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aslogd

Member

Registered: 2022-07-31

Posts: 2

[Solved]External monitor through USB-C dock only works on login screen

Hello!
I'm  trying to connect a USB-C dock (WD19TB) to my laptop. Looks like the dock is detected correctly, as well as the devices connected to it. While I'm on the login screen (using Ly), the external monitor connected to the dock works (HDMI or DisplayLink inputs on the dock have the same problem). Once I enter the credentials and my session starts, the external monitor goes off. Looks like the sources are listed in xrandr ("DP-X-X"), but it shows always as "disconnected".  If I try to connect the monitor through DP without the dock, it can be enabled (although I'm seeing only the mouse, this will be the next issue to solve)

Here's the output of journalctl -b. The only interesting thing that I see is some output from noveau towards the end. It gives some error a bunch of times:

Jul 31 22:08:23 archlinux kernel: nouveau 0000:01:00.0: i2c: aux 0004: begin idle timeout ffffffff

and it ends with this:

Jul 31 22:08:23 archlinux kernel: nouveau 0000:01:00.0: disp: init failed, -16
Jul 31 22:08:23 archlinux kernel: nouveau 0000:01:00.0: init failed with -16
Jul 31 22:08:23 archlinux kernel: nouveau: systemd-logind[412]:00000000:00000080: init failed with -16
Jul 31 22:08:23 archlinux kernel: nouveau: DRM-master:00000000:00000000: init failed with -16
Jul 31 22:08:23 archlinux kernel: nouveau: DRM-master:00000000:00000000: init failed with -16
Jul 31 22:08:23 archlinux kernel: nouveau 0000:01:00.0: DRM: Client resume failed with error: -16
Jul 31 22:08:23 archlinux kernel: nouveau 0000:01:00.0: DRM: resume failed with: -16

Also, the xorg.log. Looks like the monitor is being detected at some point, and it's showing the available modes:

[    12.222] (II) modeset(G0): Printing probed modes for output DP-1-2-3

Since it looked like noveau was the problem, I tried blacklisting it as intructed by "Impossible to activate displaylink's screen" here, but this seemed to make things worse, and now the sources weren't even being listed with xrandr.

Thank you so much for your help, please let me know if I can provide more information or check some ohter logs.

Last edited by aslogd (2022-08-07 12:46:14)

aslogd

Member

Registered: 2022-07-31

Posts: 2

Re: [Solved]External monitor through USB-C dock only works on login screen

I solved it by first installing nvidia-lts. then, the display appeared always correctly connected in xrandr. I still couldn't enable the screen. xrandr would say "configure crtc X failed". I read that this may indicate that while the display supports the listed modes, the graphics card doesn't. At this point I decided to take a look at the BIOS settings and found one for changing the card in use so I changed "Switchable graphics" to "Discrete graphics" in the BIOS. After that, looks like the screen fails to update the image on the login screen, but it works well after login. I have amdgpu+nvidia on my system, it's possible that there's some issue there. For reference, the system is a ThinkBook 16p gen 2.