2 files changed, 7 insertions, 2 deletions
diff --git a/services/surfaceflinger/DispSync.cpp b/services/surfaceflinger/DispSync.cpp
index 73b3897..dda896e 100644
--- a/services/surfaceflinger/DispSync.cpp
+++ b/services/surfaceflinger/DispSync.cpp
@@ -317,6 +317,7 @@ void DispSync::reset() {
 
     mNumResyncSamples = 0;
     mFirstResyncSample = 0;
+    mResyncReferenceTime = 0;
     mNumResyncSamplesSincePresent = 0;
     resetErrorLocked();
 }
@@ -356,6 +357,9 @@ bool DispSync::addResyncSample(nsecs_t timestamp) {
 
     size_t idx = (mFirstResyncSample + mNumResyncSamples) % MAX_RESYNC_SAMPLES;
     mResyncSamples[idx] = timestamp;
+    if (mNumResyncSamples == 0) {
+        mResyncReferenceTime = timestamp;
+    }
 
     if (mNumResyncSamples < MAX_RESYNC_SAMPLES) {
         mNumResyncSamples++;
@@ -432,7 +436,7 @@ void DispSync::updateModelLocked() {
         double scale = 2.0 * M_PI / double(mPeriod);
         for (size_t i = 0; i < mNumResyncSamples; i++) {
             size_t idx = (mFirstResyncSample + i) % MAX_RESYNC_SAMPLES;
-            nsecs_t sample = mResyncSamples[idx];
+            nsecs_t sample = mResyncSamples[idx] - mResyncReferenceTime;
             double samplePhase = double(sample % mPeriod) * scale;
             sampleAvgX += cos(samplePhase);
             sampleAvgY += sin(samplePhase);
@@ -472,7 +476,7 @@ void DispSync::updateErrorLocked() {
     nsecs_t sqErrSum = 0;
 
     for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) {
-        nsecs_t sample = mPresentTimes[i];
+        nsecs_t sample = mPresentTimes[i] - mResyncReferenceTime;
         if (sample > mPhase) {
             nsecs_t sampleErr = (sample - mPhase) % period;
             if (sampleErr > period / 2) {
diff --git a/services/surfaceflinger/DispSync.h b/services/surfaceflinger/DispSync.h
index ebe19a5..fabb875 100644
--- a/services/surfaceflinger/DispSync.h
+++ b/services/surfaceflinger/DispSync.h
@@ -154,6 +154,7 @@ private:
     // These member variables are the state used during the resynchronization
     // process to store information about the hardware vsync event times used
     // to compute the model.
+    nsecs_t mResyncReferenceTime;
     nsecs_t mResyncSamples[MAX_RESYNC_SAMPLES];
     size_t mFirstResyncSample;
     size_t mNumResyncSamples;