Comment 6 for bug 338328

Ah, that explains it. Indeed in lshal-1.txt the brightness_in_hardware property is set to false on one device, and on the other it's not existing.

With the fdi files that got you the original hal.txt in comment 3, was brightness working correctly there?

If you replace your /usr/share/hal/fdi/information/10freedesktop/10-laptop-panel-hardware.fdi with this version, does it work correctly?