The ultimate Pro Display XDR info thread

joevt

macrumors 6502a
Jun 21, 2012
812
402
FYI - I have my Pro Display XDR connected to my 2019 MBP 16", and I get DSC status: Enabled. Just in case someone is wondering.
Thanks. I have already received info for the following connection types from other people:
  • Dual HBR2 (5K) (Thunderbolt only, Alpine Ridge, or Blackmagic eGPU before firmware update)
  • HBR2 DSC (6K) (Navi GPUs such as the 5300M or 5500M in the MBP 16", 5700XT, W5700, W5700X, RTX GPUs)
  • Dual HBR3 (6K) (Thunderbolt only, non-Navi GPUs, macOS only until PCs get new Titan Ridge drivers or firmware)
The product IDs are ae22 for the first two and ae2e for the last one. ae22 has an overlay EDID using ae23 product ID. ae2e has an overlay EDID using ae2f product ID. I am still wondering where ae21 or ae2d might come from.

I am looking for info about non-DSC single cable connection (such as Moshi USB-C to DisplayPort cable from a Radeon VII or RX 580 (or Vega II with Cable Matters USB-C to DisplayPort adapter or Thunderbolt 3 dock with DisplayPort output). There is a question of whether this mode allows HBR3.

Another thread elsewhere has experiments attempting to use YCbCr modes with 4:4:4, 4:2:2, or 4:2:0 chroma sub sampling. Windows was used with a Nvidia Pascal GTX card because the Pascal card supports DisplayPort 1.4 (required for HBR3 testing and 4:2:0 testing) and doesn't support DSC (because DSC is more preferable for compression than chroma sub sampling) and the Nvidia control panel has control over color format (RGB/YCbCr), and chroma sub sampling (4:4:4, 4:2:2, 4:2:0), and bit depth (6,8,10,12 bpc). The tests were unable to get any YCbCr mode to work or HBR3. What did work is 6 bpc for RGB to get 5K using only HBR2.

Also, I am wondering if HBR2 DSC works with USB through a Sunix UPD2018, Huawei VR 2 Computer Connection Cable, or Wacom Link Plus (for people with a card that supports DSC but doesn't have a USB-C port like the RTX or W5700 cards - the USB connection should enable brightness control, preset selection, etc. in macOS and maybe Windows if you can get the Boot Camp drivers installed which is a question for PCs).
 

blackadde

macrumors member
Dec 11, 2019
75
107
Hardware calibration AND/OR profiling is touted as coming soon. See: https://www.apple.com/mt/pro-display-xdr/specs/
“Hardware calibration” is a specific term in color correction. It refers to the ability to upload corrective LUTs to the monitor’s internal driver circuitry, bypassing the OS and graphics driver. It’s not something that can be added through software updates later on down the road.

High end (Eizo, NEC, some BenQ) monitors usually have this feature. As far as I know, the XDR doesn’t. It’s a ‘dumb’ display in that it entirely relies on an attached MacOS computer to manage its color output.
 

simonnelli

macrumors member
Jun 21, 2012
40
17
I always understood hardware calibration differently: the ability to set a specific target in hardware (luminosity, gamma, gamut and color temperature), after the hardware calibration profiling (measuring color patterns to correct slight differences from the specified target and saving them in a icc Profile to correct in software).
What you describe with Eizos et al, is correct but not the complete way to color accurate viewing as profiling is always needed to correct for specific differences of every unique monitor. Profiling also corrects changes that happen because of aging components (backlight and color shifts).
 
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joevt

macrumors 6502a
Jun 21, 2012
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It’s a ‘dumb’ display in that it entirely relies on an attached MacOS computer to manage its color output.
It has a USB interface so it's not so dumb. Have you seen the output from DisplayDiagnose?
Code:
/System/Library/Extensions/AppleGraphicsControl.kext/Contents/MacOS/DisplayDiagnose -a > DisplayDiagnose.txt 2>&1
 
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blackadde

macrumors member
Dec 11, 2019
75
107
I always understood hardware calibration differently: the ability to set a specific target in hardware (luminosity, gamma, gamut and color temperature), after the hardware calibration profiling (measuring color patterns to correct slight differences from the specified target and saving them in a icc Profile to correct in software).
What you describe with Eizos et al, is correct but not the complete way to color accurate viewing as profiling is always needed to correct for specific differences of every unique monitor. Profiling also corrects changes that happen because of agent components (backlight and color shifts).
You can use ICC profiles with a monitor set to it’s natural gamut (and obviously adjust luminosity and white point to their correct values for the target you’re chasing), or you can just create a proper LUT with those corrections in place and upload it to the monitor to run directly. The latter tends to be more accurate, depending on the LUT generation process, and you need to do it to run through any signal path that avoids the graphics driver (eg. via a BlackMagic card). It has the added bonus of not relying on any OS at all, meaning you can plug the display into any other PC or Mac and begin work immediately.

As you may know, video work never uses ICC profiles. That’s something that only exists in print-land, and has its own set of challenges and inaccuracies.
- - Post merged: - -

It has a USB interface so it's not so dumb. Have you seen the output from DisplayDiagnose?
Code:
/System/Library/Extensions/AppleGraphicsControl.kext/Contents/MacOS/DisplayDiagnose -a > DisplayDiagnose.txt 2>&1
I haven’t. Can you upload a LUT or not?
 

joevt

macrumors 6502a
Jun 21, 2012
812
402
I haven’t. Can you upload a LUT or not?
No. I'm just saying there's a lot of info that can be read from the display and therefore maybe a way to write info to the display but we have to wait for Apple to make the software to do that (maybe there'll be an XDR firmware updater - I think I've seen different versions of the firmware being used already from different people that posted results from the DisplayDiagnose command).
 
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cmsj

macrumors regular
Oct 9, 2012
203
67
In the original post, it was noted that macOS doesn't offer any display modes between the native @2x and the @1x.

This is obviously different to many other displays (such as 5K iMacs and the 5K LG) where there's a mode that's about 25% larger, which is then scaled down to fit the display.

When I unboxed my XDR I didn't realise this and would have returned it because of this, because the native @2x looks comically large to my eyes (I'm coming from a 5K iMac where I always ran the 25% larger mode).

The good news is that it's possible to force a 25% larger mode if you have a tool that can interact with the CoreGraphics APIs directly. I used Hammerspoon, because it's my project, but presumably SwitchResX could do it too. I'm now running 3840x2160@2x - ie the framebuffer is 8K. Works great even on the 580X.
 

henrymyf

macrumors newbie
Dec 2, 2015
25
1
That’s been done already and it’s here:

Thanks, I have also succeeded in getting the 6K from PC laptop.
- - Post merged: - -

I've seen AGDCDiagnose for 0xae22 but not that one. Can you send me the output so I can compare?
I'm using a PC laptop to drive the XDR with native 6K resolution, and everything looks perfect. I wonder if there is any similar diagnose script that I can run in Windows or Linux to compare with these results? Thanks.
 
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joevt

macrumors 6502a
Jun 21, 2012
812
402
I'm using a PC laptop to drive the XDR with native 6K resolution, and everything looks perfect. I wonder if there is any similar diagnose script that I can run in Windows or Linux to compare with these results?
What laptop? Are you using Intel Ice Lake, AMD Navi, or Nvidia RTX? Anything else doesn't support DSC and would require Thunderbolt 3 for dual HBR3 but Windows Thunderbolt drivers don't allow dual HBR3 as far as I know.

Maybe try GPU-Z and look at the advanced tab? It hasn't been updated to show DSC though.
CRU and Monitor Asset Manager (moninfo.exe) can get the EDID of the display. sysfs in linux might have some info (especially for Intel graphics).
 

henrymyf

macrumors newbie
Dec 2, 2015
25
1
What laptop? Are you using Intel Ice Lake, AMD Navi, or Nvidia RTX? Anything else doesn't support DSC and would require Thunderbolt 3 for dual HBR3 but Windows Thunderbolt drivers don't allow dual HBR3 as far as I know.

Maybe try GPU-Z and look at the advanced tab? It hasn't been updated to show DSC though.
CRU and Monitor Asset Manager (moninfo.exe) can get the EDID of the display. sysfs in linux might have some info (especially for Intel graphics).
My Razer laptop has Nvidia RTX, so I ssume it supports DSC and that's why it could drive the monitor with 6K.

CPU-Z.PNG

GPU-Z.PNG

Monitor Asset Manager.PNG

CRU.PNG
 

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joevt

macrumors 6502a
Jun 21, 2012
812
402
My Razer laptop has Nvidia RTX, so I ssume it supports DSC and that's why it could drive the monitor with 6K.
I think so. GPU-Z says you are connecting with HBR2 link rate (5.4 Gbps) which requires DSC to do 6K 60Hz 12bpc (YCbCr 4:2:0 8bpc HBR2 can do 6K too but it's not as good as DSC and the XDR does not support YCbCr).

Both CRU and MAM show virtually empty EDIDs (no timings, only one extension block). Does MAM show any more info using the Active option?

With the EDID you're seeing, you should not be able to get 6K. Maybe the EDID that gets used is elsewhere. Maybe the Boot Camp driver works around this.

Something strange may be happening in Windows with Nvidia and the XDR. Another way to get the display to work (without Boot Camp driver) is to use CRU to override the EDID but you still need the Boot Camp driver to set brightness or use presets.