I recently acquired a Dell U2720Q which supports HDMI, DisplayPort, and USB-C inputs.
My hopes was to use just USB-C to connect my laptop to the monitor and connect all of my peripherals to the monitor so it functions as a dock (power, peripherals, and display all over one USB-C connection).
However the monitor appeared to have a tiny resolution over the USB-C link and both X11 and Wayland refused to display to it. I ended up plugging in an additional HDMI cable and that drives it just fine at full resolution. X11 thinks I have three monitors, but I can disable the USB-C connected display. So this works but is sub-optimal to have two cables.
Iām running Pop!_OS 21.10 with all the latest updates. Has anyone had similar experiences?
Update after a day of use. It appears that the USB-A ethernet dongle that was plugged into the monitor was causing all of the problems. Once I moved the dongle to another expansion slot on the laptop, the monitor and laptop were able to operate over single USB-C connection and everything is solid.
I am not sure why the USB-A ethernet was causing so much grief, but the ethernet link was bouncing up and down all day as well; which was the hint as to where the problem was.
I hope this helps any one else who encounters similar problems.
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Hi there,
I just wanted to add that this issue appears with a mouse and a keyboard connected to the back USB ports of the Dell monitor as well. Thankfully your solution works for this case as well. 