Display lag AMD 13 7040 USB-C dock - Linux 6.11

Framework Laptop 13 Linux
1

I have started noticing severe lag when using an external display via my Lenovo/ThinkPad USB-C dock.

Hardware setup

  • Framework AMD 13 (7040)
  • ThinkPad USB-C dock
  • Single external 2560x1440 screen connected via HDMI

Behavior

The resolution is correct, but there is a massive display lag which makes the setup basically unusable.
It is like I had 10fps and a massive input lag on my devices.

Potential causes

If I boot with the LTS kernel (6.6), it works fine.
However, it fails with the latest kernel (6.11.5 at the time of writing).

If I remember well, the issue appeared sometime between mid-September and early October.
I have not (yet) bisected the exact kernel change that causes the problem.

Detailed software setup

  • Distribution: NixOS 24.11 (unstable)
  • Kernel: pkgs.linuxPackages_latest (i.e. 6.11.5 today)
  • BIOS revision: 3.5

Thanks in advance for your help !

EDIT: could be https://gitlab.freedesktop.org/drm/amd/-/issues/3647

2

I can confirm that the 6.10 kernel does work fine.

3

This other AMD driver issue may also be the culprit: