Nexus7 Ubuntu backlight brightness control

Nexus7 Ubuntu 13.04 backlight brightness control 

[System Settings] -> [Brightness & Lock] is not possible to adjust the brightness on.

Enter the terminal

sudo tee /sys/class/backlight/pwm-backlight/brightness 

or

echo 200 | sudo tee /sys/class/backlight/pwm-backlight/brightness

or

sudo /usr/lib/gnome-settings-daemon/gsd-backlight-helper --set-brightness 200

If you enter 0 to 255 brightness changes.

(Max brightness can be seen with the command.
cat /sys/class/backlight/pwm-backlight/max_brightness
or
sudo /usr/lib/gnome-settings-daemon/gsd-backlight-helper --get-max-brightness)

After the [System Settings] -> [Brightness & Lock] in the brightness can be adjusted.

However, after a reboot of 40 brightness changes....-_-;;;;