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 PM_SYSFS_DEPRECATED 69 bool "Driver model /sys/devices/.../power/state files (DEPRECATED)" 70 depends on PM && SYSFS 71 default n 72 help 73 The driver model started out with a sysfs file intended to provide 74 a userspace hook for device power management. This feature has never 75 worked very well, except for limited testing purposes, and so it will 76 be removed. It's not clear that a generic mechanism could really 77 handle the wide variability of device power states; any replacements 78 are likely to be bus or driver specific. 79 80config SOFTWARE_SUSPEND 81 bool "Software Suspend (Hibernation)" 82 depends on PM && SWAP && (((X86 || PPC64_SWSUSP) && (!SMP || SUSPEND_SMP)) || ((FRV || PPC32) && !SMP)) 83 ---help--- 84 Enable the suspend to disk (STD) functionality, which is usually 85 called "hibernation" in user interfaces. STD checkpoints the 86 system and powers it off; and restores that checkpoint on reboot. 87 88 You can suspend your machine with 'echo disk > /sys/power/state'. 89 Alternatively, you can use the additional userland tools available 90 from <http://suspend.sf.net>. 91 92 In principle it does not require ACPI or APM, although for example 93 ACPI will be used for the final steps when it is available. One 94 of the reasons to use software suspend is that the firmware hooks 95 for suspend states like suspend-to-RAM (STR) often don't work very 96 well with Linux. 97 98 It creates an image which is saved in your active swap. Upon the next 99 boot, pass the 'resume=/dev/swappartition' argument to the kernel to 100 have it detect the saved image, restore memory state from it, and 101 continue to run as before. If you do not want the previous state to 102 be reloaded, then use the 'noresume' kernel command line argument. 103 Note, however, that fsck will be run on your filesystems and you will 104 need to run mkswap against the swap partition used for the suspend. 105 106 It also works with swap files to a limited extent (for details see 107 <file:Documentation/power/swsusp-and-swap-files.txt>). 108 109 Right now you may boot without resuming and resume later but in the 110 meantime you cannot use the swap partition(s)/file(s) involved in 111 suspending. Also in this case you must not use the filesystems 112 that were mounted before the suspend. In particular, you MUST NOT 113 MOUNT any journaled filesystems mounted before the suspend or they 114 will get corrupted in a nasty way. 115 116 For more information take a look at <file:Documentation/power/swsusp.txt>. 117 118config PM_STD_PARTITION 119 string "Default resume partition" 120 depends on SOFTWARE_SUSPEND 121 default "" 122 ---help--- 123 The default resume partition is the partition that the suspend- 124 to-disk implementation will look for a suspended disk image. 125 126 The partition specified here will be different for almost every user. 127 It should be a valid swap partition (at least for now) that is turned 128 on before suspending. 129 130 The partition specified can be overridden by specifying: 131 132 resume=/dev/<other device> 133 134 which will set the resume partition to the device specified. 135 136 Note there is currently not a way to specify which device to save the 137 suspended image to. It will simply pick the first available swap 138 device. 139 140config SUSPEND_SMP 141 bool 142 depends on HOTPLUG_CPU && (X86 || PPC64) && PM 143 default y 144 145config APM_EMULATION 146 tristate "Advanced Power Management Emulation" 147 depends on PM && SYS_SUPPORTS_APM_EMULATION 148 help 149 APM is a BIOS specification for saving power using several different 150 techniques. This is mostly useful for battery powered laptops with 151 APM compliant BIOSes. If you say Y here, the system time will be 152 reset after a RESUME operation, the /proc/apm device will provide 153 battery status information, and user-space programs will receive 154 notification of APM "events" (e.g. battery status change). 155 156 In order to use APM, you will need supporting software. For location 157 and more information, read <file:Documentation/pm.txt> and the 158 Battery Powered Linux mini-HOWTO, available from 159 <http://www.tldp.org/docs.html#howto>. 160 161 This driver does not spin down disk drives (see the hdparm(8) 162 manpage ("man 8 hdparm") for that), and it doesn't turn off 163 VESA-compliant "green" monitors. 164 165 Generally, if you don't have a battery in your machine, there isn't 166 much point in using this driver and you should say N. If you get 167 random kernel OOPSes or reboots that don't seem to be related to 168 anything, try disabling/enabling this option (or disabling/enabling 169 APM in your BIOS). 170