Apple M1 - LG 4k monitor, not showing 2560 x 1440 resolution?
 

MacBook pro M1

I have 2 identical LG 32uk50T-w monitors connect to a startech.com USB32DP24K60 (usb3 to Displayport adaptor)

Using DisplayLink Manager 1.2.0 (Build 55.125)

--
problem:

only on 1 of the monitors, I can switch to 2560x1440 the other one doesn't display that resolution at all?

see image: https://imgur.com/a/1rV9aDg

how to troubleshoot/what to do?

go4it,
Rene

I'm using an M1 MacBook with the Targus dock and an active HDMI to DisplayPort converter. Then the DisplayPort is connected to the LG Ultrafine via the Moshi DisplayPort to USB-C adapter sold by Apple.

In this configuration, I'm able to get resolutions from 3840x2160 to 1280x720, including 2560x1440.

I've got dual LG Ultrafine 4ks—one is on the native thunderbolt port and the second is on the hack (dock HDMI port -> DisplayPort adapter -> DisplayPort to USB-C cable).

However... I've yet to figure out how to adjust brightness on my LG Ultrafine. Any idea how you do that?

LG 32UK50T-W * NO 1440P either *
 

- M1 Macbook Air 16/1TB
- Targus 180USZ

-Displaylink 1.2
-Mac OS 11.1

Two monitors an LG 32UK50T-W (4K native) and Asus 32 Native (1440p native).

No issues with the Asus.

The LG will not do 1440p while hooked up to the Targus.
Naturally 1440p is my preferred resolution.

I tried both Display port 1.4 and HDMI 2.1 cables again these all work fine directly connected. Also tried hooking up only one monitor.

4K is great but its to damn small. I can choose Native, 4K, 1080p, 900p, 720. Holding down the option key does not change the resolution choices.

1440p
 

So reading around it seems Displaylink software does not support 1440p unless the display is native 1440p. 4K monitors seem to support 4K, 1080p, 900p, 720p.

Since my Targus 180 takes care of power, usb devices, ethernet, the Asus 1440p monitor, etc. My M1 still had a port free so I used the xtra M1 USB4/Thunderbolt port and a usb-c to HDMI adapter and plugged my LG 4K monitor directly and set to 1440p. Works for now until displaylink properly supports1440p on 4K monitors.

* Note USB-C to display port adapter works too. I have two macs a my desk. Macbook Pro 15 2017 from work and M1 Macbook Air. So no need to unplug display cables by using Display port with Pro 15 and HDMI with the M1 Air..

Similar issue, any comments?
 

I'm facing a similar issue but my same LG model monitor received no signal via a hdmi-to-hdmi connection with my targus docking station. The same setup works on my Dell monitors and I can connect my LG monitor with HDMI cables to my Nintendo switch (which kind of means the port is working). Any comments? Thanks!

(I don't have a HDMI to DP cable to test with.)

Update:

I was able to use the LG monitor with 1280x720. No signal at all if I choose the other three options (3840x2160, 1920x1080, nor 1600x900). I am using a M1 Macbook Air with OS 11.1, targus dock310, lg32uk50t, connection hdmi to hdmi.

Any ideas on how to make it display better?

Thanks!

Last update:
Problem solved: find a different HDMI cable. Apparently they have different capabilities albeit the same look.

Click on "Scaled" while holding down the alt key gives you more resolutions.

There is def a missing resolution on my Dell 4K monitor as well. Makes the device unusable on the same setup. Works fine on my Intel based MB

Display link 1.3
 

So I updated to DisplayLink 1.3 on both my M1 and 15 MacBook Pro 2017. Nice to have a universal binary.

Interestingly the 1440 resolution on my LG 4K display works correctly only 2017 not the M1. So I am back to using Displaylink on only 1 monitor and using a USB-C to Displayport or HDMI adapter directly for the LG. This solution has in is fine for me. I feel it makes the setup more stable in clamshell mode and during boot up.

None the less it would be nice if it worked as it should. I have to play a little further as well I think I noticed a new anomaly on at least 1 of my two computers. Even with the lid shut 1.3 DisplayLink was advertising the built in display on 2017 MacBook Pro, but not my M1. Naturally with the lid shut this display should not be active.

I was hoping the 1.3 update would let me use additional retina modes on my LG 4K 32" display, but the options are the same as with 1.2: Either full 4K (too tiny for me), or 1080p (too big).

1440 on 4K appears to be problematic on a number of displays over display link
 

You do not mention your Display link device or Mac model and how many displays you have, In my case I have an M1 Air and 15 inch Retina (two 32 inch displays [1 4K LG like yours and one 1440]). I do have both a thunderbolt dock as well Display link basked Targus 180. Generally Thunderbolt docs are better generally for Intel MACS as no driver is required at all and of course thunderbolt runs at 40Gbs second versus 5GB for most USB-C/displaylink based devices. Plenty for most uses, but not all.

None the less with my Targus 180 having so many ports including power delivery for either computers even my M1 has a port free. So I run my 4K display direct via a USB-C display port adapter (you can do the same with a USB-C to HDMI as well).

This increases the reliability of clam shell mode, solves the 1440 on 4K display issue and more.

In my case I ended up using the Targus for both computers even though the 15 inch Retina spends 85 percent of the time at the Dock. It much less recabling that way,

I have the MBP M1 and dual LG 32UL950W displays, and am using the StarTech USB 3.0 to Dual DisplayPort adapter.

Has there been any progress on these scaled resolution issues?

Are they at least being looked into? Can we expect a software update in the future?

You can vote for this feature:
https://support.displaylink.com/foru...eat-but-it-wou

I gave it my vites. Was excited with the displaylink responses in that thread that displaymanager 1.3.1 was goping to restore the 4k resolutions that were missing. Unfrtunately that never occurred with that release and there has been no subsequent updates from displaylink on the matter. I'll watch from the sidelines on if this ever gets fixed for M1 as i have now returned my dock and M1. I suspect that the missing resolutions is an Apple issue and may never be solved on the existing M1 hardware. I had a intel MAC that works perfectly with HiDPI at the missing resolutions with my dock and displaylink. Change out the intel Mac for the M1 and the higher resolutions are gone. Either M1 hardware or bigsur as the intel mac i have is running Catalina. End answer is the same unfortunately. 4k, displaylink and a M1 your limited to an external display of 1920x1080 if you want some thing that is readable and not blurred.

I see displaylink manager 1.4 has just been released. The release notes have alot of change for UI behaviour and delivers upon screen rotation. Also states returns 4096x2160 resolution on M1 but does not state anything about supporting the resolutions that are missing between 1920x1080. So no changes to using anything other than too large or too small text on a M1.