For 3 months or so my MBP was fine under Ubuntu. About a month ago (I think after an update), my screen started flickering whenever there is a screen refresh. The flickering varies from slight jitter to split-second screen tearing. It is hard to work with.
I found that if I attach an external monitor via HDMI the screen flicker stops on both monitors.
MacBook Pro (Retina, 15-inch, Mid 2015) Graphics: Intel Iris Pro 1536 MB
I tried getting the appropriate 16.04 Intel drivers from 01.org, but I still have the same problem. Edit from comment: If I boot or come out of suspend with the power cable disconnected, the flicker doesn't happen. I can then plug in the power cable and there is no flicker. Also, this problem does not happen under OSX/MacOS