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_NVS 104 bool 105 106config SUSPEND 107 bool "Suspend to RAM and standby" 108 depends on PM && ARCH_SUSPEND_POSSIBLE 109 select SUSPEND_NVS if HAS_IOMEM 110 default y 111 ---help--- 112 Allow the system to enter sleep states in which main memory is 113 powered and thus its contents are preserved, such as the 114 suspend-to-RAM state (e.g. the ACPI S3 state). 115 116config PM_TEST_SUSPEND 117 bool "Test suspend/resume and wakealarm during bootup" 118 depends on SUSPEND && PM_DEBUG && RTC_CLASS=y 119 ---help--- 120 This option will let you suspend your machine during bootup, and 121 make it wake up a few seconds later using an RTC wakeup alarm. 122 Enable this with a kernel parameter like "test_suspend=mem". 123 124 You probably want to have your system's RTC driver statically 125 linked, ensuring that it's available when this test runs. 126 127config SUSPEND_FREEZER 128 bool "Enable freezer for suspend to RAM/standby" \ 129 if ARCH_WANTS_FREEZER_CONTROL || BROKEN 130 depends on SUSPEND 131 default y 132 help 133 This allows you to turn off the freezer for suspend. If this is 134 done, no tasks are frozen for suspend to RAM/standby. 135 136 Turning OFF this setting is NOT recommended! If in doubt, say Y. 137 138config HIBERNATION 139 bool "Hibernation (aka 'suspend to disk')" 140 depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE 141 select LZO_COMPRESS 142 select LZO_DECOMPRESS 143 select SUSPEND_NVS if HAS_IOMEM 144 ---help--- 145 Enable the suspend to disk (STD) functionality, which is usually 146 called "hibernation" in user interfaces. STD checkpoints the 147 system and powers it off; and restores that checkpoint on reboot. 148 149 You can suspend your machine with 'echo disk > /sys/power/state' 150 after placing resume=/dev/swappartition on the kernel command line 151 in your bootloader's configuration file. 152 153 Alternatively, you can use the additional userland tools available 154 from <http://suspend.sf.net>. 155 156 In principle it does not require ACPI or APM, although for example 157 ACPI will be used for the final steps when it is available. One 158 of the reasons to use software suspend is that the firmware hooks 159 for suspend states like suspend-to-RAM (STR) often don't work very 160 well with Linux. 161 162 It creates an image which is saved in your active swap. Upon the next 163 boot, pass the 'resume=/dev/swappartition' argument to the kernel to 164 have it detect the saved image, restore memory state from it, and 165 continue to run as before. If you do not want the previous state to 166 be reloaded, then use the 'noresume' kernel command line argument. 167 Note, however, that fsck will be run on your filesystems and you will 168 need to run mkswap against the swap partition used for the suspend. 169 170 It also works with swap files to a limited extent (for details see 171 <file:Documentation/power/swsusp-and-swap-files.txt>). 172 173 Right now you may boot without resuming and resume later but in the 174 meantime you cannot use the swap partition(s)/file(s) involved in 175 suspending. Also in this case you must not use the filesystems 176 that were mounted before the suspend. In particular, you MUST NOT 177 MOUNT any journaled filesystems mounted before the suspend or they 178 will get corrupted in a nasty way. 179 180 For more information take a look at <file:Documentation/power/swsusp.txt>. 181 182config PM_STD_PARTITION 183 string "Default resume partition" 184 depends on HIBERNATION 185 default "" 186 ---help--- 187 The default resume partition is the partition that the suspend- 188 to-disk implementation will look for a suspended disk image. 189 190 The partition specified here will be different for almost every user. 191 It should be a valid swap partition (at least for now) that is turned 192 on before suspending. 193 194 The partition specified can be overridden by specifying: 195 196 resume=/dev/<other device> 197 198 which will set the resume partition to the device specified. 199 200 Note there is currently not a way to specify which device to save the 201 suspended image to. It will simply pick the first available swap 202 device. 203 204config APM_EMULATION 205 tristate "Advanced Power Management Emulation" 206 depends on PM && SYS_SUPPORTS_APM_EMULATION 207 help 208 APM is a BIOS specification for saving power using several different 209 techniques. This is mostly useful for battery powered laptops with 210 APM compliant BIOSes. If you say Y here, the system time will be 211 reset after a RESUME operation, the /proc/apm device will provide 212 battery status information, and user-space programs will receive 213 notification of APM "events" (e.g. battery status change). 214 215 In order to use APM, you will need supporting software. For location 216 and more information, read <file:Documentation/power/pm.txt> and the 217 Battery Powered Linux mini-HOWTO, available from 218 <http://www.tldp.org/docs.html#howto>. 219 220 This driver does not spin down disk drives (see the hdparm(8) 221 manpage ("man 8 hdparm") for that), and it doesn't turn off 222 VESA-compliant "green" monitors. 223 224 Generally, if you don't have a battery in your machine, there isn't 225 much point in using this driver and you should say N. If you get 226 random kernel OOPSes or reboots that don't seem to be related to 227 anything, try disabling/enabling this option (or disabling/enabling 228 APM in your BIOS). 229 230config PM_RUNTIME 231 bool "Run-time PM core functionality" 232 depends on PM 233 ---help--- 234 Enable functionality allowing I/O devices to be put into energy-saving 235 (low power) states at run time (or autosuspended) after a specified 236 period of inactivity and woken up in response to a hardware-generated 237 wake-up event or a driver's request. 238 239 Hardware support is generally required for this functionality to work 240 and the bus type drivers of the buses the devices are on are 241 responsible for the actual handling of the autosuspend requests and 242 wake-up events. 243 244config PM_OPS 245 bool 246 depends on PM_SLEEP || PM_RUNTIME 247 default y 248 249config ARCH_HAS_OPP 250 bool 251 252config PM_OPP 253 bool "Operating Performance Point (OPP) Layer library" 254 depends on PM 255 depends on ARCH_HAS_OPP 256 ---help--- 257 SOCs have a standard set of tuples consisting of frequency and 258 voltage pairs that the device will support per voltage domain. This 259 is called Operating Performance Point or OPP. The actual definitions 260 of OPP varies over silicon within the same family of devices. 261 262 OPP layer organizes the data internally using device pointers 263 representing individual voltage domains and provides SOC 264 implementations a ready to use framework to manage OPPs. 265 For more information, read <file:Documentation/power/opp.txt> 266