This seems to be a hardware issue rather than a Ubuntu issue, but nevertheless, here goes. I have an Acer ao756-2617 with Ubuntu 14.04, elementary os luna, bodhi linux, and zorin os 8. most of these if not all are Ubuntu or Debian related (not sure bout Bodhi). anyway, every time i try to use my brightness controls for the screen, they don't work. when i use them, all i get is the animation on the upper right corner that its working, but it doesn't actually do anything. so i did some research. I found that I could manually change the brightness using one of two things:
sudo intel_backlight <% no. of brightness>
echo <no. from 0 - 976> | sudo tee - /sys/class/backlight/intel_backlight/brightness
Apparently, the file controlling the brightness for the screen is the one described on the command above. I did an
acpi_listen to see what I got when I used the Fn+brightness controls and I got:
video/brightnessdown BRTDN 00000087 00000000 video/brightnessup BRTUP 00000086 00000000
(those come from Ubuntu 14.04. the other OS's give similar output)
This suggests that these keys are being mapped to be handled to acpi drivers, instead of the intel ones. I tried changing that, but I have no idea what to do. I dont even know if I'm on the right track. granted, I know that a backlight problem mustn't be much of a concern for the devs, but this could help others like me. help, anyone?