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 configure 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)