Comment 193 for bug 568611

Addressing several recent posts regarding the linux-kamal-mjgbacklight PPA:
https://launchpad.net/~kamalmostafa/+archive/linux-kamal-mjgbacklight

A few of you have reported problems with the backlight not coming back on after power management / lid events (or after 'xset dpms force off')... It is not clear whether this problem is specific to the linux-kamal-mjgbacklight PPA kernel or a new problem introduced in the mainline 11.04 kernel (as suggested by bug 765438). Those experiencing this problem: Please advise whether booting with the parameter "i915.alse_backlight=1" affects it (and also whether that parameter adversely affect the normal backlight control, which it might).

The "inverted brightness controls" problem reported on some Acer systems (Acer TravelMate, Acer eMachines G525) is a known issue and is being investigated.

Some users have asked whether these backlight patches can be applied to Ubuntu 10.04 (Lucid): No. The linux-kamal-mjgbacklight PPA is only applicable to Ubuntu 10.10 (Maverick) and Ubuntu 11.04 (Natty). I do not expect that this work will be ported to Lucid or earlier releases due to technical incompatibilities.

Upstream status of the patch set: We are still waiting for one (critical) patch to be applied to the upstream linux kernel before we can integrate this functionality into the main Ubuntu kernel. Until such time, I will continue to maintain up-to-date Maverick and Natty kernels including the patches at the PPA linked above.