Unable to adjust screen brightness

[Shamess707]

I have a gateway m-series laptop, and I just recently installed ubuntu 9.04 (x64) in attempts to broadening my OS use. For the most part this is working great, but my current issue is with my screen brightness. When attempting to adjust the brightness either through ubuntu or on my keyboard(fn+up or down) ubuntu shows that I am adjusting the brightness but there is no actual change. Any help would be greatly appriciated

[urmish]

try this

echo -n 20 > /proc/acpi/video/GFX0/DD03/brightness

here 20 is the % brightness
set it up to anything you like till 100

you might have to do
sudo su
for this

[tomjennings]

I'm having the same problem with a Samsung x460, has the Intel Mobile Series 4 (07) chipset.

There are a number of threads about this chip, most people give advice like yours, poking a value into /proc, but does nto work here. I brute-furce tried DD01..DD05.

But here's an odd one: I get a write error if I do

echo -n 30 > /proc/acpi/video/GFX0/DD03/brightness

but no error if I use:

echo -n 20 > /proc/acpi/video/GFX0/DD03/brightness

Various other values fail/succeed., but none change screen brightness which on my machine is unusably dim. I may have to switch back to Win7 simply for screen brightness!

try this

echo -n 20 > /proc/acpi/video/GFX0/DD03/brightness

for this