HOWTO - Fix your laptops brightness function keys operating properly in 8.04 Hardy

[AaronMT]

Hello folks,

If you're like me, you recently installed Ubuntu Hardy Heron 8.04 and discovered that your laptops function keys are not properly adjusting the brightness. In essence, you are pressing the key combination and nothing is happening.

I have written a fix that simply replaces two script files. This may or may not work for you. Always create a backup first.

Here is what I edited within two files:

First we are going to change brightness up

sudo gedit /etc/acpi/video_brightnessup.sh

Replace everything in the file with the following

#!/bin/bash

CURRENT=$(grep "current:" /proc/acpi/video/VGA/LCD/brightness |awk '{print $2}')


case "$CURRENT" in

100)
echo -n 100 > /proc/acpi/video/VGA/LCD/brightness;
;;
87)
echo -n 100 > /proc/acpi/video/VGA/LCD/brightness;
;;
75)
echo -n 87 > /proc/acpi/video/VGA/LCD/brightness;
;;
62)
echo -n 75 > /proc/acpi/video/VGA/LCD/brightness;
;;
50)
echo -n 62 > /proc/acpi/video/VGA/LCD/brightness;
;;
37)
echo -n 50 > /proc/acpi/video/VGA/LCD/brightness;
;;
25)
echo -n 37 > /proc/acpi/video/VGA/LCD/brightness;
;;
12)
echo -n 25 > /proc/acpi/video/VGA/LCD/brightness;
;;
*)
echo -n 100 > /proc/acpi/video/VGA/LCD/brightness ;
;;
esac

Save and quit

Now we are going to edit brightness down

sudo gedit /etc/acpi/video_brightnessdown.sh

Replace everything in the file with the following

#!/bin/bash

CURRENT=$(grep "current:" /proc/acpi/video/VGA/LCD/brightness |awk '{print $2}')


case "$CURRENT" in

12)
echo -n 12 > /proc/acpi/video/VGA/LCD/brightness;
;;
25)
echo -n 12 > /proc/acpi/video/VGA/LCD/brightness;
;;
37)
echo -n 25 > /proc/acpi/video/VGA/LCD/brightness;
;;
50)
echo -n 37 > /proc/acpi/video/VGA/LCD/brightness;
;;
62)
echo -n 50 > /proc/acpi/video/VGA/LCD/brightness;
;;
75)
echo -n 62 > /proc/acpi/video/VGA/LCD/brightness;
;;
87)
echo -n 75 > /proc/acpi/video/VGA/LCD/brightness;
;;
100)
echo -n 87 > /proc/acpi/video/VGA/LCD/brightness;
;;
*)
echo -n 50 > /proc/acpi/video/VGA/LCD/brightness ;
;;
esac

Save and quit

No reboot or logout required, simply press your function combination on your laptop to change brightness. If you're laptop is like mine, I press FN + Up/Down Arrow.

Let me know how it works. If this does nothing, it's best to restore the backup you made prior.

Post your comments in this thread, let me know how it goes.


- AaronMT

[AaronMT]

Just want to add that I have tested this as well on a new HP Laptop and it works.

[pritamps]

Tested on Dell Latitude 131L and it works!

Thanks!

[likwid]

Unfortunately does not work with Samsung R60plus.

[JJ_Kame_R]

Unfortunaly it doesn't work on asus notebook.

My brightness with asus_laptop module on is always set to minimum and controls don't change a thing.

Only way to use the notebook is to boot with acpi=off option or to blacklist asus_laptop module.

I'm sorry but I have to admit that hardy is 2 steps behind gutsy.

[coachwhip]

Do you think it will work with Kubuntu ?

i will try it once I get the 'sudo' working. i can open files with kate but not with sudo kate.

I'll let you know once i get to try it.

Mike

Edit. I've just tried it and it appears to work, not rebooted yet but so far so good, got brightness back and funcion keys work fine.

Thanks for that

[windwisp]

works on dell vostro.

[pormogo]

Tried this fix on my Dell m1330n and it didn't do anything. I still have the 3 "stages" of brightness. I am also having another issue where anytime I watch a video (in say VLC) the backlight turns back up to maximum brightness for some reason.

[ra300z]

I have an HP DV2000 laptop and this did not work for me.

This thread did solve the problem
http://ubuntuforums.org/showthread.p...ght=brightness

[guevara]

why do we need change brightness for battery?
I almost never changed