I have same kind of problem in Kubuntu Edgy. Hardware: HP omnibook vt6200, ati mobility radeon. Video driver is ati (issue is also with vesa driver). Laptop backlight stays always on. Screen blanking only makes display black but backlight stays on. If I switch backlight off with "xset dpms force off" backlight will stay off 30-60 seconds, then it will switch back on. With "sudo radeontool light off" backlight stays off.
-- Laptop backlight does not turn off https://launchpad.net/bugs/19410 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
