We probably want to still do this for fullscreen surfaces, since we may be

clearing the edges of a centered video mode or garbage left over from a mode
switch.

--HG--
branch : SDL-1.2

src/video/SDL_video.c

@@ -503,6 +503,9 @@ static void SDL_ClearSurface(SDL_Surface *surface)
 		SDL_Flip(surface);
 		SDL_FillRect(surface, NULL, black);
 	}
+	if (surface->flags&SDL_FULLSCREEN) {
+		SDL_Flip(surface);
+	}
 }
 
 /*