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 90 select HOTPLUG_CPU 91 default y 92 93config PM_SLEEP 94 bool 95 depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE 96 default y 97 98config PM_SLEEP_ADVANCED_DEBUG 99 bool 100 depends on PM_ADVANCED_DEBUG 101 default n 102 103config SUSPEND 104 bool "Suspend to RAM and standby" 105 depends on PM && ARCH_SUSPEND_POSSIBLE 106 default y 107 ---help--- 108 Allow the system to enter sleep states in which main memory is 109 powered and thus its contents are preserved, such as the 110 suspend-to-RAM state (e.g. the ACPI S3 state). 111 112config PM_TEST_SUSPEND 113 bool "Test suspend/resume and wakealarm during bootup" 114 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 115 ---help--- 116 This option will let you suspend your machine during bootup, and 117 make it wake up a few seconds later using an RTC wakeup alarm. 118 Enable this with a kernel parameter like "test_suspend=mem". 119 120 You probably want to have your system's RTC driver statically 121 linked, ensuring that it's available when this test runs. 122 123config SUSPEND_FREEZER 124 bool "Enable freezer for suspend to RAM/standby" \ 125 if ARCH_WANTS_FREEZER_CONTROL || BROKEN 126 depends on SUSPEND 127 default y 128 help 129 This allows you to turn off the freezer for suspend. If this is 130 done, no tasks are frozen for suspend to RAM/standby. 131 132 Turning OFF this setting is NOT recommended! If in doubt, say Y. 133 134config HIBERNATION 135 bool "Hibernation (aka 'suspend to disk')" 136 depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE 137 select LZO_COMPRESS 138 select LZO_DECOMPRESS 139 ---help--- 140 Enable the suspend to disk (STD) functionality, which is usually 141 called "hibernation" in user interfaces. STD checkpoints the 142 system and powers it off; and restores that checkpoint on reboot. 143 144 You can suspend your machine with 'echo disk > /sys/power/state' 145 after placing resume=/dev/swappartition on the kernel command line 146 in your bootloader's configuration file. 147 148 Alternatively, you can use the additional userland tools available 149 from <http://suspend.sf.net>. 150 151 In principle it does not require ACPI or APM, although for example 152 ACPI will be used for the final steps when it is available. One 153 of the reasons to use software suspend is that the firmware hooks 154 for suspend states like suspend-to-RAM (STR) often don't work very 155 well with Linux. 156 157 It creates an image which is saved in your active swap. Upon the next 158 boot, pass the 'resume=/dev/swappartition' argument to the kernel to 159 have it detect the saved image, restore memory state from it, and 160 continue to run as before. If you do not want the previous state to 161 be reloaded, then use the 'noresume' kernel command line argument. 162 Note, however, that fsck will be run on your filesystems and you will 163 need to run mkswap against the swap partition used for the suspend. 164 165 It also works with swap files to a limited extent (for details see 166 <file:Documentation/power/swsusp-and-swap-files.txt>). 167 168 Right now you may boot without resuming and resume later but in the 169 meantime you cannot use the swap partition(s)/file(s) involved in 170 suspending. Also in this case you must not use the filesystems 171 that were mounted before the suspend. In particular, you MUST NOT 172 MOUNT any journaled filesystems mounted before the suspend or they 173 will get corrupted in a nasty way. 174 175 For more information take a look at <file:Documentation/power/swsusp.txt>. 176 177config PM_STD_PARTITION 178 string "Default resume partition" 179 depends on HIBERNATION 180 default "" 181 ---help--- 182 The default resume partition is the partition that the suspend- 183 to-disk implementation will look for a suspended disk image. 184 185 The partition specified here will be different for almost every user. 186 It should be a valid swap partition (at least for now) that is turned 187 on before suspending. 188 189 The partition specified can be overridden by specifying: 190 191 resume=/dev/<other device> 192 193 which will set the resume partition to the device specified. 194 195 Note there is currently not a way to specify which device to save the 196 suspended image to. It will simply pick the first available swap 197 device. 198 199config APM_EMULATION 200 tristate "Advanced Power Management Emulation" 201 depends on PM && SYS_SUPPORTS_APM_EMULATION 202 help 203 APM is a BIOS specification for saving power using several different 204 techniques. This is mostly useful for battery powered laptops with 205 APM compliant BIOSes. If you say Y here, the system time will be 206 reset after a RESUME operation, the /proc/apm device will provide 207 battery status information, and user-space programs will receive 208 notification of APM "events" (e.g. battery status change). 209 210 In order to use APM, you will need supporting software. For location 211 and more information, read <file:Documentation/power/pm.txt> and the 212 Battery Powered Linux mini-HOWTO, available from 213 <http://www.tldp.org/docs.html#howto>. 214 215 This driver does not spin down disk drives (see the hdparm(8) 216 manpage ("man 8 hdparm") for that), and it doesn't turn off 217 VESA-compliant "green" monitors. 218 219 Generally, if you don't have a battery in your machine, there isn't 220 much point in using this driver and you should say N. If you get 221 random kernel OOPSes or reboots that don't seem to be related to 222 anything, try disabling/enabling this option (or disabling/enabling 223 APM in your BIOS). 224 225config PM_RUNTIME 226 bool "Run-time PM core functionality" 227 depends on PM 228 ---help--- 229 Enable functionality allowing I/O devices to be put into energy-saving 230 (low power) states at run time (or autosuspended) after a specified 231 period of inactivity and woken up in response to a hardware-generated 232 wake-up event or a driver's request. 233 234 Hardware support is generally required for this functionality to work 235 and the bus type drivers of the buses the devices are on are 236 responsible for the actual handling of the autosuspend requests and 237 wake-up events. 238 239config PM_OPS 240 bool 241 depends on PM_SLEEP || PM_RUNTIME 242 default y 243 244config ARCH_HAS_OPP 245 bool 246 247config PM_OPP 248 bool "Operating Performance Point (OPP) Layer library" 249 depends on PM 250 depends on ARCH_HAS_OPP 251 ---help--- 252 SOCs have a standard set of tuples consisting of frequency and 253 voltage pairs that the device will support per voltage domain. This 254 is called Operating Performance Point or OPP. The actual definitions 255 of OPP varies over silicon within the same family of devices. 256 257 OPP layer organizes the data internally using device pointers 258 representing individual voltage domains and provides SOC 259 implementations a ready to use framework to manage OPPs. 260 For more information, read <file:Documentation/power/opp.txt> 261