diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.cpp b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
index e7d0d23..32c55fd 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.cpp
@@ -87,12 +87,17 @@
       mFbDev(0), mHwc(0), mNumDisplays(1),
       mCBContext(new cb_context),
       mEventHandler(handler),
-      mVSyncCount(0), mDebugForceFakeVSync(false)
+      mDebugForceFakeVSync(false)
 {
     for (size_t i =0 ; i<MAX_HWC_DISPLAYS ; i++) {
         mLists[i] = 0;
     }
 
+    for (size_t i=0 ; i<HWC_NUM_PHYSICAL_DISPLAY_TYPES ; i++) {
+        mLastHwVSync[i] = 0;
+        mVSyncCounts[i] = 0;
+    }
+
     char value[PROPERTY_VALUE_MAX];
     property_get("debug.sf.no_hw_vsync", value, "0");
     mDebugForceFakeVSync = atoi(value);
@@ -278,10 +283,15 @@
 }
 
 void HWComposer::vsync(int disp, int64_t timestamp) {
-    ATRACE_INT("VSYNC", ++mVSyncCount&1);
-    mEventHandler.onVSyncReceived(disp, timestamp);
-    Mutex::Autolock _l(mLock);
-    mLastHwVSync = timestamp;
+    if (uint32_t(disp) < HWC_NUM_PHYSICAL_DISPLAY_TYPES) {
+        char tag[16];
+        snprintf(tag, sizeof(tag), "VSYNC_%1u", disp);
+        ATRACE_INT(tag, ++mVSyncCounts[disp] & 1);
+
+        mEventHandler.onVSyncReceived(disp, timestamp);
+        Mutex::Autolock _l(mLock);
+        mLastHwVSync[disp] = timestamp;
+    }
 }
 
 void HWComposer::hotplug(int disp, int connected) {
@@ -415,7 +425,7 @@
     // the refresh period and whatever closest timestamp we have.
     Mutex::Autolock _l(mLock);
     nsecs_t now = systemTime(CLOCK_MONOTONIC);
-    return now - ((now - mLastHwVSync) %  mDisplayData[disp].refresh);
+    return now - ((now - mLastHwVSync[disp]) %  mDisplayData[disp].refresh);
 }
 
 sp<Fence> HWComposer::getDisplayFence(int disp) const {
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.h b/services/surfaceflinger/DisplayHardware/HWComposer.h
index d901c62..9f96113 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.h
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.h
@@ -342,14 +342,14 @@
 
     cb_context*                     mCBContext;
     EventHandler&                   mEventHandler;
-    size_t                          mVSyncCount;
+    size_t                          mVSyncCounts[HWC_NUM_PHYSICAL_DISPLAY_TYPES];
     sp<VSyncThread>                 mVSyncThread;
     bool                            mDebugForceFakeVSync;
     BitSet32                        mAllocatedDisplayIDs;
 
     // protected by mLock
     mutable Mutex mLock;
-    mutable nsecs_t mLastHwVSync;
+    mutable nsecs_t mLastHwVSync[HWC_NUM_PHYSICAL_DISPLAY_TYPES];
 
     // thread-safe
     mutable Mutex mEventControlLock;