Ubuntu Linux on Samsung N150/N210/N220 Netbook: how to adjust brightness

Installed Lubuntu 13.10 on my old Samsung N220 laptop, everything is ok except the screen is dark. And could not find the fn key to adjust the brightness. Tried install samsung-tools:

sudo add-apt-repository ppa:voria/ppa
sudo apt-get install samsung-tools

then use the Fn+F5 you can turn on/off the screen. However, still cannot adjust the brightness.
Searched around and found the following commands can turn screen bright/dark:

• To turn it bright:

  sudo setpci -s 00:02.0 F4.B=CC

• To turn it dark:

  sudo setpci -s 00:02.0 F4.B=50

Where CC and 50 are the brightness values. To check the current brightness value:

lspci -s 00:02.0 -xxx | grep f0: | awk '{print $6}'

With the above commands, it is possible to write a script to adjust the brightness and bind it to key combination.