Looks like you've got a pretty similar setup as janith who started this
thread. These are your video cards
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core
Processor Family Integrated Graphics Controller (rev 09)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
Thames [Radeon HD 7500M/7600M Series]
The Intel card should probably work nicely but the radeon will give you
trouble...
If you try this mentioned command, what happens?
echo 500 > /sys/class/backlight/intel_backlight/brightness
(if nothing, try different numbers)
