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. Say Y if that's your case. 31 32config HIBERNATE_CALLBACKS 33 bool 34 35config HIBERNATION 36 bool "Hibernation (aka 'suspend to disk')" 37 depends on SWAP && ARCH_HIBERNATION_POSSIBLE 38 select HIBERNATE_CALLBACKS 39 select LZO_COMPRESS 40 select LZO_DECOMPRESS 41 select CRC32 42 ---help--- 43 Enable the suspend to disk (STD) functionality, which is usually 44 called "hibernation" in user interfaces. STD checkpoints the 45 system and powers it off; and restores that checkpoint on reboot. 46 47 You can suspend your machine with 'echo disk > /sys/power/state' 48 after placing resume=/dev/swappartition on the kernel command line 49 in your bootloader's configuration file. 50 51 Alternatively, you can use the additional userland tools available 52 from <http://suspend.sf.net>. 53 54 In principle it does not require ACPI or APM, although for example 55 ACPI will be used for the final steps when it is available. One 56 of the reasons to use software suspend is that the firmware hooks 57 for suspend states like suspend-to-RAM (STR) often don't work very 58 well with Linux. 59 60 It creates an image which is saved in your active swap. Upon the next 61 boot, pass the 'resume=/dev/swappartition' argument to the kernel to 62 have it detect the saved image, restore memory state from it, and 63 continue to run as before. If you do not want the previous state to 64 be reloaded, then use the 'noresume' kernel command line argument. 65 Note, however, that fsck will be run on your filesystems and you will 66 need to run mkswap against the swap partition used for the suspend. 67 68 It also works with swap files to a limited extent (for details see 69 <file:Documentation/power/swsusp-and-swap-files.rst>). 70 71 Right now you may boot without resuming and resume later but in the 72 meantime you cannot use the swap partition(s)/file(s) involved in 73 suspending. Also in this case you must not use the filesystems 74 that were mounted before the suspend. In particular, you MUST NOT 75 MOUNT any journaled filesystems mounted before the suspend or they 76 will get corrupted in a nasty way. 77 78 For more information take a look at <file:Documentation/power/swsusp.rst>. 79 80config ARCH_SAVE_PAGE_KEYS 81 bool 82 83config PM_STD_PARTITION 84 string "Default resume partition" 85 depends on HIBERNATION 86 default "" 87 ---help--- 88 The default resume partition is the partition that the suspend- 89 to-disk implementation will look for a suspended disk image. 90 91 The partition specified here will be different for almost every user. 92 It should be a valid swap partition (at least for now) that is turned 93 on before suspending. 94 95 The partition specified can be overridden by specifying: 96 97 resume=/dev/<other device> 98 99 which will set the resume partition to the device specified. 100 101 Note there is currently not a way to specify which device to save the 102 suspended image to. It will simply pick the first available swap 103 device. 104 105config PM_SLEEP 106 def_bool y 107 depends on SUSPEND || HIBERNATE_CALLBACKS 108 select PM 109 select SRCU 110 111config PM_SLEEP_SMP 112 def_bool y 113 depends on SMP 114 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE 115 depends on PM_SLEEP 116 select HOTPLUG_CPU 117 118config PM_SLEEP_SMP_NONZERO_CPU 119 def_bool y 120 depends on PM_SLEEP_SMP 121 depends on ARCH_SUSPEND_NONZERO_CPU 122 ---help--- 123 If an arch can suspend (for suspend, hibernate, kexec, etc) on a 124 non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This 125 will allow nohz_full mask to include CPU0. 126 127config PM_AUTOSLEEP 128 bool "Opportunistic sleep" 129 depends on PM_SLEEP 130 default n 131 ---help--- 132 Allow the kernel to trigger a system transition into a global sleep 133 state automatically whenever there are no active wakeup sources. 134 135config PM_WAKELOCKS 136 bool "User space wakeup sources interface" 137 depends on PM_SLEEP 138 default n 139 ---help--- 140 Allow user space to create, activate and deactivate wakeup source 141 objects with the help of a sysfs-based interface. 142 143config PM_WAKELOCKS_LIMIT 144 int "Maximum number of user space wakeup sources (0 = no limit)" 145 range 0 100000 146 default 100 147 depends on PM_WAKELOCKS 148 149config PM_WAKELOCKS_GC 150 bool "Garbage collector for user space wakeup sources" 151 depends on PM_WAKELOCKS 152 default y 153 154config PM 155 bool "Device power management core functionality" 156 ---help--- 157 Enable functionality allowing I/O devices to be put into energy-saving 158 (low power) states, for example after a specified period of inactivity 159 (autosuspended), and woken up in response to a hardware-generated 160 wake-up event or a driver's request. 161 162 Hardware support is generally required for this functionality to work 163 and the bus type drivers of the buses the devices are on are 164 responsible for the actual handling of device suspend requests and 165 wake-up events. 166 167config PM_DEBUG 168 bool "Power Management Debug Support" 169 depends on PM 170 ---help--- 171 This option enables various debugging support in the Power Management 172 code. This is helpful when debugging and reporting PM bugs, like 173 suspend support. 174 175config PM_ADVANCED_DEBUG 176 bool "Extra PM attributes in sysfs for low-level debugging/testing" 177 depends on PM_DEBUG 178 ---help--- 179 Add extra sysfs attributes allowing one to access some Power Management 180 fields of device objects from user space. If you are not a kernel 181 developer interested in debugging/testing Power Management, say "no". 182 183config PM_TEST_SUSPEND 184 bool "Test suspend/resume and wakealarm during bootup" 185 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 186 ---help--- 187 This option will let you suspend your machine during bootup, and 188 make it wake up a few seconds later using an RTC wakeup alarm. 189 Enable this with a kernel parameter like "test_suspend=mem". 190 191 You probably want to have your system's RTC driver statically 192 linked, ensuring that it's available when this test runs. 193 194config PM_SLEEP_DEBUG 195 def_bool y 196 depends on PM_DEBUG && PM_SLEEP 197 198config DPM_WATCHDOG 199 bool "Device suspend/resume watchdog" 200 depends on PM_DEBUG && PSTORE && EXPERT 201 ---help--- 202 Sets up a watchdog timer to capture drivers that are 203 locked up attempting to suspend/resume a device. 204 A detected lockup causes system panic with message 205 captured in pstore device for inspection in subsequent 206 boot session. 207 208config DPM_WATCHDOG_TIMEOUT 209 int "Watchdog timeout in seconds" 210 range 1 120 211 default 120 212 depends on DPM_WATCHDOG 213 214config PM_TRACE 215 bool 216 help 217 This enables code to save the last PM event point across 218 reboot. The architecture needs to support this, x86 for 219 example does by saving things in the RTC, see below. 220 221 The architecture specific code must provide the extern 222 functions from <linux/resume-trace.h> as well as the 223 <asm/resume-trace.h> header with a TRACE_RESUME() macro. 224 225 The way the information is presented is architecture- 226 dependent, x86 will print the information during a 227 late_initcall. 228 229config PM_TRACE_RTC 230 bool "Suspend/resume event tracing" 231 depends on PM_SLEEP_DEBUG 232 depends on X86 233 select PM_TRACE 234 ---help--- 235 This enables some cheesy code to save the last PM event point in the 236 RTC across reboots, so that you can debug a machine that just hangs 237 during suspend (or more commonly, during resume). 238 239 To use this debugging feature you should attempt to suspend the 240 machine, reboot it and then run 241 242 dmesg -s 1000000 | grep 'hash matches' 243 244 CAUTION: this option will cause your machine's real-time clock to be 245 set to an invalid time after a resume. 246 247config APM_EMULATION 248 tristate "Advanced Power Management Emulation" 249 depends on SYS_SUPPORTS_APM_EMULATION 250 help 251 APM is a BIOS specification for saving power using several different 252 techniques. This is mostly useful for battery powered laptops with 253 APM compliant BIOSes. If you say Y here, the system time will be 254 reset after a RESUME operation, the /proc/apm device will provide 255 battery status information, and user-space programs will receive 256 notification of APM "events" (e.g. battery status change). 257 258 In order to use APM, you will need supporting software. For location 259 and more information, read <file:Documentation/power/apm-acpi.rst> 260 and the Battery Powered Linux mini-HOWTO, available from 261 <http://www.tldp.org/docs.html#howto>. 262 263 This driver does not spin down disk drives (see the hdparm(8) 264 manpage ("man 8 hdparm") for that), and it doesn't turn off 265 VESA-compliant "green" monitors. 266 267 Generally, if you don't have a battery in your machine, there isn't 268 much point in using this driver and you should say N. If you get 269 random kernel OOPSes or reboots that don't seem to be related to 270 anything, try disabling/enabling this option (or disabling/enabling 271 APM in your BIOS). 272 273config PM_CLK 274 def_bool y 275 depends on PM && HAVE_CLK 276 277config PM_GENERIC_DOMAINS 278 bool 279 depends on PM 280 281config WQ_POWER_EFFICIENT_DEFAULT 282 bool "Enable workqueue power-efficient mode by default" 283 depends on PM 284 default n 285 help 286 Per-cpu workqueues are generally preferred because they show 287 better performance thanks to cache locality; unfortunately, 288 per-cpu workqueues tend to be more power hungry than unbound 289 workqueues. 290 291 Enabling workqueue.power_efficient kernel parameter makes the 292 per-cpu workqueues which were observed to contribute 293 significantly to power consumption unbound, leading to measurably 294 lower power usage at the cost of small performance overhead. 295 296 This config option determines whether workqueue.power_efficient 297 is enabled by default. 298 299 If in doubt, say N. 300 301config PM_GENERIC_DOMAINS_SLEEP 302 def_bool y 303 depends on PM_SLEEP && PM_GENERIC_DOMAINS 304 305config PM_GENERIC_DOMAINS_OF 306 def_bool y 307 depends on PM_GENERIC_DOMAINS && OF 308 309config CPU_PM 310 bool 311 312config ENERGY_MODEL 313 bool "Energy Model for CPUs" 314 depends on SMP 315 depends on CPU_FREQ 316 default n 317 help 318 Several subsystems (thermal and/or the task scheduler for example) 319 can leverage information about the energy consumed by CPUs to make 320 smarter decisions. This config option enables the framework from 321 which subsystems can access the energy models. 322 323 The exact usage of the energy model is subsystem-dependent. 324 325 If in doubt, say N. 326