Screen Brightness controls
The sven keyboard daemon, which is in the system tray,
calls a couple scripts to control the screen brightness.
Unfortunately this varies a bit between computers. There's three
things that can go wrong with this.
1) Sven isn't configured to use the correct keys for your
2) The two scripts that Sven calls
(/usr/bin/brightness-up and /usr/bin/brightness-down) could be
using the wrong file in /sys
3) The two scripts that Sven calls (brightness-up and
brightness-down) could be using too low of a value to increase
or decrease the brightness. So it's actually working but it
doesn't seem like it because you have to hit the key a hundred
So the first thing to do is open a terminal and type: brightness-up
and then press Enter.
If it changes the screen brightness then it's probably problem 1.
If you get an error about file not found , then it's probably
problem 2. If it doesn't return an error, but nothing seems to
happen, then it's probably problem 3.
The brightness-up script looks like this:
DEVICE= #radeon_bl0, acpi_video0, etc
[ -z $DEVICE ] && DEVICE=$(ls $DEVPATH | head
[ -z $DEVICE ] && exit 1
CURRENT=$(( CURRENT + 1 ))
if [ "$CURRENT" -gt "$MAX" ]; then CURRENT=$MAX; fi
echo $CURRENT > $DEVPATH/$DEVICE/brightness
For problem 3, you'll want to change CURRENT + 1 to maybe CURRENT
+ 100 and try again. For problem 2, you'll need to replace
/sys/class/backlight/acpi_video0/ with the correct path. You'll
also need to make the corresponding changes to