Asrock 6600 XT - DP blackscreen 12.3.1 - Restart shutdown freeze

[felixity]

I have a 100% working RX 570 (using DP port) Monterey 12.3.1 build based on golden build thanks to CaseySJ - GA Z690 Aero G DDR4 with 12600k and Alpine Ridge TB3 card. Sleep, restart and shutdown works flawlessly thanks to CaseySJ's guide and contributors.

Tried to upgrade to a 6600 XT (Asrock Challenger Pro) - 1st DP closest to screw edge connects to my monitor, 2nd and 3rd DP goes to TB3 card, HDMI is not used.

After apple boot screen, display (Xiaomi curved 34") goes black (using DP port - I tried swapping over all 3 of them, same result).

I have done the following tests:

1. DP plugged in Xiaomi 34 (blackscreen). HDMI plugged into another display - HDMI works and I can see the main display is the Xiaomi and online in "System Preferences". But there is no way to get it out of black screen, the monitor LED indicator shows that the monitor is active. Tried change the refresh rate to 50 or 60 Hz and changing res does not help.;
   
   
2. USB-C display (GMK KD1) via TB3 card (connected to 6600XT DP) works, and touch screen works too. Connecting via HDMI only also works;
   
   
3. Using HDMI instead of DP to connect to Xiaomi 34 works, but I am already using all the HDMI ports on this monitor so ideally would like to use DP.

So it seems the card is working fine, but DP is outputting blackscreen on my Xiaomi 34. DP connection works with this monitor in Windows, my previous RX 570 have also had no issues with DP connected to this monitor. So I have eliminated the monitor as culprit from this issue.

Argument agdpmod=pikera had to be used in 12.3.1 (without it, HDMI and USB C display will not work).

Another issue that became apparent after inserting the 6600 XT card, is that restart and shutdown have issues - it will go to blackscreen but the system is hung, the only way is the power cycle down. This was never an issue with RX 570.

Tried combing through other 6600 XT threads but others seems to have no problems with their DP?

I have plans to insert SoftPowerPlay table (@miliuco thread here) and also frame buffer here, but that is something to try once I can get the DP port to work.

Could someone help me work this problem please??

 

[felixity]

Update:

I have tried reinstalling 12.3.1 from scratch, during the 1st, 2nd and 3rd phase of installation (up to the point of setting up language settings ETC), the DP port works.

Once the setup is completed, the next boot will go to black screen, no matter which DP port I use.

In the end I am using HDMI, it works, but it breaks sleep and shutdown (RAM is active and acting like sleep - I am using RGB RAM, eventually system "shuts down" after a long period, but powering on again feels like strange).

At this stage I can only think the Asrock 6600 XT is causing compatibility issues, as using MSI RX 570 with the same EFI have "0" issues with DP and sleep/restart/shutdown.

 

[Edhawk]

Are you using the agdpmod=pikera boot argument to your OC config.plist, as that boot argument is essential in order to boot MacOS Monterey with your RX 6600 XT dGPU.

The RX 570 doesn't require any additional boot arguments to work.

 

[felixity]

Are you using the agdpmod=pikera boot argument to your OC config.plist, as that boot argument is essential in order to boot MacOS Monterey with your RX 6600 XT dGPU.

The RX 570 doesn't require any additional boot arguments to work.

Yes! I have to use agdpmod=pikera in order for card to work after OpenCore OS selection screen.

For some weird reason, RX 570 wouldn't have any display if I do not use the argument. Nevetherless, the RX 570 has been retired.

Still trying to get this DP issue resolved, but seems like I am out of luck~!

Thank you @Edhawk ,

 

[mari]

I had similar issue. Rx6600 is pci-e 4.0 but my riser cable was 3.0. If your mobo has pcie 5.0 slot, try putting it to 4.0 in bios.

 

[Edhawk]

Checking the bios to see if the top PCIE x16 5.0 slot is set to work correctly is a good call.

As the bios may have options for the x16 slot to work at different standards, i.e. 3.0 or 4.0 as well as 5.0.

The other two x16 slots only work at x4 speed and use 3.0 standard.

So making sure the GPU is in the correct slot would be beneficial too.

 

[felixity]

Thank you @mari & @Edhawk , will try that in a few days.
I have upgraded the TB3 GC-ALPINE RIDGE to TB4 GC-MAPLE RIDGE, having a little problem with getting the card driver loaded.
P.S. only the USB 3 from TB4 card is recognised and driver is loaded, TB4 is not loaded.