glFinish() at the end of each frame; I'm seeing the "buffer swap with unfinished frame" issue at lower framerates when this isn't being done. (FYI, this doesn't fix choppiness with X11 driver, but helps a little bit.)

stepmania/src/RageDisplay_OGL.cpp

@@ -797,6 +797,11 @@ bool RageDisplay_OGL::BeginFrame()
 
 void RageDisplay_OGL::EndFrame()
 {
+	// Give up the CPU to the OpenGL host if it wants it; in any case, make
+	// sure the frame is done. This helps graphics smoothness a lot by
+	// making sure we get the most out of each frame.
+	glFinish();
+
 	wind->SwapBuffers();
 	ProcessStatsOnFlip();
 }