Display Issues after update

Question

I updated my OS last March 4, 2017. After the update, I have the following display issues.

1) Laptop display is shown as Unknown Display

2) Laptop display brightness cannot be adjusted

3) External monitor cannot be connected. It can be connected before bootup, but the GUI won't allow me to extend displays. Both displays (external and built-in) are shown as Unknown Display

Answer 1

download a free app from the AppCenter called Dimmer