commit b1b9d41c73cfb388a81a2bc45b0c6708e2e627f7
author Ady Abraham <adyabr@google.com> Mon Jun 01 19:53:52 2020 -0700
committer Ady Abraham <adyabr@google.com> Tue Jun 09 16:59:33 2020 -0700
tree fb39bff05fb24b784939352229330b6eea078d86
parent 607a0c6d5a2bb18fdf11374a40f5ffedca96d650

SurfaceFlinger: define a known frame rates list

Keep a list of known frame rates that would be used when we calculated
heuristically the frame rate of a layer. This keeps the signal to the
algorithm that chooses the refresh rate steady and avoid strange
frame rates like 57.2 due to inconsistent presentation timestamps.

Bug: 157540021
Test: adb shell /data/nativetest64/libsurfaceflinger_unittest/libsurfaceflinger_unittest
Change-Id: I97a24b74605256646e9b8444bd9f3818fe0a4a2a

services/surfaceflinger/Scheduler/LayerInfoV2.cpp

diff --git a/services/surfaceflinger/Scheduler/LayerInfoV2.cpp b/services/surfaceflinger/Scheduler/LayerInfoV2.cpp
index 82da007..f4bbc37 100644
--- a/services/surfaceflinger/Scheduler/LayerInfoV2.cpp
+++ b/services/surfaceflinger/Scheduler/LayerInfoV2.cpp
@@ -27,6 +27,8 @@
 
 namespace android::scheduler {
 
+const RefreshRateConfigs* LayerInfoV2::sRefreshRateConfigs = nullptr;
+
 LayerInfoV2::LayerInfoV2(const std::string& name, nsecs_t highRefreshRatePeriod,
                          LayerHistory::LayerVoteType defaultVote)
       : mName(name),
@@ -168,7 +170,6 @@
 
 std::optional<float> LayerInfoV2::calculateRefreshRateIfPossible() {
     static constexpr float MARGIN = 1.0f; // 1Hz
-
     if (!hasEnoughDataForHeuristic()) {
         ALOGV("Not enough data");
         return std::nullopt;
@@ -177,7 +178,7 @@
     const auto [averageFrameTime, missingPresentTime] = calculateAverageFrameTime();
 
     // If there are no presentation timestamps provided we can't calculate the refresh rate
-    if (missingPresentTime && mLastReportedRefreshRate == 0) {
+    if (missingPresentTime && mLastRefreshRate.reported == 0) {
         return std::nullopt;
     }
 
@@ -186,12 +187,16 @@
     }
 
     const auto refreshRate = 1e9f / averageFrameTime;
-    if (std::abs(refreshRate - mLastReportedRefreshRate) > MARGIN) {
-        mLastReportedRefreshRate = refreshRate;
+    const auto knownRefreshRate = sRefreshRateConfigs->findClosestKnownFrameRate(refreshRate);
+    if (std::abs(mLastRefreshRate.calculated - refreshRate) > MARGIN &&
+        mLastRefreshRate.reported != knownRefreshRate) {
+        mLastRefreshRate.calculated = refreshRate;
+        mLastRefreshRate.reported = knownRefreshRate;
     }
 
-    ALOGV("Refresh rate: %.2f", mLastReportedRefreshRate);
-    return mLastReportedRefreshRate;
+    ALOGV("%s %.2fHz rounded to nearest known frame rate %.2fHz", mName.c_str(), refreshRate,
+          mLastRefreshRate.reported);
+    return mLastRefreshRate.reported;
 }
 
 std::pair<LayerHistory::LayerVoteType, float> LayerInfoV2::getRefreshRate(nsecs_t now) {