diff --git a/camera/device/default/ExternalCameraDeviceSession.h b/camera/device/default/ExternalCameraDeviceSession.h
index 795b589..1c6ed06 100644
--- a/camera/device/default/ExternalCameraDeviceSession.h
+++ b/camera/device/default/ExternalCameraDeviceSession.h
@@ -382,6 +382,9 @@
     std::string mExifMake;
     std::string mExifModel;
     /* End of members not changed after initialize() */
+
+    // The max tolerant lag between the dequeued v4l2 buffer and current capture request.
+    uint64_t mMaxLagNs;
 };
 
 }  // namespace implementation