2.6.28-15 acpi regression

[SoulTaker]

Binary package hint: acpi

After update of linux kernel (10.09.2009) - which reverted acpi driver old problem of brightness control appeared once again.

I had a brightness control problem on Packard Bell laptop: While Ubuntu on loading screen brightness drops to zero. When X started it's possible to adjust it back with FN keys (but can't reach max value), but adjustment is not linear: pressing UP button brings it to some value and pressing button once more - drops value to minimum. And when any graphical is app started (linux prey demo for example or anything else but glxgears - it doesn't reproduce the BUG) brightness once again drops to zero. When adjusted and app is exited - one again and so on). Not to mention constant random flickering when nothing is going on: it might be text reading when brightness drops to zero for a couple of frames and then going back for it's previous value - very annoying.

After last update of linux kernel (2.6.28-15) prior to 10.09.2009 - this problem gone. It was all fine until now: after today update the problem appeared once again.

PS.
$ lsb_release -rd
Description: Ubuntu 9.04
Release: 9.04

$ uname -a
Linux abbys 2.6.28-15-generic #52-Ubuntu SMP Wed Sep 9 10:49:34 UTC 2009 i686 GNU/Linux

Video: Intel GM965

ProblemType: Bug
Architecture: i386
Dependencies:
 libgcc1 1:4.3.3-5ubuntu4
 gcc-4.3-base 4.3.3-5ubuntu4
 findutils 4.4.0-2ubuntu4
 libc6 2.9-4ubuntu6.1
DistroRelease: Ubuntu 9.04
Package: acpi 1.2-1ubuntu1
ProcEnviron:
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: acpi
Uname: Linux 2.6.28-15-generic i686