diff --git a/camera/device/3.7/ICameraInjectionSession.hal b/camera/device/3.7/ICameraInjectionSession.hal
index f5797c3..9be9b25 100644
--- a/camera/device/3.7/ICameraInjectionSession.hal
+++ b/camera/device/3.7/ICameraInjectionSession.hal
@@ -24,7 +24,10 @@
 import @3.7::ICameraDeviceSession;
 
 /**
- * Injection Camera device active session interface.
+ * Injection camera device active session interface.
+ *
+ * Note that this is implemented on a special camera injection hal, if it is a
+ * general camera hal, it is not necessary to implement this interface.
  *
  * When an external camera is injected to replace the internal camera session, the
  * injection session will be established in camera framework, and then