Hi, I have a late 2011 macbook pro with mountain lion installed. Auto brightness has been working well for me since I bought the mac. But today I re-installed mountain lion and now the auto brightness seems to be not going below a certain point somewhere a little below the middle in the brightness adjuster in the system preferences. But it suddenly climbs if I bring a bright light near it. At the moment I my room is completely dark with all the lights off but still it doesn't fall below the mid-range. Any ideas?