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 verbose debugging support in the Power Management 37 code. This is helpful when debugging and reporting various PM bugs, 38 like suspend support. 39 40config DISABLE_CONSOLE_SUSPEND 41 bool "Keep console(s) enabled during suspend/resume (DANGEROUS)" 42 depends on PM && PM_DEBUG 43 default n 44 ---help--- 45 This option turns off the console suspend mechanism that prevents 46 debug messages from reaching the console during the suspend/resume 47 operations. This may be helpful when debugging device drivers' 48 suspend/resume routines, but may itself lead to problems, for example 49 if netconsole is used. 50 51config PM_TRACE 52 bool "Suspend/resume event tracing" 53 depends on PM && PM_DEBUG && X86_32 && EXPERIMENTAL 54 default n 55 ---help--- 56 This enables some cheesy code to save the last PM event point in the 57 RTC across reboots, so that you can debug a machine that just hangs 58 during suspend (or more commonly, during resume). 59 60 To use this debugging feature you should attempt to suspend the machine, 61 then reboot it, then run 62 63 dmesg -s 1000000 | grep 'hash matches' 64 65 CAUTION: this option will cause your machine's real-time clock to be 66 set to an invalid time after a resume. 67 68config SOFTWARE_SUSPEND 69 bool "Software Suspend (Hibernation)" 70 depends on PM && SWAP && (((X86 || PPC64_SWSUSP) && (!SMP || SUSPEND_SMP)) || ((FRV || PPC32) && !SMP)) 71 ---help--- 72 Enable the suspend to disk (STD) functionality, which is usually 73 called "hibernation" in user interfaces. STD checkpoints the 74 system and powers it off; and restores that checkpoint on reboot. 75 76 You can suspend your machine with 'echo disk > /sys/power/state'. 77 Alternatively, you can use the additional userland tools available 78 from <http://suspend.sf.net>. 79 80 In principle it does not require ACPI or APM, although for example 81 ACPI will be used for the final steps when it is available. One 82 of the reasons to use software suspend is that the firmware hooks 83 for suspend states like suspend-to-RAM (STR) often don't work very 84 well with Linux. 85 86 It creates an image which is saved in your active swap. Upon the next 87 boot, pass the 'resume=/dev/swappartition' argument to the kernel to 88 have it detect the saved image, restore memory state from it, and 89 continue to run as before. If you do not want the previous state to 90 be reloaded, then use the 'noresume' kernel command line argument. 91 Note, however, that fsck will be run on your filesystems and you will 92 need to run mkswap against the swap partition used for the suspend. 93 94 It also works with swap files to a limited extent (for details see 95 <file:Documentation/power/swsusp-and-swap-files.txt>). 96 97 Right now you may boot without resuming and resume later but in the 98 meantime you cannot use the swap partition(s)/file(s) involved in 99 suspending. Also in this case you must not use the filesystems 100 that were mounted before the suspend. In particular, you MUST NOT 101 MOUNT any journaled filesystems mounted before the suspend or they 102 will get corrupted in a nasty way. 103 104 For more information take a look at <file:Documentation/power/swsusp.txt>. 105 106config PM_STD_PARTITION 107 string "Default resume partition" 108 depends on SOFTWARE_SUSPEND 109 default "" 110 ---help--- 111 The default resume partition is the partition that the suspend- 112 to-disk implementation will look for a suspended disk image. 113 114 The partition specified here will be different for almost every user. 115 It should be a valid swap partition (at least for now) that is turned 116 on before suspending. 117 118 The partition specified can be overridden by specifying: 119 120 resume=/dev/<other device> 121 122 which will set the resume partition to the device specified. 123 124 Note there is currently not a way to specify which device to save the 125 suspended image to. It will simply pick the first available swap 126 device. 127 128config SUSPEND_SMP 129 bool 130 depends on HOTPLUG_CPU && (X86 || PPC64) && PM 131 default y 132 133config APM_EMULATION 134 tristate "Advanced Power Management Emulation" 135 depends on PM && SYS_SUPPORTS_APM_EMULATION 136 help 137 APM is a BIOS specification for saving power using several different 138 techniques. This is mostly useful for battery powered laptops with 139 APM compliant BIOSes. If you say Y here, the system time will be 140 reset after a RESUME operation, the /proc/apm device will provide 141 battery status information, and user-space programs will receive 142 notification of APM "events" (e.g. battery status change). 143 144 In order to use APM, you will need supporting software. For location 145 and more information, read <file:Documentation/pm.txt> and the 146 Battery Powered Linux mini-HOWTO, available from 147 <http://www.tldp.org/docs.html#howto>. 148 149 This driver does not spin down disk drives (see the hdparm(8) 150 manpage ("man 8 hdparm") for that), and it doesn't turn off 151 VESA-compliant "green" monitors. 152 153 Generally, if you don't have a battery in your machine, there isn't 154 much point in using this driver and you should say N. If you get 155 random kernel OOPSes or reboots that don't seem to be related to 156 anything, try disabling/enabling this option (or disabling/enabling 157 APM in your BIOS). 158