Turns out the issue masked by recent updates was just a suddenly bad video adaptor... lol
I've been using my P2317H as second screen for months with no issues and instant install on my Linux Mint 18. However, probably after some software update, after starting the computer today it's not recognized by the Displays Manager on MATE and it's only shown as "Unknown", with no native resolution (max 1024x768). I can't find drivers for this screen (drivers for a screen? 2019?) and even going to earlier kernel versions didn't make it come back to life. There's no "real" video card, so there's no proprietary drivers I can install/change to have caused that. What could have caused that? Any diagnostic suggestions?What can I do to get my screen working again?   I'm running an i5-5200U, 16GB RAM, Mate 1.14.1, Mint 18.Kernel 4.4.0-97 (last safe version I had, although I also tried 4.4.0-142, 4.4.0-145, 4.15.0-65).
P2317H suddenly unrecognized by Mint 18 / Ubuntu LTS 16.04