diff --git a/drivers/wdm/audio/backpln/portcls/portcls.spec b/drivers/wdm/audio/backpln/portcls/portcls.spec
index 1af797cafed..366e6af5b71 100644
--- a/drivers/wdm/audio/backpln/portcls/portcls.spec
+++ b/drivers/wdm/audio/backpln/portcls/portcls.spec
@@ -1,5 +1,5 @@
-@ stdcall DllInitialize(long)
-@ stdcall DllUnload()
+@ stdcall -private DllInitialize(long)
+@ stdcall -private DllUnload()
 
 ; Adapters (adapter.c)
 @ stdcall PcAddAdapterDevice(ptr ptr ptr long long)