Contribute
Register

Dual 6900 XT Issues

Joined
Oct 4, 2018
Messages
235
Motherboard
Gigabyte C246-WU4
CPU
E-2278G
Graphics
WX7100
Mac
  1. MacBook Pro
  2. Mac mini
"He who never mistyped shall throw the first keyboard." Or something like that… ;)

If both SSDT-GFX have the correct path, and WEG does not work, the question is then: What information should be injected by these SSDTs (or set by DeviceProperties) for the cards to work properly? Device-id, connectors, framebuffers, etc.
@ramazarusx how did you wrote these SSDTs? They do not have the same code, and GFX0 features a string for a Radeon 5700 XT.
 
Joined
Oct 4, 2018
Messages
235
Motherboard
Gigabyte C246-WU4
CPU
E-2278G
Graphics
WX7100
Mac
  1. MacBook Pro
  2. Mac mini
Some slightly confusing information from the RX 6800 XT support thread:
#1401 AMD RX 6900 XT "works out of the box on 11.5.2" (WEG + agdpmod=pikera)… but the poster still tries to modify DeviceProperties (why?)
#1317 RX 6900 XTXH variant require additional work (but IOReg shows device-id=73bf (bf73000) for both cards, so this does not apply here)

Are both cards the exact same model?
 
Joined
Apr 11, 2014
Messages
62
Motherboard
ASUS X299 SAGE/10G
CPU
i9-7980XE
Graphics
Radeon VII
Then, if WhateverGreen, enabled, did not suffice to activate your two GPUs we need to look into the contents of the SSDTs.

Looking at all ACPI tables, this Asus board defines exactly the same CPU methods as my Gigabyte board, spread exactly in the same manner between the DSDT, one SSDT and four OEM1-OEM4 files which are conditionally loaded from methods in the SSDT. I saw the same situation in the tables of the X11SRA-F, BIOS v.2.4—which is not even a C621 board.
I thought wrapping SSDTs would be board-specific, or at least manufacturer-specific, but so far my SSDT fits boards from three manufacturers. @metacollin 's X11DAi-N is so far a lone outsider.
From what I gathered most workstation boards got similar DSDT/SSDT structure.


I suppose that "Clean IOReg" was produced by booting from the accompanying EFI folder; so WhateverGreen was still disabled and no SSDT-GFX was loaded. Correct?
Clean IOReg was no SSDT injections for GFX, no WAG and the 2nd GPU in Slot-3 was physically disabled in the BIOS(Asus BIOS have option to disable PCIE ports).


I have a doubt about the USB-C ports (Framebuffer@3 with connector-type 0 instead of 0x400 for DP).
My 6900 XTs don't have USB its 3 DP and 1 HDMI, Sapphire Nitro+ 6900 XT.

There was nothing from PC03 ("slot-3"): Was the secondary GPU removed or was it present and not detected at all?
The PCIE Slot 3 was disabled in the BIOS


I took an educated guess that the USB2 header is HS07/08 and edited your EFI folder to load WhateverGreen
Thank you will test it out in a bit.


Yep, I made a couple of typing errors, my Bad!
You should see my emails, red strokes everywhere, fat fingers here I guess.


If both SSDT-GFX have the correct path, and WEG does not work, the question is then: What information should be injected by these SSDTs (or set by DeviceProperties) for the cards to work properly? Device-id, connectors, framebuffers, etc.
Thats the million $ question.


@ramazarusx how did you wrote these SSDTs? They do not have the same code, and GFX0 features a string for a Radeon 5700 XT.
They're generic SSDTs from OpenCore just modified by me to fit my needs.


Some slightly confusing information from the RX 6800 XT support thread:
#1401 AMD RX 6900 XT "works out of the box on 11.5.2" (WEG + agdpmod=pikera)… but the poster still tries to modify DeviceProperties (why?)
#1317 RX 6900 XTXH variant require additional work (but IOReg shows device-id=73bf (bf73000) for both cards, so this does not apply here)
Yeah I got kind of lost in that thread.


Are both cards the exact same model?
Yup, they are identical Sapphire Nitro+ 6900 XT.
 
Joined
Oct 4, 2018
Messages
235
Motherboard
Gigabyte C246-WU4
CPU
E-2278G
Graphics
WX7100
Mac
  1. MacBook Pro
  2. Mac mini
From what I gathered most workstation boards got similar DSDT/SSDT structure.
That's a useful information, as it makes wrapping easier.

Clean IOReg was no SSDT injections for GFX, no WAG and the 2nd GPU in Slot-3 was physically disabled in the BIOS(Asus BIOS have option to disable PCIE ports).
Great feature here…

My 6900 XTs don't have USB its 3 DP and 1 HDMI, Sapphire Nitro+ 6900 XT.
Ah, I was looking at the AMD-branded Radeon. So both are this model
SKU#: 11308-01-20G SAPPHIRE NITRO+ AMD Radeon™ RX 6900 XT
No Special Edition
SKU#: 11308-03-20G SAPPHIRE NITRO+ AMD Radeon™ RX 6900 XT SE or
SKU#: 11308-07-20G SAPPHIRE NITRO+ AMD Radeon™ RX 6900 XT SE ?

They're generic SSDTs from OpenCore just modified by me to fit my needs.


Some slightly confusing information from the RX 6800 XT support thread:

Yeah I got kind of lost in that thread.
Browsing this thread I gathered that all Radeon RX 6900 XT are equal, that some require device-id spoofing, and that support is rapidly evolving, in OS X as well as in WhateverGreen. The last point implies that your earlier experiments may no longer be relevant with the current versions of OS X, OpenCore and WhateverGreen—and explains why SSDT-GFX0 (which template?) is more elaborate than SSDT-GFX1 (based on current SSDT-BRG0).

I also understand that you got one card before the other. Let's say "card A" and "card B".
Card A came first, sits in slot-1—and has possibly never moved out of this slot.
Card A is the card in 'Clean IOReg.ioreg' and '1 GPU Active 3 Displays.ioreg' (any way to test with a fourth display?).
With your current OS X (11.6?), card A works even without SSDT or WhateverGreen.

Card B came later, and sits in slot-3.
With card B active, card A misbehaves and provides only one display as in '2 GPU Active One Display.ioreg'.
Have you ever tried card B alone?

If not, can you disable slot-1 and test card B alone? With/without SSDT, with/without WhateverGreen, 1 or several displays… Please provide a copy of the IOReg to compare with that from card A.

With some luck, A and B are not identical and we have a single card issue rather than a dual card issue.
 
Joined
Apr 11, 2014
Messages
62
Motherboard
ASUS X299 SAGE/10G
CPU
i9-7980XE
Graphics
Radeon VII
Ah, I was looking at the AMD-branded Radeon. So both are this model
SKU#: 11308-01-20G SAPPHIRE NITRO+ AMD Radeon™ RX 6900 XT
No Special Edition
SKU#: 11308-03-20G SAPPHIRE NITRO+ AMD Radeon™ RX 6900 XT SE or
SKU#: 11308-07-20G SAPPHIRE NITRO+ AMD Radeon™ RX 6900 XT SE ?
They're both 11308-01-20G


Browsing this thread I gathered that all Radeon RX 6900 XT are equal, that some require device-id spoofing, and that support is rapidly evolving, in OS X as well as in WhateverGreen. The last point implies that your earlier experiments may no longer be relevant with the current versions of OS X, OpenCore and WhateverGreen—and explains why SSDT-GFX0 (which template?) is more elaborate than SSDT-GFX1 (based on current SSDT-BRG0).
Actually I got both GFX0/1 from SSDT-BRG0


I also understand that you got one card before the other. Let's say "card A" and "card B".
Card A came first, sits in slot-1—and has possibly never moved out of this slot.
Card A is the card in 'Clean IOReg.ioreg' and '1 GPU Active 3 Displays.ioreg' (any way to test with a fourth display?).
With your current OS X (11.6?), card A works even without SSDT or WhateverGreen.
No I got both cards at the same time so I can kind go presume that they're from the similar batch. I just used Card A in the slot 1 solo before because of the way case was and didn't have the water blocks for it. I'll bring the small 4th monitor tomorrow and will see if all 3DP and 1HDMI will work together.

Yup single card works perfectly well without anything.


If not, can you disable slot-1 and test card B alone? With/without SSDT, with/without WhateverGreen, 1 or several displays… Please provide a copy of the IOReg to compare with that from card A.
I'll disable the slot-1 and enable the slot-2 in the morning and will see if it'll work.
 
Top