commit 75b0b62124456af4d070bb7f4d1093ab48f16610
author Alec Mouri <alecmouri@google.com> Tue Mar 12 18:56:00 2019 +0000
committer Alec Mouri <alecmouri@google.com> Tue Mar 12 13:01:01 2019 -0700
tree 83691720ac5dfafdcf223961823ca32afaf81026
parent dd50a3cf4c9f41bf0e4952246cd559da5cfb503a

Revert "Revert "Fix up reference times for period changes.""

This reverts commit d6598315a36eaad3e4e45f51e0f1cc986e539896.

Reason for revert: Including divide-by-zero fix

Test: build no longer breaks
Change-Id: I186f020d9a6edd6793f52bcb234b2cc68b42e69a

services/surfaceflinger/Scheduler/DispSync.cpp

diff --git a/services/surfaceflinger/Scheduler/DispSync.cpp b/services/surfaceflinger/Scheduler/DispSync.cpp
index 1eccf9a..798d1a4 100644
--- a/services/surfaceflinger/Scheduler/DispSync.cpp
+++ b/services/surfaceflinger/Scheduler/DispSync.cpp
@@ -76,9 +76,18 @@
     void updateModel(nsecs_t period, nsecs_t phase, nsecs_t referenceTime) {
         if (mTraceDetailedInfo) ATRACE_CALL();
         Mutex::Autolock lock(mMutex);
-        mPeriod = period;
+
         mPhase = phase;
         mReferenceTime = referenceTime;
+        if (mPeriod != 0 && mPeriod != period && mReferenceTime != 0) {
+            // Inflate the reference time to be the most recent predicted
+            // vsync before the current time.
+            const nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+            const nsecs_t baseTime = now - mReferenceTime;
+            const nsecs_t numOldPeriods = baseTime / mPeriod;
+            mReferenceTime = mReferenceTime + (numOldPeriods)*mPeriod;
+        }
+        mPeriod = period;
         if (mTraceDetailedInfo) {
             ATRACE_INT64("DispSync:Period", mPeriod);
             ATRACE_INT64("DispSync:Phase", mPhase + mPeriod / 2);
@@ -429,8 +438,16 @@
 
 void DispSync::resetLocked() {
     mPhase = 0;
-    mReferenceTime = 0;
+    const size_t lastSampleIdx = (mFirstResyncSample + mNumResyncSamples - 1) % MAX_RESYNC_SAMPLES;
+    // Keep the most recent sample, when we resync to hardware we'll overwrite this
+    // with a more accurate signal
+    if (mResyncSamples[lastSampleIdx] != 0) {
+        mReferenceTime = mResyncSamples[lastSampleIdx];
+    }
     mModelUpdated = false;
+    for (size_t i = 0; i < MAX_RESYNC_SAMPLES; i++) {
+        mResyncSamples[i] = 0;
+    }
     mNumResyncSamples = 0;
     mFirstResyncSample = 0;
     mNumResyncSamplesSincePresent = 0;
@@ -530,7 +547,6 @@
     Mutex::Autolock lock(mMutex);
     mPeriod = period;
     mPhase = 0;
-    mReferenceTime = 0;
     mThread->updateModel(mPeriod, mPhase, mReferenceTime);
 }