Comment # 43 on bug 1220569 from Takashi Iwai

(In reply to Roger Whittaker from comment #42)
> 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.

Which commit (or changelog entry) are you referring to?

> 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?

TW history repo contains the old packages for a few weeks
  http://download.opensuse.org/history/

But it's for TW, i.e. with user-merge.