diff --git a/12to11-test.xml b/12to11-test.xml
index 64180b7..7604a4c 100644
--- a/12to11-test.xml
+++ b/12to11-test.xml
@@ -154,6 +154,13 @@
       </description>
     </request>
 
+    <request name="set_always_garbage">
+      <description summary="set_always_garbage">
+	Force the subcompositor to be garbaged, and all contents
+	redrawn from scratch upon any damage.
+      </description>
+    </request>
+
     <event name="mapped">
       <description summary="role initialized">
 	The map event is sent once the window is mapped and its
diff --git a/compositor.h b/compositor.h
index 3894f27..a3fcef7 100644
--- a/compositor.h
+++ b/compositor.h
@@ -820,6 +820,7 @@ extern SubcompositorDestroyCallback *SubcompositorOnDestroy (Subcompositor *,
 							     void (*) (void *),
 							     void *);
 extern void SubcompositorRemoveDestroyCallback (SubcompositorDestroyCallback *);
+extern void SubcompositorSetAlwaysGarbaged (Subcompositor *);
 
 extern void ViewSetSubcompositor (View *, Subcompositor *);
 
diff --git a/subcompositor.c b/subcompositor.c
index a228da9..cde4ab3 100644
--- a/subcompositor.c
+++ b/subcompositor.c
@@ -133,6 +133,8 @@ enum
     SubcompositorIsPartiallyMapped = (1 << 4),
     /* This means that the subcompositor has a target attached.  */
     SubcompositorIsTargetAttached  = (1 << 5),
+    /* This means the subcompositor is always garbaged.  */
+    SubcompositorIsAlwaysGarbaged  = (1 << 6),
   };
 
 #define IsGarbaged(subcompositor)				\
@@ -160,6 +162,11 @@ enum
 #define IsTargetAttached(subcompositor)				\
   ((subcompositor)->state & SubcompositorIsTargetAttached)
 
+#define SetAlwaysGarbaged(subcompositor)			\
+  ((subcompositor)->state |= SubcompositorIsAlwaysGarbaged)
+#define IsAlwaysGarbaged(subcompositor)				\
+  ((subcompositor)->state & SubcompositorIsAlwaysGarbaged)
+
 enum
   {
     /* This means that the view and all its inferiors should be
@@ -3042,8 +3049,11 @@ SubcompositorUpdate (Subcompositor *subcompositor)
 
       EndFrame (subcompositor);
 
-      /* Clear the garbaged flag.  */
-      subcompositor->state &= ~SubcompositorIsGarbaged;
+      /* Clear the garbaged flag, unless for debugging purposes the
+	 subcompositor is always garbaged.  */
+
+      if (!IsAlwaysGarbaged (subcompositor))
+	subcompositor->state &= ~SubcompositorIsGarbaged;
 
       return;
     }
@@ -3282,3 +3292,10 @@ SubcompositorRemoveDestroyCallback (SubcompositorDestroyCallback *callback)
 
   XLFree (callback);
 }
+
+void
+SubcompositorSetAlwaysGarbaged (Subcompositor *subcompositor)
+{
+  SetGarbaged (subcompositor);
+  SetAlwaysGarbaged (subcompositor);
+}
diff --git a/test.c b/test.c
index 6d67ead..48d47a4 100644
--- a/test.c
+++ b/test.c
@@ -363,9 +363,21 @@ Activate (Surface *surface, Role *role, int deviceid,
     }
 }
 
+static void
+SetAlwaysGarbage (struct wl_client *client, struct wl_resource *resource)
+{
+  TestSurface *test;
+
+  test = wl_resource_get_user_data (resource);
+
+  /* Make the subcompositor always garbaged.  */
+  SubcompositorSetAlwaysGarbaged (test->subcompositor);
+}
+
 static const struct test_surface_interface test_surface_impl =
   {
     .destroy = Destroy,
+    .set_always_garbage = SetAlwaysGarbage,
   };
 
 static void
diff --git a/tests/test_harness.c b/tests/test_harness.c
index 3dcf35e..5e15cb1 100644
--- a/tests/test_harness.c
+++ b/tests/test_harness.c
@@ -421,6 +421,9 @@ make_test_surface (struct test_display *display,
       return false;
     }
 
+  if (getenv ("TEST_ALWAYS_GARBAGE"))
+    test_surface_set_always_garbage (test_surface);
+
   *surface_return = surface;
   *test_surface_return = test_surface;
   return true;