855GM not changing resolutions for games

[Wayne Smith]

Recently, I upgraded to xorg 6.9.  I can actually get the higher, native 
resolution (1280x800) and 1024x768.  All is well, except for when I try to 
play a game, such as tuxracer, supertux, or enemy territory.  When the game 
begins, it cannot seem to lower the resolution to what is needed, and the 
game remains fairly small and only takes up a portion of the screen, usually 
the center.  (Enemy Territory actually becomes bottom and left justified.)  A 
screenshot of what is happening can be found here:  
http://staff.norman.k12.ok.us/~wsmith/snapshot1.png.  

Everything was fine with 6.8.2: resolution and games.  My window manager and 
all other apps seem fine.  Using 855resolution and 915resolution, I can see 
all the modes I need (800x600, 640x480, etc.), but for some reason can't seem 
to get Xorg to see them, as it only allows me the two higher resolutions, no 
matter what combination of modes and modelines I employ.

Any ideas?  

Wayne