I'm running Ubuntu 18.04 on a Lenovo Carbon X1 5th, 2017 model.
A Lenovo P27u display, containing an integrated USB-3 hub with three USB-3 connectors (blue) is connected via USB-C (also used as power supply) to the laptop. I can use an i-tec USB-3 with an integrated Ethernet adapter without problems when I connect it directly to my laptop: It shows up as two USB devices:
Bus 002 Device 013: ID 0bda:8153 Realtek Semiconductor Corp. Bus 002 Device 012: ID 2109:0813 VIA Labs, Inc.
However, when I plug the i-tec USB3 hub into one of the USB ports of my Lenovo P27u display I only see the USB hub device (VIA Labs, Inc.) but the integrated Ethernet adapter in the i-tec USB3 hub doesn't show up in
lsusb nor in
In lack of other hardware, I can not directly test, if this is related specifically to the display or if this is a problem, when connecting such adapters after another hub in general.
I also tried to install the Realtek 8152 driver from their webpage, which did not change anything.
Any ideas how to tackle this problem? Does anybody have similar hardware to troubleshoot this issue?
Note: On the Display hub is a fourth connector colored in yellow, where opinions seem to disagree, if this is for charging only, but I'm not talking about that one.
Note II: I figured out another part of this issue: The on-screen menu of the display has an option called "USB Select", which can be set to either USB2 or USB3. If set to USB, the USB + ETH adapter also works on any of the "regular" i.e. non-yellow USB3 ports on the display. I did not try all possible combinations of settings though.