Screen goes black for 2-3 seconds

[Etyel]

Hi, I wanted to resume this thread but it is closed.

I have the same problem and I'm also desperate to find a solution to this defect which seems to be quite rare since very few forums talk about it. Looking at these configurations and comparing with mine, I don't see any obvious common point that would allow to determine the origin of this phenomenon. For my part, it appeared after passing from Mojave to Big Sur and first manifested itself as a crash upon waking. By disabling iGPU in the Bios, I only have these blackouts for a couple of seconds that we are dealing with here. I thought the cause might be my Vega 64, but I see this happening with other cards. I tested my card by starting Windows and nothing to report. So I'm not even sure if finding a 6800XT is a solution. I'm running Clover 5140, does this "blackout" also occur on Open Core?

 

[Edhawk]

Did you try the fix offered by Jaymonkey - Post #7 in the thread you linked?

Questions:

1. How are you connecting your display(s) to the graphics card, HDMI, DP or DVI?
2. How many displays are connected?
3. Does the black screen issue effect all the displays, if you have more than one connected?
4. From what I read it appears to be an issue introduced with Catalina, that doesn't happen in Mojave. Is that the same case for your setup?

 

[Etyel]

The screen is unique and is connected via DP. In the previous thread there is an example with Mojave, although it seems that the problem started with Catalina for the most part (Big Sur for me because I went directly from Mojave to Big Sur). Also, using HDMI didn't solve the problem either, and unfortunately my monitor doesn't allow you to choose between DP variants (1.2, 1.3, etc.) which seems to have solved the problem in at least one case.

 

[Edhawk]

What is unique about the display?
What make and model is the ‘unique’ display?
Are you using a single display?
Have you switched the display to a different DisplayPort connector on your Vega 64?
Have you tried using a different DP cable?

 

[Etyel]

By unique, I meant a single display. Sorry if I was not clear. It is a Benq 3270. I don't have another display but it works normally with Windows. The problem is not with the cable as I have been able to verify and as others have been able to verify in the closed thread. I did not test with a different connector because the phenomenon does not occur with Windows with the connector currently used. But I can change if you think that could be the explanation, but as it is really related to the transition from Mojave to Big Sur, I do not think that the connector became defective precisely at that time. The blackout is random and infrequent, it happens regardless of what I'm doing, desktop, internet browsing or watching a video.

EDIT: I changed the connector, the blackout is still there

 

[Etyel]

I think that in my case the "blackout" is software and not hardware, since it appeared after the switch to Big Sur and while I was trying to remove intermittent crashes in wakeup. Several methods allowed me to remove these crashes, but none of them prevented me from ending up with these "blackout". Finally, I opted to disable the iGPU and I'm looking in vain for ways to avoid the "blackout" that affect only a few users and for which there seems to be no common thread. That's why I was wondering if switching to Open Core could be a solution, knowing that if I don't try it automatically, it's because my previous attempts to use it ended up with an "unknown error" each time I booted on the Hack while everything was working fine with the USB key (and, of course, strictly the same EFI). So, I'll try Open Core again if someone can tell me if it can solve my "blackout" problem. Or if the problem is independent of the bootloader?

 

[Edhawk]

If the blackouts occur when you are running macOS then they will not be related to the boot loader. So switching to OpenCore from Clover will not solve this issue.

 

[Etyel]

Thanks for your answer (and the previous ones too), it's not what I was secretly hoping for because I imagined that maybe, since Open Core doesn't work like Clover, the way of managing the display would be different and that my problem would be solved that way. When I see that this also affects the Radeon 5700s, I'm not sure that finding a 6800 XT is the answer either. I really don't know what to try anymore. A "blackout" is always better than a crash, but it's annoying not to find the cause when the same configuration works on others.

 

[Edhawk]

Post a copy of your CLOVER folder so we can see what you are using. There may be something in or missing from your setup that can help with this issue. So far I have been assuming your CLOVER setup is all good, that may not be the case.

Redact or delete your Serial Number, Board Serial Number, SmUUID, MLB and ROM from your config.plist before you post a copy here.

 

[Etyel]

Here's my EFI