I recently purchased an Oculus Rift S. It works great - responsive tracking and no black screen when using Oculus Home (monitor is plugged in at this point).
However when I wish to play games (Dirt Rally, Moss, Skyrim VR) on either Oculus purchase games or Steam purchased games it will not work unless I unplug my main monitor. It works amazingly well if I unplug my monitor, yet is unresponsive / black screen with sound / black screen with orange light if I have the monitor plugged in.
The only thing I could think of is could this be that my PSU is not giving enough power? Specs below. PSU is 4 1/2 years old.
I have an I5 4460 CPU, XFX RX 580 GTS XXX Edition GPU, Corsair VS550 ATX PSU and ASUS H81M-PLus Motherboard. The rift is running on a powered RSHTECH USB hub out of a Inatech Superspeed 4 port PCI. 8GB Ram, Windows 10.
My monitor is an iiyama G2730HSU 27".
All of the above are within the minimum required specs for the Rift S.
I have unplugged and replugged in display port, USB 3, tried new PCI port, tried a new externally powered USB hub, set my USB to not disable power, reinstalled the software, repaired the software, deleted and reinstalled Rift S, updated drivers on USB, updated drivers on Card, Updated Windows and created a new user with admin rights.
I have been in touch with support but we seem to go round in circles of the same question.
HDMI should be fine, I just wanted to make sure you weren't plugging your monitor into the motherboard video outputs (which can cause issues for VR). You could try the other DisplayPort sockets for your Rift S--some people have had success switching to a different DP.