Mac mini driving two LG UltraFine (5K) Display thunderbolt displays?

[turbineseaplane]

Also…

What an unbelievably laughable crock that their video actually had a Mac mini hooked up to a $5000 monitor.

I wonder what universe they all live in at Apple.

I’d be surprised if there is literally anybody in the world desiring to run that combo.

(I am sure there’s someone. There always is...but sheesh)

It’s like putting 24 karat gold plated “rapper rims” on a Toyota corolla

 

[MacModMachine]

Apple's LG 5K page now shows compatibility with the M1s. So means TB does have access to 2 DP streams so should support 2 TB attached 4k monitors.

it only supports 1 display...its 2 ports over a single controller. the mac mini had 2 controllers over 4 ports , 2 displays over thunderbolt.

 

[saulinpa]

All are possible…

But at the end of the day, it’s just mind blowing to me they are OK with people hooking up their beautifully designed computers to the range of “ugh” displays one can find in any random tech store.

One would think, in this new single cable USb-C future, Apple would have been all over making an unbelievably gorgeous monitor docking situation with just one single cable needed.

Jobs is gone. Ive is gone. Who is left to care about Apple's image? Cook and company only care about the stock price.

 

[saulinpa]

it only supports 1 display...its 2 ports over a single controller. the mac mini had 2 controllers over 4 ports , 2 displays over thunderbolt.

Controllers are distinct from DP streams. Pre M1 Air had single TB controller but could support 2 4K monitors on its 2 TB3/USB-C ports.

 

[deconstruct60]

I'm wondering if you can only have one display on the TB bus.

This isn't Thunderbolt this is a limitation of the Apple GPU being used here. It can only drive two displays; regardless of what the TB can do.

M1 has all the appearances of being effectively just the "A14X". Part of the design constraints here is iPad Pro. ... which only has to deal with two screens.


The other part is Apple probably being a getting tangled up with their integrated Thunderbolt controllers. If this was a discrete Thunderbolt controller set up then there would be a DisplayPort data stream feed that they could run through a switch to either drive the HDMI port of feed Thunderbolt.

No conclusive proof but my guess is that since the other set ups don't need a "two DP input" Thunderbolt controller that Apple didn't build two inputs. Just one. The other stream is hardwired to run to a embedded screen only. Apple is taking that embedded DP only stream and just running it through a HDMI single adapter. There is probably zero DP data switching even possible with this SoC. That would make both their TB controllers simpler (and smaller) and the GPU display output system simpler and smaller.

None of that has anything to do with Thunderbolt.

The mini is probably a bit gimped because coupled to iPad Pro display constraints.



Most likely Apple knew that most folks only hook only one "mainstream" display up to a Mini. This will work for a large fraction of Mini customers. Even a mainstream computer monitor + "TV as monitor" will work just fine.

 

[turbineseaplane]

Jobs is gone. Ive is gone. Who is left to care about Apple's image? Cook and company only care about the stock price.

sadly...you are correct

 

[deconstruct60]

All are possible…

But at the end of the day, it’s just mind blowing to me they are OK with people hooking up their beautifully designed computers to the range of “ugh” displays one can find in any random tech store.

One would think, in this new single cable USb-C future, Apple would have been all over making an unbelievably gorgeous monitor docking situation with just one single cable needed.

Not if Apple is concerned about margins. Apple isn't doing a $400-600 Mini either.

Just plain monitors are in a large downward pressure on prices. Apple hasn't done a straight "monitor" in over a decade. (actually creeping up on two decades. The last non-docking station monitor was introduced in 2004 ). the Apple has done Thunderbolt Docking station "monitors". And USB-C boing mainstream basically does far more to take the "price premium, value add " edge off that docking station aspect than entice Apple to go deeper into the market.

More folks stretching hard to move upmarket to buy XDRs lines Apple's pockets.

Nobody "has to" buy the LG Ultrafines.

There is a decent chance that sometime in 2021 there will be yet another UltraFine 27" (and 24" ) update. Those new monitors will get a TCON that can handle DisplayPort 1.3+ and it will be full resolution.


In mean time the minii gets the resolution the iPad Pro gets. Which isn't too surprising. ( that too saves Apple some money).

 

[turbineseaplane]

Not if Apple is concerned about margins. Apple isn't doing a $400-600 Mini either.

Just plain monitors are in a large downward pressure on prices. Apple hasn't done a straight "monitor" in over a decade. (actually creeping up on two decades. The last non-docking station monitor was introduced in 2004 ). the Apple has done Thunderbolt Docking station "monitors". And USB-C boing mainstream basically does far more to take the "price premium, value add " edge off that docking station aspect than entice Apple to go deeper into the market.

More folks stretching hard to move upmarket to buy XDRs lines Apple's pockets.

Nobody "has to" buy the LG Ultrafines.

There is a decent chance that sometime in 2021 there will be yet another UltraFine 27" (and 24" ) update. Those new monitors will get a TCON that can handle DisplayPort 1.3+ and it will be full resolution.


In mean time the minii gets the resolution the iPad Pro gets. Which isn't too surprising. ( that too saves Apple some money).

All well said.

There is so much pricing room between the XDR and main stream options…

There has to be a way to make money somewhere between $400-$1200 range and all the way up to $5000 for the XDR

 

[joevt]

does this mean the 5k LG connected to TB will down res to 4k?

Yes. If you want larger than 5K then find a display that does not require two DisplayPort connections over Thunderbolt. Like the XDR. There exist some 5120x2880 or 5120x2160 or 5120x1440 displays that only require one DisplayPort 1.4 connection.

I doubt DisplayLink will work anymore either.

DisplayLink uses USB and doesn't depend on GPU. They have Big Sur 11.0 Public Beta software. It seems to be compiled only for x86. It might work on M1 using Rosetta?

 

[dogslobber]

DisplayLink uses USB and doesn't depend on GPU. They have Big Sur 11.0 Public Beta software. It seems to be compiled only for x86. It might work on M1 using Rosetta?

Wow, I just installed and am typing this on an Intel Mac running Big Sur and a Display Link'd monitor. I must say it's really fast and I'm not seeing any lag or artifacts. I'm mightily impressed with that. From what I can see it is not using any kernel drivers and did NOT require a reboot after installing the Display Link Manager software. I'm not really sure how they're doing it but the fact they are doing it suggests this might be feasible on ARM Macs too. If it's not a driver then perhaps it might work with Rosetta 2 so we wait with baited breath. FWIW, it should be feasible to recompile natively for ARM Big Sur if no kernel drivers are needed. But my short play with it on a 1920x1080 screen looks very nice indeed although no Night Shift support.

 

[Anonymous Freak]

Just got my M1 Mac mini.

Can confirm - only one single display over Thunderbolt, regardless of how you attempt to connect.

I tried:

• Two USB-C-to-DisplayPort connections direct to back of Mini - only the first one got signal.

I tried a Thunderbolt 3 Dock that has two DisplayPort connections, one DP-enabled USB-C, plus a Thunderbolt 3 "outbound" connection - when connecting to my Intel MacBook Pro, to support two displays in macOS, I have to use one DisplayPort connection, and the outbound TB3 via USB-C-to-DisplayPort. (In Windows 10 on the same MBP, I can run two DisplayPort plus a third on the TB3 outbound. The "only one on DP, the other on TB3" is a macOS limitation.)

• One DisplayPort, one USB-C-to-TB3-port - this is what works on my MBP in macOS - if I plug the DP in first, then the TB3, the TB3 takes precedence, only displaying on the display on the TB3 port. If I plug the TB3 in first, the DisplayPort is ignored. (Both are true for any of the "DisplayPort" connections, the two native DP, or the DP-enabled-USB-C.)
• Two DisplayPort - same as two direct to the ports on the Mini, only the first one is recognized. (Again, doesn't matter which two DisplayPort, either the two full ones or the DP-equipped-USB-C.)

I tried two Thunderbolt 3 Docks - one display to each TB3 dock. Only the display on the first TB3 dock was recognized, regardless of port plugged in to on either one. Unlike connecting to a TB3 port on a single dock, plugging in to the TB3 on the second-connected dock doesn't make that display take over.

The *ONLY* way to get two displays is one to the HDMI port, and one to a TB3 port (either direct or through a dock.)

This is disappointing, because I was hoping to use dual displays through a TB3 dock. Oh well.

 

[saulinpa]

The *ONLY* way to get two displays is one to the HDMI port, and one to a TB3 port (either direct or through a dock.)

There are at least two other options.

1. In other thread someone has two monitors connected to a DisplayLink hub via USB.
2. Sidecar lets you use an iPad as an extended display.

 

[Anonymous Freak]

There are at least two other options.

1. In other thread someone has two monitors connected to a DisplayLink hub via USB.
2. Sidecar lets you use an iPad as an extended display.

Neither of those are really using the internal graphics chip, so I excluded them. They're both "software virtual" displays. DisplayLink has definitely gotten better than it had been once upon a time, but it still isn't sufficient for "heavy" use like watching video or playing games, nor does it support anything higher than 4K/30. (Unless there's a brand new revision I haven't heard of.)

If they meet your needs, great. (I use iPad-via-Sidecar as a second display on-the-go with my MacBook Pro. It's fine as a quick-need-extra-space, but I wouldn't try to use it as a "primary second display" - even with a big iPad Pro it's still tiny compared to "real external monitors.")

 

[saulinpa]

Back to the opening subject of this thread.

I can confirm that attaching two LG Ultrafine 5K displays (original vintage) to an AS Mac (specifically M1 MBAir with 8-core GPU, 16GB RAM, 512GB SSD) does not work. Only one display comes up. It does appear to be running at full 5K using a visual check with a test pattern.

 

[JW Pepper]

Jobs is gone. Ive is gone. Who is left to care about Apple's image? Cook and company only care about the stock price.

Jony Ive cared but he has left the stage.

 

[joevt]

Back to the opening subject of this thread.

I can confirm that attaching two LG Ultrafine 5K displays (original vintage) to an AS Mac (specifically M1 MBAir with 8-core GPU, 16GB RAM, 512GB SSD) does not work. Only one display comes up. It does appear to be running at full 5K using a visual check with a test pattern.

Can you take a photo?

I don't think this is possible. Since you can't check with SwitchResX or AGDCDiagnose, then maybe the log command will show something. Go to #2,043

 

[Paul F]

Can you take a photo?

I don't think this is possible. Since you can't check with SwitchResX or AGDCDiagnose, then maybe the log command will show something. Go to #2,043

Screenshots are posted in the 4k thread here, you can get native 5k resolution, but only on one screen, which is expected.

 

[Lammers]

Jobs is gone. Ive is gone. Who is left to care about Apple's image? Cook and company only care about the stock price.

Ive was most certainly still at Apple when they discontinued the Apple Thunderbolt Display and didn't replace it.

 

[joevt]

Screenshots are posted in the 4k thread here, you can get native 5k resolution, but only on one screen, which is expected.

Which 4K thread? Can you post a url? 5K resolution cannot work on the LG UltraFine 5K. Are you talking about a different 5K display?

 

[joevt]

I may be wrong about the M1 not supporting 5K on displays like the LG UltraFine 5K. Read more at #2,055 . If you have a 5K display then consider providing the ioreg output mentioned there.

 

[jazz1]

Just got my M1 Mac mini.

Can confirm - only one single display over Thunderbolt, regardless of how you attempt to connect.

I tried:

• Two USB-C-to-DisplayPort connections direct to back of Mini - only the first one got signal.

I tried a Thunderbolt 3 Dock that has two DisplayPort connections, one DP-enabled USB-C, plus a Thunderbolt 3 "outbound" connection - when connecting to my Intel MacBook Pro, to support two displays in macOS, I have to use one DisplayPort connection, and the outbound TB3 via USB-C-to-DisplayPort. (In Windows 10 on the same MBP, I can run two DisplayPort plus a third on the TB3 outbound. The "only one on DP, the other on TB3" is a macOS limitation.)

• One DisplayPort, one USB-C-to-TB3-port - this is what works on my MBP in macOS - if I plug the DP in first, then the TB3, the TB3 takes precedence, only displaying on the display on the TB3 port. If I plug the TB3 in first, the DisplayPort is ignored. (Both are true for any of the "DisplayPort" connections, the two native DP, or the DP-enabled-USB-C.)
• Two DisplayPort - same as two direct to the ports on the Mini, only the first one is recognized. (Again, doesn't matter which two DisplayPort, either the two full ones or the DP-equipped-USB-C.)

I tried two Thunderbolt 3 Docks - one display to each TB3 dock. Only the display on the first TB3 dock was recognized, regardless of port plugged in to on either one. Unlike connecting to a TB3 port on a single dock, plugging in to the TB3 on the second-connected dock doesn't make that display take over.

The *ONLY* way to get two displays is one to the HDMI port, and one to a TB3 port (either direct or through a dock.)

This is disappointing, because I was hoping to use dual displays through a TB3 dock. Oh well.

How does the HDMI vs. The TB3 displays look quality wise? I’ll be running both outputs.

 

[Anonymous Freak]

How does the HDMI vs. The TB3 displays look quality wise? I’ll be running both outputs.

Identical as far as I can tell. I'm running to two identical 4K displays, one through DisplayPort, one through HDMI 2.0. Both are running at full 3840x2160 at 60 Hz. Can't tell which is on which interface.

 

[joevt]

Identical as far as I can tell. I'm running to two identical 4K displays, one through DisplayPort, one through HDMI 2.0. Both are running at full 3840x2160 at 60 Hz. Can't tell which is on which interface.

The display on the HDMI interface is using 8 bpc or using chroma sub sampling (4:2:0 or maybe 4:2:2).
Does {ioreg -filr -n "disp0"; ioreg -filr -n "dispext0"} > ioreg_M1_displays.txt show a difference between the two displays? From the four examples I have, I cannot see where the pixel format is specified. This info was available from AGDCDiagnose command for Intel Macs with AMD graphics, but this doesn't work on M1 Macs. Do your displays have an onscreen menu that shows the color format? Granted, there's not much visible difference between 8bpc and 10bpc (especially since dithering may be used) or between 4:4:4 and 4:2:0 (you can find test images that show the issue with chroma sub sampling).

Chroma Subsampling: 4:4:4 vs 4:2:2 vs 4:2:0

What is Chroma Subsampling and where is this visible? Chroma subsampling is a type of compression that reduces the color information in a signal in favor of luminance data.

www.rtings.com

 

[Anonymous Freak]

The display on the HDMI interface is using 8 bpc or using chroma sub sampling (4:2:0 or maybe 4:2:2).
Does {ioreg -filr -n "disp0"; ioreg -filr -n "dispext0"} > ioreg_M1_displays.txt show a difference between the two displays? From the four examples I have, I cannot see where the pixel format is specified. This info was available from AGDCDiagnose command for Intel Macs with AMD graphics, but this doesn't work on M1 Macs. Do your displays have an onscreen menu that shows the color format? Granted, there's not much visible difference between 8bpc and 10bpc (especially since dithering may be used) or between 4:4:4 and 4:2:0 (you can find test images that show the issue with chroma sub sampling).

Chroma Subsampling: 4:4:4 vs 4:2:2 vs 4:2:0

What is Chroma Subsampling and where is this visible? Chroma subsampling is a type of compression that reduces the color information in a signal in favor of luminance data.

www.rtings.com

Attached is the "Color Elements" section of the two ioreg runs, damned if I can interpret anything from that. I put my Terminal window on both displays, and didn't see any obvious color artifacting; but I'll try the actual image test a little later. Both displays are older Samsung models, I'm not positive if either has any issues that might make the display itself have problems. I know that of the two HDMI ports on the back, only one is HDMI 2.0, so if I want 60 Hz, I have to make sure to use the right port.

 

[joevt]

Attached is the "Color Elements" section of the two ioreg runs, damned if I can interpret anything from that. I put my Terminal window on both displays, and didn't see any obvious color artifacting; but I'll try the actual image test a little later. Both displays are older Samsung models, I'm not positive if either has any issues that might make the display itself have problems. I know that of the two HDMI ports on the back, only one is HDMI 2.0, so if I want 60 Hz, I have to make sure to use the right port.

This is comparing disp0 and dispext0? Only the Color Elements property differs? Both displays are identical?

Chroma sub sampling does not affect grayscale text and graphics (which only use luminance). Chroma sub sampling affects only parts that contain color (chroma).