 351 anything, try disabling/enabling this option (or disabling/enabling 352 APM in your BIOS). 353 354config PM_CLK 355 def_bool y 356 depends on PM && HAVE_CLK 357 358config PM_GENERIC_DOMAINS 359 bool 360 depends on PM 361 362config WQ_POWER_EFFICIENT_DEFAULT 363 bool "Enable workqueue power-efficient mode by default" 364 depends on PM 365 help 366 Per-cpu workqueues are generally preferred because they show 367 better performance thanks to cache locality; unfortunately, 368 per-cpu workqueues tend to be more power hungry than unbound 369 workqueues. 370 371 Enabling workqueue.power_efficient kernel parameter makes the 372 per-cpu workqueues which were observed to contribute 373 significantly to power consumption unbound, leading to measurably 374 lower power usage at the cost of small performance overhead. 375 376 This config option determines whether workqueue.power_efficient 377 is enabled by default. 378 379 If in doubt, say N. 380 381config PM_GENERIC_DOMAINS_SLEEP 382 def_bool y 383 depends on PM_SLEEP && PM_GENERIC_DOMAINS 384 385config PM_GENERIC_DOMAINS_OF 386 def_bool y 387 depends on PM_GENERIC_DOMAINS && OF 388 389config CPU_PM 390 bool 391 392config ENERGY_MODEL 393 bool "Energy Model for devices with DVFS (CPUs, GPUs, etc)" 394 depends on CPU_FREQ || PM_DEVFREQ 395 help 396 Several subsystems (thermal and/or the task scheduler for example) 397 can leverage information about the energy consumed by devices to 398 make smarter decisions. This config option enables the framework 399 from which subsystems can access the energy models. 400 401 The exact usage of the energy model is subsystem-dependent. 402 403 If in doubt, say N. 404