diff --git a/lib/src/protocols/jsd_line.dart b/lib/src/protocols/jsd_line.dart
index 7e9d0d1..b289742 100644
--- a/lib/src/protocols/jsd_line.dart
+++ b/lib/src/protocols/jsd_line.dart
@@ -146,7 +146,7 @@ class JdsLine implements CustomProtocolLine {
             final point = _dataPointFromJson(jsonPoint);
             sink.add(point);
           } catch(_) {
-            _log.warning('invalid json string: $rawPoint');
+            _log.warning('[._dataPointFromJson()] invalid json string: $rawPoint');
           }
         }
       }