the reason of this behavior is the lack of appropriate screen modes in xorg.conf - if only dual-head modes are defined, full screen-apps fail to change to an appropriate resolution. also using the "radeon" driver, the following MetaModes in xorg.conf should have the desired effect:
Option "MetaModes" "1024x768-1024x768 1024x768 800x600 640x480" this defines one dualhead mode with two times 1024x768, yielding in 2048x768 resolution and three additional modes without any definition for the second screen. during switching to these modes, xorg switches on-the-fly to a clone mode with the requested resolution. starting of full-screen apps (like SDL-games) now automatically triggers switching to a clone mode - no more centering of full screen apps between both monitors. Therefore I don't think that this is a SDL problem but due to a non- optimal xorg configuration (at least not in dapper; could also be that the problem was fixed in the meantime). -- Fullscreen display split between screens with Xinerama/MergedFB https://launchpad.net/bugs/14044 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
