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_VERBOSE 31 bool "Verbose Power Management debugging" 32 depends on PM_DEBUG 33 default n 34 ---help--- 35 This option enables verbose messages from the Power Management code. 36 37config CAN_PM_TRACE 38 def_bool y 39 depends on PM_DEBUG && PM_SLEEP && EXPERIMENTAL 40 41config PM_TRACE 42 bool 43 help 44 This enables code to save the last PM event point across 45 reboot. The architecture needs to support this, x86 for 46 example does by saving things in the RTC, see below. 47 48 The architecture specific code must provide the extern 49 functions from <linux/resume-trace.h> as well as the 50 <asm/resume-trace.h> header with a TRACE_RESUME() macro. 51 52 The way the information is presented is architecture- 53 dependent, x86 will print the information during a 54 late_initcall. 55 56config PM_TRACE_RTC 57 bool "Suspend/resume event tracing" 58 depends on CAN_PM_TRACE 59 depends on X86 60 select PM_TRACE 61 default n 62 ---help--- 63 This enables some cheesy code to save the last PM event point in the 64 RTC across reboots, so that you can debug a machine that just hangs 65 during suspend (or more commonly, during resume). 66 67 To use this debugging feature you should attempt to suspend the 68 machine, reboot it and then run 69 70 dmesg -s 1000000 | grep 'hash matches' 71 72 CAUTION: this option will cause your machine's real-time clock to be 73 set to an invalid time after a resume. 74 75config PM_SLEEP_SMP 76 bool 77 depends on SMP 78 depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE 79 depends on PM_SLEEP 80 select HOTPLUG_CPU 81 default y 82 83config PM_SLEEP 84 bool 85 depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE 86 default y 87 88config SUSPEND 89 bool "Suspend to RAM and standby" 90 depends on PM && ARCH_SUSPEND_POSSIBLE 91 default y 92 ---help--- 93 Allow the system to enter sleep states in which main memory is 94 powered and thus its contents are preserved, such as the 95 suspend-to-RAM state (e.g. the ACPI S3 state). 96 97config PM_TEST_SUSPEND 98 bool "Test suspend/resume and wakealarm during bootup" 99 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 100 ---help--- 101 This option will let you suspend your machine during bootup, and 102 make it wake up a few seconds later using an RTC wakeup alarm. 103 Enable this with a kernel parameter like "test_suspend=mem". 104 105 You probably want to have your system's RTC driver statically 106 linked, ensuring that it's available when this test runs. 107 108config SUSPEND_FREEZER 109 bool "Enable freezer for suspend to RAM/standby" \ 110 if ARCH_WANTS_FREEZER_CONTROL || BROKEN 111 depends on SUSPEND 112 default y 113 help 114 This allows you to turn off the freezer for suspend. If this is 115 done, no tasks are frozen for suspend to RAM/standby. 116 117 Turning OFF this setting is NOT recommended! If in doubt, say Y. 118 119config HAS_WAKELOCK 120 bool 121 122config HAS_EARLYSUSPEND 123 bool 124 125config WAKELOCK 126 bool "Wake lock" 127 depends on PM && RTC_CLASS 128 default n 129 select HAS_WAKELOCK 130 ---help--- 131 Enable wakelocks. When user space request a sleep state the 132 sleep request will be delayed until no wake locks are held. 133 134config WAKELOCK_STAT 135 bool "Wake lock stats" 136 depends on WAKELOCK 137 default y 138 ---help--- 139 Report wake lock stats in /proc/wakelocks 140 141config USER_WAKELOCK 142 bool "Userspace wake locks" 143 depends on WAKELOCK 144 default y 145 ---help--- 146 User-space wake lock api. Write "lockname" or "lockname timeout" 147 to /sys/power/wake_lock lock and if needed create a wake lock. 148 Write "lockname" to /sys/power/wake_unlock to unlock a user wake 149 lock. 150 151config EARLYSUSPEND 152 bool "Early suspend" 153 depends on WAKELOCK 154 default y 155 select HAS_EARLYSUSPEND 156 ---help--- 157 Call early suspend handlers when the user requested sleep state 158 changes. 159 160choice 161 prompt "User-space screen access" 162 default FB_EARLYSUSPEND if !FRAMEBUFFER_CONSOLE 163 default CONSOLE_EARLYSUSPEND 164 depends on HAS_EARLYSUSPEND 165 166 config NO_USER_SPACE_SCREEN_ACCESS_CONTROL 167 bool "None" 168 169 config CONSOLE_EARLYSUSPEND 170 bool "Console switch on early-suspend" 171 depends on HAS_EARLYSUSPEND && VT 172 ---help--- 173 Register early suspend handler to perform a console switch to 174 when user-space should stop drawing to the screen and a switch 175 back when it should resume. 176 177 config FB_EARLYSUSPEND 178 bool "Sysfs interface" 179 depends on HAS_EARLYSUSPEND 180 ---help--- 181 Register early suspend handler that notifies and waits for 182 user-space through sysfs when user-space should stop drawing 183 to the screen and notifies user-space when it should resume. 184endchoice 185 186config HIBERNATION 187 bool "Hibernation (aka 'suspend to disk')" 188 depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE 189 ---help--- 190 Enable the suspend to disk (STD) functionality, which is usually 191 called "hibernation" in user interfaces. STD checkpoints the 192 system and powers it off; and restores that checkpoint on reboot. 193 194 You can suspend your machine with 'echo disk > /sys/power/state' 195 after placing resume=/dev/swappartition on the kernel command line 196 in your bootloader's configuration file. 197 198 Alternatively, you can use the additional userland tools available 199 from <http://suspend.sf.net>. 200 201 In principle it does not require ACPI or APM, although for example 202 ACPI will be used for the final steps when it is available. One 203 of the reasons to use software suspend is that the firmware hooks 204 for suspend states like suspend-to-RAM (STR) often don't work very 205 well with Linux. 206 207 It creates an image which is saved in your active swap. Upon the next 208 boot, pass the 'resume=/dev/swappartition' argument to the kernel to 209 have it detect the saved image, restore memory state from it, and 210 continue to run as before. If you do not want the previous state to 211 be reloaded, then use the 'noresume' kernel command line argument. 212 Note, however, that fsck will be run on your filesystems and you will 213 need to run mkswap against the swap partition used for the suspend. 214 215 It also works with swap files to a limited extent (for details see 216 <file:Documentation/power/swsusp-and-swap-files.txt>). 217 218 Right now you may boot without resuming and resume later but in the 219 meantime you cannot use the swap partition(s)/file(s) involved in 220 suspending. Also in this case you must not use the filesystems 221 that were mounted before the suspend. In particular, you MUST NOT 222 MOUNT any journaled filesystems mounted before the suspend or they 223 will get corrupted in a nasty way. 224 225 For more information take a look at <file:Documentation/power/swsusp.txt>. 226 227config PM_STD_PARTITION 228 string "Default resume partition" 229 depends on HIBERNATION 230 default "" 231 ---help--- 232 The default resume partition is the partition that the suspend- 233 to-disk implementation will look for a suspended disk image. 234 235 The partition specified here will be different for almost every user. 236 It should be a valid swap partition (at least for now) that is turned 237 on before suspending. 238 239 The partition specified can be overridden by specifying: 240 241 resume=/dev/<other device> 242 243 which will set the resume partition to the device specified. 244 245 Note there is currently not a way to specify which device to save the 246 suspended image to. It will simply pick the first available swap 247 device. 248 249config APM_EMULATION 250 tristate "Advanced Power Management Emulation" 251 depends on PM && SYS_SUPPORTS_APM_EMULATION 252 help 253 APM is a BIOS specification for saving power using several different 254 techniques. This is mostly useful for battery powered laptops with 255 APM compliant BIOSes. If you say Y here, the system time will be 256 reset after a RESUME operation, the /proc/apm device will provide 257 battery status information, and user-space programs will receive 258 notification of APM "events" (e.g. battery status change). 259 260 In order to use APM, you will need supporting software. For location 261 and more information, read <file:Documentation/power/pm.txt> and the 262 Battery Powered Linux mini-HOWTO, available from 263 <http://www.tldp.org/docs.html#howto>. 264 265 This driver does not spin down disk drives (see the hdparm(8) 266 manpage ("man 8 hdparm") for that), and it doesn't turn off 267 VESA-compliant "green" monitors. 268 269 Generally, if you don't have a battery in your machine, there isn't 270 much point in using this driver and you should say N. If you get 271 random kernel OOPSes or reboots that don't seem to be related to 272 anything, try disabling/enabling this option (or disabling/enabling 273 APM in your BIOS). 274