https://bugs.freedesktop.org/show_bug.cgi?id=110371
--- Comment #4 from Michel Dänzer michel@daenzer.net --- (In reply to Nicholas Kazlauskas from comment #3)
It's hitting the "." as part of the video mode and erroring out because DRM doesn't consider it a valid character.
Or maybe there's two separate issues? Failure to parse the mode name shouldn't affect whether or not DC picks up EDID, should it?