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