Index: /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/gallium/Svga.cpp
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/gallium/Svga.cpp	(revision 75459)
+++ /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/gallium/Svga.cpp	(revision 75460)
@@ -73,5 +73,6 @@
 }
 
-void SvgaAdapterStop(PVBOXWDDM_EXT_VMSVGA pSvga)
+void SvgaAdapterStop(PVBOXWDDM_EXT_VMSVGA pSvga,
+                     DXGKRNL_INTERFACE *pDxgkInterface)
 {
     if (pSvga)
@@ -93,4 +94,11 @@
         }
 
+        /* Enable SVGA device. */
+        SVGARegWrite(pSvga, SVGA_REG_IRQMASK, 0);
+        SVGARegWrite(pSvga, SVGA_REG_ENABLE, SVGA_REG_ENABLE_DISABLE);
+
+        NTSTATUS Status = pDxgkInterface->DxgkCbUnmapMemory(pDxgkInterface->DeviceHandle,
+                                                            (PVOID)pSvga->pu32FIFO);
+        Assert(Status == STATUS_SUCCESS); RT_NOREF(Status);
         GaMemFree(pSvga);
     }
Index: /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/gallium/Svga.h
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/gallium/Svga.h	(revision 75459)
+++ /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/gallium/Svga.h	(revision 75460)
@@ -120,5 +120,6 @@
                           PHYSICAL_ADDRESS physIO,
                           ULONG cbIO);
-void SvgaAdapterStop(PVBOXWDDM_EXT_VMSVGA pSvga);
+void SvgaAdapterStop(PVBOXWDDM_EXT_VMSVGA pSvga,
+                     DXGKRNL_INTERFACE *pDxgkInterface);
 
 NTSTATUS SvgaQueryInfo(PVBOXWDDM_EXT_VMSVGA pSvga,
Index: /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/gallium/VBoxMPGaWddm.cpp
===================================================================
--- /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/gallium/VBoxMPGaWddm.cpp	(revision 75459)
+++ /trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/gallium/VBoxMPGaWddm.cpp	(revision 75460)
@@ -266,5 +266,5 @@
         if (pGaDevExt->hw.pSvga)
         {
-            SvgaAdapterStop(pGaDevExt->hw.pSvga);
+            SvgaAdapterStop(pGaDevExt->hw.pSvga, &pDevExt->u.primary.DxgkInterface);
             pGaDevExt->hw.pSvga = NULL;
         }