I'm the creator of oBacklight and will try to help you utilize the script i created for nvidiabl. It looks like there is 2 different problems that you are experiencing, one with the brightness changes and the other with FN keys.
When it comes to my script have you looked at the document page for the script(http://dev.osource.se/docs/obacklight/
), especially the configuration part
What you can do to see what range your values that could work for you is not to start my script but instead put your own values directly into /sys/class/backlight/nvidia_backlight/brightness
Do as follows:
- Open a terminal window and enter into admin mode(sudo -i)
- Run the following command start with for example 10 and if nothing happens go upwards until you get an reaction, otherwise if you get a response on 10 go down until you have a satisfactory low value, then do the same upwards until you reach maximum brightness.
echo "10" > /sys/class/backlight/nvidia_backlight/brightness
Get back to me with what values you get and we go from there.