XPS13 - ubuntu 16.4 - display port usb-c stopped working

Hi,

I am new to linux myself, and so far I have nothing but love for ubuntu.  

Anyway, I recently did a system update on my Dell XPS 13 - Ubuntu 16.4.  Afterward, the display port (thunderbolt usb-c) port stopped working altogether.  

Not sure if it's hardware related or not.  I really don't want to reinstall to check.  Could someone please help and point me to the right direction?

Thanks,

Allan