diff --git a/include/utils/Trace.h b/include/utils/Trace.h
index 93e228546..41bce0095 100644
--- a/include/utils/Trace.h
+++ b/include/utils/Trace.h
@@ -54,6 +54,8 @@
 #define ATRACE_TAG_CAMERA           (1<<10)
 #define ATRACE_TAG_LAST             ATRACE_TAG_CAMERA
 
+#define ATRACE_TAG_NOT_READY        (1LL<<63)   // Reserved for use during init
+
 #define ATRACE_TAG_VALID_MASK ((ATRACE_TAG_LAST - 1) | ATRACE_TAG_LAST)
 
 #ifndef ATRACE_TAG
diff --git a/libs/utils/Trace.cpp b/libs/utils/Trace.cpp
index 5cd5731d5..f5aaea322 100644
--- a/libs/utils/Trace.cpp
+++ b/libs/utils/Trace.cpp
@@ -25,7 +25,7 @@ namespace android {
 
 volatile int32_t Tracer::sIsReady = 0;
 int Tracer::sTraceFD = -1;
-uint64_t Tracer::sEnabledTags = 0;
+uint64_t Tracer::sEnabledTags = ATRACE_TAG_NOT_READY;
 Mutex Tracer::sMutex;
 
 void Tracer::changeCallback() {
@@ -46,7 +46,7 @@ void Tracer::init() {
         sTraceFD = open(traceFileName, O_WRONLY);
         if (sTraceFD == -1) {
             ALOGE("error opening trace file: %s (%d)", strerror(errno), errno);
-            // sEnabledTags remains zero indicating that no tracing can occur
+            sEnabledTags = 0;   // no tracing can occur
         } else {
             loadSystemProperty();
         }