[ltp] When/where/what for low power consumption?

[Ulrich Kuehn]

On Wed, 2005-11-16 at 16:59 +0100, Felix E. Klee wrote:
[...]
> Now, some questions remain:
> 
> * What ACPI events indicate attachment/detachment to/from mains (I
>    should be able to find that out myself)?
> 

In the acpi event directory have a file containing

==========================

event=ac_adapter
action=/etc/acpi/actions/ac_adapter.sh

==========================

> * How do I find out whether the system is running on batteries on
>    startup (probably using "/proc/acpi/ac_adapter/AC/state")?
> 
Yes, I do exactly that. In the ACPI action script for the ac power
event:
===========================================
status=`awk '/^state: / { print $2 }' /proc/acpi/ac_adapter/AC/state`

case $status in
       "on-line")
                $log "AC adapter is on-line."
                /sbin/laptop-mode.sh stop
                echo "Setting HD spindown for AC mode."
                /sbin/hdparm -S $ACAD_HD /dev/hda > /dev/null 2>&1
                /sbin/hdparm -B $ACAD_PM /dev/hda > /dev/null 2>&1
                #echo -n $ACAD_CPU:$ACAD_THR
> /proc/acpi/processor/CPU0/limit
                exit 0
                ;;
       "off-line")
                $log "AC adapter is off-line."
                sleep 2
                $log $(acpi -b)
                /sbin/laptop-mode.sh start
                echo "Setting HD spindown for battery mode."
                /sbin/hdparm -S $BATT_HD /dev/hda # > /dev/null 2>&1
                /sbin/hdparm -B $BATT_PM /dev/hda > /dev/null 2>&1
                #echo -n $BATT_CPU:$BATT_THR
> /proc/acpi/processor/CPU0/limit
                exit 0
                ;;
esac
=============================

and this script I do actively call during boot, as the acpi event is
only reported on a change.

Ulrich