I just risked updating my Ubuntu to 12.10 Beta 2 - and now DOSBox (self compiled from the same SVN source I used before in Ubuntu 12.04) is behaving very strangely when in fullscreen mode: Only the upper left quarter of the DOS screen is visible, magnified to double height and width so as to fill the whole screen. This seems to be independent of ouput= setting - happens in surface, overlay, opengl equally. It's also independent of whatever VGA mode the game is using - it's the same whether in text mode, 320x200, 640x200, 640x480 or any of the others I tried.

Any idea what might be causing this?

System info: Core2Quad, 64-bit Ubuntu 12.10 Beta 2, GTX 260 Graphics with NVIDIA binary driver version 304.43. DOSBox is compiled as a 32-bit application, which I've always done to have the full FPU precision in dynamic core. SDL-1.2 and SDL_net and SDL_sound also self compiled from current Mercurial source code as 32-bit libraries.

EDIT: The same happens with DOSBox compiled as native 64-bit application with the system provided SDL libraries, so that wasn't the cause. Also, no change when I go from scaler=none to scaler=normal2x.

EDIT: When I pre-set the screen mode before I start DOSBox, with xrandr -s 720x400, the problem seems to be gone temporarily. Very odd indeed.