30" Cinema Display - USB ports don't work
I have a 30" ACD plugged into my 15" Retina MBP. Both the MiniDisplay Port and USB cables from the ACD are plugged into the MBP.
The ACD works fine, except for one thing: the USB ports on the rear of the ACD don't work. Any idea what I can do about that?
MacBook Pro with Retina display, OS X El Capitan (10.11)