diff --git a/services/oboeservice/AAudioServiceEndpointMMAP.cpp b/services/oboeservice/AAudioServiceEndpointMMAP.cpp
index 713ce60..5f1de76 100644
--- a/services/oboeservice/AAudioServiceEndpointMMAP.cpp
+++ b/services/oboeservice/AAudioServiceEndpointMMAP.cpp
@@ -84,6 +84,7 @@
 
     const audio_content_type_t contentType =
             AAudioConvert_contentTypeToInternal(getContentType());
+    // Usage only used for OUTPUT
     const audio_usage_t usage = (direction == AAUDIO_DIRECTION_OUTPUT)
             ? AAudioConvert_usageToInternal(getUsage())
             : AUDIO_USAGE_UNKNOWN;