I have a 2011 15 inch macbook pro with the i7. When I had mountain lion, lion, and snow leopard installed the brightness controls all worked perfectly fine and the monitor would gradually either brighten or darken, until I had 0 left and it would turn off. Since installing mavericks, it only changes brightness every 2-3 squares/clicks, and then when there are still about 5 left it completely turns off the monitor. I have to turn the brightness all the way back up before the image comes back. I have done a search for that as well as looked through the forums but I have been unable to find a solution. Any ideas? Thanks!