Comment # 4 on bug 1016312 from Wolfgang Bauer

(In reply to Fabian Vogt from comment #3)
> That's not implemented upstream yet, so please open an issue on
> https://github.com/sddm/sddm for proper PAM support.

There already are some open upstream issues about this problem, and a patch is
available too (still waiting for review though), see bug 969813...