diff --git a/audio/6.0/IDevice.hal b/audio/6.0/IDevice.hal
index e885fe2..520e776 100644
--- a/audio/6.0/IDevice.hal
+++ b/audio/6.0/IDevice.hal
@@ -280,4 +280,15 @@
      */
     setConnectedState(DeviceAddress address, bool connected)
             generates (Result retval);
+
+    /**
+     * Called by the framework to deinitialize the device and free up
+     * all currently allocated resources. It is recommended to close
+     * the device on the client side as soon as it is becomes unused.
+     *
+     * @return retval OK in case the success.
+     *                INVALID_STATE if the device was already closed.
+     */
+    @exit
+    close() generates (Result retval);
 };
diff --git a/audio/6.0/IStream.hal b/audio/6.0/IStream.hal
index 451e116..1f62017 100644
--- a/audio/6.0/IStream.hal
+++ b/audio/6.0/IStream.hal
@@ -300,13 +300,17 @@
 
     /**
      * Called by the framework to deinitialize the stream and free up
-     * all the currently allocated resources. It is recommended to close
+     * all currently allocated resources. It is recommended to close
      * the stream on the client side as soon as it is becomes unused.
      *
+     * The client must ensure that this function is not called while
+     * audio data is being transferred through the stream's message queues.
+     *
      * @return retval OK in case the success.
      *                NOT_SUPPORTED if called on IStream instead of input or
      *                              output stream interface.
      *                INVALID_STATE if the stream was already closed.
      */
+    @exit
     close() generates (Result retval);
 };