Index: /trunk/src/VBox/Additions/x11/vboxvideo/vboxvideo.c
===================================================================
--- /trunk/src/VBox/Additions/x11/vboxvideo/vboxvideo.c	(revision 53345)
+++ /trunk/src/VBox/Additions/x11/vboxvideo/vboxvideo.c	(revision 53346)
@@ -288,6 +288,10 @@
     VBOXPtr pVBox = VBOXGetRec(crtc->scrn);
     unsigned cDisplay = (uintptr_t)crtc->driver_private;
+    bool fDisabled = (mode == DPMSModeOff);
+
     TRACE_LOG("cDisplay=%u, mode=%i\n", cDisplay, mode);
-    pVBox->pScreens[cDisplay].afDisabled = (mode == DPMSModeOff);
+    if (pVBox->pScreens[cDisplay].afDisabled == fDisabled)
+        return;
+    pVBox->pScreens[cDisplay].afDisabled = fDisabled;
     /* Don't fiddle with the hardware if we are switched
      * to a virtual terminal. */