Comment 49 for bug 538256

The bug also affects Lenovo Ideapad U150. On this laptop, the brightness buttons work, the brightness applet notification pops up to show current brightness level and the respective files in /sys and /proc folders are updated with the brightness value, but the display brightness level stays at maximum value.

Only by using setpci command I am able to set display brightness, so I am using /etc/acpi/ideapad-video.sh script as a temporary
workaround.

I've also tried upgrading to 2.6.36 kernel from the Kernel PPA, but there is no improvement to the brightness setting issue.