Arch Linux

Veldora

Member

From: Sol III, Milky Way

Registered: 2023-01-26

Posts: 55

External display no signal, when laptop connected via tb4 dock.

Hi

When connecting my external display via DP, HDMI or both with a Lenovo thunderbolt 4 dock and the dock with my Lenovo Thinkpad T16 G1 via TB4, which supports thunderbolt 4 out of the box, the display-manager (neither gdm nor sddm) won't get a signal. However, the monitor is being recognised by the DE and I can change it's resolution and the other settings. (DE: Gnome 43)

When changing the resolution of the monitor, it detects a signal and starts to work.
When closing the lid of the laptop, the monitor detects a signal and also starts to work.
When letting the lid closed on boot and typing the password blind, the screen starts to works, as gnome starts.
When dis- and reconnecting the dock, it also starts to work.

There's a long list of possible workarounds, but those aren't real solutions to my problem.

The notebook and the docking-station has the latest firmware installed.
Arch Linux is up-to-date.
The kernel is a NEXT-Kernel (6.3.0-rc5-next-20230404), which had some some drm-fixes merged, in the hopes they would solve the problem I'm now describing.
It's also not working with the current stable (6.2.10) kernel.

Did anyone else stumble over this problem?
Is there a possible fix out there, that I haven't heard of?

If you need some logs, please let me know.

Thanks everyone for helping out.
Veldora

Last edited by Veldora (2023-04-11 15:12:42)