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 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_32 && 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 SOFTWARE_SUSPEND 76 bool "Software Suspend (Hibernation)" 77 depends on PM && SWAP && (((X86 || PPC64_SWSUSP) && (!SMP || SUSPEND_SMP)) || ((FRV || PPC32) && !SMP)) 78 ---help--- 79 Enable the suspend to disk (STD) functionality, which is usually 80 called "hibernation" in user interfaces. STD checkpoints the 81 system and powers it off; and restores that checkpoint on reboot. 82 83 You can suspend your machine with 'echo disk > /sys/power/state'. 84 Alternatively, you can use the additional userland tools available 85 from <http://suspend.sf.net>. 86 87 In principle it does not require ACPI or APM, although for example 88 ACPI will be used for the final steps when it is available. One 89 of the reasons to use software suspend is that the firmware hooks 90 for suspend states like suspend-to-RAM (STR) often don't work very 91 well with Linux. 92 93 It creates an image which is saved in your active swap. Upon the next 94 boot, pass the 'resume=/dev/swappartition' argument to the kernel to 95 have it detect the saved image, restore memory state from it, and 96 continue to run as before. If you do not want the previous state to 97 be reloaded, then use the 'noresume' kernel command line argument. 98 Note, however, that fsck will be run on your filesystems and you will 99 need to run mkswap against the swap partition used for the suspend. 100 101 It also works with swap files to a limited extent (for details see 102 <file:Documentation/power/swsusp-and-swap-files.txt>). 103 104 Right now you may boot without resuming and resume later but in the 105 meantime you cannot use the swap partition(s)/file(s) involved in 106 suspending. Also in this case you must not use the filesystems 107 that were mounted before the suspend. In particular, you MUST NOT 108 MOUNT any journaled filesystems mounted before the suspend or they 109 will get corrupted in a nasty way. 110 111 For more information take a look at <file:Documentation/power/swsusp.txt>. 112 113config PM_STD_PARTITION 114 string "Default resume partition" 115 depends on SOFTWARE_SUSPEND 116 default "" 117 ---help--- 118 The default resume partition is the partition that the suspend- 119 to-disk implementation will look for a suspended disk image. 120 121 The partition specified here will be different for almost every user. 122 It should be a valid swap partition (at least for now) that is turned 123 on before suspending. 124 125 The partition specified can be overridden by specifying: 126 127 resume=/dev/<other device> 128 129 which will set the resume partition to the device specified. 130 131 Note there is currently not a way to specify which device to save the 132 suspended image to. It will simply pick the first available swap 133 device. 134 135config SUSPEND_SMP 136 bool 137 depends on HOTPLUG_CPU && (X86 || PPC64) && PM 138 default y 139 140config APM_EMULATION 141 tristate "Advanced Power Management Emulation" 142 depends on PM && SYS_SUPPORTS_APM_EMULATION 143 help 144 APM is a BIOS specification for saving power using several different 145 techniques. This is mostly useful for battery powered laptops with 146 APM compliant BIOSes. If you say Y here, the system time will be 147 reset after a RESUME operation, the /proc/apm device will provide 148 battery status information, and user-space programs will receive 149 notification of APM "events" (e.g. battery status change). 150 151 In order to use APM, you will need supporting software. For location 152 and more information, read <file:Documentation/pm.txt> and the 153 Battery Powered Linux mini-HOWTO, available from 154 <http://www.tldp.org/docs.html#howto>. 155 156 This driver does not spin down disk drives (see the hdparm(8) 157 manpage ("man 8 hdparm") for that), and it doesn't turn off 158 VESA-compliant "green" monitors. 159 160 Generally, if you don't have a battery in your machine, there isn't 161 much point in using this driver and you should say N. If you get 162 random kernel OOPSes or reboots that don't seem to be related to 163 anything, try disabling/enabling this option (or disabling/enabling 164 APM in your BIOS). 165