Arch Linux

nicovell3

Member

Registered: 2015-06-12

Posts: 12

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Thinkpad Thunderbolt Dock 4 without image after latest update

I had a working setup which includes The Lenovo Thinkpad Thunderbolt Dock 4. I had it working with two laptops, the first with Intel processor and the second with AMD. The installation is almost the same, trying to be the most standard possible, with GDM and Gnome, running the mainstream kernel and booting with systemd-boot.

After an update in installed on both computers on 23 of December, the dock keeps "working" but the screen has no signal. All the data from the external screen is shown at the display settings panel, but it doesn't work.

I booted a RedHat installation in the AMD laptop and the screen works just fine, so it had to be a software problem. I installed the kernel linux-lts and booted it, but the problem persisted.

The only way to have my external screen active was to downgrade the main kernel to 6.17.9. There must be a problem with linux 6.18 and this dock which has also been backported to the linux-lts kernel.

I don't want to avoid upgrading my kernel, so does anyone know how to investigate this problem in order to solve it through configuration or to send useful logs so it can be fixed?

Thank you in advance!

5hridhyan

Member

From: Asia

Registered: 2025-12-25

Posts: 295

Re: Thinkpad Thunderbolt Dock 4 without image after latest update

This looks like a  kernel regression, from what you explained  "Works on Intel and AMD, EDID/modes are detected, works on RHEL, works on Arch with 6.17.9, broken on 6.18.x and linux-lts". Nothing to fix in config I guess. Collect logs on the broken kernel also on 6.17.9, diff them, and report to Arch bug tracker / upstream. Likely a DRM / DP-MST or Thunderbolt regression in 6.18.

Last edited by 5hridhyan (2026-01-01 06:54:28)

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