diff --git a/include/private/performance_hint_private.h b/include/private/performance_hint_private.h
index eaf3b5e..d50c5f8 100644
--- a/include/private/performance_hint_private.h
+++ b/include/private/performance_hint_private.h
@@ -17,6 +17,8 @@
 #ifndef ANDROID_PRIVATE_NATIVE_PERFORMANCE_HINT_PRIVATE_H
 #define ANDROID_PRIVATE_NATIVE_PERFORMANCE_HINT_PRIVATE_H
 
+#include <stdint.h>
+
 __BEGIN_DECLS
 
 /**
@@ -27,7 +29,7 @@
 /**
  * Hints for the session used to signal upcoming changes in the mode or workload.
  */
-enum SessionHint {
+enum SessionHint: int32_t {
     /**
      * This hint indicates a sudden increase in CPU workload intensity. It means
      * that this hint session needs extra CPU resources immediately to meet the
@@ -61,7 +63,7 @@
  * @return 0 on success
  *         EPIPE if communication with the system service has failed.
  */
-int APerformanceHint_sendHint(void* session, int hint);
+int APerformanceHint_sendHint(void* session, SessionHint hint);
 
 /**
  * Return the list of thread ids, this API should only be used for testing only.