Only one external screen recognized via USB C dock

Graphics / Linux Linux
1

Dear nvidia linux community,

My setup involves a laptop screen and two external displays. Both external displays are available as they should be when one of them is connected directly via the HDMI port of the laptop and the other via usb-c (or via a usb c dock, DP-0). However, when connecting both displays via a usb c docking station, only one display is recognized in the system. Both work fine individually via the dock when they are the first to be connected. But the one that is connected second is not recognized in the system, independent of the port (HDMI/usb-c) or monitor type (tried one display from another manufacturer).

OS: Ubuntu 20.04
kernel: 5.15.0
X11
driver: 535.129.03
edids.zip (808 Bytes)
nvidia-bug-report.log.gz (738.2 KB)
Please find attached EDIDs of the displays and an nividia-bug-report.

Any help would be much appreciated.

2

One thing I noticed is that the dock doesn’t seem to be recognized as multistream device. Please create one nvidia-bug-report.log where the hdmi port on the dock is working after reboot and one with the displayport active.
What dock model are you using?

3

Thanks for coming back so quickly.

Dock is: Icy Box IB-DK2501-TB3

Here are three logs. EDIT/: All connections via the dock. /EDIT

  1. HDMI working after reboot (with both cables connected):
    nvidia-bug-report-HDMIworking.log.gz (553.9 KB)
  2. DP working after reboot (with both cables connected):
    nvidia-bug-report-DPworking.log.gz (528.4 KB)
  3. Unplugging DP, leaving HDMI connected:
    nvidia-bug-report-UnpluggingDP.log.gz (601.8 KB)

EDIT: Btw: I have tried displaylink without success, which is not too surprising given that to dock doc does not mention displaylink. Relating to this post

4

Actually I think the dock doesn’t support using two monitors. The second monitor connector is a USB-C which i suspect is simply passed-through from the host so you can use either HDMI or USB-C, not both. The datasheet of the dock also just mentions HDMI and no multistream support.

5

That’s a bit embarrassing. Thank you for looking into it!