Thanks for posting this!Looks like DSC is broken on Big Sur.
A problem with Big Sur and Pro Display XDR.
I have a Ryzen PC with AMD X570 itx mainboard and Radeon 5700 XT. I use a Belkin Charge and Sync VR cable to connect a DisplayPort port and USB 2.0 port to Pro Display XDR. All works great with DSC at 6k in Catalina. But when I upgraded to Big Sur, Pro Display XDR Looked like 4k or 5k with...forums.macrumors.com
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MP 7,1 AMD Radeon Pro W5700's USB-C Port and Pro Display XDR
- Thread starter ibuick
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There's nothing new related to DSC in the Overrides for Big Sur 11.0.1. There are a few new iMac 27 inch display product IDs but that's about it. And one third party 5120x1440 display.
I guess this means the problem is in Big Sur display drivers - maybe CoreDisplay has a change where it's not adding a DSC mode in this non-Thunderbolt situation.
I think the CoreDisplay APIs should be reverse engineered so we can get control of display modes to change DSC, chroma sub sampling, pixel depth, color range, etc.
It’s not the first time when apple cripples technology on purpose. They want to sell their expensive hardware and don’t like people connecting XDRs to cards with DisplayPort. It could also be to prevent people from connecting more than 1 XDR to the new M1 Mac mini.
I wouldn’t be surprised though if people figure out how to port things from Catalina.
MBP 16" + Razer Core X + rx5700xt + Pro Display XDR + Belkin cable
Since I upgraded to Big Sur, the setup works for 0.5 - 5 minutes, then I get kernel panic. Haven't noticed if it's switching to 4k or 5k, looked like 6k I think. There are also graphic glitches (half screen grey) on the login screen.
I guess I have to revert back to connecting the display straight into the machine, but that sucks.
Ordered a Mac Mini with M1 until there's a solution.
Since I upgraded to Big Sur, the setup works for 0.5 - 5 minutes, then I get kernel panic. Haven't noticed if it's switching to 4k or 5k, looked like 6k I think. There are also graphic glitches (half screen grey) on the login screen.
I guess I have to revert back to connecting the display straight into the machine, but that sucks.
Ordered a Mac Mini with M1 until there's a solution.
My XDR display all of a sudden stopped working with my Mac Pro when I woke up a few nights ago, after what I assume was a firmware update to the XDR and/or an update to the Mac Pro that occurred the prior night.
Here‘s my setup: 2019 Mac Pro, Radeon Pro W5700X graphics card, with 25m Corning thunderbolt 3 usb-c cable connecting the Mac Pro in my server closet to my XDR on my home office desk. Up until a few days ago, this setup had been working perfectly for me for the prior six months (including after I’d upgraded to Big Sur).
But as of a few days ago, I just get a blank black screen on the XDR when I turn the Mac Pro on. Nothing happens at all on the XDR when the Mac Pro is turned on.
I thought maybe something had happened to the Corning cable, so I tested it by plugging the same cable into my MBP instead of my Mac Pro, and the XDR worked perfectly when connected to the MBP using the same Corning 25m cable.
Then I moved my Mac Pro next to the XDR and connected it to the XDR using the short 2m Apple thunderbolt 3 cable that came with the XDR, and the XDR worked perfectly with this cable connected to the Mac Pro.
I've also done a clean install of Catalina thinking maybe something in Big Sur caused this, but the XDR still won't work with the Corning cable that it previously worked perfectly fine with.
So I think whatever update was installed on my XDR (looks like firmware 4.2.37) a few nights ago has caused it to stop working with my Mac Pro when its connected to it with the 25m Corning cable (that I spent like $600 on).
Any ideas on why this is happening and how I can fix it?
Here‘s my setup: 2019 Mac Pro, Radeon Pro W5700X graphics card, with 25m Corning thunderbolt 3 usb-c cable connecting the Mac Pro in my server closet to my XDR on my home office desk. Up until a few days ago, this setup had been working perfectly for me for the prior six months (including after I’d upgraded to Big Sur).
But as of a few days ago, I just get a blank black screen on the XDR when I turn the Mac Pro on. Nothing happens at all on the XDR when the Mac Pro is turned on.
I thought maybe something had happened to the Corning cable, so I tested it by plugging the same cable into my MBP instead of my Mac Pro, and the XDR worked perfectly when connected to the MBP using the same Corning 25m cable.
Then I moved my Mac Pro next to the XDR and connected it to the XDR using the short 2m Apple thunderbolt 3 cable that came with the XDR, and the XDR worked perfectly with this cable connected to the Mac Pro.
I've also done a clean install of Catalina thinking maybe something in Big Sur caused this, but the XDR still won't work with the Corning cable that it previously worked perfectly fine with.
So I think whatever update was installed on my XDR (looks like firmware 4.2.37) a few nights ago has caused it to stop working with my Mac Pro when its connected to it with the 25m Corning cable (that I spent like $600 on).
Any ideas on why this is happening and how I can fix it?
That's a tricky one. Apple will blame the Corning cable if the XDR works when using their supplied cable
Does it matter which port you plug the cable into?
Are your MBP and Mac Pro on different macOS versions?
Does it matter which port you plug the cable into?
Are your MBP and Mac Pro on different macOS versions?
I've tried every port and none of them work. The MBP is on Catalina, and the Mac Pro is on Big Sur. However, I did a clean install of Catalina on the Mac Pro, and the XDR display still won't work when the Corning cable is used. I also bought a new Corning cable just in case there was actually something wrong with it (even though the original Corning cable still worked to connect the XDR to the MBP), and the same problem occurs with the new cable when I connect it from the XDR to the Mac Pro -- still totally blank black screen. I've called Corning and they're looking into it and said they'd get back to me.
And yes, when I called Apple they blamed the Corning cable even though I explained that the cable had worked perfectly on the same setup until a few days ago when the computer and I believe the XDR firmware were updated overnight, and even though the same Corning cable works perfectly when I use it to connect my MBP to the XDR.
Have you tried unplugging then plugging the cable back into the card after boot? Ive similar issue with a 2k
Is DSC being used when you're using the Apple cable? Check the AGDCDiagnose command.
Probably the firmware update made DSC stop working. Without DSC, a dual HBR3 connection mode is used, but this doesn't work when there's a Thunderbolt dock or optical cable between the Mac Pro and the XDR, even if the connection is working properly at 40 Gbps x1 Link width: 0x2.
With DSC, only a single HBR2 connection is required, and that can work just a 20 Gbps connection.
I did the following while using the Apple cable:
system_profiler SPUSBDataType SPThunderboltDataType SPPCIDataType > system_profile.txt
ioreg -ilrw0 -c IOPCIDevice > ioregpci.txt
/System/Library/Extensions/AppleGraphicsControl.kext/Contents/MacOS/AGDCDiagnose -a > AGDCDiagnose_a.txt 2>&1
/System/Library/Extensions/AppleGraphicsControl.kext/Contents/MacOS/DisplayDiagnose -a > DisplayDiagnose_a.txt 2>&1
See attached ZIP file containing the output files. Any assistance you can give me in deciphering the contents of the files, and whether they reveal the cause of the issue I'm having, would really be a huge help!
Seems you have 6K working with DSC using the Apple cable as expected.
One problem I see is that it's only connecting at 20 Gb/s x1, Current Link Width: 0x2. I think I've seen that before (I would have to search for it). I don't remember if it's accurate or if it means there's a problem. If it's accurate, then it means the display is only connecting using Thunderbolt 2 link rate (10 Gb/s, two lanes). Ask the Corning people if the Corning cable can work at 10 Gb/s link rate.
The 20 Gb/s connection might reduce USB 3.0 performance (5 Gbps) of the XDR's USB 3.0 hub to below 400 MB/s. Do you have a USB storage device capable of the normal 450 MB/s speed? 6K with DSC uses HBR2 but I don't know how much of the total HBR2 bandwidth (17.28 Gbps) is used so this test is only meaningful if the USB performance is low. Compare with result using MacBook Pro + XDR, and direct connect to USB 3.1 Gen 2 port of Mac Pro.
Can you get the Thunderbolt info from the Mac Book Pro + XDR with both cables?
Can you get the same info with the Mac Pro + XDR and Corning Cable (use screen sharing if necessary to execute the commands).
One thing to test is:
what happens when there's a Thunderbolt device between the Mac Pro and the XDR: try with the Corning cable
1) between the Mac Pro and the dock.
2) between the dock and the XDR.
I'm wondering if you ever figured this out, @Fhed3040 — I'd *really* like to duplicate your setup (keep my Rackmount Mac Pro 7,1 in my server-closet, instead of in a minirack behind my workstation), and have been gently planning on upgrading to a W5700 and a pair of Corning cables for my XDRs, but ... that'd be a lot of money to spend if the damn things won't work with the W5700!
I bought the Corning TB3 cable and can confirm it works between W5700X and PD XDR. I have the 50ft (15 meter) version. Full 6K and fully working USB ports. Works exactly like the official apple cable. I’m running Catalina and have not tried Big Sur
Latest firmware on the PD XDR (4.2.37) and latest Catalina version (10.15.7)
Latest firmware on the PD XDR (4.2.37) and latest Catalina version (10.15.7)
So I have no idea what issue @Fhed3040 is facing, could either be a failing GPU in a weird way, or could be related to cable length. Their’s is 25 meter, mine is 15 meter.
I’ve only been running mine for a few days, so feel free to ping me in some months to see if it fails in the same odd way. But yeah, @elliottcable I would cautiously recommend it as working for what you wanted to do, depending on cable run length
I’ve only been running mine for a few days, so feel free to ping me in some months to see if it fails in the same odd way. But yeah, @elliottcable I would cautiously recommend it as working for what you wanted to do, depending on cable run length
Do you see a 40 Gbps x1 connection (link width x2)? AGDCDiagnose shows DSC enabled?
It might continue to work in Big Sur or it might disable DSC.
How do I actually run AGDCDiagnose in Catalina?
i'm seeing this:
i'm seeing this:
Code:
command not found: AGDCDiagnose