MacBook Pro M1 + Dell D6000 + LG Ultrafine 24" Issues

[TheGreatCornjoelio]

I have the following setup:

MacBook Pro (13-inch, M1, 2020) 16GB
Dell D6000 Docking Station (with DisplayLink Plug and Display sticker on the bottom)
2 of the LG 24MD4KL-B 24" Ultrafine 4K UHD IPS LED Monitor with Built-in Speakers, 3840x2160

I have one of the LG monitors plugged in directly to the Thunderbolt port on the MacBook Pro using the supplied Thunderbolt cable.

I have the Dell D6000 plugged into the second Thunderbolt port on the MacBook Pro.

I have installed the DisplayLink Manager 1.4.0 (Build 57.120) and have attempted connecting the second LG monitor using the following cables:

USB C to Displayport Cable 4K 60Hz, ELUTENG Thunderbolt 3 to Displayport Cable
USB-A to USB-C cable

I have tried them both in the Thunderbolt port and the USB-C port on the back of the LG monitor but I keep getting the "Connection Status: No Monitor Connected" message in the DisplayLink Manager application.

Any help you can offer is greatly appreciated! Both of these monitors worked flawlessly when connected to my old MacBook Pro 16" (Intel), so I know it's not a hardware issue on that side of things.

[KatarzynaCzaja]

Hello,

Thank you for reaching out!

If I understand correctly you are trying to connect the LG monitor to the Thunderbolt/USB-C port in the docking station. If that is correct then please keep in mind that the USB-C port in the docking station does not support video. It is for charging and data transfer.
No USB-C monitor will work with this port.
To produce video you have to use the available video ports so HDMI and 2x DisplayPort.

Best regards,
Kate

[TheGreatCornjoelio]

Originally Posted by KatarzynaKowalczyk

Hello,

Thank you for reaching out!

If I understand correctly you are trying to connect the LG monitor to the Thunderbolt/USB-C port in the docking station. If that is correct then please keep in mind that the USB-C port in the docking station does not support video. It is for charging and data transfer.
No USB-C monitor will work with this port.
To produce video you have to use the available video ports so HDMI and 2x DisplayPort.

Best regards,
Kate

Kate, I'm using the DisplayPort out on the Dell D6000 connected to the DisplayPort - USB-C cable which is connected to the LG monitor using USB-C.

I've also tried connecting using USB-A out from the Dell D6000 to USB-C on the LG monitor.

The LG monitor has 5 ports on the back - 2 of which are Thunderbolt and 3 of which are USB-C. I've tried connecting to all of these with no success.

[czazic11]

I have the same Monitors on my MacMini M1, using a Startech dual displaylink adapter, primary monitor is connected to Thunderbolt on the mac same as you.

Firstly, It wont work correctly even when it does "work", you can only select 3840x2160 (which just gives me a black screen), or 1920x1080 low resolution not HiDPI so it looks garbage. I tried SwitchResX which lists the correct HiDPI resolutions but just gives a black screen, apparently this is a M1 issue with the displaylink driver as people have reported it works fine with Intel Macs.

EDIT: Apparently the extra resolutions are just hidden, they show up fine on Monterey beta. The black screen I am getting at higher resolutions may be due to the Displayport -> USB-C cable I am using (Cablematters) I have ordered a certified displayport cable by Moshi to see if that helps.

You will need to plug the cable from the displayport on the Dock to one of the two thunderbolt ports, not the USB-C as they are output only.

If its not working you probably have the wrong cable, it must be a bi-directional Display port to USB-C cable, most of them are only for USBC output to Displayport which is the wrong way around.

If display link shows monitor detected, but the screen is black then you have the same issue as me which is that the 4k resolution is broken. I had to click gather windows on the display prefs window on the thunderbolt connected monitor, then manually change the resolution to 1920x1080 on the window for the display link monitor.

[TheGreatCornjoelio]

Originally Posted by czazic11

If its not working you probably have the wrong cable, it must be a bi-directional Display port to USB-C cable, most of them are only for USBC output to Displayport which is the wrong way around.

Thanks for pointing this out - I've ordered the cable you recommended and will post back once that's arrived. Many thanks!

[TheGreatCornjoelio]

Originally Posted by TheGreatCornjoelio

Thanks for pointing this out - I've ordered the cable you recommended and will post back once that's arrived. Many thanks!

Bit the bullet and purchased 3 different cables - all bidirectional from CableCreation, Monoprice, and finally the $60 Moshi 5K version - all with the same result. I can use the external monitor, but only at 1920x1080. Otherwise, it's just a black screen. Super frustrating - why oh why won't this work?!?