Disable DVI chip on Beagleboard to save power

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tallakt

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Apr 10, 2010, 2:09:23 AM4/10/10
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Hi

Just wanted to post this as I have searched for it myself and never
found any good tips for it. (I use Angstrom and kernel version 2.5.32)

The magic line is:


echo 0 > /sys/devices/platform/omapdss/display0/enabled
echo 0 > /sys/devices/platform/omapdss/display1/enabled


This brings nominal power consumption from 1.7W to 1.0W (very
approximate) - a substantial saving.


I also made scripts to perform this automatically when starting in
runlevel 3 (console, default level is specified in /etc/inittab):

First, I made a script file and put it in /etc/init.d/beagleboard-
disable-display.sh

It looks like this:

#! /bin/sh
### BEGIN INIT INFO
# Provides:
# Required-Start:
# Required-Stop:
# Default-Start: 3
# Default-Stop: 0 1 2 4 5 6
# Short-Description: Switches off the DVI on Beagleboard to save power
# Description:
### END INIT INFO

# Author: Tallak Tveide <tal...@tveide.net>
#

# PATH should only include /usr/* if it runs after the mountnfs.sh
script

case "$1" in
start)
echo "Switching off DVI to save power"
echo 0 > /sys/devices/platform/omapdss/display0/enabled
echo 0 > /sys/devices/platform/omapdss/display1/enabled
;;
stop)
echo "Switching on DVI"
echo 1 > /sys/devices/platform/omapdss/display0/enabled
echo 1 > /sys/devices/platform/omapdss/display1/enabled
;;
restart)
echo "Switching off DVI to save power"
echo 0 > /sys/devices/platform/omapdss/display0/enabled
echo 0 > /sys/devices/platform/omapdss/display1/enabled
;;
run)
echo "Switching on DVI"
echo 0 > /sys/devices/platform/omapdss/display0/enabled
echo 0 > /sys/devices/platform/omapdss/display1/enabled
;;
*)
echo "Usage: $SCRIPTNAME {start|stop|restart|run}" >&2
exit 3
;;
esac


Next, i run the following command:

update-rc.d beagleboard-disable-display.sh start 99 3 .


Youre all set ;-)

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