diff --git a/include/hardware/audio.h b/include/hardware/audio.h
index fa34467..1e68cd1 100644
--- a/include/hardware/audio.h
+++ b/include/hardware/audio.h
@@ -184,6 +184,14 @@
      */
     int (*get_render_position)(const struct audio_stream_out *stream,
                                uint32_t *dsp_frames);
+
+    /**
+     * get the local time at which the next write to the audio driver will be
+     * presented
+     */
+    int (*get_next_write_timestamp)(const struct audio_stream_out *stream,
+                                    int64_t *timestamp);
+
 };
 typedef struct audio_stream_out audio_stream_out_t;
 
@@ -272,6 +280,15 @@
     int (*set_master_volume)(struct audio_hw_device *dev, float volume);
 
     /**
+     * Get the current master volume value for the HAL, if the HAL supports
+     * master volume control.  AudioFlinger will query this value from the
+     * primary audio HAL when the service starts and use the value for setting
+     * the initial master volume across all HALs.  HALs which do not support
+     * this method should may leave it set to NULL.
+     */
+    int (*get_master_volume)(struct audio_hw_device *dev, float *volume);
+
+    /**
      * set_mode is called when the audio mode changes. AUDIO_MODE_NORMAL mode
      * is for standard audio playback, AUDIO_MODE_RINGTONE when a ringtone is
      * playing, and AUDIO_MODE_IN_CALL when a call is in progress.