Comment 15 for bug 82188

I tried a newer BIOS (f.39) again in the hope that bug would have been fixed, as the older bioses cause other bugs for me, but the brighness adjustment still will not work.

I think the bug actually isn't in hal but in the kernel (acpi module?). It seems that the /proc/acpi interface is deprecated and hal won't be supporting it in the future. At least according to this thread on the hal mailing list
http://lists.freedesktop.org/archives/hal/2007-September/009557.html
If I understood correctly the kernel should supply a /sys/class/backlight directory to control the lcd backlight brightness.

On my laptop (HP dv2100t) with the f.39 BIOS I too can control the brightness like grybba explained through
/proc/acpi/video/GFX0/LCD/brightness
or
/proc/acpi/video/VGA/LCD/brightness
but my /sys/class/backlight directory is empty and thus hal can't control the brigthtness.

If the others suffering from this bug also have no /sys/class/backlight, but can control the brightness via /proc then in my understanding this bug should be assigned to the kernel.

If there is any further information on my system you need, just let me know. I'll happily run some tests.