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 ARCH_SAVE_PAGE_KEYS 84 bool 85 86config PM_STD_PARTITION 87 string "Default resume partition" 88 depends on HIBERNATION 89 default "" 90 ---help--- 91 The default resume partition is the partition that the suspend- 92 to-disk implementation will look for a suspended disk image. 93 94 The partition specified here will be different for almost every user. 95 It should be a valid swap partition (at least for now) that is turned 96 on before suspending. 97 98 The partition specified can be overridden by specifying: 99 100 resume=/dev/<other device> 101 102 which will set the resume partition to the device specified. 103 104 Note there is currently not a way to specify which device to save the 105 suspended image to. It will simply pick the first available swap 106 device. 107 108config PM_SLEEP 109 def_bool y 110 depends on SUSPEND || HIBERNATE_CALLBACKS 111 select PM 112 select SRCU 113 114config PM_SLEEP_SMP 115 def_bool y 116 depends on SMP 117 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE 118 depends on PM_SLEEP 119 select HOTPLUG_CPU 120 121config PM_SLEEP_SMP_NONZERO_CPU 122 def_bool y 123 depends on PM_SLEEP_SMP 124 depends on ARCH_SUSPEND_NONZERO_CPU 125 ---help--- 126 If an arch can suspend (for suspend, hibernate, kexec, etc) on a 127 non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This 128 will allow nohz_full mask to include CPU0. 129 130config PM_AUTOSLEEP 131 bool "Opportunistic sleep" 132 depends on PM_SLEEP 133 default n 134 ---help--- 135 Allow the kernel to trigger a system transition into a global sleep 136 state automatically whenever there are no active wakeup sources. 137 138config PM_WAKELOCKS 139 bool "User space wakeup sources interface" 140 depends on PM_SLEEP 141 default n 142 ---help--- 143 Allow user space to create, activate and deactivate wakeup source 144 objects with the help of a sysfs-based interface. 145 146config PM_WAKELOCKS_LIMIT 147 int "Maximum number of user space wakeup sources (0 = no limit)" 148 range 0 100000 149 default 100 150 depends on PM_WAKELOCKS 151 152config PM_WAKELOCKS_GC 153 bool "Garbage collector for user space wakeup sources" 154 depends on PM_WAKELOCKS 155 default y 156 157config PM 158 bool "Device power management core functionality" 159 ---help--- 160 Enable functionality allowing I/O devices to be put into energy-saving 161 (low power) states, for example after a specified period of inactivity 162 (autosuspended), and woken up in response to a hardware-generated 163 wake-up event or a driver's request. 164 165 Hardware support is generally required for this functionality to work 166 and the bus type drivers of the buses the devices are on are 167 responsible for the actual handling of device suspend requests and 168 wake-up events. 169 170config PM_DEBUG 171 bool "Power Management Debug Support" 172 depends on PM 173 ---help--- 174 This option enables various debugging support in the Power Management 175 code. This is helpful when debugging and reporting PM bugs, like 176 suspend support. 177 178config PM_ADVANCED_DEBUG 179 bool "Extra PM attributes in sysfs for low-level debugging/testing" 180 depends on PM_DEBUG 181 ---help--- 182 Add extra sysfs attributes allowing one to access some Power Management 183 fields of device objects from user space. If you are not a kernel 184 developer interested in debugging/testing Power Management, say "no". 185 186config PM_TEST_SUSPEND 187 bool "Test suspend/resume and wakealarm during bootup" 188 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 189 ---help--- 190 This option will let you suspend your machine during bootup, and 191 make it wake up a few seconds later using an RTC wakeup alarm. 192 Enable this with a kernel parameter like "test_suspend=mem". 193 194 You probably want to have your system's RTC driver statically 195 linked, ensuring that it's available when this test runs. 196 197config PM_SLEEP_DEBUG 198 def_bool y 199 depends on PM_DEBUG && PM_SLEEP 200 201config DPM_WATCHDOG 202 bool "Device suspend/resume watchdog" 203 depends on PM_DEBUG && PSTORE && EXPERT 204 ---help--- 205 Sets up a watchdog timer to capture drivers that are 206 locked up attempting to suspend/resume a device. 207 A detected lockup causes system panic with message 208 captured in pstore device for inspection in subsequent 209 boot session. 210 211config DPM_WATCHDOG_TIMEOUT 212 int "Watchdog timeout in seconds" 213 range 1 120 214 default 120 215 depends on DPM_WATCHDOG 216 217config PM_TRACE 218 bool 219 help 220 This enables code to save the last PM event point across 221 reboot. The architecture needs to support this, x86 for 222 example does by saving things in the RTC, see below. 223 224 The architecture specific code must provide the extern 225 functions from <linux/resume-trace.h> as well as the 226 <asm/resume-trace.h> header with a TRACE_RESUME() macro. 227 228 The way the information is presented is architecture- 229 dependent, x86 will print the information during a 230 late_initcall. 231 232config PM_TRACE_RTC 233 bool "Suspend/resume event tracing" 234 depends on PM_SLEEP_DEBUG 235 depends on X86 236 select PM_TRACE 237 ---help--- 238 This enables some cheesy code to save the last PM event point in the 239 RTC across reboots, so that you can debug a machine that just hangs 240 during suspend (or more commonly, during resume). 241 242 To use this debugging feature you should attempt to suspend the 243 machine, reboot it and then run 244 245 dmesg -s 1000000 | grep 'hash matches' 246 247 CAUTION: this option will cause your machine's real-time clock to be 248 set to an invalid time after a resume. 249 250config APM_EMULATION 251 tristate "Advanced Power Management Emulation" 252 depends on SYS_SUPPORTS_APM_EMULATION 253 help 254 APM is a BIOS specification for saving power using several different 255 techniques. This is mostly useful for battery powered laptops with 256 APM compliant BIOSes. If you say Y here, the system time will be 257 reset after a RESUME operation, the /proc/apm device will provide 258 battery status information, and user-space programs will receive 259 notification of APM "events" (e.g. battery status change). 260 261 In order to use APM, you will need supporting software. For location 262 and more information, read <file:Documentation/power/apm-acpi.rst> 263 and the Battery Powered Linux mini-HOWTO, available from 264 <http://www.tldp.org/docs.html#howto>. 265 266 This driver does not spin down disk drives (see the hdparm(8) 267 manpage ("man 8 hdparm") for that), and it doesn't turn off 268 VESA-compliant "green" monitors. 269 270 Generally, if you don't have a battery in your machine, there isn't 271 much point in using this driver and you should say N. If you get 272 random kernel OOPSes or reboots that don't seem to be related to 273 anything, try disabling/enabling this option (or disabling/enabling 274 APM in your BIOS). 275 276config PM_CLK 277 def_bool y 278 depends on PM && HAVE_CLK 279 280config PM_GENERIC_DOMAINS 281 bool 282 depends on PM 283 284config WQ_POWER_EFFICIENT_DEFAULT 285 bool "Enable workqueue power-efficient mode by default" 286 depends on PM 287 default n 288 help 289 Per-cpu workqueues are generally preferred because they show 290 better performance thanks to cache locality; unfortunately, 291 per-cpu workqueues tend to be more power hungry than unbound 292 workqueues. 293 294 Enabling workqueue.power_efficient kernel parameter makes the 295 per-cpu workqueues which were observed to contribute 296 significantly to power consumption unbound, leading to measurably 297 lower power usage at the cost of small performance overhead. 298 299 This config option determines whether workqueue.power_efficient 300 is enabled by default. 301 302 If in doubt, say N. 303 304config PM_GENERIC_DOMAINS_SLEEP 305 def_bool y 306 depends on PM_SLEEP && PM_GENERIC_DOMAINS 307 308config PM_GENERIC_DOMAINS_OF 309 def_bool y 310 depends on PM_GENERIC_DOMAINS && OF 311 312config CPU_PM 313 bool 314 315config ENERGY_MODEL 316 bool "Energy Model for CPUs" 317 depends on SMP 318 depends on CPU_FREQ 319 default n 320 help 321 Several subsystems (thermal and/or the task scheduler for example) 322 can leverage information about the energy consumed by CPUs to make 323 smarter decisions. This config option enables the framework from 324 which subsystems can access the energy models. 325 326 The exact usage of the energy model is subsystem-dependent. 327 328 If in doubt, say N. 329