apm
—
control the APM BIOS and display its information
apm |
[-ablstzZ ] [-d
enable] [-e
enable] [-h
enable] [-r
delta] |
The apm
utility controls the Intel / Microsoft APM
(Advanced Power Management) BIOS and displays the current status of APM on
laptop PCs.
The options are as follows:
-a
- Display the current AC-line status as an integer value. The values 0, 1
and 2 correspond to the “off-line” state,
“on-line” state or “backup power” state,
respectively.
-b
- Display an integer value reflecting the current battery status. The values
0, 1, 2, 3, correspond to the “high” status,
“low” status, “critical” status,
“charging” status respectively.
-d
enable
- Disable/enable suspending of the display separately from a normal suspend
using the boolean value for enable. This feature
seems to not work on many different laptops, including the Libretto 30CT
and 50CT.
-e
enable
- Enable or disable APM functions of the computer, depending on the boolean
enable argument.
-h
enable
- Depending on the boolean value of enable, enable or
disable the HLT instruction in the kernel context switch routine. These
options are not necessary for almost all APM implementations, but for some
implementations whose “Idle CPU”
call executes both CPU clock slowdown and HLT instruction,
-h
false
is necessary to
prevent the system from reducing its peak performance. See
apm(4)
for details.
-l
- Display the remaining battery percentage. If your laptop does not support
this function, 255 is displayed.
-r
delta
- Enable the resume wakeup timer, if the laptop supports it. This does not
actually suspend the laptop, but if the laptop is suspended, and it
supports resume from suspend, then it will be resumed after
delta seconds (from when you run this command, not
from when you suspend).
-s
- Display the status of the APM support as an integer value. The values 0
and 1 correspond to the “disabled” state or
“enabled” state respectively.
-t
- Display the estimated remaining battery lifetime in seconds. If it is
unknown, -1 is displayed.
-Z
- Transition the system into standby mode. This mode uses less power than
full power mode, but more than suspend mode. Some laptops support resuming
from this state on timer or Ring Indicator events. The output of
apm
tells what your laptop claims to support.
-z
- Suspend the system. It is used by
zzz(8).
If no options are specified, apm
displays
information and current status of APM in verbose mode. If multiple display
options are given, the values are displayed one per line in the order given
here.
apmconf(8)
has been merged in apm
and thus
apm
replaces all of its functionality.
Some APM implementations do not support parameters needed by
apm
. On such systems, apm
displays them as unknown.
Some APM implementations cannot handle events such as pushing the
power button or closing the cover. On such implementations, the system
must be suspended only by using
apm
or zzz
.