Comment 6 for bug 1053269

@Lucazade- Thanks very much for reporting this regression. We're reasonably sure that the problem was introduced by one of the two backlight patches which were included in the 3.5.0-15.22 kernel. I've prepared two new test kernels -- each has just one of those patches applied:

http://people.canonical.com/~kamal/lp1053269/patch1only/
http://people.canonical.com/~kamal/lp1053269/patch2only/

Please try both of those test kernels, and let us know which one causes the problem. (Its not likely that the problem will occur with both, but please do test both to confirm that).