From 505e730e7d67f7a068ce5b3d2384643d0e04a282 Mon Sep 17 00:00:00 2001
From: Ady Abraham <adyabr@google.com>
Date: Wed, 23 Jun 2021 15:03:48 -0700
Subject: [PATCH] vsyncId should always be incremental

In some conditions of scheduling delays, Choreographer may
synthetically advance the indented vsync time. In that case we can't
send a vsync id since there is no one that corresponds to that time.

Test: TBD
Bug: 191840734
Change-Id: I7b2754d5dcb0a3f5fd6cda00a3a2469041116f67
---
 libs/hwui/renderthread/TimeLord.cpp | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/libs/hwui/renderthread/TimeLord.cpp b/libs/hwui/renderthread/TimeLord.cpp
index 406066c92bab2..a43fcdc6e202e 100644
--- a/libs/hwui/renderthread/TimeLord.cpp
+++ b/libs/hwui/renderthread/TimeLord.cpp
@@ -15,22 +15,28 @@
  */
 #include "TimeLord.h"
 #include <limits>
+#include "FrameInfo.h"
 
 namespace android {
 namespace uirenderer {
 namespace renderthread {
 
-TimeLord::TimeLord() : mFrameIntervalNanos(milliseconds_to_nanoseconds(16)),
-                       mFrameTimeNanos(0),
-                       mFrameIntendedTimeNanos(0),
-                       mFrameVsyncId(-1),
-                       mFrameDeadline(std::numeric_limits<int64_t>::max()){}
+TimeLord::TimeLord()
+        : mFrameIntervalNanos(milliseconds_to_nanoseconds(16))
+        , mFrameTimeNanos(0)
+        , mFrameIntendedTimeNanos(0)
+        , mFrameVsyncId(UiFrameInfoBuilder::INVALID_VSYNC_ID)
+        , mFrameDeadline(std::numeric_limits<int64_t>::max()) {}
 
 bool TimeLord::vsyncReceived(nsecs_t vsync, nsecs_t intendedVsync, int64_t vsyncId,
                              int64_t frameDeadline, nsecs_t frameInterval) {
     if (intendedVsync > mFrameIntendedTimeNanos) {
         mFrameIntendedTimeNanos = intendedVsync;
-        mFrameVsyncId = vsyncId;
+
+        // The intendedVsync might have been advanced to account for scheduling
+        // jitter. Since we don't have a way to advance the vsync id we just
+        // reset it.
+        mFrameVsyncId = (vsyncId > mFrameVsyncId) ? vsyncId : UiFrameInfoBuilder::INVALID_VSYNC_ID;
         mFrameDeadline = frameDeadline;
         if (frameInterval > 0) {
             mFrameIntervalNanos = frameInterval;