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Commit 6de88c47 authored by Ady Abraham's avatar Ady Abraham
Browse files

SurfaceFlinger: expectedVsyncTimestamp can be 0 

Scheduler::isVsyncValid can be called with expectedVsyncTimestamp as 0
if it is called from Layer::latchAndReleaseBuffer. If we send the vsync
timestamp as 0 to VSyncTracker, it may change the phase for the current
divider which will cause jank.

Test: run bouncyball and observe systraces
Change-Id: Ic0b0ea895497891a22badc9c67cea5c23698fc2c
parent c12fbffe

services/surfaceflinger/Scheduler/VSyncPredictor.cpp

+6 −6
Original line number Diff line number Diff line
@@ -222,10 +222,10 @@ nsecs_t VSyncPredictor::nextAnticipatedVSyncTimeFrom(nsecs_t timePoint) const { 


/*

 * Returns whether a given vsync timestamp is in phase with a vsync divider.

 * For example, if the vsync timestamps are (0,16,32,48):

 * isVSyncInPhase(0, 2) = true

 * isVSyncInPhase(16, 2) = false

 * isVSyncInPhase(32, 2) = true

 * For example, if the vsync timestamps are (16,32,48,64):

 * isVSyncInPhase(16, 2) = true

 * isVSyncInPhase(32, 2) = false

 * isVSyncInPhase(48, 2) = true

 */

bool VSyncPredictor::isVSyncInPhase(nsecs_t timePoint, int divider) const {

    struct VsyncError {
@@ -235,11 +235,11 @@ bool VSyncPredictor::isVSyncInPhase(nsecs_t timePoint, int divider) const { 
        bool operator<(const VsyncError& other) const { return error < other.error; }

    };



    std::lock_guard lock(mMutex);

    if (divider <= 1) {

    if (divider <= 1 || timePoint == 0) {

        return true;

    }



    std::lock_guard lock(mMutex);

    const nsecs_t period = mRateMap[mIdealPeriod].slope;

    const nsecs_t justBeforeTimePoint = timePoint - period / 2;

    const nsecs_t dividedPeriod = mIdealPeriod / divider;