Power Management control program
communicates with the Advanced Power Management
making requests of it for current power status or to place the system into a
suspend or stand-by state. With no flags, apm
displays the current power management state in verbose form.
The options are as follows:
- Switch to automatic performance adjustment mode.
- Display the external charger (A/C status). 0 means
disconnected, 1 means connected, 2 means backup power source, and 255
- Display the battery status. 0 means high, 1 means low, 2
means critical, 3 means charging, 4 means absent, and 255 means
- Set the name of the socket via which to contact
- Set hw.setperf to
- Set hw.setperf to 0.
- Display the estimated battery lifetime (in percent).
- Display the estimated battery lifetime (in minutes).
- Display the performance adjustment mode. 0 means manual
mode. 1 means automatic mode.
- Put the system into stand-by (light sleep) state.
- Request more verbose description of the displayed
- Put the system into hibernation. System memory is saved to
disk (swap space) and the machine is powered down. For machines supporting
the acpi(4) style
hibernate functionality, on resume a full kernel boot will occur, followed
by the reading of the saved memory image. The image will then be unpacked
and the system resumed at the point immediately after the hibernation
- Put the system into suspend (deep sleep) state.
commands are shortcuts for suspending and hibernating the system,
respectively. With no arguments, they are placed into their respective states.
The command line flags serve the same purpose as for
These commands do not wait for positive confirmation that the requested state
has been entered; to do so would mean the command does not return until the
system resumes from its sleep state.
Each system provides methods for waking from suspend or hibernate. For those
suspend/resume (or hibernate/unhibernate) semantics, the wakeup devices for
each sleep state are printed during system boot in
The system will attempt to provide as much feedback as is possible on the
specific hardware being suspended/resumed. This includes setting system LEDs
or other indicators to illustrate progress throughout the suspend/resume (or
hibernate/unhibernate) process. Such feedback is machine-dependent.
- The default UNIX-domain socket for
-f flag may be used to specify an alternate
socket name. The protection modes on this socket govern which users may
access the APM functions.
Advanced Power Management (APM) BIOS Interface Specification (revision 1.2),
Intel Corporation and Microsoft Corporation
command appeared in NetBSD
support was added in