I am facing a problem when connecting a ASUS 4k screen to my DELL Latitude E7450 running on ubuntu 16.04 (unity).
I have a “bumblebee-like” setup with: An integrated Intel and an NVIDIA GM108M (GeForce840M)
Initially, only the Intel graphic card was used and I could connect my screen up to resolution, 2560x1600 (16:9) and the image is obviously distorted and a little blurry. After that when trying in 4k (3840x2160 (16:9)), I would just get a black screen with the message: no signal.
My screen is connected via a display port 1.2 to a dell docking station.
I installed NVIDIA Prime and allowed ubuntu to only run using NVIDIA drivers (this holds when rebooting the computer and having the screen plugged in. At some point it was only working if booting and plugging-in the screen afterwards …).
I have tried with several drivers for NVIDIA: 367, 331 and 361. 331 does not work at all while 361 and 367 provide the same result. The result being that I can see my screen in 4k display (60Hz) but it is flickering. The top part of the screen is pretty stable and as you go down it shake more and more (tracking/recognition issue).
Thank you for your eventual support!