MP 1,1-5,1 Displayport KVM Issues

[mckyvlle]

Hey all,

I have a Mac Pro 5.1, with a NVidia GeForce GTX 680 (2GB) patched with the native ROM, running Open Core and Big Sur 11.7.

My monitor is an Apple LED Cinema Display 24'' plugged into the NVidia's DisplayPort output.

I've just been trying to get the Cinema Display hooked up to a DisplayPort KVM. With the KVM set to the Mac Pro, the monitor works perfectly. However, once I switch away and then back to the Mac Pro, I lose the display completely. It's as if the Mac Pro can longer see the monitor and nothing short of a reboot will bring the display output back.

Anyone facing similar issues before?

 

[mattspace]

Part of the displayport spec, is that a display sleep event disconnects the display from the host computer. That may be part of the problem.

Something to try, would be a second display plugged into the card directly, and see what happens to your menubar and application windows when the KVM switches. What else is plugged into the KVM? If you have another system plugged in, try VNC/ARDing into the Mac Pro and seeing if the screen is showing up, then try the detect displays option.

 

[mckyvlle]

Thanks for the suggestion, took me a couple of days to get round testing!

The other device on the KVM is a laptop running Linux (Pop OS 22.04).

With a second display plugged into the DVI socket on the Mac Pro, all windows move to that display when I switch away from the Mac. (edit: Tried with a HDMI monitor, same behaviour!)

Mac can't wake up the Cinema Display after switching back. Detect Display doesn't do anything. Using Apple Screen Sharing (from my MacBook Pro) only shows the DVI display. So basically as if the DisplayPort has gone completely missing once it's unplugged

Linux laptop has no problems waking up the Cinema Display via the KVM even switching back and forth with the Mac. Though always no display from the Mac in this case.