Sebastian Schwarz, Thu 2011-11-10 @ 16:36:54+0100: > My display comes back with the minimal brightness setting. Also the > XF86MonBrightnessUp (Fn+Up) and XF86MonBrightnessDown (Fn+Down) > buttons stopped working. I can restore the previous brightness level > and the buttons by running: > > cat /sys/class/backlight/intel_backlight/max_brightness \ > > /sys/class/backlight/intel_backlight/brightness > > The bug can easily triggered in X by running: > > xset dpms force off Yes, this is the same behavior that I'm seeing. Writing the max_brightness value into the sysfs brightness file restores normal backlight brightness. I can also restore it with `xbacklight -set 100`. > I found this I my dmesg output: > > [Firmware Bug]: Duplicate ACPI video bus devices for the same VGA > controller, please try module parameter > "video.allow_duplicates=1"if the current driver doesn't work. > > But I also haven't tried this, as the incorrect brightness has not > annoyed me enough, yet. I have this message in my dmesg output as well, but unfortunately, setting the mentioned module parameter doesn't have any effect on the problems I'm seeing.
