SF: fix expected vsync time when changing work duration

When changing the work duration for a scheduled callback, we should
apply it on the next frame only if we would skip a callback call.
This change fixes the condition where we apply a different work
duration that doesn't change the wake up time but rather changes
the expected vsync time.

Test: TouchLatency bouncy ball + expand notification shade
Bug: 191969790
Change-Id: I067693fe361200a6f899bd81b74d8a1a155a452d

2 files changed, 26 insertions, 2 deletions

diff --git a/services/surfaceflinger/Scheduler/VSyncDispatchTimerQueue.cpp b/services/surfaceflinger/Scheduler/VSyncDispatchTimerQueue.cpp
index 28be962f2c..b805bf68e4 100644
--- a/services/surfaceflinger/Scheduler/VSyncDispatchTimerQueue.cpp
+++ b/services/surfaceflinger/Scheduler/VSyncDispatchTimerQueue.cpp
@@ -84,10 +84,13 @@ ScheduleResult VSyncDispatchTimerQueueEntry::schedule(VSyncDispatch::ScheduleTim
                                                       VSyncTracker& tracker, nsecs_t now) {
     auto nextVsyncTime = tracker.nextAnticipatedVSyncTimeFrom(
             std::max(timing.earliestVsync, now + timing.workDuration + timing.readyDuration));
+    auto nextWakeupTime = nextVsyncTime - timing.workDuration - timing.readyDuration;
 
     bool const wouldSkipAVsyncTarget =
             mArmedInfo && (nextVsyncTime > (mArmedInfo->mActualVsyncTime + mMinVsyncDistance));
-    if (wouldSkipAVsyncTarget) {
+    bool const wouldSkipAWakeup =
+            mArmedInfo && ((nextWakeupTime > (mArmedInfo->mActualWakeupTime + mMinVsyncDistance)));
+    if (wouldSkipAVsyncTarget && wouldSkipAWakeup) {
         return getExpectedCallbackTime(nextVsyncTime, timing);
     }
 
@@ -97,9 +100,9 @@ ScheduleResult VSyncDispatchTimerQueueEntry::schedule(VSyncDispatch::ScheduleTim
     if (alreadyDispatchedForVsync) {
         nextVsyncTime =
                 tracker.nextAnticipatedVSyncTimeFrom(*mLastDispatchTime + mMinVsyncDistance);
+        nextWakeupTime = nextVsyncTime - timing.workDuration - timing.readyDuration;
     }
 
-    auto const nextWakeupTime = nextVsyncTime - timing.workDuration - timing.readyDuration;
     auto const nextReadyTime = nextVsyncTime - timing.readyDuration;
     mScheduleTiming = timing;
     mArmedInfo = {nextWakeupTime, nextVsyncTime, nextReadyTime};
diff --git a/services/surfaceflinger/tests/unittests/VSyncDispatchTimerQueueTest.cpp b/services/surfaceflinger/tests/unittests/VSyncDispatchTimerQueueTest.cpp
index d59d64bc02..ddc02bfbe6 100644
--- a/services/surfaceflinger/tests/unittests/VSyncDispatchTimerQueueTest.cpp
+++ b/services/surfaceflinger/tests/unittests/VSyncDispatchTimerQueueTest.cpp
@@ -942,6 +942,27 @@ TEST_F(VSyncDispatchTimerQueueTest, basicAlarmSettingFutureWithReadyDuration) {
     EXPECT_THAT(cb.mReadyTime[0], 970);
 }
 
+TEST_F(VSyncDispatchTimerQueueTest, updatesVsyncTimeForCloseWakeupTime) {
+    Sequence seq;
+    EXPECT_CALL(mMockClock, alarmAt(_, 600)).InSequence(seq);
+
+    CountingCallback cb(mDispatch);
+
+    mDispatch.schedule(cb, {.workDuration = 400, .readyDuration = 0, .earliestVsync = 1000});
+    mDispatch.schedule(cb, {.workDuration = 1400, .readyDuration = 0, .earliestVsync = 1000});
+
+    advanceToNextCallback();
+
+    advanceToNextCallback();
+
+    ASSERT_THAT(cb.mCalls.size(), Eq(1));
+    EXPECT_THAT(cb.mCalls[0], Eq(2000));
+    ASSERT_THAT(cb.mWakeupTime.size(), Eq(1));
+    EXPECT_THAT(cb.mWakeupTime[0], Eq(600));
+    ASSERT_THAT(cb.mReadyTime.size(), Eq(1));
+    EXPECT_THAT(cb.mReadyTime[0], Eq(2000));
+}
+
 class VSyncDispatchTimerQueueEntryTest : public testing::Test {
 protected:
     nsecs_t const mPeriod = 1000;