I'm running ubuntu 14.04 on a Dell laptop (XPS 13 Developer Edition). The brightness slider stopped working (the slider would fill up and empty as usual but the brightness wouldn't change).
This fix got it working again: this is the text I added to the conf file
Section "Device"
Identifier "card0"
Driver "intel"
Option "Backlight" "intel_backlight"
BusID "PCI:0:2:0"
EndSection
However, now the brightness changes in what I assume is 1% increments - way too fine, especially given it takes a few ms to actually change, so if you bash it repeatedly then the brightness keeps changing long after you stop.
This answer suggests that it's hardware based, which is unlikely given the problems I'm having.
This answer looks promising (I read elsewhere that Windows pseudo-supports 100 brightness levels even if the hardware actually rounds them up) but is really vague.
How can I implement the fix in the last link? Or, how can I disable the native brightness buttons and remap them to just run xbacklight commands?
