commit 4fc2fcea7641d91c7eb2d0228779d4fc600a274c
author Ady Abraham <adyabr@google.com> Fri Mar 08 06:43:44 2024 +0000
committer Ady Abraham <adyabr@google.com> Thu Mar 07 23:07:14 2024 -0800
tree 6dc1886ba5a172e11f409fe43f1b1a6e99b4d321
parent 940b7a60c29646c8424d479323a495ffcc45ded5

SF: change the render rate directly instead of starting a new VsyncTimeline

So we would preserve the old vsync cadence

Bug: 328140524
Change-Id: Ibdd4e49ab5494605e39957cedc6fba00146d18d9
Test: presubmit

services/surfaceflinger/Scheduler/VSyncPredictor.cpp

diff --git a/services/surfaceflinger/Scheduler/VSyncPredictor.cpp b/services/surfaceflinger/Scheduler/VSyncPredictor.cpp
index 3fc9a07..db1930d 100644
--- a/services/surfaceflinger/Scheduler/VSyncPredictor.cpp
+++ b/services/surfaceflinger/Scheduler/VSyncPredictor.cpp
@@ -379,9 +379,16 @@
             prevRenderRate ? prevRenderRate->getPeriodNsecs() - renderRate.getPeriodNsecs() : 0;
     const bool newRenderRateIsHigher = renderPeriodDelta > renderRate.getPeriodNsecs() &&
             mLastCommittedVsync.ns() - mClock->now() > 2 * renderRate.getPeriodNsecs();
-    if (applyImmediately || newRenderRateIsHigher) {
+    if (applyImmediately) {
+        while (mTimelines.size() > 1) {
+            mTimelines.pop_front();
+        }
+
+        mTimelines.front().setRenderRate(renderRate);
+    } else if (newRenderRateIsHigher) {
         mTimelines.clear();
         mLastCommittedVsync = TimePoint::fromNs(0);
+
     } else {
         mTimelines.back().freeze(
                 TimePoint::fromNs(mLastCommittedVsync.ns() + mIdealPeriod.ns() / 2));

services/surfaceflinger/Scheduler/VSyncPredictor.h

diff --git a/services/surfaceflinger/Scheduler/VSyncPredictor.h b/services/surfaceflinger/Scheduler/VSyncPredictor.h
index c840cbd..3ed1d41 100644
--- a/services/surfaceflinger/Scheduler/VSyncPredictor.h
+++ b/services/surfaceflinger/Scheduler/VSyncPredictor.h
@@ -97,6 +97,7 @@
         std::optional<TimePoint> validUntil() const { return mValidUntil; }
         bool isVSyncInPhase(Model, nsecs_t vsync, Fps frameRate);
         void shiftVsyncSequence(Duration phase);
+        void setRenderRate(Fps renderRate) { mRenderRateOpt = renderRate; }
 
     private:
         nsecs_t snapToVsyncAlignedWithRenderRate(Model model, nsecs_t vsync);
@@ -104,7 +105,7 @@
         std::optional<VsyncSequence> makeVsyncSequence(TimePoint knownVsync);
 
         const Period mIdealPeriod = Duration::fromNs(0);
-        const std::optional<Fps> mRenderRateOpt;
+        std::optional<Fps> mRenderRateOpt;
         std::optional<TimePoint> mValidUntil;
         std::optional<VsyncSequence> mLastVsyncSequence;
     };