diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index dc2c171..ae9fc64 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -413,13 +413,18 @@
 /* static */
 int AudioFlinger::onExternalVibrationStart(const sp<os::ExternalVibration>& externalVibration) {
     sp<os::IExternalVibratorService> evs = getExternalVibratorService();
-    if (evs != 0) {
+    if (evs != nullptr) {
         int32_t ret;
         binder::Status status = evs->onExternalVibrationStart(*externalVibration, &ret);
         if (status.isOk()) {
+            ALOGD("%s, start external vibration with intensity as %d", __func__, ret);
             return ret;
         }
     }
+    ALOGD("%s, start external vibration with intensity as MUTE due to %s",
+            __func__,
+            evs == nullptr ? "external vibration service not found"
+                           : "error when querying intensity");
     return static_cast<int>(os::HapticScale::MUTE);
 }