$OpenBSD$
--- grguBuffer.cpp.orig	Sun Feb 15 14:53:23 2009
+++ grguBuffer.cpp	Sat Oct 22 10:49:18 2011
@@ -98,6 +98,13 @@ grBufferSwap( int swap_interval )
     OGLRender.FrameTriangles = 0;
 #endif
 
+    // Carmageddon never unlocks the buffer before calling BufferSwap
+    if ( Glide.DstBuffer.Lock )
+    {
+        grLfbUnlock ( Glide.DstBuffer.Type, Glide.DstBuffer.Buffer );
+        Glide.DstBuffer.Lock = true;    // Re-lock the buffer
+    }
+
     SwapBuffers( );
 
 #ifdef OGL_DEBUG