Daisy Chain Dell U2715H from Macbook

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Daisy Chain Dell U2715H from Macbook

I'm considering purchasing a few Dell U2715H displays for my home office. I want to know if I can run them in a daisy chain type setup from my MacBook Air or my MacBook Pro.

Can anyone tell me if this will work with the newest updates to High Sierra? My MacBook Air is running version 10.13.6. From all the reading I have done on this topic, a lot of people have had issues running these displays in a daisy chain setup, never getting the second display to go beyond mirrored mode.

Currently I have a Mini DisplayPort to DisplayPort cable (here) that I use to feed my Dell U3011 from my MacBook Air. It runs that display at 2560x1600@60Hz no problem. I plan to use that cable to feed the first Dell U2715H, running in 1.2 mode. I then plan to run either the same cable or a DisplayPort to DisplayPort cable from the first Dell U2715H to the second, running in 1.1 mode. I have an Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 (Mini DisplayPort) adapter (here) that I hope to use with my MacBook Pro for this setup when I need to, if it will work.

Reading over the tech specs on the MacBook Pro, under video support, it does say:

Up to two displays with 5120-by-2880 resolution at 60Hz at over a billion colors
Up to four displays with 4096-by-2304 resolution at 60Hz at over a billion colors

Thunderbolt 3 digital video output

Native DisplayPort output over USB‑C
VGA, HDMI, and Thunderbolt 2 output supported using adapters (sold separately)

Reading over the tech specs on the MacBook Air, under graphics and video support, it says:

Intel HD Graphics 6000
Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 3840-by-2160 resolution at 60Hz on an external display, both at millions of colors.
Thunderbolt digital video output
- Native Mini DisplayPort output
- DVI output using Mini DisplayPort to DVI Adapter (sold separately)
- VGA output using Mini DisplayPort to VGA Adapter (sold separately)
- Dual-link DVI output using Mini DisplayPort to Dual-Link DVI Adapter (sold separately)
- HDMI audio and video output using third-party Mini DisplayPort to HDMI Adapter (sold separately)

Listed below are the details on each of my MacBooks in case this helps.

MacBook Air (13 inch, 2017)

- macOS High Sierra 10.13.6

- Intel HD Graphics 6000

- Thunderbolt 2 port

MacBook Pro Touchbar (15 inch, 2016)

- macOS Sierra 10.12.6

- Radeon Pro 455 2GB

- Intel HD Graphics 530

- Thunderbolt 3 (USB C) port

MacBook Air, macOS High Sierra (10.13.6)

Posted on Jul 29, 2018 8:55 PM

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Answer 1

.NGX. Author

Level 1

9 points

Aug 10, 2018 2:26 AM in response to Almojgar

I received the displays and tested them today. Unfortunately it looks like Apple has still not addressed this issue. macOS still does not support DisplayPort Multi-Stream Transport (MST), even with the most recent updates in macOS High Sierra 10.13.6. They really need to get with the program here... it's pretty sad.

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Answer 2

.NGX. Author

Level 1

9 points

Aug 10, 2018 2:27 AM in response to John Lockwood

It looks like I'll need to look into a Thunderbolt 2 dock or one of these displaylink adapters. Thanks for the links John.

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Answer 3

Aug 1, 2018 6:42 AM in response to .NGX.

I have never heard of anyone successfully daisy-chaining Dell screens with a Mac. You will have to directly connect each to the Mac. You could even with the same make of screen mix connecting to the Mac via different connections, for example one via HDMI and another via Displayport.

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Answer 4

Aug 2, 2018 11:11 PM in response to .NGX.

Your best bet is to get a Thunderbolt2 dock which contains other video ports. Typically these will give you a usable Thunderbolt2 aka mini Displayport socket and an HDMI socket which would allow two monitors. See - https://www.omnicoreagency.com/best-thunderbolt-2-docks/

There are USB adapters to allow connecting a display and these do work on a Mac, they are generically referred to as Displaylink adapters and here is the Mac driver - http://www.displaylink.com/downloads/macos

This is a list of Displaylink USB adapters - http://www.displaylink.com/products/usb-adapters

Of course a final option is to sell your MacBook Air and get a new MacBook Pro with four Thunderbolt3 ports. (Or a secondhand older MacBook Pro.)

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Answer 5

.NGX. Author

Level 1

9 points

Jul 31, 2018 4:52 PM in response to Almojgar

Thanks Almojgar,

I'm most likely going to be using a Thunderbolt 2 (mini DisplayPort) to DisplayPort cable from the MacBook Air to the first monitor. From there I will be planning on using a DisplayPort to DisplayPort cable to the second monitor. Hopefully using those cables I will not have any issues!

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Answer 6

Almojgar

Level 2

432 points

Aug 1, 2018 3:43 AM in response to .NGX.

Please report here after your tests if the second display in your daisy-chain in the precise configuration you have described is receiving normally orders from the Display prefs about placement, etc. I suspect it won't, and that all that you can get starting from this second link will be only mirroring, but I may be totally wrong of course... (sorry to use you as a Guinea pig for my lab, but as you seem decided to attempt the experience...)

Regards.

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Answer 7

.NGX. Author

Level 1

9 points

Aug 2, 2018 12:15 AM in response to John Lockwood

Hey John,

Thanks for the reply. I was thinking that may very well still be the case, and is what I’m afraid may happen. I was hoping the latest updates to macOS in High Sierra would address this, and that my post here may catch someone’s attention that has attempted this and can either confirm or deny.

Unfortunately with the MacBook Air, it has the single Thunderbolt 2 (mini DisplayPort) output and that’s it. I’m not sure if it would support display out over usb, where I could use a dongle to convert to hdmi or something. So I’m stuck with one ouput for two monitors, which is why I’m wanting to daisy chain if possible.

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Answer 8

.NGX. Author

Level 1

9 points

Aug 2, 2018 1:27 AM in response to John Lockwood

Nice! Thanks for the recommendations, I’ll check those out. The MacBook Air is my lady’s, as I was saying in my earlier posts I also have a newer MacBook Pro that has the four Thunderbolt 3 (USB-C) ports. That one is mine :) I plan to also use that system with the two monitors in the exact same configuration, down to the cables. Only thing that would be different is the official Apple dongle that I would use to go from Thunderbolt 3 to 2.

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Answer 9

Aug 2, 2018 2:10 AM in response to .NGX.

You can get a USB-C aka Thunderbolt3 to mini Displayport cable - USB-C to Mini DisplayPort Cable - 4K 60Hz - Black - 1.8 m (6 ft.) | StarTech.com United Kingdom

However whilst this maybe cheaper than Apple's Thunderbolt3 to 2 adapter it would require you to unplug the cable at the monitor end and assumes your monitor as a mini Displayport connection. (Actually the later is not a problem as there is also a cable to go to a full-size Displayport socket.) See - USB-C to DisplayPort Adapter Cable - 1m (3 ft.) | USB-C Video Adapters | StarTech.com United Kingdom

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Answer 10

.NGX. Author

Level 1

9 points

Aug 2, 2018 12:20 PM in response to John Lockwood

I already have the adapter that I use at work with my thunderbolt displays and it works great, so I can just bring that with me and use it at home when needed. The goal here is to use the same cable for both laptops, using the adapter for the Pro. That way all I have to do is plug one cable in and I’m good.

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Answer 11

Almojgar

Level 2

432 points

Jul 30, 2018 8:19 AM in response to .NGX.

Hi,

Daisy-chain passthrough seems to work only with standard cables, e.g. Thunderbolt2 cable -> Display -> Thunderbolt2 cable -> Display, etc. or else USB-C -> Display -> USB-C -> Display, etc.

As I have encountered here and there, and that you have probably already noticed yourself, the chain seems not to work with Thunderbolt2 to USB-C cable -> Display (on the first display in the chain, it works) -> then USB-C to USB-C cable -> Display (here the global settings don't work anymore).

Inference without further knowledge: or there's no more complete passthrough — something missing — in Thunderbolt2's previous signal, after traversing the first USB-C display, or maybe more probable: "knowing" that it is connected to a supposed Thunderbolt3 signal, the second display expects further orders that Thunderbolt2 of the first element of the chain is unable to give...

Regards.

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Daisy Chain Dell U2715H from Macbook

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