Do you get any error on the console when trying to use gamma? What does the initial log-output say about your installed drivers, what's the performance like?
If gamma fails it should output the SDL-error, that might help in fixing the problem - I suspect, most likely, you're running with mesa not proper OpenGL drivers!!
If gamma fails it should output the SDL-error, that might help in fixing the problem - I suspect, most likely, you're running with mesa not proper OpenGL drivers!!