diff -r 5dc02b23752f -r 3e2da88830cd src/opengl/qgl_egl.cpp
--- a/src/opengl/qgl_egl.cpp	Tue Jul 06 15:10:48 2010 +0300
+++ b/src/opengl/qgl_egl.cpp	Wed Aug 18 10:37:55 2010 +0300
@@ -138,7 +138,7 @@
     format.setDepthBufferSize(depthSize);
     format.setStencilBufferSize(stencilSize);
     format.setSamples(sampleCount);
-    format.setPlane(level + 1);      // EGL calls level 0 "normal" whereas Qt calls 1 "normal"
+    format.setPlane(level);
     format.setDirectRendering(true); // All EGL contexts are direct-rendered
     format.setRgba(true);            // EGL doesn't support colour index rendering
     format.setStereo(false);         // EGL doesn't support stereo buffers
@@ -190,7 +190,7 @@
         if (!d->workaroundsCached) {
             d->workaroundsCached = true;
             const char *renderer = reinterpret_cast<const char *>(glGetString(GL_RENDERER));
-            if (strstr(renderer, "SGX") || strstr(renderer, "MBX")) {
+            if (renderer && (strstr(renderer, "SGX") || strstr(renderer, "MBX"))) {
                 // PowerVR MBX/SGX chips needs to clear all buffers when starting to render
                 // a new frame, otherwise there will be a performance penalty to pay for
                 // each frame.
@@ -200,7 +200,8 @@
                 // bug which prevents glCopyTexSubImage2D() to work with a POT
                 // or GL_ALPHA texture bound to an FBO. The only way to
                 // identify that driver is to check the EGL version number for it.
-                if (strstr(eglQueryString(d->eglContext->display(), EGL_VERSION), "1.3"))
+                const char *egl_version = eglQueryString(d->eglContext->display(), EGL_VERSION);
+                if (egl_version && strstr(egl_version, "1.3"))
                     d->workaround_brokenFBOReadBack = true;
             }
         }
@@ -231,17 +232,20 @@
     if (eglSurface != EGL_NO_SURFACE) {
 #ifdef Q_WS_X11
         // Make sure we don't call eglDestroySurface on a surface which
-        // was created for a different winId:
+        // was created for a different winId. This applies only to QGLWidget
+        // paint device, so make sure this is the one we're operating on
+        // (as opposed to a QGLWindowSurface use case).
         if (paintDevice && paintDevice->devType() == QInternal::Widget) {
-            QGLWidget* w = static_cast<QGLWidget*>(paintDevice);
-
-            if (w->d_func()->eglSurfaceWindowId == w->winId())
-                eglDestroySurface(eglContext->display(), eglSurface);
-            else
-                qWarning("WARNING: Potential EGL surface leak!");
-        } else
+            QWidget *w = static_cast<QWidget *>(paintDevice);
+            if (QGLWidget *wgl = qobject_cast<QGLWidget *>(w)) {
+                if (wgl->d_func()->eglSurfaceWindowId != wgl->winId()) {
+                    qWarning("WARNING: Potential EGL surface leak! Not destroying surface.");
+                    return;
+                }
+            }
+        }
 #endif
-            eglDestroySurface(eglContext->display(), eglSurface);
+        eglDestroySurface(eglContext->display(), eglSurface);
         eglSurface = EGL_NO_SURFACE;
     }
 }
@@ -270,6 +274,14 @@
     return eglSurface;
 }
 
+void QGLContextPrivate::swapRegion(const QRegion *region)
+{
+    if (!valid || !eglContext)
+        return;
+
+    eglContext->swapBuffersRegion2NOK(eglSurfaceForDevice(), region);
+}
+
 void QGLWidget::setMouseTracking(bool enable)
 {
     QWidget::setMouseTracking(enable);