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_LEGACY 23 bool "Legacy Power Management API (DEPRECATED)" 24 depends on PM 25 default n 26 ---help--- 27 Support for pm_register() and friends. This old API is obsoleted 28 by the driver model. 29 30 If unsure, say N. 31 32config PM_DEBUG 33 bool "Power Management Debug Support" 34 depends on PM 35 ---help--- 36 This option enables various debugging support in the Power Management 37 code. This is helpful when debugging and reporting PM bugs, like 38 suspend support. 39 40config PM_VERBOSE 41 bool "Verbose Power Management debugging" 42 depends on PM_DEBUG 43 default n 44 ---help--- 45 This option enables verbose messages from the Power Management code. 46 47config DISABLE_CONSOLE_SUSPEND 48 bool "Keep console(s) enabled during suspend/resume (DANGEROUS)" 49 depends on PM_DEBUG && PM_SLEEP 50 default n 51 ---help--- 52 This option turns off the console suspend mechanism that prevents 53 debug messages from reaching the console during the suspend/resume 54 operations. This may be helpful when debugging device drivers' 55 suspend/resume routines, but may itself lead to problems, for example 56 if netconsole is used. 57 58config PM_TRACE 59 bool "Suspend/resume event tracing" 60 depends on PM_DEBUG && X86 && PM_SLEEP && EXPERIMENTAL 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 machine, 68 then reboot it, 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 SUSPEND_SMP_POSSIBLE 76 bool 77 depends on (X86 && !X86_VOYAGER) || (PPC64 && (PPC_PSERIES || PPC_PMAC)) 78 depends on SMP 79 default y 80 81config SUSPEND_SMP 82 bool 83 depends on SUSPEND_SMP_POSSIBLE && PM_SLEEP 84 select HOTPLUG_CPU 85 default y 86 87config PM_SLEEP 88 bool 89 depends on SUSPEND || HIBERNATION 90 default y 91 92config SUSPEND 93 bool "Suspend to RAM and standby" 94 depends on PM 95 depends on !SMP || SUSPEND_SMP_POSSIBLE 96 default y 97 ---help--- 98 Allow the system to enter sleep states in which main memory is 99 powered and thus its contents are preserved, such as the 100 suspend-to-RAM state (i.e. the ACPI S3 state). 101 102config HIBERNATION 103 bool "Hibernation (aka 'suspend to disk')" 104 depends on PM && SWAP 105 depends on ((X86 || PPC64_SWSUSP || FRV || PPC32) && !SMP) || SUSPEND_SMP_POSSIBLE 106 ---help--- 107 Enable the suspend to disk (STD) functionality, which is usually 108 called "hibernation" in user interfaces. STD checkpoints the 109 system and powers it off; and restores that checkpoint on reboot. 110 111 You can suspend your machine with 'echo disk > /sys/power/state'. 112 Alternatively, you can use the additional userland tools available 113 from <http://suspend.sf.net>. 114 115 In principle it does not require ACPI or APM, although for example 116 ACPI will be used for the final steps when it is available. One 117 of the reasons to use software suspend is that the firmware hooks 118 for suspend states like suspend-to-RAM (STR) often don't work very 119 well with Linux. 120 121 It creates an image which is saved in your active swap. Upon the next 122 boot, pass the 'resume=/dev/swappartition' argument to the kernel to 123 have it detect the saved image, restore memory state from it, and 124 continue to run as before. If you do not want the previous state to 125 be reloaded, then use the 'noresume' kernel command line argument. 126 Note, however, that fsck will be run on your filesystems and you will 127 need to run mkswap against the swap partition used for the suspend. 128 129 It also works with swap files to a limited extent (for details see 130 <file:Documentation/power/swsusp-and-swap-files.txt>). 131 132 Right now you may boot without resuming and resume later but in the 133 meantime you cannot use the swap partition(s)/file(s) involved in 134 suspending. Also in this case you must not use the filesystems 135 that were mounted before the suspend. In particular, you MUST NOT 136 MOUNT any journaled filesystems mounted before the suspend or they 137 will get corrupted in a nasty way. 138 139 For more information take a look at <file:Documentation/power/swsusp.txt>. 140 141config PM_STD_PARTITION 142 string "Default resume partition" 143 depends on HIBERNATION 144 default "" 145 ---help--- 146 The default resume partition is the partition that the suspend- 147 to-disk implementation will look for a suspended disk image. 148 149 The partition specified here will be different for almost every user. 150 It should be a valid swap partition (at least for now) that is turned 151 on before suspending. 152 153 The partition specified can be overridden by specifying: 154 155 resume=/dev/<other device> 156 157 which will set the resume partition to the device specified. 158 159 Note there is currently not a way to specify which device to save the 160 suspended image to. It will simply pick the first available swap 161 device. 162 163config APM_EMULATION 164 tristate "Advanced Power Management Emulation" 165 depends on PM && SYS_SUPPORTS_APM_EMULATION 166 help 167 APM is a BIOS specification for saving power using several different 168 techniques. This is mostly useful for battery powered laptops with 169 APM compliant BIOSes. If you say Y here, the system time will be 170 reset after a RESUME operation, the /proc/apm device will provide 171 battery status information, and user-space programs will receive 172 notification of APM "events" (e.g. battery status change). 173 174 In order to use APM, you will need supporting software. For location 175 and more information, read <file:Documentation/pm.txt> and the 176 Battery Powered Linux mini-HOWTO, available from 177 <http://www.tldp.org/docs.html#howto>. 178 179 This driver does not spin down disk drives (see the hdparm(8) 180 manpage ("man 8 hdparm") for that), and it doesn't turn off 181 VESA-compliant "green" monitors. 182 183 Generally, if you don't have a battery in your machine, there isn't 184 much point in using this driver and you should say N. If you get 185 random kernel OOPSes or reboots that don't seem to be related to 186 anything, try disabling/enabling this option (or disabling/enabling 187 APM in your BIOS). 188