Index: code/unix/sdl_glimp.c
===================================================================
--- code/unix/sdl_glimp.c	(revision 1014)
+++ code/unix/sdl_glimp.c	(working copy)
@@ -666,6 +666,12 @@
     SDL_GL_SetAttribute( SDL_GL_STENCIL_SIZE, tstencilbits );
     SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
 
+#ifdef SDL_GL_SWAP_CONTROL
+    if( SDL_GL_SetAttribute( SDL_GL_SWAP_CONTROL, r_swapInterval->integer ) )
+#else
+    #warning libSDL >= 1.2.10  required for r_swapInterval support
+#endif // SDL_GL_SWAP_CONTROL
+
     SDL_WM_SetCaption(CLIENT_WINDOW_TITLE, CLIENT_WINDOW_ICON);
     SDL_ShowCursor(0);
     SDL_EnableUNICODE(1);
@@ -1085,6 +1091,19 @@
 */
 void GLimp_EndFrame (void)
 {
+
+  if ( r_swapInterval->modified )
+  {
+    r_swapInterval->modified = qfalse;
+#ifdef SDL_GL_SWAP_CONTROL
+    if( SDL_GL_SetAttribute( SDL_GL_SWAP_CONTROL, r_swapInterval->integer ) )
+    {
+        ri.Printf( PRINT_ALL, "Warning: SDL_GL_SWAP_CONTROL failed, make sure "
+            "you have libSDL >= 1.2.10" );
+    }
+#endif // SDL_GL_SWAP_CONTROL
+  }
+
   // don't flip if drawing to front buffer
   if ( Q_stricmp( r_drawBuffer->string, "GL_FRONT" ) != 0 )
   {