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
but no error if I use:
echo -n 30 > /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!
echo -n 20 > /proc/acpi/video/GFX0/DD03/brightness
Originally Posted by urmish