diff --git a/reactos/drivers/wdm/audio/backpln/portcls/portcls.spec b/reactos/drivers/wdm/audio/backpln/portcls/portcls.spec
index 366e6af5b71..f60523ada30 100644
--- a/reactos/drivers/wdm/audio/backpln/portcls/portcls.spec
+++ b/reactos/drivers/wdm/audio/backpln/portcls/portcls.spec
@@ -41,6 +41,7 @@
 ; Power Management
 @ stdcall PcRegisterAdapterPowerManagement(ptr ptr)
 @ stdcall PcRequestNewPowerState(ptr long)
+@ stdcall PcUnregisterAdapterPowerManagement(ptr)
 
 ; Properties
 @ stdcall PcCompletePendingPropertyRequest(ptr long)
diff --git a/reactos/drivers/wdm/audio/backpln/portcls/power.cpp b/reactos/drivers/wdm/audio/backpln/portcls/power.cpp
index 6371952b115..24862211b8d 100644
--- a/reactos/drivers/wdm/audio/backpln/portcls/power.cpp
+++ b/reactos/drivers/wdm/audio/backpln/portcls/power.cpp
@@ -48,6 +48,30 @@ PcRegisterAdapterPowerManagement(
     return STATUS_SUCCESS;
 }
 
+NTSTATUS
+NTAPI
+PcUnregisterAdapterPowerManagement(
+    IN PDEVICE_OBJECT DeviceObject)
+{
+    PPCLASS_DEVICE_EXTENSION DeviceExt;
+    
+    DPRINT("PcUnregisterAdapterPowerManagement pUnknown %p pvContext %p\n", DeviceObject);
+    PC_ASSERT_IRQL_EQUAL(PASSIVE_LEVEL);
+
+    if (!DeviceObject)
+        return STATUS_INVALID_PARAMETER;
+
+    DeviceExt = (PPCLASS_DEVICE_EXTENSION)DeviceObject->DeviceExtension;
+
+    if (DeviceExt->AdapterPowerManagement)
+    {
+        DeviceExt->AdapterPowerManagement->Release();
+    }
+    DeviceExt->AdapterPowerManagement = NULL;
+    return STATUS_SUCCESS;
+}
+
+
 
 static
 VOID