Florian Forster to sdl in SDL 1.3 (revision 5508 from SVN), the method used to calculate the bits per pixel from a “int format” differ between “SDL_ListModes” (which always uses the “SDL_BITSPERPIXEL” macro) and “SDL_PixelFormatEnumTo- Masks” (which uses either “SDL_BITSPERPIXEL” or “SDL_BYTESPERPIXEL * 8”, depending on the value of “SDL_BYTESPERPIXEL”). Because the values are later compared in “SDL_ListModes” this may lead to some valid video modes not being returned. In my case the only mode returned by “SDL_GetNumDisplayModes” was dismissed and NULL was returned. (This led to the calling application sticking its head in the sand.) The attached patch copies the method used within “SDL_PixelFormatEnumTo- Masks” to “SDL_ListModes”. This solved the problem for me though I don't fully understand the method used by “SDL_PixelFormatEnumToMasks”.

The reason these libraries are built outside of the standard XFree86
tree is so that they can be linked as shared object code directly into
SDL without causing any symbol collisions with code in the application.

You can't link static library code into shared libraries on non-x86
Linux platforms.  Since these libraries haven't become standard yet,
we'll just include them directly.

These sources are synchronized with XFree86 4.2.1