Screen resolution incorrect after last OpenSUSE 13.1 kernel update

After the (auto) update of Dec 21 2014 (i.e the update that brought the OpenSUSE 13.1 kernel from 3.11.10-21-desktop to 3.11.10-25-desktop) my screen resolution is no longer 1920x1200 as it should be (and has been for the past 4 years or so, since OpenSUSE 11.2), but is now defaulting down to 1600x1200 and there is no apparent way to change it. When viewing the ‘available’ modes (via Configure Desktop -> Display and Monitor) the only one listed is now 1600x1200.

I am using the default Nouveau driver and had been for some time - had been working seamlessly until this last OpenSUSE update. No special hacks and no proprietary drivers - all default OpenSUSE 13.1 repositories.