.\" apmsleep.1.\".TH APMSLEEP 1 "sleep in APM suspend/standby mode" "APM" \" -*- nroff -*-.SH NAMEapmsleep \- go into suspend or standby mode and wake-up later.SH SYNOPSIS.B apmsleep[\-sSnwhVd] [\-\-suspend] [\-\-standby] [\-\-noapm][\-\-wait] [\-\-precise] [\-\-help]  [\-\-version] [\-\-debug][+]hh:mm.SH DESCRIPTIONSome computers, especially laptops, can wake-up from a low-power suspendto DRAM mode using the Real-time-clock (RTC) chip. .B Apmsleepcan be used to set the alarm time in the RTC and to go into suspend orstandby mode. An interrupt from the RTC causes the computer to wake-up.The program detects this event, by waiting for a leap in the kernel timeand terminates successfully. If no time leap occurs within one minute, or something goes wrong, the exit value will be non-zero. .PPThe wake-up time can be specified in two formats:.PP.B +hh:mmspecifies a relative offset to the current time. The computerwill suspend for exactly hh hours and mm minutes plus a few secondsto wake up.  On some laptops, the timing is not completely accurate so itmay be a few minutes (or more?) late..PP.B hh:mmspecifies absolute .B local time in 24-hour format. The time stored in the RTC is not important.You may change the time zone used, withthe TZ environment variable as usual. Daylight saving time isnot obeyed in this version, but might be in a future release..B WARNING:Do not close cover of laptop after suspending the laptop with apmsleep.Most laptops overheat when running with closed cover..PPEnergy conservation with APM is little for a desktop. Turning of thescreen will save 1/2, going into standby with drives turned off will save another 1/6th of the current..TP.B \-V, \-\-versionPrint the.B apmsleepprogram version and exit immediately..TP.B \-s, \-\-suspendPut the machine into suspend mode if possible (default). On my laptop,suspend mode turns off everything except the memory. .TP.B \-S, \-\-standbyPut the machine into standby mode if possible. On my laptop, standby modeturns off screen, hard disk, and CPU..TP.B \-w, \-\-waitWait indefinitely for the time leap..TP.B \-p, \-\-preciseWait for alarm time to match actual time. Do not wait for time leap.This might be useful even without APM..TP.B \-n, \-\-noapmDo not call apm bios to suspend computer, just set the alarm clockand wait for time leap indefinitely..TP.B \-d, \-\-debugPrint some information about what is going on..SH REQUIRED SYSTEM CONFIGURATION.TP.B KernelThe special character device /dev/rtc must exist and the Linux kernel needsto be compiled with APM and RTC support (CONFIG_RTC, and relevant CONFIG_APM* options). .TP.B BIOSThe computer must have the 'suspend to RAM'feature enabled in the BIOS; 'suspend to Disk' will not work, because thecomputer is turned off completely. You do not need to enable the ALARMtimer, it will be activated by apmsleep. On some boards, you can configurewhich interrupts can be used to awake from suspend mode. If you have sucha board, you might want to make sure that keyboard (IRQ 1) and RTC (IRQ 8) are among those interrupts. If your computer does not wake up, try toenable 'modem ring' in the BIOS, even if you do not have a modem..TP.B PrivilegesThe program must be run as root or have the SUID attribute set (see chmod(1))..PP.SH BUGSApmsleep cannot detect which event terminated the suspension. Possibleevents are: keyboard or mouse activity, modem ring, alarm from RTC, anyother interrupt. Sometimes, the time leap is not detected properly (causing a wrong exit value).Should use APM BIOS calls to set alarm clock (not yet supported bykernel).This program was tested on a Winbook XL laptop (Pentium) only. It may not function on your hardware..SH AUTHORWritten by Peter Englmaier (ppe@mpe.mpg.de) and may be freelydistributed under the terms of the GNU General Public License.  Thecode is based on Paul Gortmacher's RTC test/example program.  There isABSOLUTELY NO WARRANTY for this program.  The current maintainer isPeter Englmaier..SH "SEE ALSO".BR xapm "(1), "apmd (8), rtc.txt "(Linux Kernel Documentation)"