SF: Tune RefreshRateConfigs for close refresh rates am: 3819b9fe0b am: f99d336d62

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/15640420

Change-Id: I62c70ee7498fccd8b538e0597e668cf1619e63a3
diff --git a/services/surfaceflinger/Scheduler/RefreshRateConfigs.cpp b/services/surfaceflinger/Scheduler/RefreshRateConfigs.cpp
index c38cd68..81a669a 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateConfigs.cpp
+++ b/services/surfaceflinger/Scheduler/RefreshRateConfigs.cpp
@@ -910,7 +910,10 @@
 int RefreshRateConfigs::getFrameRateDivider(Fps displayFrameRate, Fps layerFrameRate) {
     // This calculation needs to be in sync with the java code
     // in DisplayManagerService.getDisplayInfoForFrameRateOverride
-    constexpr float kThreshold = 0.1f;
+
+    // The threshold must be smaller than 0.001 in order to differentiate
+    // between the fractional pairs (e.g. 59.94 and 60).
+    constexpr float kThreshold = 0.0009f;
     const auto numPeriods = displayFrameRate.getValue() / layerFrameRate.getValue();
     const auto numPeriodsRounded = std::round(numPeriods);
     if (std::abs(numPeriods - numPeriodsRounded) > kThreshold) {
diff --git a/services/surfaceflinger/tests/unittests/RefreshRateConfigsTest.cpp b/services/surfaceflinger/tests/unittests/RefreshRateConfigsTest.cpp
index 6870fd4..c1dba2b 100644
--- a/services/surfaceflinger/tests/unittests/RefreshRateConfigsTest.cpp
+++ b/services/surfaceflinger/tests/unittests/RefreshRateConfigsTest.cpp
@@ -2116,7 +2116,11 @@
     refreshRateConfigs->setCurrentModeId(HWC_CONFIG_ID_90);
     displayRefreshRate = refreshRateConfigs->getCurrentRefreshRate().getFps();
     EXPECT_EQ(4, RefreshRateConfigs::getFrameRateDivider(displayRefreshRate, Fps(22.5f)));
-    EXPECT_EQ(4, RefreshRateConfigs::getFrameRateDivider(displayRefreshRate, Fps(22.6f)));
+
+    EXPECT_EQ(0, RefreshRateConfigs::getFrameRateDivider(Fps(24.f), Fps(25.f)));
+    EXPECT_EQ(0, RefreshRateConfigs::getFrameRateDivider(Fps(24.f), Fps(23.976f)));
+    EXPECT_EQ(0, RefreshRateConfigs::getFrameRateDivider(Fps(30.f), Fps(29.97f)));
+    EXPECT_EQ(0, RefreshRateConfigs::getFrameRateDivider(Fps(60.f), Fps(59.94f)));
 }
 
 TEST_F(RefreshRateConfigsTest, getFrameRateOverrides_noLayers) {