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Dell 8K Dual Displayport 1.4 Monitor on macOS Catalina
 

Dell 8K Dual Displayport 1.4 Monitor on macOS Catalina  

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Ray
 Ray
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I remember this being discussed earlier (though I can't quite remember where), and the consensus was that macOS didn't know how to handle an 8K image with dual Displayport inputs. Instead, people would see two separate 4K displays as options. This was always bit odd, because dual input 5K monitors (also from Dell) DID work just fine.

It could only be assumed that Apple hadn't added the ability to drive 8k dual input yet, but now with Catalina out and Navi eGPUs supported (although 8K was added in Vega 2 years ago…) I thought that maybe things had changed.

If anyone has an 8K Dell available and could check this out, it would be much appreciated.

Pending: Add my system information and expected eGPU configuration to my signature to give context to my posts


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joevt
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I have a Asus XV273K which is a 4K 144Hz dual cable DisplayPort 1.4 display that I'm trying to get working at 144Hz. Single cable DisplayPort 1.4 supports 120Hz.

There was an attempt to get the Dell UP3218K working but I don't think it went all the way:  https://www.tonymacx86.com/threads/up3218k-only-runs-at-4k.242444

There does not appear to be support for dual cable mode in macOS Catalina for the Dell UP3218K:
/System/Library/Displays/Cotents/Resources/Overrides/DisplayVendorID-10ac/DisplayProductID-4147
because there's no corresponding .mtdd file like there is for the Dell UP2715K (DisplayProductID-40b6).

The Apple Pro Display XDR (6K display) is also probably a dual cable DisplayPort 1.4 display (because DisplayPort 1.4 and dual DisplayPort 1.2 are not enough for 6K60 10 bpc). Looking in the Apple overrides folder (DisplayVendorID-610) in Catalina, I see that files for the Apple Pro Display XDR (6K display) have been added (find the .tiff icon that looks like the XDR display or grep for XDR). Strangely, there are separate pictures for landscape and portrait. The product ID is ae2f but there also exists product ID ae2e. Both sets of files have stuff I haven't seen before. The mtdd file belongs to product ID ae2e. The mtdd seems to indicate that it supports both dual cable DisplayPort 1.2 (5120x2880) and dual cable DisplayPort 1.4 (6016x3384) modes with refresh rates of 60, 59.94, 50, 48, and 47.95 Hz. The overlay (EDID included in the m2dd) also has modes for 3840x2160 at those same refresh rates, and also a 2560x1440 60Hz mode which is useful for a DisplayPort 1.1 connection.

Similarly, there are product IDs ae21 (7.32 p/mm), ae22 (8.58 p/mm), and ae23 (7.32 p/mm) which might be only for DisplayPort 1.2 because the mtdd for ae22 only has the 5120x2880 dual cable mode (but the overlay includes the 6K modes like the overlay for ae2e). Actually, it seems that ae22 is for supporting 12 bit mode which explains the removal of the 6K mode. ae2e is for 10 bit mode.

 

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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Ray
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Posted by: @joevt

There does not appear to be support for dual cable mode in macOS Catalina for the Dell UP3218K

Could it possibly be added manually somehow? I find it strange Apple's added support for 6K but didn't also add 8K support at the same time.

 

EDIT: I'm strongly considering purchasing this display and trying to get it to work. I would like to question though, do I need to get an eGPU up and running too, or is there some Thunderbolt 3 dock out there that has dual DP 1.4 outputs? Would the 555x in my MacBook Pro even be powerful enough to run this display? If not, I'll work on getting an enclosure for my Vega 56 Nano too.

This post was modified 3 weeks ago

Pending: Add my system information and expected eGPU configuration to my signature to give context to my posts


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joevt
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Posted by: @ray

Could it possibly be added manually somehow?

Maybe. That was the point of my previous post - to describe what is known so far and what has been tried before. Maybe the current macOS has changed things.

Posted by: @ray

I find it strange Apple's added support for 6K but didn't also add 8K support at the same time.

Maybe they want you to buy their 6K display instead of Dell's 8K display.

EDIT: I'm strongly considering purchasing this display and trying to get it to work. I would like to question though, do I need to get an eGPU up and running too, or is there some Thunderbolt 3 dock out there that has dual DP 1.4 outputs? Would the 555x in my MacBook Pro even be powerful enough to run this display? If not, I'll work on getting an enclosure for my Vega 56 Nano too.

You might not need an eGPU. You have a current generation MacBook Pro with Titan Ridge Thunderbolt controller and the 555X supports DisplayPort 1.4.

First get the display to work in Boot Camp. Then try creating mtdd and override files for the display. I am currently working on creating such files for the Asus XV273K (first need to finish my EDID editor).

For the Dell 8K display, I would try creating files similar to those for the 6K display, with multiple backend/front end resolutions for 5K, 6K, and 8K, as well as the single cable resolutions of 4K and 1440p.

To connect the Dell 8K display, you need a Thunderbolt 3 dock with Titan Ridge controller, otherwise you would need to use two of your MacBook Pro's Thunderbolt 3 ports. One such dock is the HP Thunderbolt Dock G2 but one of the DisplayPort connections has to come from The Thunderbolt port of the dock which has a separate DisplayPort signal from all the other ports of the dock which share a DisplayPort signal (DisplayPort 1.4 MST hub). Hopefully, the MST hub won't affect the shared DisplayPort signal (for example, the Asus XV273K can achieve 4K 120Hz from a direct DisplayPort output but a DisplayPort 1.4 MST hub reduces the max refresh rate to 117 Hz). The HP Thunderbolt Dock G2 seems to work with my Dell UP2715K from RX580 eGPU through GC-TITAN RIDGE.

A Thunderbolt 3 adapter with Titan Ridge controller and no MST hub might be cheaper/simpler.
https://www.amazon.com/Wavlink-Thunderbolt-DisplayPort-Resolution-Compatible/dp/B07S8W49T1

But wait! I already explained that 8K 60Hz cannot be achieved from a single Thunderbolt 3 port because there's not enough bandwidth over Thunderbolt 3 for two full DisplayPort 1.4 signals - there's only enough bandwidth over Thunderbolt 3 for 6K. Therefore, you'll need to use two Thunderbolt 3 ports of your MacBook Pro. I suppose the single Thunderbolt 3 port solutions can be tested for 6K support on the Dell 8K (or 8K support with lower refresh rate). That would be interesting. It depends on if the Dell 8K will accept different dual cable timings other than 3840x4320 60Hz.

The Cable Matters USB-C to DisplayPort adapter is the only such adapter (with female DisplayPort connector) that I could find that advertises DisplayPort 1.4 capability (but it isn't VESA DisplayPort certified). The Moshi USB-C to DisplayPort cable available at the Apple store is VESA DisplayPort Certified for 8K (it's also one of the only cables that advertises being bi-directional).

About the 6K display, I wonder if it has multiple tile info blocks in the DisplayID extension blocks of the EDID - one for 5K and one for 6K...

8K has some interesting implications about supported HiDPI resolutions. You can expect 4K HiDPI. But if you want a lower resolution HiDPI mode, it will use fewer pixels than 8K (for example, 1440p will use 5K resolution). This is disappointing. It would be cool to be able to use a 3x HiDPI mode for that (7680÷3 = 2560) but Apple only support 2x (but maybe there's a way to enable 3x, as this was an option in earlier versions of macOS via Quartz Debug.app). On the other hand, you can't use a HiDPI mode greater than 4096x2304 because the AMD graphics driver has an 8K limit for scaled modes. Or maybe not - I was able to create a 14Kx8K resolution on my eGPU - the limit of 8192 is vertical only. I wonder if this changed since Mojave. Different graphics cards have different limits (Intel, AMD, Nvidia, and all their different generations).

 

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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Ray
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Posted by: @joevt

8K has some interesting implications about supported HiDPI resolutions. You can expect 4K HiDPI. But if you want a lower resolution HiDPI mode, it will use fewer pixels than 8K (for example, 1440p will use 5K resolution). This is disappointing. It would be cool to be able to use a 3x HiDPI mode for that (7680÷3 = 2560) but Apple only support 2x (but maybe there's a way to enable 3x, as this was an option in earlier versions of macOS via Quartz Debug.app).

Oh man, this kills the entire idea for me. I wanted to use 300% scaling to get an effective 2560 x 1440 worth of desk space. If this is impossible and it’s just a bigger 5K display, there is no point to me spending thousands more than a 5K 27” display. I like the bigger size, but I don’t like it THAT much. 

I guess it’s back to deciding between the LG Ultrafine 5K and the Dell 5K. 🙁

Pending: Add my system information and expected eGPU configuration to my signature to give context to my posts


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joevt
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@ray Well, it's not difficult to find the code that adds a HiDPI resolution for each normal resolution. I think it passes the number 2 for the scaling factor. So I would patch it to pass the number 3 to see what happens. Or create code that adds resolutions by calling the code that adds a HiDPI resolution (may also require patching to get at the code).

Ideally, you would want the system to choose different scale factors for different resolutions:

x1 7680x4320
x2 3840x2160
x3 2560x1440
x4 1920x1080
x5 1536x864
x6 1280x720
x8 960x540
x10 768x432
x12 640x360
x15 512x288
x16 480x270
For example, x1 is for 7680x4320 and greater, x2 is for resolutions between 3840x2160 and 7680x4320, x3 is for resolutions between 2560x1440 and 3840x2160, etc.

But even if x3 or greater works, some apps may have artifacts since they have not been tested with higher scaling factors.

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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Ray
 Ray
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Posted by: @joevt

Or create code that adds resolutions by calling the code that adds a HiDPI resolution (may also require patching to get at the code).

Oh, it's very kind of you to think that I can do that, but I don't have those kinds of skills! 😛

Honestly, I wouldn't even know where to start. It's really just a recipe for me to get stuck with a $3.5K display that only does 5K ;(

Posted by: @joevt

But even if x3 or greater works, some apps may have artifacts since they have not been tested with higher scaling factors.

That's another problem I didn't think of. If Apple did this themselves, developers would probably take notice and optimize their apps for 3x scaling. At the very least, we'd have some assurance that Apple's own native applications (I use Safari more than anything) would work properly.

Pending: Add my system information and expected eGPU configuration to my signature to give context to my posts


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