diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index f78ca7f18bb2..a249c73ec1b5 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -4051,6 +4051,7 @@ int num_ioctls;</synopsis>
 	<title>High Definition Audio</title>
 !Pdrivers/gpu/drm/i915/intel_audio.c High Definition Audio over HDMI and Display Port
 !Idrivers/gpu/drm/i915/intel_audio.c
+!Iinclude/drm/i915_component.h
       </sect2>
       <sect2>
 	<title>Panel Self Refresh PSR (PSR/SRD)</title>
diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index 72d696b0e7d4..56c2f54801c4 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -50,6 +50,11 @@
  * co-operation between the graphics and audio drivers is handled via audio
  * related registers. (The notable exception is the power management, not
  * covered here.)
+ *
+ * The struct i915_audio_component is used to interact between the graphics
+ * and audio drivers. The struct i915_audio_component_ops *ops in it is
+ * defined in graphics driver and called in audio driver. The
+ * struct i915_audio_component_audio_ops *audio_ops is called from i915 driver.
  */
 
 static const struct {