Black Screen After Turning off Monitor w/ Vega 56

[kramerkramer]

I have a RX 560 (that shows up as a Radeon Pro 555 in System Report) and it worked fine under High Sierra. I just upgraded to Catalina and this exact problem is showing up. I have a 4K HDMI KVM switch and when I switch to another computer and then switch back the video signal is gone and I cannot wake it up. Only way I was able to get the screen back was to unplug the HDMI from the graphics card and plug in back in. I was able to find a work around that is a little annoying: I set my power settings to turn off the display after 1 minute. It turns out that if the power save turns it off, it WILL turn back on when I switch back to it from the KVM. As long as I do not switch back and forth faster than a minute this works. But I would love to have a fix. It seems that it must be detecting the monitor being "turned off" and turn off the video signal. And then it is unable to notice that the monitor is back when the KVM is switched to it. Seems like there powerd is a likely culprit.

 

[alerteman]

im having the same problem with z390i strix and vega 56 nano. Catalina 10.5.3
please help. how to fix this? very annoying. If i turn off the monitor , or unplug and replug hdmi cable, the monitor never turn back on.Only way to fix this to restart the computer. I tried smbios imacpro 1,1 and macpro 7,1.

any possible solution?

 

[pastrychef]

HDMI is your problem. HDMI just doesn't work well with macOS. Use a good DisplayPort cable and you shouldn't have these problems.

 

[alerteman]

very strange, if i use keyboard short cut key to lock the screen, the display is back on. <- this might be the temporary solution instead of restart.

 

[Shiitaki]

im having the same problem with z390i strix and vega 56 nano. Catalina 10.5.3
please help. how to fix this? very annoying. If i turn off the monitor , or unplug and replug hdmi cable, the monitor never turn back on.Only way to fix this to restart the computer. I tried smbios imacpro 1,1 and macpro 7,1.

any possible solution?

I've been having this issue for over a year now, and 3 graphics cards two versions of macOS later I think the problem is with the monitor. Windows users are also having this issue with AMD GPUs as I have occasional with Windows myself. I have an 8K display port cable that no matter what it won't work with macOS but works fine with Windows. Currently I have the GPU routed through a thunderbolt 3 card using a USB C to display port cable which at least means I can simply turn the monitor off and on using the power button.

I suspect it's actually a problem between AMD GPUs and certain monitors that can be affected by the cable used, but you are not alone and it is not entirely a macOS issue either.

To be clear, for me, the issue is the monitor not initializing the display properly. This varies from a image with a red tinge to a black screen with the monitor in sleep mode and requiring a hardware reset to get it back, power cycling and plugging cables doesn't bring it back. This can happen on any of the display ports and HDMI ports on a RX580, Vega56, and 5700XT.

 

[alerteman]

thanks for your help. but how come other people dont have this issue? only handful number of people have this issue.
i tried 3 different monitor, its the same. i tried asus, lg and dell.

i even tried with vega 64 . its the same. its just annoying thats it.