[kernel 2.6.31.4] backlight controls gone mad

["Nélson «VuDu» Cunha" <vudu.curse@gmail.com>]

Hello,

I'm using ArchLinux (here's the "downstream" bug report:
http://bugs.archlinux.org/task/16698) and with the last update to
kernel 2.6.31.4 my backlight/brightness controls have gone mad.

My laptop's screen keeps blinking, slowly increasing or decreasing its
luminosity randomly. Sometimes it stays still for a couple of minutes
at any random brightness level, but it's very uncomfortable for the
eyes when it's blinking.
Here's a video of what's happening:
http://www.mediafire.com/download.php?z4mi4uzidjn

I've tried to use /proc/acpi/video/VGA/LCDD/brightness and
/sys/class/backlight/acpi_video0/brightness but with no luck, because
they make no changes and when I cat them I get wrong values.

I tried using xbacklight but it gives me "No outputs have backlight property".

With the previous (2.6.30.6) version I had no problems and after
getting this problem I installed Arch's "kernel26-lts" package
(2.6.27.37) and I'm having no issues with that kernel.

My laptop is an ASUS M51VA with an Intel C2D and an ATI HD 3650. I
tried fglrx, radeon and radeonhd and it made no difference.

If you need more details, please say so.

Best Regards.