Latitude 5420 - second screen resolution issues DP-USBC connection

@PatrickStar0  Sounds like you might be dealing with a very strange interoperability problem that only gets triggered with specific combinations of equipment.  I just encountered a problem like that when my wife got a new Mac and docking station.  It didn't output her displays properly, even though four other laptops worked fine with that setup, and her Mac worked when I tried a different docking station, and her Mac and docking station both worked fine when I tried different displays.  I only had a problem specifically with her Mac, her new docking station, and her displays.  So you might want to just try another brand of USB-C to DP cable.  I realize that shouldn't be necessary, but not everything in tech that SHOULD work always DOES work.  For what it's worth, I've had consistently good luck with Cable Matters cables, including their USB-C to DP cables.

@PatrickStar0 Try fully uninstalling the Intel Graphics drivers under Programs and Features and then reinstalling them. And then is 640x480 the ONLY resolution available for you to choose in Windows Display Settings? Is that also true in Intel Graphics Command Center? Intel GPUs have supported 4K for almost a decade now, and the Xe GPU you have can support up to 8K.

@PatrickStar0  I suggested completely uninstalling the existing drivers and then reinstalling them. That isn’t quite the same as updating. And I suggested that you check available options under Windows Display Settings and Intel Graphics Command Center, regardless of the device name you’re seeing. Did you actually do that?

@jphughan when the problem came up I first try to update the drivers. I don't know why but for some reason my laptop recognize the screen as Digital Flat Panel 640x480 and not as for example generic PnP Monitor 

Hello @jphughan thank you for the advice,

I tried with another cable but it not resolved my issue.

hi all, am facing the same issue as PatrickStar.

By chance have anyone found the solution to this? i've tried rolling back the driver and installing the latest one, but problem is not solved. the Usb C - DP cable is working perfectly on my other laptop expect this. 

I have the same issue. Latitude 5420 using USB C to DisplayPort cable only offers 640x480 as output resolution on my Acer XB280HK UHD monitor. The same monitor and cable support 3840 x 2040 when I connect a Lenovo laptop.