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 206 bool "Device power management core functionality" 207 help 208 Enable functionality allowing I/O devices to be put into energy-saving 209 (low power) states, for example after a specified period of inactivity 210 (autosuspended), and woken up in response to a hardware-generated 211 wake-up event or a driver's request. 212 213 Hardware support is generally required for this functionality to work 214 and the bus type drivers of the buses the devices are on are 215 responsible for the actual handling of device suspend requests and 216 wake-up events. 217 218config PM_DEBUG 219 bool "Power Management Debug Support" 220 depends on PM 221 help 222 This option enables various debugging support in the Power Management 223 code. This is helpful when debugging and reporting PM bugs, like 224 suspend support. 225 226config PM_ADVANCED_DEBUG 227 bool "Extra PM attributes in sysfs for low-level debugging/testing" 228 depends on PM_DEBUG 229 help 230 Add extra sysfs attributes allowing one to access some Power Management 231 fields of device objects from user space. If you are not a kernel 232 developer interested in debugging/testing Power Management, say "no". 233 234config PM_TEST_SUSPEND 235 bool "Test suspend/resume and wakealarm during bootup" 236 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 237 help 238 This option will let you suspend your machine during bootup, and 239 make it wake up a few seconds later using an RTC wakeup alarm. 240 Enable this with a kernel parameter like "test_suspend=mem". 241 242 You probably want to have your system's RTC driver statically 243 linked, ensuring that it's available when this test runs. 244 245config PM_SLEEP_DEBUG 246 def_bool y 247 depends on PM_DEBUG && PM_SLEEP 248 249config DPM_WATCHDOG 250 bool "Device suspend/resume watchdog" 251 depends on PM_DEBUG && PSTORE && EXPERT 252 help 253 Sets up a watchdog timer to capture drivers that are 254 locked up attempting to suspend/resume a device. 255 A detected lockup causes system panic with message 256 captured in pstore device for inspection in subsequent 257 boot session. 258 259config DPM_WATCHDOG_TIMEOUT 260 int "Watchdog timeout in seconds" 261 range 1 120 262 default 120 263 depends on DPM_WATCHDOG 264 265config PM_TRACE 266 bool 267 help 268 This enables code to save the last PM event point across 269 reboot. The architecture needs to support this, x86 for 270 example does by saving things in the RTC, see below. 271 272 The architecture specific code must provide the extern 273 functions from <linux/resume-trace.h> as well as the 274 <asm/resume-trace.h> header with a TRACE_RESUME() macro. 275 276 The way the information is presented is architecture- 277 dependent, x86 will print the information during a 278 late_initcall. 279 280config PM_TRACE_RTC 281 bool "Suspend/resume event tracing" 282 depends on PM_SLEEP_DEBUG 283 depends on X86 284 select PM_TRACE 285 help 286 This enables some cheesy code to save the last PM event point in the 287 RTC across reboots, so that you can debug a machine that just hangs 288 during suspend (or more commonly, during resume). 289 290 To use this debugging feature you should attempt to suspend the 291 machine, reboot it and then run 292 293 dmesg -s 1000000 | grep 'hash matches' 294 295 CAUTION: this option will cause your machine's real-time clock to be 296 set to an invalid time after a resume. 297 298config APM_EMULATION 299 tristate "Advanced Power Management Emulation" 300 depends on SYS_SUPPORTS_APM_EMULATION 301 help 302 APM is a BIOS specification for saving power using several different 303 techniques. This is mostly useful for battery powered laptops with 304 APM compliant BIOSes. If you say Y here, the system time will be 305 reset after a RESUME operation, the /proc/apm device will provide 306 battery status information, and user-space programs will receive 307 notification of APM "events" (e.g. battery status change). 308 309 In order to use APM, you will need supporting software. For location 310 and more information, read <file:Documentation/power/apm-acpi.rst> 311 and the Battery Powered Linux mini-HOWTO, available from 312 <http://www.tldp.org/docs.html#howto>. 313 314 This driver does not spin down disk drives (see the hdparm(8) 315 manpage ("man 8 hdparm") for that), and it doesn't turn off 316 VESA-compliant "green" monitors. 317 318 Generally, if you don't have a battery in your machine, there isn't 319 much point in using this driver and you should say N. If you get 320 random kernel OOPSes or reboots that don't seem to be related to 321 anything, try disabling/enabling this option (or disabling/enabling 322 APM in your BIOS). 323 324config PM_CLK 325 def_bool y 326 depends on PM && HAVE_CLK 327 328config PM_GENERIC_DOMAINS 329 bool 330 depends on PM 331 332config WQ_POWER_EFFICIENT_DEFAULT 333 bool "Enable workqueue power-efficient mode by default" 334 depends on PM 335 help 336 Per-cpu workqueues are generally preferred because they show 337 better performance thanks to cache locality; unfortunately, 338 per-cpu workqueues tend to be more power hungry than unbound 339 workqueues. 340 341 Enabling workqueue.power_efficient kernel parameter makes the 342 per-cpu workqueues which were observed to contribute 343 significantly to power consumption unbound, leading to measurably 344 lower power usage at the cost of small performance overhead. 345 346 This config option determines whether workqueue.power_efficient 347 is enabled by default. 348 349 If in doubt, say N. 350 351config PM_GENERIC_DOMAINS_SLEEP 352 def_bool y 353 depends on PM_SLEEP && PM_GENERIC_DOMAINS 354 355config PM_GENERIC_DOMAINS_OF 356 def_bool y 357 depends on PM_GENERIC_DOMAINS && OF 358 359config CPU_PM 360 bool 361 362config ENERGY_MODEL 363 bool "Energy Model for devices with DVFS (CPUs, GPUs, etc)" 364 depends on SMP 365 depends on CPU_FREQ 366 help 367 Several subsystems (thermal and/or the task scheduler for example) 368 can leverage information about the energy consumed by devices to 369 make smarter decisions. This config option enables the framework 370 from which subsystems can access the energy models. 371 372 The exact usage of the energy model is subsystem-dependent. 373 374 If in doubt, say N. 375