This is a wild guess based on no knowledge of how the code works, but I was wondering if the change has anything to do with the references to psmouse_from_serio which I see in drivers/input/mouse/psmouse.* in 6.7.6-1 but not in 5.14.21-150500.55.49. Also, I was wondering if there's a convenient place to find all the historic Tumbleweed kernels so that I could bisect by downgrading the kernel on a Tumbleweed VM?