--- qt4-x11-4.6.3~git20100411-orig/src/opengl/qglpaintdevice.cpp	2010-04-27 09:28:27.000000000 +0200
+++ qt4-x11-4.6.3~git20100411/src/opengl/qglpaintdevice.cpp	2010-05-13 02:17:29.000000000 +0200
@@ -163,7 +163,14 @@
             float alpha = c.alphaF();
             glClearColor(c.redF() * alpha, c.greenF() * alpha, c.blueF() * alpha, alpha);
         }
+#if defined(QT_OPENGL_ES)
+        // In egl chips like SGX and MBX clearing all buffers is a signal for the driver
+        // that we're starting a new frame and that the previous one can be thrown away. Without this
+        // we're suffering from a very noticable perf penalty. 
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); 
+#else
         glClear(GL_COLOR_BUFFER_BIT);
+#endif
     }
 }