RHEL 7.4 does not see two screens on Asus PRIME Z370-P system

I installed RHEL 7.4 on a system based on the new Asus PRIME Z370-P (latest BIOS 0610) motherboard.
The system has a DVI and HDMI displays connected to it.
However, even though I did 'yum update', I see only one display in all-setup/displays, and it is discovered as 'Unknown Display'.