Recently I came across a Radeon graphics related issue: it turns out that the
xbacklight brightness-related commands do not work with it. After a short research, I found the light-git (AUR) package, which seems to work as well on Intel as on Radeon card. I added light-git as an optional obhud dependency. If found,
light will be used instead of
xbacklight to increase/decrease the brightness level.
Also several bug fixes have been added to the obhud package.
See the project site for more info.