1config PM 2 bool "Power Management support" 3 depends on !IA64_HP_SIM 4 ---help--- 5 "Power Management" means that parts of your computer are shut 6 off or put into a power conserving "sleep" mode if they are not 7 being used. There are two competing standards for doing this: APM 8 and ACPI. If you want to use either one, say Y here and then also 9 to the requisite support below. 10 11 Power Management is most important for battery powered laptop 12 computers; if you have a laptop, check out the Linux Laptop home 13 page on the WWW at <http://www.linux-on-laptops.com/> or 14 Tuxmobil - Linux on Mobile Computers at <http://www.tuxmobil.org/> 15 and the Battery Powered Linux mini-HOWTO, available from 16 <http://www.tldp.org/docs.html#howto>. 17 18 Note that, even if you say N here, Linux on the x86 architecture 19 will issue the hlt instruction if nothing is to be done, thereby 20 sending the processor to sleep and saving power. 21 22config PM_DEBUG 23 bool "Power Management Debug Support" 24 depends on PM 25 ---help--- 26 This option enables various debugging support in the Power Management 27 code. This is helpful when debugging and reporting PM bugs, like 28 suspend support. 29 30config PM_ADVANCED_DEBUG 31 bool "Extra PM attributes in sysfs for low-level debugging/testing" 32 depends on PM_DEBUG 33 default n 34 ---help--- 35 Add extra sysfs attributes allowing one to access some Power Management 36 fields of device objects from user space. If you are not a kernel 37 developer interested in debugging/testing Power Management, say "no". 38 39config PM_VERBOSE 40 bool "Verbose Power Management debugging" 41 depends on PM_DEBUG 42 default n 43 ---help--- 44 This option enables verbose messages from the Power Management code. 45 46config CAN_PM_TRACE 47 def_bool y 48 depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL 49 50config PM_TRACE 51 bool 52 help 53 This enables code to save the last PM event point across 54 reboot. The architecture needs to support this, x86 for 55 example does by saving things in the RTC, see below. 56 57 The architecture specific code must provide the extern 58 functions from <linux/resume-trace.h> as well as the 59 <asm/resume-trace.h> header with a TRACE_RESUME() macro. 60 61 The way the information is presented is architecture- 62 dependent, x86 will print the information during a 63 late_initcall. 64 65config PM_TRACE_RTC 66 bool "Suspend/resume event tracing" 67 depends on CAN_PM_TRACE 68 depends on X86 69 select PM_TRACE 70 default n 71 ---help--- 72 This enables some cheesy code to save the last PM event point in the 73 RTC across reboots, so that you can debug a machine that just hangs 74 during suspend (or more commonly, during resume). 75 76 To use this debugging feature you should attempt to suspend the 77 machine, reboot it and then run 78 79 dmesg -s 1000000 | grep 'hash matches' 80 81 CAUTION: this option will cause your machine's real-time clock to be 82 set to an invalid time after a resume. 83 84config PM_SLEEP_SMP 85 bool 86 depends on SMP 87 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE 88 depends on PM_SLEEP 89 select HOTPLUG_CPU 90 default y 91 92config PM_SLEEP 93 bool 94 depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE 95 default y 96 97config PM_SLEEP_ADVANCED_DEBUG 98 bool 99 depends on PM_ADVANCED_DEBUG 100 default n 101 102config SUSPEND_NVS 103 bool 104 105config SUSPEND 106 bool "Suspend to RAM and standby" 107 depends on PM && ARCH_SUSPEND_POSSIBLE 108 select SUSPEND_NVS if HAS_IOMEM 109 default y 110 ---help--- 111 Allow the system to enter sleep states in which main memory is 112 powered and thus its contents are preserved, such as the 113 suspend-to-RAM state (e.g. the ACPI S3 state). 114 115config PM_TEST_SUSPEND 116 bool "Test suspend/resume and wakealarm during bootup" 117 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 118 ---help--- 119 This option will let you suspend your machine during bootup, and 120 make it wake up a few seconds later using an RTC wakeup alarm. 121 Enable this with a kernel parameter like "test_suspend=mem". 122 123 You probably want to have your system's RTC driver statically 124 linked, ensuring that it's available when this test runs. 125 126config SUSPEND_FREEZER 127 bool "Enable freezer for suspend to RAM/standby" \ 128 if ARCH_WANTS_FREEZER_CONTROL || BROKEN 129 depends on SUSPEND 130 default y 131 help 132 This allows you to turn off the freezer for suspend. If this is 133 done, no tasks are frozen for suspend to RAM/standby. 134 135 Turning OFF this setting is NOT recommended! If in doubt, say Y. 136 137config HIBERNATION 138 bool "Hibernation (aka 'suspend to disk')" 139 depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE 140 select SUSPEND_NVS if HAS_IOMEM 141 ---help--- 142 Enable the suspend to disk (STD) functionality, which is usually 143 called "hibernation" in user interfaces. STD checkpoints the 144 system and powers it off; and restores that checkpoint on reboot. 145 146 You can suspend your machine with 'echo disk > /sys/power/state' 147 after placing resume=/dev/swappartition on the kernel command line 148 in your bootloader's configuration file. 149 150 Alternatively, you can use the additional userland tools available 151 from <http://suspend.sf.net>. 152 153 In principle it does not require ACPI or APM, although for example 154 ACPI will be used for the final steps when it is available. One 155 of the reasons to use software suspend is that the firmware hooks 156 for suspend states like suspend-to-RAM (STR) often don't work very 157 well with Linux. 158 159 It creates an image which is saved in your active swap. Upon the next 160 boot, pass the 'resume=/dev/swappartition' argument to the kernel to 161 have it detect the saved image, restore memory state from it, and 162 continue to run as before. If you do not want the previous state to 163 be reloaded, then use the 'noresume' kernel command line argument. 164 Note, however, that fsck will be run on your filesystems and you will 165 need to run mkswap against the swap partition used for the suspend. 166 167 It also works with swap files to a limited extent (for details see 168 <file:Documentation/power/swsusp-and-swap-files.txt>). 169 170 Right now you may boot without resuming and resume later but in the 171 meantime you cannot use the swap partition(s)/file(s) involved in 172 suspending. Also in this case you must not use the filesystems 173 that were mounted before the suspend. In particular, you MUST NOT 174 MOUNT any journaled filesystems mounted before the suspend or they 175 will get corrupted in a nasty way. 176 177 For more information take a look at <file:Documentation/power/swsusp.txt>. 178 179config PM_STD_PARTITION 180 string "Default resume partition" 181 depends on HIBERNATION 182 default "" 183 ---help--- 184 The default resume partition is the partition that the suspend- 185 to-disk implementation will look for a suspended disk image. 186 187 The partition specified here will be different for almost every user. 188 It should be a valid swap partition (at least for now) that is turned 189 on before suspending. 190 191 The partition specified can be overridden by specifying: 192 193 resume=/dev/<other device> 194 195 which will set the resume partition to the device specified. 196 197 Note there is currently not a way to specify which device to save the 198 suspended image to. It will simply pick the first available swap 199 device. 200 201config APM_EMULATION 202 tristate "Advanced Power Management Emulation" 203 depends on PM && SYS_SUPPORTS_APM_EMULATION 204 help 205 APM is a BIOS specification for saving power using several different 206 techniques. This is mostly useful for battery powered laptops with 207 APM compliant BIOSes. If you say Y here, the system time will be 208 reset after a RESUME operation, the /proc/apm device will provide 209 battery status information, and user-space programs will receive 210 notification of APM "events" (e.g. battery status change). 211 212 In order to use APM, you will need supporting software. For location 213 and more information, read <file:Documentation/power/pm.txt> and the 214 Battery Powered Linux mini-HOWTO, available from 215 <http://www.tldp.org/docs.html#howto>. 216 217 This driver does not spin down disk drives (see the hdparm(8) 218 manpage ("man 8 hdparm") for that), and it doesn't turn off 219 VESA-compliant "green" monitors. 220 221 Generally, if you don't have a battery in your machine, there isn't 222 much point in using this driver and you should say N. If you get 223 random kernel OOPSes or reboots that don't seem to be related to 224 anything, try disabling/enabling this option (or disabling/enabling 225 APM in your BIOS). 226 227config PM_RUNTIME 228 bool "Run-time PM core functionality" 229 depends on PM 230 ---help--- 231 Enable functionality allowing I/O devices to be put into energy-saving 232 (low power) states at run time (or autosuspended) after a specified 233 period of inactivity and woken up in response to a hardware-generated 234 wake-up event or a driver's request. 235 236 Hardware support is generally required for this functionality to work 237 and the bus type drivers of the buses the devices are on are 238 responsible for the actual handling of the autosuspend requests and 239 wake-up events. 240 241config PM_OPS 242 bool 243 depends on PM_SLEEP || PM_RUNTIME 244 default y 245