diff --git a/audio/audio.c b/audio/audio.c
index 25371770f8..6c1f018979 100644
--- a/audio/audio.c
+++ b/audio/audio.c
@@ -760,6 +760,39 @@ static inline void audio_complete(FAR struct audio_upperhalf_s *upper,
     }
 }
 
+/****************************************************************************
+ * Name: audio_message
+ *
+ * Description:
+ *   Send an custom message to the client to indicate that the
+ *   active message has delivered.  The lower-half driver initiates this
+ *   call via its callback pointer to our upper-half driver.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static inline void audio_message(FAR struct audio_upperhalf_s *upper,
+                    FAR struct ap_buffer_s *apb, uint16_t status,
+                    FAR void *session)
+#else
+static inline void audio_message(FAR struct audio_upperhalf_s *upper,
+                    FAR struct ap_buffer_s *apb, uint16_t status)
+#endif
+{
+  struct audio_msg_s *msg = (FAR struct audio_msg_s *)apb;
+
+  /* Send a message to the user if a message queue is registered */
+
+  if (upper->usermq != NULL)
+    {
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+      msg.session = session;
+#endif
+      (void)nxmq_send(upper->usermq, (FAR const char *)msg, sizeof(*msg),
+                      CONFIG_AUDIO_BUFFER_DEQUEUE_PRIO);
+    }
+}
+
 /****************************************************************************
  * Name: audio_callback
  *
@@ -831,6 +864,16 @@ static void audio_callback(FAR void *handle, uint16_t reason,
         }
         break;
 
+      case AUDIO_CALLBACK_MESSAGE:
+        {
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+          audio_message(upper, apb, status, session);
+#else
+          audio_message(upper, apb, status);
+#endif
+        }
+        break;
+
       default:
         {
           auderr("ERROR: Unknown callback reason code %d\n", reason);
diff --git a/include/nuttx/audio/audio.h b/include/nuttx/audio/audio.h
index 50753ab4c0..fd80f8f0f3 100644
--- a/include/nuttx/audio/audio.h
+++ b/include/nuttx/audio/audio.h
@@ -1,7 +1,7 @@
 /****************************************************************************
  * include/nuttx/audio/audio.h
  *
- *   Copyright (C) 2017 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2017, 2019 Gregory Nutt. All rights reserved.
  *   Copyright (C) 2013 Ken Pettit. All rights reserved.
  *   Author: Ken Pettit <pettitkd@gmail.com>
  *
@@ -283,6 +283,7 @@
 /* Extension Unit controls **************************************************/
 
 #define AUDIO_EU_HW_FORMAT          0x0001
+#define AUDIO_EU_LOAD_MODULE        0x0002
 
 /* Audio Callback Reasons ***************************************************/
 
@@ -290,6 +291,7 @@
 #define AUDIO_CALLBACK_DEQUEUE      0x01
 #define AUDIO_CALLBACK_IOERR        0x02
 #define AUDIO_CALLBACK_COMPLETE     0x03
+#define AUDIO_CALLBACK_MESSAGE      0x04
 
 /* Audio Pipeline Buffer (AP Buffer) flags **********************************/
 
@@ -316,6 +318,9 @@
 #define AUDIO_MSG_DATA_REQUEST      6
 #define AUDIO_MSG_ENQUEUE           7
 #define AUDIO_MSG_COMPLETE          8
+#define AUDIO_MSG_WAKEUP            9
+#define AUDIO_MSG_COMMAND          10
+#define AUDIO_MSG_SLIENCE          11
 #define AUDIO_MSG_USER             64
 
 /* Audio Pipeline Buffer flags */
@@ -357,6 +362,9 @@ struct audio_caps_s
     uint8_t  b[4];          /*   by this lower-half driver. */
     uint16_t hw[2];
     uint32_t w;
+ifdef CONFIG_HAVE_LONG_LONG
+    uint64_t qw;
+endif
   } ac_controls;
 };