http://bugs.winehq.org/show_bug.cgi?id=33396
--- Comment #4 from Sam Edwards CFSworks@gmail.com 2013-04-18 01:46:07 CDT --- (In reply to comment #3)
Yeah, that's just NVIDIA RandR being broken. Note that afaik it's limited to display panels without a hardware scaler (which typically means laptops), so you may get better results when you attach an external monitor. As far as I'm aware NVIDIA already knows about the issue, but doesn't consider it their problem.
I looked at their discussion on wine-devel. They seem to be more focused on the purity of their XRandR 1.2 interface than apathetic about bugs. That is, they want the XRandR 1.2 configuration to control the physical signal being sent to the monitor rather than the size of the "screen" (in X11 terminology). It's not a bug in the driver, but rather the developers are trying to be really "exact" about their implementation. (I make no judgement on whether this design is good or bad, but I'd still like to make Wine work with it regardless.)
XRandR 1.0 still determines the screen mode, so using the 1.0 interface into their driver allows reconfiguration of the screen (not the monitor) even if the monitor doesn't support it, because it implicitly sets up scaling and letterboxing appropriately.
However, Xinerama is concerned with screen/desktop, not monitor/CRTC, so the fact that my physical monitor size is coming back from Xinerama is most likely a bug.
That said, should this be reported to NVIDIA as a bug, or worked-around in Wine? I'm in favor of the former, but at a loss for how to get in contact with them.