HP MT645 Gen7 Display Port Issues

[Hayo-naise]

So we have HP MT645 thin clients and Kensington SD4839P USB-C docking stations connected to two HP 22in screens. one via HDMI and the other via display port.

If the user plugs the docking station in and powers up from cold boot both screens are detected and displayed correctly at the right resolution. if the users disconnects the USB dock, goes to a meeting and comes back the display port screen is detected at 640x480 resolution and cannot be changed.

This issue occurs on a completely fresh HP image build. We have installed dock works and display link and no change. it has the latest drivers installed but no joy.

The setup with cables and hardware is fine as our older MT46 laptops work perfectly straight out the box. The issue appears to be with either the MT645 missing a driver or something broken on their images. I've tried the latest AMD drivers and the latest drivers from HP. I've tried the HP support agent and that shows we have the latest everything installed.

Not sure how to proceed. We have 250 of these laptops that currently serve as paper weights.

[Hayo-naise]

So further to this madness a Displayport to HDMI adapter fixes this issue. So the problem appears to be the laptop not correctly negotiating with the screen when its connected via displayport to displayport. Quick solution is to purchase these cables but given we have over 1000 screens seams like a poor fix to the issue.