diff --git a/transport/manager/1.0/IServiceManager.hal b/transport/manager/1.0/IServiceManager.hal
index 77cf253..9e1c2fc 100644
--- a/transport/manager/1.0/IServiceManager.hal
+++ b/transport/manager/1.0/IServiceManager.hal
@@ -113,11 +113,19 @@
         generates (bool success);
 
     /**
+     * Special values for InstanceDebugInfo pids.
+     */
+    enum PidConstant : int32_t {
+        NO_PID = -1,
+    };
+
+    /**
      * Returned object for debugDump().
      */
     struct InstanceDebugInfo {
         string interfaceName;
         string instanceName;
+        int32_t pid; // PidConstants:NO_PID if unavailable
         vec<int32_t> clientPids;
         Architecture arch;
     };