Dysfunctional DisplayPort

[Sooly890]

macOS Version

macOS Catalina, macOS Big Sur, macOS Monterey

What is the precise OS version on which the bug is occurring?

10.15.7 Release (19H15), 11.7.10 according to recovery (Build number: HDMI output is garbled), 12.7.4 Release (21H1123)

What is your CPU's model?

AMD Ryzen 5600G

Describe the unexpected behaviour in detail.

I installed the latest MacOS Catalina, Big Sur and Monterey, plugged in my monitor through DisplayPort, and my computer turned on, but it didn't display anything, and my monitor showed No Signal. I shutdown, plugged into HDMI, and it showed the login screen. I have tried adding -NRedDPDelay to boot-args.

EDIT: I must note, it did work on Sonoma 14.4.1, on an older version maybe?

What should've happened instead?

I install the latest MacOS Catalina or Big Sur or Monterey, plug in my monitor through DisplayPort, my computer turns on, and it displays the login screen.

Attach any logs related to this issue. For example .gpuRestart, .panic, etc files.

EDIT: I managed to find a .spin file that comes every time I boot with DisplayPort on Catalina (I wasn't sure if it was from my many times attempting to install), but I'm not sure how relevant it is so it's an edit, not a comment.
WindowServer_2024-11-29-140547_Soolys-iMac-Pro.userspace_watchdog_timeout.spin.txt

Issue Submission Terms

• You have made sure that there are no other reports about this bug.
• You do not use configurator software (e.g. OpenCore Auxiliary Tools, OpenCore Configurator).
• You have made your own EFI according to the ChefKiss Hackintosh Guide.
• You are not using any software that may conflict, including, but not limited to, OpenCore Legacy Patcher, BFixup, WhateverGreen.
• You acknowledge that violation of these terms may result in your issue being closed or your user being blocked from the organisation.

[Sooly890]

I've just tested Big Sur, it also happens there.
EDIT: now I can't see the screen beyond the login screnn because I set the HZ to 170, trying to set the Resolution in hopes of seeing some details.

[EraserCN]

On Monterey here with 3500U, DP doesn't work either.

[Sooly890]

@EraserCN I'm just installing Monterey now, seeing if it persists. I'll get back to this issue.

[Sooly890]

Yup, indeed, Monterey doesn't work on DisplayPort but is working fine on HDMI.

[Sooly890]

I just tested Ventura - that works fine.

[Sooly890]

If it helps - Sonoma and Sequoia are working fine too.

[VisualEhrmanntraut]

It doesn’t, I don’t have an AMD desktop with integrated graphics, only an AMD laptop with one HDMI port. My main machine is an M3 MacBook Pro.

[VisualEhrmanntraut]

So, I’m going to spend some time improving DiskDbg and creating instructions on how to gather the required debugging information so I don’t repeat myself all the time. Although, I must admit that the issue here isn’t really a bug with NootedRed, rather the AMD drivers, but maybe the fix can be back-ported.

[VisualEhrmanntraut]

https://github.com/ChefKissInc/DiskDbg follow instructions in README. latest log will always be current boot. boot with NRed disabled, install the pkg, enable NRed, boot, then reboot with NRed disabled, fetch the first to last log, and send it here.

[VisualEhrmanntraut]

(assuming you can't access the system while NRed is enabled, otherwise optional)

[Sooly890]

Hmm - this is confusing. I installed DiskDbg onto Monterey, Big Sur, and Catalina, however I only managed to get logs from Monterey (I did launchctl list | grep -v com.apple and on Catalina and Big Sur and DiskDbg was nowhere to be found). However, NootedRed worked fine on DisplayPort, and the only thing I can think of that changed is my Monitor. I still have it, so I will try again with that one shortly.

[redacted]

(I have edited the ioreg file, but only to prevent doxing myself)

[VisualEhrmanntraut]

I need logs only during the black screen. And the ioreg is probably not useful at this moment, so you don't need to attach it for now.

[VisualEhrmanntraut]

You also need -NRedDebug in the boot args to enable the driver's logging. And please put msgbuf=10485760 as well to increase the dmesg buffer size.

[Sooly890]

dmesg-1736807604.txt

AGDCDiagnose-1736807604.txt

There we go - I'm pretty sure those are the ones with the black screen. I knew that the logs before probably were useless, but I posted them anyways in case they were. My boot-args are: -v debug=0x100 keepsyms=1 revpatch=auto,cpuname,sbvmm alcid=11 -NRedDPDelay -NRedDebug msgbuf=10485760.

[VisualEhrmanntraut]

The monitor with the black screen is the only monitor plugged in? It's an "AOC" monitor?

[Sooly890]

Yes, that's correct. I don't have 2 DisplayPorts on my Motherboard (I'm too lazy to grab an HDMI cord for the time being), and it is an AOC monitor.

[VisualEhrmanntraut]

The dmesg suggests you turned the machine off too early but I'm not sure. Regardless, if it's not working with this monitor, but working with another, that suggests a different problem. What are the specifications of those two monitors? (Resolution, Refresh rate, etc)

[VisualEhrmanntraut]

I am asking because there might be an artificial bandwidth limitation happening, causing this issue.

[Sooly890]

The AOC one, is 16:9 1440p (QHD), 170HZ (might be 165HZ but IIRC it's 170HZ), IPS, 24 inches (uh probably didn't need that but still). The Xiaomi one, which is the one that works, is 21:9 1440p, 180HZ, VA, 32 inches, curved.

[Sooly890]

I did indeed shut off the computer, but only after it wouldn't output to the monitor after waiting and turning the monitor off and on.

[VisualEhrmanntraut]

By resolution, I meant in pixels. E.g. My M3 MacBook Pro's pixel resolution would be 3024x1964

[Sooly890]

My bad, AOC resolution is 2560 x 1440, Xiaomi is 3440 x 1440

[VisualEhrmanntraut]

Hm, may not be a bandwidth problem then. I'll take a closer look tomorrow as it's 1 in the morning here.

[Sooly890]

Sure thing.

[VisualEhrmanntraut]

I have pushed a new commit to the DiskDbg code, it should be a bit more stable with the dmesg logging now.

[Sooly890]

For whatever reason my Xiaomi one didn't work for a few reboots - though I was not able to reproduce it, so I have no logs to share.

Anyhow, I have made some new logs with the new DiskDbg with my AOC monitor:

AGDCDiagnose-1736892047.txt

dmesg-1736892047.txt

[VisualEhrmanntraut]

did you remove msgbuf? cause the dmesg is truncated to 128kb

[VisualEhrmanntraut]

but from the logs that are here, I do see this:

[   11.176938]: [48:0:0] [DAL][EVENT][link:1] >>> type:"Link Training End", status: FAIL, lane_status: 0.

[Sooly890]

Nope, my boot-args remain as -v debug=0x100 keepsyms=1 revpatch=auto,cpuname,sbvmm alcid=11 -NRedDPDelay -NRedDebug msgbuf=10485760

[Sooly890]

I haven't been able to get DiskDbg working on Catalina or Big Sur however, all the logs I can share are Monterey logs.

[VisualEhrmanntraut]

Regardless, it seems to be a usual link training failure. Unfortunately the cause is not easy to track down. It could be bandwidth calculations, incorrect timing, race conditions, anything.

[Sooly890]

Great. I wonder why my Xiaomi one wasn't working for a moment though, will do some more testing at some point.

[VisualEhrmanntraut]

(and it doesn't help that there's no actual documentation or debugging manual/guide. amd like any other company expects you to use their software as they intend, and just to make a bug report with some pictures and some logs and maybe they look at it and maybe they fix it. I even tried back when NRed had no display signal at all to ask in their mailing list, and they just ignored the message)