I have the same problem on my macbook, made the same test with xrandr with the same results.
The gnome-power-manager brightness applet shows the same behavior, if you move the slider the bl flickers like crazy. AFAIK, it also uses libXrandr.
I have the same problem on my macbook, made the same test with xrandr with the same results.
The gnome-power-manager brightness applet shows the same behavior, if you move the slider the bl flickers like crazy. AFAIK, it also uses libXrandr.