apmsleep

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
              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)