Fix up reference times for period changes.
* When the model is reset, use the last seen reference time instead
of 0, since the reference time of 0 is guaranteed to yield inaccurate
pulses.
* When the DispSync model is updated, reduce the reference time by a
period to derisk spurious events firing when the model is updated.
Bug: 124383894
Test: systrace
Change-Id: Idb7fd5a9bacdd78133ab6451b5a79789a32e339e
diff --git a/services/surfaceflinger/Scheduler/DispSync.cpp b/services/surfaceflinger/Scheduler/DispSync.cpp
index 1eccf9a..5178836 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 != 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);
}
diff --git a/services/surfaceflinger/Scheduler/DispSync.h b/services/surfaceflinger/Scheduler/DispSync.h
index f629697..6f3bd00 100644
--- a/services/surfaceflinger/Scheduler/DispSync.h
+++ b/services/surfaceflinger/Scheduler/DispSync.h
@@ -213,7 +213,7 @@
// 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 mResyncSamples[MAX_RESYNC_SAMPLES];
+ nsecs_t mResyncSamples[MAX_RESYNC_SAMPLES] = {0};
size_t mFirstResyncSample;
size_t mNumResyncSamples;
int mNumResyncSamplesSincePresent;