Black Screen After Turning off Monitor w/ Vega 56

[Ikyo]

hi. i have same situation. Vega 64 and imac18,3 system definition.
i can't enable my monitor after powering it off.
did you find a solution?

I ended up switching monitors and using DP, but I still sometimes have issue with it.

 

[xelanaiznac]

I ended up switching monitors and using DP, but I still sometimes have issue with it.

I think it's a power management issue of Mac OS kext.
with my rx580 no issue on Mac or Windows. with my Vega 64 issue only on Mac OS (not on windows).
furthemore, my vega64 red power led are always on in Mac OS, while it's behavior is completely different on windows

 

[Ikyo]

I think it's a power management issue of Mac OS kext.
with my rx580 no issue on Mac or Windows. with my Vega 64 issue only on Mac OS (not on windows).
furthemore, my vega64 red power led are always on in Mac OS, while it's behavior is completely different on windows

That is very possible. I didn't have the issue with my RX580 either.

 

[benjackson]

I think I have this issue too. I have the iMac Pro build as per that big thread, but with a Vega 56. I never sleep my mac (it's a Plex Server) but I do like to turn the displays off. It's fine at first but if I don't come back for a night or so, the displays will never wake up and yet the computer still seems to be going fine. Restart fixes. If I set my displays to not sleep and screen saver only, I never have issues, I never get black screen. Power management of a KEXT seems to make sense to me given I only see it over long periods of displays being off. I'm stumped as to what to try next - have tried everything you guys have down. VegaGraphicsFixup was very important for me to make an ASUS MST 4K display work properly. I had to take out WhateverGreen. I use everything that I'm supposed to with SSDTs etc for this build, everything else works great. Just this last remaining issue.

Edit: not looking for support, just adding my experience, so don't jump on me if I didn't include every detail of my build!

Edit 2: I had one crash yesterday even with the monitors awake and only on screensaver. Big 'there was a problem with your computer' message on restart so it wasn't happy again. Not sure what's causing it.

Edit 3: I sometimes also get panics, so I read my panic report and didn't really get very far but it gave me some key words to search for. Vague references to potential hardware problems, or GPU acting up. But given it was working before when I first set up the machine, I was not convinced. But it did lead me to realise it was probably related to the GPU after idle doing something weird. Over the last few months with this I've been updating as everything came up...but Lilu was updated only just the other day, and so I updated it and I haven't had a crash since (2 nights). So I feel it's a software glitch that can be fixed when all these little tweaks get improved. Power Management working great, Intel Power Gadget shows dropping to very low frequencies when needed and about 28-29 degrees celsius. Hope this helps someone.

Edit 4: I was still getting graphics lock ups, not panics now, but just black screen after a long time away from the computer, whether displays off or keeping them on and just screen saver. So delved in deeper. Noticed that WhateverGreen isn't just for Nvidia (my mistake thinking it was), as I had not installed it before for that reason and because it caused issues with my setup. Installed latest version, but then my Asus MST monitor showed up as 2 separate screens - same reason I elected to not install it before. Then looked thru possible boot flags and recognised that ngfxpatch=pikera changed the board-id to something random, and remembered that was a solution I came up with on my own years ago to edit plist files with board-ids which made my MST monitor work. So put in that bootflag ngfxpatch=pikera and it worked with WhateverGreen kext for first time, in MST mode 60hz. And for "whatever" reason (pun intended!), machine hasn't locked up in a few days even turning displays off. Again, hope this helps someone.

Edit 5: Month or so later now - the system was a lot more stable but would still get the displays not turning back on every so often. Seemed random, couldn't figure it out. I finally figured out that if I keep Apple Remote Desktop open with an active screen sharing to my Mac server, it will be crashed the next day. If I quit ARD then I'm good. Haven't had an issue since! I'm thinking almost all my troubles have been attributed to this! Nothing to do with graphics cards or software. Just ARD not having been updated and not compatible properly with Mojave! Also, having 'sync all cores' on in the BIOS can also cause issues with Handbrake rendering but otherwise it's fine to keep on (speeds up my CINEBENCH score from about 2200 to 2800 by having Sync All Cores on so it's worth it). I think this will be my final edit on this post. Wohoo!

 

[littlecreature]

Are you guys still dealing with this issue? I am, on a Vega 64. It is rare, but damned annoying.

 

[VMoradian]

I, too, have a similar problem. I have a Sapphire Radeon Rx Vega 64 card in a triple-monitor setup. I can only get two of the three display ports to work. The third display port goes black after getting to the mac desktop. If I use the HDMI port I can get triple monitors but I need the HDMI port for my Oculus Rift under windows (I have a dual-boot system). I have tried all the suggestions in this post but still no joy. Any thoughts? My EFI folder with the config.plist is attached. Thanks.

My build:
MSI Z270 Gaming Pro Carbon
Intel Core i7-7700K Kaby Lake
Sapphire Radeon Rx Vega 64 8gb
High Sierra 10.13.6
32gb DDR4 3200 mhz
750w Corsair power supply

 

[carbonimax]

Hi

I have same situation. Did you find any solution?

 

[VMoradian]

In my case, updating to the latest Mojave (10.14.6) seems to have solved the problem.

 

[carbonimax]

It's OK for you on Catalina ?

 

[VMoradian]

I haven't updated to Catalina.