Take a look at https://wiki.ubuntu.com/Kernel/Debugging/Backlight and provide the information requested in the "Debugging information to provide in your bug report" section of that page.
** Changed in: linux (Ubuntu) Status: Confirmed => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1266485 Title: backlight problem... I cannot configure the backlight To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1266485/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs