P2000 and DP 1.2

I have a quadro P2000 card and a Dell UP3214Q (32" 4K monitor). When I set the monitor into DP 1.2 mode, the X server does not display an output. the screen goes blank, and eventually goes into sleep mode. The Xorg.0.log file says that the server could not find a valid display mode. When I set my monitor to DP 1.1 mode, the driver and card work fine.

I’m running NVIDIA driver version 387.12, Fedora 26, Linux 4.13.9

Any ideas?

Please insert

Option "ModeDebug" "true"

into screen or device section of your xorg.conf, run nvidia-bug-report.sh as root when switched to DP1.2 and attach the tar.gz file it creates to your post.