diff --git a/dlls/wined3d/context.c b/dlls/wined3d/context.c
index 0878985..0e79b66 100644
--- a/dlls/wined3d/context.c
+++ b/dlls/wined3d/context.c
@@ -920,6 +920,13 @@ static void Context_MarkStateDirty(struct wined3d_context *context, DWORD state,
     DWORD idx;
     BYTE shift;
 
+    if (!rep || !StateTable[rep].representative)
+    {
+        ERR("Tried to make state %s (%#x) without rep dirty.\n",
+            debug_d3dstate(state), state);
+        DebugBreak();
+    }
+
     if (isStateDirty(context, rep)) return;
 
     context->dirtyArray[context->numDirtyEntries++] = rep;
diff --git a/dlls/wined3d/device.c b/dlls/wined3d/device.c
index 578d8e4..a11fb50 100644
--- a/dlls/wined3d/device.c
+++ b/dlls/wined3d/device.c
@@ -7087,6 +7087,13 @@ void IWineD3DDeviceImpl_MarkStateDirty(IWineD3DDeviceImpl *This, DWORD state) {
     BYTE shift;
     UINT i;
 
+    if (!rep || !This->StateTable[rep].representative)
+    {
+        ERR("Tried to make state %s (%#x) without rep dirty.\n",
+            debug_d3dstate(state), state);
+        DebugBreak();
+    }
+
     for(i = 0; i < This->numContexts; i++) {
         context = This->contexts[i];
         if(isStateDirty(context, rep)) continue;