APMSLEEP(1)															       APMSLEEP(1)

NAME

       apmsleep - go into suspend or standby mode and wake-up later

SYNOPSIS

       apmsleep [-sSnwhVd] [--suspend] [--standby] [--noapm] [--wait] [--precise] [--help]  [--version] [--debug] [+]hh:mm

DESCRIPTION

       Some  computers,  especially laptops, can wake-up from a low-power suspend to DRAM mode using the Real-time-clock (RTC) chip.  Apmsleep can
       be used to set the alarm time in the RTC and to go into suspend or standby 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 time and terminates successfully. If no time leap occurs within one
       minute, or something goes wrong, the exit value will be non-zero.

       The wake-up time can be specified in two formats:

       +hh:mm specifies a relative offset to the current time. The computer will suspend for exactly hh hours and mm minutes plus a few seconds to
       wake up.  On some laptops, the timing is not completely accurate so it may be a few minutes (or more?) late.

       hh:mm  specifies  absolute  local  time in 24-hour format. The time stored in the RTC is not important.	You may change the time zone used,
       with the TZ environment variable as usual. Daylight saving time is not obeyed in this version, but might be in a future release.   WARNING:
       Do not close cover of laptop after suspending the laptop with apmsleep.	Most laptops overheat when running with closed cover.

       Energy  conservation  with APM is little for a desktop. Turning of the screen will save 1/2, going into standby with drives turned off will
       save another 1/6th of the current.

       -V, --version
	      Print the apmsleep program version and exit immediately.

       -s, --suspend
	      Put the machine into suspend mode if possible (default). On my laptop, suspend mode turns off everything except the memory.

       -S, --standby
	      Put the machine into standby mode if possible. On my laptop, standby mode turns off screen, hard disk, and CPU.

       -w, --wait
	      Wait indefinitely for the time leap.

       -p, --precise
	      Wait for alarm time to match actual time. Do not wait for time leap.  This might be useful even without APM.

       -n, --noapm
	      Do not call apm bios to suspend computer, just set the alarm clock and wait for time leap indefinitely.

       -d, --debug
	      Print some information about what is going on.

REQUIRED SYSTEM CONFIGURATION

       Kernel The special character device /dev/rtc must exist and the kernel needs to be compiled with APM and RTC support.

       BIOS   The computer must have the 'suspend to RAM' feature enabled in the BIOS; 'suspend to Disk' will not work, because  the  computer	is
	      turned  off completely. You do not need to enable the ALARM timer, it will be activated by apmsleep. On some boards, you can config-
	      ure which interrupts can be used to awake from suspend mode. If you have such a 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 to enable 'modem ring' in the BIOS, even
	      if you do not have a modem.

       Privileges
	      The program must be run as root or have the SUID attribute set (see chmod(1)).

BUGS

       Apmsleep cannot detect which event terminated the suspension. Possible events are: keyboard or mouse activity, modem ring, alarm from  RTC,
       any other 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 by kernel).

       This program was tested on a Winbook XL laptop (Pentium) only.  It may not function on your hardware.

AUTHOR

       Written	by  Peter Englmaier (ppe@mpe.mpg.de) and may be freely distributed under the terms of the GNU General Public License.  The code is
       based on Paul Gortmacher's RTC test/example program.  There is ABSOLUTELY NO WARRANTY for this program.	The current  maintainer  is  Peter
       Englmaier.

SEE ALSO

       xapm(1), apmd(8).

								   January 2004 						       APMSLEEP(1)