Sunday, 10 July 2011

[How to] Solve Brightness problem in ubuntu

If you are facing brightness adjustment problem on you laptop like you can not adjust your laptop brightness using fn keys then try following one...

1. In a terminal window, type in:
Code:
mousepad ./backlight_d.sh
(the mousepad application will open if doesnt then install it first)

2. Copy and paste the following into the mousepad application that just opened:
Quote:
#!/bin/bash

old_b=9;
declare -i curr_b=240;
declare -i target_b=240;

while : ; do
b=`cat /sys/class/backlight/acpi_video0/brightness`;
delay="0.5"

if [ $old_b != $b ]; then
old_b=$b
let "target_b=$b * 20 + 12"
#printf "Target: %10d\n" $target_b
fi

hex_b=".";

if [ "$curr_b" -lt "$target_b" ] ; then
let "curr_b=$curr_b + 2"
if [ "$curr_b" -gt "$target_b" ] ; then
let "curr_b=$target_b"
fi

hex_b="-"
elif [ "$curr_b" -gt "$target_b" ] ; then
let "curr_b=$curr_b - 2"
if [ "$curr_b" -lt "$target_b" ] ; then
let "curr_b=$target_b"
fi

hex_b="-"
fi

if [ $hex_b != "." ] ; then
hex_b=`printf "%02X" $curr_b`
delay="0.005"
setpci -s 00:02.0 F4.B=$hex_b
fi

sleep $delay
done
3. Save the file:
Code:
File->Save(save it through closing it)
4. Back in the terminal window, type in the following:
Code:
sudo cp ./backlight_d.sh /etc/ && sudo chmod +x /etc/backlight_d.sh
(enter your password when prompted).

5. Enter the following into the terminal window:
Code:
sudo mousepad /etc/rc.local
(mousepad will open again) and before the exit 0 line, type in the following:
Code:
nohup /etc/backlight_d.sh &
so it looks like:
Quote:
nohup /etc/backlight_d.sh &
exit 0
Restart your computer. and done..