Does a USB-C monitor support DisplayPort input over a USB-C to DisplayPort cable...
 
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Does a USB-C monitor support DisplayPort input over a USB-C to DisplayPort cable?  

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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

The only way to find out if your Thunderbolt 3 port supports two displays is to connect two displays. If you only have Intel graphics (instead of AMD graphics), then only 3 displays is supported - lap top screen, HDMI port, Thunderbolt port. So probably only one display for the Thunderbolt port. But you could have an MST hub which would let you connect two 4K 30Hz displays. But macOS doesn't support MST so you would need to move the connection of one of the displays when you connect the MacBook Pro.

Any USB 3.x port includes USB 2.0 so it doesn't matter what USB port you connect to the Hauwei or Belkin or WacomLink Plus.

I don't know why the Alogic Cable would work but other cable might not. I guess we need more testing to be sure (confirmation of the result). I think I would prefer a solution that includes USB so that you can use all the features of the display.

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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rafalo86
(@rafalo86)
Active Member
Joined: 1 month ago
 

@joevt

Big thanks for your valuable inputs and taking the time to explain various options.

I bought the Belkin Thunderbolt 3 Dock that can support 2 x 4K monitors. Since I already have that device, what is the benefit of MST hub over Belkin Thunderbolt dock?

USB-C to thunderbolt dock works well but issues I faced is that my other display is non responsive over display port.

As soon as I have answer to that, think I can move forward with ordering the cable to test and share results with you Smile

Thanks again

 

 

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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

MST hub allows a Windows PC DisplayPort or USB-C port or Thunderbolt port with one DisplayPort input to output to more than one display.

Some Thunderbolt or USB-C docks have a built-in MST hub. For example, the HP Thunderbolt Dock G2 supports 3 displays when connected to a USB-C port and 4 displays when connected to a Thunderbolt port (3 through the MST hub and one through the Thunderbolt port).

macOS doesn't allow MST hub to support more than one display but it will work for one display or mirroring displays.

The Belkin Thunderbolt 3 dock can support 2 displays only if the computer has a Thunderbolt controller with two DisplayPort inputs from the GPU (all Macs and some PCs). Your PC laptop probably has a Thunderbolt controller with one DisplayPort input from the GPU. You'll have to test the Belkin Thunderbolt 3 dock with your PC laptop to be sure - connect one display to the DisplayPort output of the dock and another display to the Thunderbolt output of the dock. If only one display works, you can replace the dock with one that has a built in MST hub or you can add an external MST hub.

Here's a list of DisplayPort 1.4 MST hubs:

https://www.cablematters.com/pc-1220-126-usb-c-triple-4k-displayport-mst-hub-with-dual-displayport-and-hdmi-for-windows.aspx
https://www.club-3d.com/en/detail/2485/multi_stream_transport_(mst)_hub_displayport_1.4_triple_monitor/
https://www.club-3d.com/en/detail/2486/usb_type_c_3.2_gen_1_multi_stream_transport_(mst)hub_displayport1.4_triple_monitor/
https://www.startech.com/ca/AV/display-and-video-adapters/Displayport-Adapters/displayport14-mst-hub~MST14DP123DP
https://www.delock.com/produkt/87737/merkmale.html

Your laptop may only support DisplayPort 1.2 (Intel graphics instead of AMD graphics) so you could use a cheaper DisplayPort 1.2 MST hub. You'll only be able to connect two 4K 30Hz displays or two 1440p 60Hz displays if you're only using DisplayPort 1.2 and MST.

 

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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rafalo86
(@rafalo86)
Active Member
Joined: 1 month ago
 

Thanks for your feedback @joevt.

To keep costs to the minimum, I decided to try out A-Logic solutions and will let you know know whether it works as soon as it arrives. I am hopeful although have some doubts as to why Alogic bidirectional cable would work but not club 3d so let's see. If this does not work, I will have to try Belkin/Hauwei cable which is a bit more expensive.

Regarding connection to my HP Elitebook, I only have USB-C / HDMI output. So do you believe USB-C/HDMI bidirectional cable would work with LG Ultrafine 21.5 22MD4k monitor? Just in case the belkin dock does not work.

Appreciate your inputs.

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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

@rafalo86, I don't think there's such thing as a HDMI bidirectional cable. Your HP Elitebook has a USB-C port so just use that to connect one LG UltraFine 4K display.

 

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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rafalo86
(@rafalo86)
Active Member
Joined: 1 month ago
 

@joevt @instrumedley

 

Thanks for your support and sharing all your insights. I finally received the ALOGIC Cable USB-C to Display port cable connected to my old LG Ultrafine 22MD4K monitor and it works. 

My set up is as follows:

Belkin Thunderbolt 3 Pro driving 1 monitor via USB c and 1 monitor via Display port. It works both with my MacBook Pro 13" and HP Elitebook 840 G5. Only thing is that I cannot adjust brightness of the monitor connected via display port on my keyboard.

I also bought Club 3d USB C 8K cable that did not work even though it is bidirectional. This is a good alternative to expensive Belkin/Hauwei cable.

Appreciate all your support and hope this post clarifies the math that old LG ultra fine displays do not work with basic USB-C to display port cable.

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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Jesus Rodero
(@jesus-rodero)
New Member
Joined: 3 weeks ago
 

Hello.

I think I have the "old" LG UltraFine 5K 27MD5KA 2018, that has the Alpine Ridge controller with only Thunderbolt 3 input (not USB-C as far as I know) connected to a Mac mini 2018.

As I have been reading here, the only plug and play solution is the Blackmagic eGPU, but I don't like it because is not upgradable.

The AMD Pro W5700 has a USB-C output but I think it will not work with the Thunderbolt 3 monitor.

My question is, the only alternative is connecting other eGPU 2 DisplayPorts to a Titan Ridge controller mounted over a PCIe powered riser adapter with Thunderbolt 3 output? Will the LG UltraFine 5K work with that?

Mac mini 2018, LG UltraFine 27K 2018, Blackmagic eGPU with AMD Radeon RX Vega 56


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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 
Posted by: @jesus-rodero

My question is, the only alternative is connecting other eGPU 2 DisplayPorts to a Titan Ridge controller mounted over a PCIe powered riser adapter with Thunderbolt 3 output? Will the LG UltraFine 5K work with that?

It should work. People have tried it before. There may be issue where you need to unplug or reconnect or something like that. I think it could be possible to put the Titan Ridge in a Thunderbolt 3 expansion box, and enable it so that you can do brightness control and USB normally but the software to do that doesn't exist yet.

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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Jesus Rodero
(@jesus-rodero)
New Member
Joined: 3 weeks ago
 

@joevt, Thanks for your work here helping all of us.

 

Mac mini 2018, LG UltraFine 27K 2018, Blackmagic eGPU with AMD Radeon RX Vega 56


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