apmd - Advanced Power Management monitor daemon
apmd [-adempqs] [-f devname] [-S sockname] [-t seconds]
apmd monitors the advanced power management (APM) pseudo-device, acting
on signaled events and upon user requests as sent by the
For suspend and standby request events delivered by the
BIOS, or via
apm(8), apmd runs the appropriate configuration program (if
syncs the buffer cache to disk and initiates the requested
resuming after suspend or standby, apmd runs the appropriate
program (if one exists). For power status change
fetches the current status and reports it via syslog(3) with
apmd announces the transition to standby mode with a single
high tone on
the speaker (using the /dev/speaker device). Suspends are
two high tones.
apmd periodically polls the APM driver for the current power
the battery charge level changes substantially or the external power status
changes, the new status is logged. The polling rate defaults to once
per 10 minutes, but may be specified using the -t commandline flag.
If the -s flag is specified, the current battery statistics
via syslog(3) and apmd exits without monitoring the APM status.
If the -a flag is specified, any BIOS-initiated suspend or
are ignored if the system is connected to line current and not
running from batteries (user requests are still honored).
If the -d flag is specified, apmd enters debug mode, logging
LOG_LOCAL1 and staying in the foreground on the controlling
If the -q flag is specified, apmd does not announce suspend
requests on the speaker.
If the -m flag is specified, apmd does not disable power
issued by the APM driver. In normal operation these status
disabled as they are the same as the information collected
by this daemon
and reported via syslog.
The -e and -p flags are used to re-enable APM driver power
In both cases apmd exits immediately after setting
option. The -e flag unconditionally enables power status
-p flag causes power status messages to be displayed only
when the battery
life expectancy changes. This minimizes message output
devices that are constantly updating the estimated time remaining based
upon current processor load. However, in no case will power
be displayed until the battery life goes below the
the sysctl(8) state variable machdep.apmwarn. Setting
zero disables all warnings.
When a client requests a suspend or stand-by mode, apmd does
not wait for
positive confirmation that the requested mode has been entered before replying
to the client; to do so would mean the client does
not get a reply
until the system resumes from its sleep state. Rather, apmd
the intended state to the client and then places the system
in the requested
mode after running the configuration script and
Actions can be configured for the following five transitions: suspend,
standby, resume, powerup and powerdown. The suspend and
are run prior to apmd performing any other actions (such as
and entering the new mode. The resume program is run after
a stand-by or suspended state. The powerup and powerdown
run after the power status (AC connected or not) changes, as
well as after
a resume (if the power status changed in the mean time).
/etc/apm/suspend, /etc/apm/standby, /etc/apm/resume,
/etc/apm/powerdown are the files that contain the host's
Each file must be an executable binary or shell
for execution by the execve(2) function. If you wish to
have the same
program or script control all transitions, it may determine
is in progress by examining its argv which is set to
suspend, standby, resume, powerup and powerdown.
/var/run/apmdev is the default UNIX-domain socket used for
with apm(8). The -S flag may be used to specify an alternate socket
name. The socket is protected to mode 0660, UID 0, GID 0;
access to suspend requests to authorized users only.
/dev/apmctl is the default device used to control the APM
The -f flag may be used to specify an alternate device file
execve(2), syslog(3), apm(4), speaker(4), apm(8), syslogd(8)
Advanced Power Management (APM) BIOS Interface Specification
1.2), Intel Corporation and Microsoft Corporation.
The apmd command appeared in NetBSD 1.3. OpenBSD support
was added in
OpenBSD 3.6 March 24, 1996
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