That's because there is no native backlight support from i915 for XRANDR to use when KMS is in use, and KMS wasn't in use in jaunty by default. Discussions are going on upstream about how to implement it [1] but it will not be available until the lucid+1 timeframe at the earliest, and you can boot with i915.modeset=0 to restore the old functionality if it's absolutely required.
[1] https://patchwork.kernel.org/patch/81187/ ** Also affects: linux (Ubuntu) Importance: Undecided Status: New ** Changed in: xserver-xorg-video-intel (Ubuntu) Status: Confirmed => Won't Fix ** Changed in: linux (Ubuntu) Importance: Undecided => Wishlist ** Changed in: linux (Ubuntu) Status: New => Confirmed -- [gm45] brightness control previously work after xrandr invocation now does not https://bugs.launchpad.net/bugs/483062 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
