Using DisplayPort over USB-C (3.1) to Dock - Not working

[HeneryH]

I have a Lenovo Laptop with a Lenovo dock that is working just fine with my two DP monitors.

I am now trying to connect either of my two Asus Mobo desktop computers to the dock to try to share my monitors and other peripherals easily between my desktop and my laptop. The idea is to just plug my dock into either the laptop or the desktop and away I go.

I cannot for the life of me get the Asus Mobos to recognize the USB-C (3.1) dock display ports. The Mobos DO recognize the dock USB ports and the Network on the dock just not the display ports.

I've read that the computer must support DP Alt Mode so to take advantage of the alternate channels over the USB cables.

Could that be my trouble?

Has anyone used a USB-C dock with their Asus Mobos?

I have two that I have tried without success: ASUS PRIME B250M-A and ASUS TUF Z390M-Pro Gaming

Thanks

Info about DP-Alt Mode at the following two links
https://t.co/VUVfxyZF9j?amp=1
https://t.co/X0HIFf9HwS?amp=1

My dock is a Lenovo ThinkPad USB-C Dock (40A9)

[HeneryH]

Well, to the best of my looking into this, it seems like neither of these motherboards support video over USB-C.

Worse, it doesn't seem like they can even have an add-in card installed because the add-in cards require a Mobo with an on-board TP Header.

Anyone know of another way to get video out to a USB-C dock?

[Perrorist]

USB-C needs to have PC Alternate Mode. You may need to install an extension card with a suitable port. The cable must also be capable of handling that mode. Cheap cables don't.