Merge "SF Generalization of Refresh Rates: Adding layer priority hint"

13 files changed, 394 insertions, 12 deletions

diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index a7c4f4670a..8b448ff3f6 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -110,6 +110,9 @@ status_t layer_state_t::write(Parcel& output) const
         }
     }
     output.writeFloat(shadowRadius);
+
+    output.writeInt32(frameRateSelectionPriority);
+
     return NO_ERROR;
 }
 
@@ -188,6 +191,9 @@ status_t layer_state_t::read(const Parcel& input)
         listeners.emplace_back(listener, callbackIds);
     }
     shadowRadius = input.readFloat();
+
+    frameRateSelectionPriority = input.readInt32();
+
     return NO_ERROR;
 }
 
@@ -406,12 +412,14 @@ void layer_state_t::merge(const layer_state_t& other) {
         what |= eMetadataChanged;
         metadata.merge(other.metadata);
     }
-
     if (other.what & eShadowRadiusChanged) {
         what |= eShadowRadiusChanged;
         shadowRadius = other.shadowRadius;
     }
-
+    if (other.what & eFrameRateSelectionPriority) {
+        what |= eFrameRateSelectionPriority;
+        frameRateSelectionPriority = other.frameRateSelectionPriority;
+    }
     if ((other.what & what) != other.what) {
         ALOGE("Unmerged SurfaceComposer Transaction properties. LayerState::merge needs updating? "
               "other.what=0x%" PRIu64 " what=0x%" PRIu64,
diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index 5e259e258c..2ef33cf253 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -1192,6 +1192,22 @@ SurfaceComposerClient::Transaction& SurfaceComposerClient::Transaction::setColor
 }
 
 SurfaceComposerClient::Transaction&
+SurfaceComposerClient::Transaction::setFrameRateSelectionPriority(const sp<SurfaceControl>& sc,
+                                                                  int32_t priority) {
+    layer_state_t* s = getLayerState(sc);
+    if (!s) {
+        mStatus = BAD_INDEX;
+        return *this;
+    }
+
+    s->what |= layer_state_t::eFrameRateSelectionPriority;
+    s->frameRateSelectionPriority = priority;
+
+    registerSurfaceControlForCallback(sc);
+    return *this;
+}
+
+SurfaceComposerClient::Transaction&
 SurfaceComposerClient::Transaction::addTransactionCompletedCallback(
         TransactionCompletedCallbackTakesContext callback, void* callbackContext) {
     auto listener = TransactionCompletedListener::getInstance();
diff --git a/libs/gui/include/gui/LayerState.h b/libs/gui/include/gui/LayerState.h
index fb186396a6..03e91c4905 100644
--- a/libs/gui/include/gui/LayerState.h
+++ b/libs/gui/include/gui/LayerState.h
@@ -99,6 +99,7 @@ struct layer_state_t {
         eBackgroundColorChanged = 0x4'00000000,
         eMetadataChanged = 0x8'00000000,
         eColorSpaceAgnosticChanged = 0x10'00000000,
+        eFrameRateSelectionPriority = 0x20'00000000,
     };
 
     layer_state_t()
@@ -128,7 +129,8 @@ struct layer_state_t {
             bgColorAlpha(0),
             bgColorDataspace(ui::Dataspace::UNKNOWN),
             colorSpaceAgnostic(false),
-            shadowRadius(0.0f) {
+            shadowRadius(0.0f),
+            frameRateSelectionPriority(-1) {
         matrix.dsdx = matrix.dtdy = 1.0f;
         matrix.dsdy = matrix.dtdx = 0.0f;
         hdrMetadata.validTypes = 0;
@@ -209,6 +211,9 @@ struct layer_state_t {
 
     // Draws a shadow around the surface.
     float shadowRadius;
+
+    // Priority of the layer assigned by Window Manager.
+    int32_t frameRateSelectionPriority;
 };
 
 struct ComposerState {
diff --git a/libs/gui/include/gui/SurfaceComposerClient.h b/libs/gui/include/gui/SurfaceComposerClient.h
index 44f29eaa6f..6a3f452f77 100644
--- a/libs/gui/include/gui/SurfaceComposerClient.h
+++ b/libs/gui/include/gui/SurfaceComposerClient.h
@@ -483,6 +483,9 @@ public:
         Transaction& setDesiredPresentTime(nsecs_t desiredPresentTime);
         Transaction& setColorSpaceAgnostic(const sp<SurfaceControl>& sc, const bool agnostic);
 
+        // Sets information about the priority of the frame.
+        Transaction& setFrameRateSelectionPriority(const sp<SurfaceControl>& sc, int32_t priority);
+
         Transaction& addTransactionCompletedCallback(
                 TransactionCompletedCallbackTakesContext callback, void* callbackContext);
 
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 2593681b6b..5bba7d312b 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -108,6 +108,7 @@ Layer::Layer(const LayerCreationArgs& args)
     mCurrentState.api = -1;
     mCurrentState.hasColorTransform = false;
     mCurrentState.colorSpaceAgnostic = false;
+    mCurrentState.frameRateSelectionPriority = PRIORITY_UNSET;
     mCurrentState.metadata = args.metadata;
     mCurrentState.shadowRadius = 0.f;
 
@@ -1120,6 +1121,7 @@ bool Layer::setTransparentRegionHint(const Region& transparent) {
     setTransactionFlags(eTransactionNeeded);
     return true;
 }
+
 bool Layer::setFlags(uint8_t flags, uint8_t mask) {
     const uint32_t newFlags = (mCurrentState.flags & ~mask) | (flags & mask);
     if (mCurrentState.flags == newFlags) return false;
@@ -1176,6 +1178,29 @@ bool Layer::setColorSpaceAgnostic(const bool agnostic) {
     return true;
 }
 
+bool Layer::setFrameRateSelectionPriority(int32_t priority) {
+    if (mCurrentState.frameRateSelectionPriority == priority) return false;
+    mCurrentState.frameRateSelectionPriority = priority;
+    mCurrentState.sequence++;
+    mCurrentState.modified = true;
+    setTransactionFlags(eTransactionNeeded);
+    return true;
+}
+
+int32_t Layer::getFrameRateSelectionPriority() const {
+    // Check if layer has priority set.
+    if (mDrawingState.frameRateSelectionPriority != PRIORITY_UNSET) {
+        return mDrawingState.frameRateSelectionPriority;
+    }
+    // If not, search whether its parents have it set.
+    sp<Layer> parent = getParent();
+    if (parent != nullptr) {
+        return parent->getFrameRateSelectionPriority();
+    }
+
+    return Layer::PRIORITY_UNSET;
+}
+
 uint32_t Layer::getLayerStack() const {
     auto p = mDrawingParent.promote();
     if (p == nullptr) {
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 174ac8da1e..b8a35392f8 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -96,6 +96,7 @@ struct LayerCreationArgs {
 
 class Layer : public compositionengine::LayerFE {
     static std::atomic<int32_t> sSequence;
+    static constexpr int32_t PRIORITY_UNSET = -1;
 
 public:
     mutable bool contentDirty{false};
@@ -220,6 +221,9 @@ public:
         // Length of the cast shadow. If the radius is > 0, a shadow of length shadowRadius will
         // be rendered around the layer.
         float shadowRadius;
+
+        // Priority of the layer assigned by Window Manager.
+        int32_t frameRateSelectionPriority;
     };
 
     explicit Layer(const LayerCreationArgs& args);
@@ -337,6 +341,10 @@ public:
     virtual bool setBackgroundColor(const half3& color, float alpha, ui::Dataspace dataspace);
     virtual bool setColorSpaceAgnostic(const bool agnostic);
     bool setShadowRadius(float shadowRadius);
+    virtual bool setFrameRateSelectionPriority(int32_t priority);
+    //  If the variable is not set on the layer, it traverses up the tree to inherit the frame
+    //  rate priority from its parent.
+    virtual int32_t getFrameRateSelectionPriority() const;
 
     virtual ui::Dataspace getDataSpace() const { return ui::Dataspace::UNKNOWN; }
 
@@ -755,6 +763,7 @@ protected:
 
     // For unit tests
     friend class TestableSurfaceFlinger;
+    friend class RefreshRateSelectionTest;
 
     virtual void commitTransaction(const State& stateToCommit);
 
diff --git a/services/surfaceflinger/Scheduler/LayerHistory.cpp b/services/surfaceflinger/Scheduler/LayerHistory.cpp
index cf79d9fcf7..aaac1ec677 100644
--- a/services/surfaceflinger/Scheduler/LayerHistory.cpp
+++ b/services/surfaceflinger/Scheduler/LayerHistory.cpp
@@ -48,6 +48,12 @@ bool traceEnabled() {
     return atoi(value);
 }
 
+bool useFrameRatePriority() {
+    char value[PROPERTY_VALUE_MAX];
+    property_get("debug.sf.use_frame_rate_priority", value, "1");
+    return atoi(value);
+}
+
 void trace(const wp<Layer>& weak, int fps) {
     const auto layer = weak.promote();
     if (!layer) return;
@@ -60,7 +66,8 @@ void trace(const wp<Layer>& weak, int fps) {
 
 } // namespace
 
-LayerHistory::LayerHistory() : mTraceEnabled(traceEnabled()) {}
+LayerHistory::LayerHistory()
+      : mTraceEnabled(traceEnabled()), mUseFrameRatePriority(useFrameRatePriority()) {}
 LayerHistory::~LayerHistory() = default;
 
 void LayerHistory::registerLayer(Layer* layer, float lowRefreshRate, float highRefreshRate) {
@@ -94,16 +101,23 @@ LayerHistory::Summary LayerHistory::summarize(nsecs_t now) {
     partitionLayers(now);
 
     // Find the maximum refresh rate among recently active layers.
-    for (const auto& [layer, info] : activeLayers()) {
+    for (const auto& [activeLayer, info] : activeLayers()) {
         const bool recent = info->isRecentlyActive(now);
+
         if (recent || CC_UNLIKELY(mTraceEnabled)) {
             const float refreshRate = info->getRefreshRate(now);
             if (recent && refreshRate > maxRefreshRate) {
+                if (const auto layer = activeLayer.promote(); layer) {
+                    const int32_t priority = layer->getFrameRateSelectionPriority();
+                    // TODO(b/142507166): This is where the scoring algorithm should live.
+                    // Layers should be organized by priority
+                    ALOGD("Layer has priority: %d", priority);
+                }
                 maxRefreshRate = refreshRate;
             }
 
             if (CC_UNLIKELY(mTraceEnabled)) {
-                trace(layer, std::round(refreshRate));
+                trace(activeLayer, std::round(refreshRate));
             }
         }
     }
diff --git a/services/surfaceflinger/Scheduler/LayerHistory.h b/services/surfaceflinger/Scheduler/LayerHistory.h
index d92e5c3136..188fa64011 100644
--- a/services/surfaceflinger/Scheduler/LayerHistory.h
+++ b/services/surfaceflinger/Scheduler/LayerHistory.h
@@ -106,6 +106,9 @@ private:
 
     // Whether to emit systrace output and debug logs.
     const bool mTraceEnabled;
+
+    // Whether to use priority sent from WindowManager to determine the relevancy of the layer.
+    const bool mUseFrameRatePriority;
 };
 
 } // namespace impl
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index b7a2c760e6..e90cf41707 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1747,12 +1747,6 @@ void SurfaceFlinger::onMessageReceived(int32_t what) NO_THREAD_SAFETY_ANALYSIS {
                 mGpuFrameMissedCount++;
             }
 
-            mScheduler->chooseRefreshRateForContent();
-
-            if (performSetActiveConfig()) {
-                break;
-            }
-
             if (frameMissed && mPropagateBackpressure) {
                 if ((hwcFrameMissed && !gpuFrameMissed) ||
                     mPropagateBackpressureClientComposition) {
@@ -1769,6 +1763,13 @@ void SurfaceFlinger::onMessageReceived(int32_t what) NO_THREAD_SAFETY_ANALYSIS {
             bool refreshNeeded = handleMessageTransaction();
             refreshNeeded |= handleMessageInvalidate();
 
+            // Layers need to get updated (in the previous line) before we can use them for
+            // choosing the refresh rate.
+            mScheduler->chooseRefreshRateForContent();
+            if (performSetActiveConfig()) {
+                break;
+            }
+
             updateCursorAsync();
             updateInputFlinger();
 
@@ -3474,6 +3475,11 @@ uint32_t SurfaceFlinger::setClientStateLocked(
     if (what & layer_state_t::eShadowRadiusChanged) {
         if (layer->setShadowRadius(s.shadowRadius)) flags |= eTraversalNeeded;
     }
+    if (what & layer_state_t::eFrameRateSelectionPriority) {
+        if (privileged && layer->setFrameRateSelectionPriority(s.frameRateSelectionPriority)) {
+            flags |= eTraversalNeeded;
+        }
+    }
     // This has to happen after we reparent children because when we reparent to null we remove
     // child layers from current state and remove its relative z. If the children are reparented in
     // the same transaction, then we have to make sure we reparent the children first so we do not
diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index e4ef19ea7a..becf484243 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -49,6 +49,7 @@ cc_test {
         "SchedulerTest.cpp",
         "SchedulerUtilsTest.cpp",
         "RefreshRateConfigsTest.cpp",
+        "RefreshRateSelectionTest.cpp",
         "RefreshRateStatsTest.cpp",
         "RegionSamplingTest.cpp",
         "TimeStatsTest.cpp",
diff --git a/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp b/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
index f055fe72ac..b5848381cc 100644
--- a/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
+++ b/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
@@ -64,6 +64,7 @@ namespace {
 TEST_F(LayerHistoryTest, oneLayer) {
     const auto layer = createLayer();
     EXPECT_CALL(*layer, isVisible()).WillRepeatedly(Return(true));
+    EXPECT_CALL(*layer, getFrameSelectionPriority()).WillRepeatedly(Return(1));
 
     EXPECT_EQ(1, layerCount());
     EXPECT_EQ(0, activeLayerCount());
@@ -90,6 +91,7 @@ TEST_F(LayerHistoryTest, oneLayer) {
 TEST_F(LayerHistoryTest, oneHDRLayer) {
     const auto layer = createLayer();
     EXPECT_CALL(*layer, isVisible()).WillRepeatedly(Return(true));
+    EXPECT_CALL(*layer, getFrameSelectionPriority()).WillRepeatedly(Return(1));
 
     EXPECT_EQ(1, layerCount());
     EXPECT_EQ(0, activeLayerCount());
@@ -109,6 +111,7 @@ TEST_F(LayerHistoryTest, oneHDRLayer) {
 TEST_F(LayerHistoryTest, explicitTimestamp) {
     const auto layer = createLayer();
     EXPECT_CALL(*layer, isVisible()).WillRepeatedly(Return(true));
+    EXPECT_CALL(*layer, getFrameSelectionPriority()).WillRepeatedly(Return(1));
 
     EXPECT_EQ(1, layerCount());
     EXPECT_EQ(0, activeLayerCount());
@@ -130,8 +133,13 @@ TEST_F(LayerHistoryTest, multipleLayers) {
     auto layer3 = createLayer();
 
     EXPECT_CALL(*layer1, isVisible()).WillRepeatedly(Return(true));
+    EXPECT_CALL(*layer1, getFrameSelectionPriority()).WillRepeatedly(Return(1));
+
     EXPECT_CALL(*layer2, isVisible()).WillRepeatedly(Return(true));
+    EXPECT_CALL(*layer2, getFrameSelectionPriority()).WillRepeatedly(Return(1));
+
     EXPECT_CALL(*layer3, isVisible()).WillRepeatedly(Return(true));
+    EXPECT_CALL(*layer3, getFrameSelectionPriority()).WillRepeatedly(Return(1));
 
     nsecs_t time = mTime;
 
diff --git a/services/surfaceflinger/tests/unittests/RefreshRateSelectionTest.cpp b/services/surfaceflinger/tests/unittests/RefreshRateSelectionTest.cpp
new file mode 100644
index 0000000000..c23a6601d0
--- /dev/null
+++ b/services/surfaceflinger/tests/unittests/RefreshRateSelectionTest.cpp
@@ -0,0 +1,283 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#undef LOG_TAG
+#define LOG_TAG "LibSurfaceFlingerUnittests"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <gui/LayerMetadata.h>
+
+#include "BufferQueueLayer.h"
+#include "BufferStateLayer.h"
+#include "ColorLayer.h"
+#include "Layer.h"
+#include "TestableSurfaceFlinger.h"
+#include "mock/DisplayHardware/MockComposer.h"
+#include "mock/MockDispSync.h"
+#include "mock/MockEventControlThread.h"
+#include "mock/MockEventThread.h"
+
+namespace android {
+
+using testing::_;
+using testing::DoAll;
+using testing::Mock;
+using testing::Return;
+using testing::SetArgPointee;
+
+using android::Hwc2::IComposer;
+using android::Hwc2::IComposerClient;
+
+using FakeHwcDisplayInjector = TestableSurfaceFlinger::FakeHwcDisplayInjector;
+
+/**
+ * This class covers all the test that are related to refresh rate selection.
+ */
+class RefreshRateSelectionTest : public testing::Test {
+public:
+    RefreshRateSelectionTest();
+    ~RefreshRateSelectionTest() override;
+
+protected:
+    static constexpr int DEFAULT_DISPLAY_WIDTH = 1920;
+    static constexpr int DEFAULT_DISPLAY_HEIGHT = 1024;
+    static constexpr uint32_t WIDTH = 100;
+    static constexpr uint32_t HEIGHT = 100;
+    static constexpr uint32_t LAYER_FLAGS = 0;
+    static constexpr int32_t PRIORITY_UNSET = -1;
+
+    void setupScheduler();
+    void setupComposer(int virtualDisplayCount);
+    sp<BufferQueueLayer> createBufferQueueLayer();
+    sp<BufferStateLayer> createBufferStateLayer();
+    sp<ColorLayer> createColorLayer();
+
+    void setParent(Layer* child, Layer* parent);
+    void commitTransaction(Layer* layer);
+
+    TestableSurfaceFlinger mFlinger;
+    Hwc2::mock::Composer* mComposer = nullptr;
+
+    sp<Client> mClient;
+    sp<Layer> mParent;
+    sp<Layer> mChild;
+    sp<Layer> mGrandChild;
+};
+
+RefreshRateSelectionTest::RefreshRateSelectionTest() {
+    const ::testing::TestInfo* const test_info =
+            ::testing::UnitTest::GetInstance()->current_test_info();
+    ALOGD("**** Setting up for %s.%s\n", test_info->test_case_name(), test_info->name());
+
+    setupScheduler();
+    setupComposer(0);
+}
+
+RefreshRateSelectionTest::~RefreshRateSelectionTest() {
+    const ::testing::TestInfo* const test_info =
+            ::testing::UnitTest::GetInstance()->current_test_info();
+    ALOGD("**** Tearing down after %s.%s\n", test_info->test_case_name(), test_info->name());
+}
+
+sp<BufferQueueLayer> RefreshRateSelectionTest::createBufferQueueLayer() {
+    sp<Client> client;
+    LayerCreationArgs args(mFlinger.flinger(), client, "buffer-queue-layer", WIDTH, HEIGHT,
+                           LAYER_FLAGS, LayerMetadata());
+    return new BufferQueueLayer(args);
+}
+
+sp<BufferStateLayer> RefreshRateSelectionTest::createBufferStateLayer() {
+    sp<Client> client;
+    LayerCreationArgs args(mFlinger.flinger(), client, "buffer-queue-layer", WIDTH, HEIGHT,
+                           LAYER_FLAGS, LayerMetadata());
+    return new BufferStateLayer(args);
+}
+
+sp<ColorLayer> RefreshRateSelectionTest::createColorLayer() {
+    sp<Client> client;
+    LayerCreationArgs args(mFlinger.flinger(), client, "color-layer", WIDTH, HEIGHT, LAYER_FLAGS,
+                           LayerMetadata());
+    return new ColorLayer(args);
+}
+
+void RefreshRateSelectionTest::setParent(Layer* child, Layer* parent) {
+    child->setParent(parent);
+}
+
+void RefreshRateSelectionTest::commitTransaction(Layer* layer) {
+    layer->commitTransaction(layer->getCurrentState());
+}
+
+void RefreshRateSelectionTest::setupScheduler() {
+    auto eventThread = std::make_unique<mock::EventThread>();
+    auto sfEventThread = std::make_unique<mock::EventThread>();
+
+    EXPECT_CALL(*eventThread, registerDisplayEventConnection(_));
+    EXPECT_CALL(*eventThread, createEventConnection(_, _))
+            .WillOnce(Return(new EventThreadConnection(eventThread.get(), ResyncCallback(),
+                                                       ISurfaceComposer::eConfigChangedSuppress)));
+
+    EXPECT_CALL(*sfEventThread, registerDisplayEventConnection(_));
+    EXPECT_CALL(*sfEventThread, createEventConnection(_, _))
+            .WillOnce(Return(new EventThreadConnection(sfEventThread.get(), ResyncCallback(),
+                                                       ISurfaceComposer::eConfigChangedSuppress)));
+
+    auto primaryDispSync = std::make_unique<mock::DispSync>();
+
+    EXPECT_CALL(*primaryDispSync, computeNextRefresh(0)).WillRepeatedly(Return(0));
+    EXPECT_CALL(*primaryDispSync, getPeriod())
+            .WillRepeatedly(Return(FakeHwcDisplayInjector::DEFAULT_REFRESH_RATE));
+    EXPECT_CALL(*primaryDispSync, expectedPresentTime()).WillRepeatedly(Return(0));
+    mFlinger.setupScheduler(std::move(primaryDispSync),
+                            std::make_unique<mock::EventControlThread>(), std::move(eventThread),
+                            std::move(sfEventThread));
+}
+
+void RefreshRateSelectionTest::setupComposer(int virtualDisplayCount) {
+    mComposer = new Hwc2::mock::Composer();
+    EXPECT_CALL(*mComposer, getCapabilities())
+            .WillOnce(Return(std::vector<IComposer::Capability>()));
+    EXPECT_CALL(*mComposer, getMaxVirtualDisplayCount()).WillOnce(Return(virtualDisplayCount));
+    mFlinger.setupComposer(std::unique_ptr<Hwc2::Composer>(mComposer));
+
+    Mock::VerifyAndClear(mComposer);
+}
+
+namespace {
+/* ------------------------------------------------------------------------
+ * Test cases
+ */
+TEST_F(RefreshRateSelectionTest, testPriorityOnBufferQueueLayers) {
+    mParent = createBufferQueueLayer();
+    mChild = createBufferQueueLayer();
+    setParent(mChild.get(), mParent.get());
+    mGrandChild = createBufferQueueLayer();
+    setParent(mGrandChild.get(), mChild.get());
+
+    ASSERT_EQ(PRIORITY_UNSET, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(PRIORITY_UNSET, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(PRIORITY_UNSET, mGrandChild->getFrameRateSelectionPriority());
+
+    // Child has its own priority.
+    mGrandChild->setFrameRateSelectionPriority(1);
+    commitTransaction(mGrandChild.get());
+    ASSERT_EQ(PRIORITY_UNSET, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(PRIORITY_UNSET, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mGrandChild->getFrameRateSelectionPriority());
+
+    // Child inherits from his parent.
+    mChild->setFrameRateSelectionPriority(1);
+    commitTransaction(mChild.get());
+    mGrandChild->setFrameRateSelectionPriority(PRIORITY_UNSET);
+    commitTransaction(mGrandChild.get());
+
+    ASSERT_EQ(PRIORITY_UNSET, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mGrandChild->getFrameRateSelectionPriority());
+
+    // Grandchild inherits from his grand parent.
+    mParent->setFrameRateSelectionPriority(1);
+    commitTransaction(mParent.get());
+    mChild->setFrameRateSelectionPriority(PRIORITY_UNSET);
+    commitTransaction(mChild.get());
+    mGrandChild->setFrameRateSelectionPriority(PRIORITY_UNSET);
+    commitTransaction(mGrandChild.get());
+    ASSERT_EQ(1, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mGrandChild->getFrameRateSelectionPriority());
+}
+
+TEST_F(RefreshRateSelectionTest, testPriorityOnBufferStateLayers) {
+    mParent = createBufferStateLayer();
+    mChild = createBufferStateLayer();
+    setParent(mChild.get(), mParent.get());
+    mGrandChild = createBufferStateLayer();
+    setParent(mGrandChild.get(), mChild.get());
+
+    ASSERT_EQ(PRIORITY_UNSET, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(PRIORITY_UNSET, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(PRIORITY_UNSET, mGrandChild->getFrameRateSelectionPriority());
+
+    // Child has its own priority.
+    mGrandChild->setFrameRateSelectionPriority(1);
+    commitTransaction(mGrandChild.get());
+    ASSERT_EQ(PRIORITY_UNSET, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(PRIORITY_UNSET, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mGrandChild->getFrameRateSelectionPriority());
+
+    // Child inherits from his parent.
+    mChild->setFrameRateSelectionPriority(1);
+    commitTransaction(mChild.get());
+    mGrandChild->setFrameRateSelectionPriority(PRIORITY_UNSET);
+    commitTransaction(mGrandChild.get());
+    ASSERT_EQ(PRIORITY_UNSET, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mGrandChild->getFrameRateSelectionPriority());
+
+    // Grandchild inherits from his grand parent.
+    mParent->setFrameRateSelectionPriority(1);
+    commitTransaction(mParent.get());
+    mChild->setFrameRateSelectionPriority(PRIORITY_UNSET);
+    commitTransaction(mChild.get());
+    mGrandChild->setFrameRateSelectionPriority(PRIORITY_UNSET);
+    commitTransaction(mGrandChild.get());
+    ASSERT_EQ(1, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mGrandChild->getFrameRateSelectionPriority());
+}
+
+TEST_F(RefreshRateSelectionTest, testPriorityOnColorLayers) {
+    mParent = createColorLayer();
+    mChild = createColorLayer();
+    setParent(mChild.get(), mParent.get());
+    mGrandChild = createColorLayer();
+    setParent(mGrandChild.get(), mChild.get());
+
+    ASSERT_EQ(PRIORITY_UNSET, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(PRIORITY_UNSET, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(PRIORITY_UNSET, mGrandChild->getFrameRateSelectionPriority());
+
+    // Child has its own priority.
+    mGrandChild->setFrameRateSelectionPriority(1);
+    commitTransaction(mGrandChild.get());
+    ASSERT_EQ(PRIORITY_UNSET, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(PRIORITY_UNSET, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mGrandChild->getFrameRateSelectionPriority());
+
+    // Child inherits from his parent.
+    mChild->setFrameRateSelectionPriority(1);
+    commitTransaction(mChild.get());
+    mGrandChild->setFrameRateSelectionPriority(PRIORITY_UNSET);
+    commitTransaction(mGrandChild.get());
+    ASSERT_EQ(PRIORITY_UNSET, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mGrandChild->getFrameRateSelectionPriority());
+
+    // Grandchild inherits from his grand parent.
+    mParent->setFrameRateSelectionPriority(1);
+    commitTransaction(mParent.get());
+    mChild->setFrameRateSelectionPriority(PRIORITY_UNSET);
+    commitTransaction(mChild.get());
+    mGrandChild->setFrameRateSelectionPriority(PRIORITY_UNSET);
+    commitTransaction(mGrandChild.get());
+    ASSERT_EQ(1, mParent->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mChild->getFrameRateSelectionPriority());
+    ASSERT_EQ(1, mGrandChild->getFrameRateSelectionPriority());
+}
+
+} // namespace
+} // namespace android
\ No newline at end of file
diff --git a/services/surfaceflinger/tests/unittests/mock/MockLayer.h b/services/surfaceflinger/tests/unittests/mock/MockLayer.h
index f375e23700..1fd0e617c2 100644
--- a/services/surfaceflinger/tests/unittests/mock/MockLayer.h
+++ b/services/surfaceflinger/tests/unittests/mock/MockLayer.h
@@ -28,6 +28,7 @@ public:
           : Layer(LayerCreationArgs(flinger, nullptr, "TestLayer", 800, 600, 0, {})) {}
 
     MOCK_CONST_METHOD0(getType, const char*());
+    MOCK_METHOD0(getFrameSelectionPriority, int32_t());
     MOCK_CONST_METHOD0(isVisible, bool());
     MOCK_METHOD0(createClone, sp<Layer>());
 };