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 default n 143 help 144 Allow the kernel to trigger a system transition into a global sleep 145 state automatically whenever there are no active wakeup sources. 146 147config PM_WAKELOCKS 148 bool "User space wakeup sources interface" 149 depends on PM_SLEEP 150 default n 151 help 152 Allow user space to create, activate and deactivate wakeup source 153 objects with the help of a sysfs-based interface. 154 155config PM_WAKELOCKS_LIMIT 156 int "Maximum number of user space wakeup sources (0 = no limit)" 157 range 0 100000 158 default 100 159 depends on PM_WAKELOCKS 160 161config PM_WAKELOCKS_GC 162 bool "Garbage collector for user space wakeup sources" 163 depends on PM_WAKELOCKS 164 default y 165 166config PM 167 bool "Device power management core functionality" 168 help 169 Enable functionality allowing I/O devices to be put into energy-saving 170 (low power) states, for example after a specified period of inactivity 171 (autosuspended), and woken up in response to a hardware-generated 172 wake-up event or a driver's request. 173 174 Hardware support is generally required for this functionality to work 175 and the bus type drivers of the buses the devices are on are 176 responsible for the actual handling of device suspend requests and 177 wake-up events. 178 179config PM_DEBUG 180 bool "Power Management Debug Support" 181 depends on PM 182 help 183 This option enables various debugging support in the Power Management 184 code. This is helpful when debugging and reporting PM bugs, like 185 suspend support. 186 187config PM_ADVANCED_DEBUG 188 bool "Extra PM attributes in sysfs for low-level debugging/testing" 189 depends on PM_DEBUG 190 help 191 Add extra sysfs attributes allowing one to access some Power Management 192 fields of device objects from user space. If you are not a kernel 193 developer interested in debugging/testing Power Management, say "no". 194 195config PM_TEST_SUSPEND 196 bool "Test suspend/resume and wakealarm during bootup" 197 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 198 help 199 This option will let you suspend your machine during bootup, and 200 make it wake up a few seconds later using an RTC wakeup alarm. 201 Enable this with a kernel parameter like "test_suspend=mem". 202 203 You probably want to have your system's RTC driver statically 204 linked, ensuring that it's available when this test runs. 205 206config PM_SLEEP_DEBUG 207 def_bool y 208 depends on PM_DEBUG && PM_SLEEP 209 210config DPM_WATCHDOG 211 bool "Device suspend/resume watchdog" 212 depends on PM_DEBUG && PSTORE && EXPERT 213 help 214 Sets up a watchdog timer to capture drivers that are 215 locked up attempting to suspend/resume a device. 216 A detected lockup causes system panic with message 217 captured in pstore device for inspection in subsequent 218 boot session. 219 220config DPM_WATCHDOG_TIMEOUT 221 int "Watchdog timeout in seconds" 222 range 1 120 223 default 120 224 depends on DPM_WATCHDOG 225 226config PM_TRACE 227 bool 228 help 229 This enables code to save the last PM event point across 230 reboot. The architecture needs to support this, x86 for 231 example does by saving things in the RTC, see below. 232 233 The architecture specific code must provide the extern 234 functions from <linux/resume-trace.h> as well as the 235 <asm/resume-trace.h> header with a TRACE_RESUME() macro. 236 237 The way the information is presented is architecture- 238 dependent, x86 will print the information during a 239 late_initcall. 240 241config PM_TRACE_RTC 242 bool "Suspend/resume event tracing" 243 depends on PM_SLEEP_DEBUG 244 depends on X86 245 select PM_TRACE 246 help 247 This enables some cheesy code to save the last PM event point in the 248 RTC across reboots, so that you can debug a machine that just hangs 249 during suspend (or more commonly, during resume). 250 251 To use this debugging feature you should attempt to suspend the 252 machine, reboot it and then run 253 254 dmesg -s 1000000 | grep 'hash matches' 255 256 CAUTION: this option will cause your machine's real-time clock to be 257 set to an invalid time after a resume. 258 259config APM_EMULATION 260 tristate "Advanced Power Management Emulation" 261 depends on SYS_SUPPORTS_APM_EMULATION 262 help 263 APM is a BIOS specification for saving power using several different 264 techniques. This is mostly useful for battery powered laptops with 265 APM compliant BIOSes. If you say Y here, the system time will be 266 reset after a RESUME operation, the /proc/apm device will provide 267 battery status information, and user-space programs will receive 268 notification of APM "events" (e.g. battery status change). 269 270 In order to use APM, you will need supporting software. For location 271 and more information, read <file:Documentation/power/apm-acpi.rst> 272 and the Battery Powered Linux mini-HOWTO, available from 273 <http://www.tldp.org/docs.html#howto>. 274 275 This driver does not spin down disk drives (see the hdparm(8) 276 manpage ("man 8 hdparm") for that), and it doesn't turn off 277 VESA-compliant "green" monitors. 278 279 Generally, if you don't have a battery in your machine, there isn't 280 much point in using this driver and you should say N. If you get 281 random kernel OOPSes or reboots that don't seem to be related to 282 anything, try disabling/enabling this option (or disabling/enabling 283 APM in your BIOS). 284 285config PM_CLK 286 def_bool y 287 depends on PM && HAVE_CLK 288 289config PM_GENERIC_DOMAINS 290 bool 291 depends on PM 292 293config WQ_POWER_EFFICIENT_DEFAULT 294 bool "Enable workqueue power-efficient mode by default" 295 depends on PM 296 default n 297 help 298 Per-cpu workqueues are generally preferred because they show 299 better performance thanks to cache locality; unfortunately, 300 per-cpu workqueues tend to be more power hungry than unbound 301 workqueues. 302 303 Enabling workqueue.power_efficient kernel parameter makes the 304 per-cpu workqueues which were observed to contribute 305 significantly to power consumption unbound, leading to measurably 306 lower power usage at the cost of small performance overhead. 307 308 This config option determines whether workqueue.power_efficient 309 is enabled by default. 310 311 If in doubt, say N. 312 313config PM_GENERIC_DOMAINS_SLEEP 314 def_bool y 315 depends on PM_SLEEP && PM_GENERIC_DOMAINS 316 317config PM_GENERIC_DOMAINS_OF 318 def_bool y 319 depends on PM_GENERIC_DOMAINS && OF 320 321config CPU_PM 322 bool 323 324config ENERGY_MODEL 325 bool "Energy Model for CPUs" 326 depends on SMP 327 depends on CPU_FREQ 328 default n 329 help 330 Several subsystems (thermal and/or the task scheduler for example) 331 can leverage information about the energy consumed by CPUs to make 332 smarter decisions. This config option enables the framework from 333 which subsystems can access the energy models. 334 335 The exact usage of the energy model is subsystem-dependent. 336 337 If in doubt, say N. 338
