Merge "Add promise for buffer releaseFence to LayerFE." into main
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/CompositionEngine.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/CompositionEngine.h
index 7c10fa5..e32cc02 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/CompositionEngine.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/CompositionEngine.h
@@ -73,6 +73,9 @@
     // TODO(b/121291683): These will become private/internal
     virtual void preComposition(CompositionRefreshArgs&) = 0;
 
+    // Resolves any unfulfilled promises for release fences
+    virtual void postComposition(CompositionRefreshArgs&) = 0;
+
     virtual FeatureFlags getFeatureFlags() const = 0;
 
     // Debugging
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFE.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFE.h
index a499928..4e080b3 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFE.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFE.h
@@ -133,6 +133,15 @@
         uint64_t frameNumber = 0;
     };
 
+    // Describes the states of the release fence. Checking the states allows checks
+    // to ensure that set_value() is not called on the same promise multiple times,
+    // and can indicate if the promise has been fulfilled.
+    enum class ReleaseFencePromiseStatus {
+        UNINITIALIZED, // Promise not created
+        INITIALIZED,   // Promise created, fence has not been set
+        FULFILLED      // Promise fulfilled, fence is set
+    };
+
     // Returns the LayerSettings to pass to RenderEngine::drawLayers. The state may contain shadows
     // casted by the layer or the content of the layer itself. If the layer does not render then an
     // empty optional will be returned.
@@ -142,6 +151,19 @@
     // Called after the layer is displayed to update the presentation fence
     virtual void onLayerDisplayed(ftl::SharedFuture<FenceResult>, ui::LayerStack layerStack) = 0;
 
+    // Initializes a promise for a buffer release fence and provides the future for that
+    // fence. This should only be called when a promise has not yet been created, or
+    // after the previous promise has already been fulfilled. Attempting to call this
+    // when an existing promise is INITIALIZED will fail because the promise has not
+    // yet been fulfilled.
+    virtual ftl::Future<FenceResult> createReleaseFenceFuture() = 0;
+
+    // Sets promise with its buffer's release fence
+    virtual void setReleaseFence(const FenceResult& releaseFence) = 0;
+
+    // Checks if the buffer's release fence has been set
+    virtual LayerFE::ReleaseFencePromiseStatus getReleaseFencePromiseStatus() = 0;
+
     // Gets some kind of identifier for the layer for debug purposes.
     virtual const char* getDebugName() const = 0;
 
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/CompositionEngine.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/CompositionEngine.h
index c699557..45208dd 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/CompositionEngine.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/CompositionEngine.h
@@ -48,6 +48,8 @@
 
     void preComposition(CompositionRefreshArgs&) override;
 
+    void postComposition(CompositionRefreshArgs&) override;
+
     FeatureFlags getFeatureFlags() const override;
 
     // Debugging
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/CompositionEngine.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/CompositionEngine.h
index 9b2387b..a1b7282 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/CompositionEngine.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/CompositionEngine.h
@@ -52,6 +52,7 @@
     MOCK_METHOD1(updateCursorAsync, void(CompositionRefreshArgs&));
 
     MOCK_METHOD1(preComposition, void(CompositionRefreshArgs&));
+    MOCK_METHOD1(postComposition, void(CompositionRefreshArgs&));
 
     MOCK_CONST_METHOD0(getFeatureFlags, FeatureFlags());
 
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/LayerFE.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/LayerFE.h
index 1b8cc27..05a5d38 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/LayerFE.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/LayerFE.h
@@ -20,6 +20,7 @@
 #include <compositionengine/LayerFECompositionState.h>
 #include <gmock/gmock.h>
 #include <ui/Fence.h>
+#include "ui/FenceResult.h"
 
 namespace android::compositionengine::mock {
 
@@ -52,6 +53,9 @@
     MOCK_METHOD(void, onLayerDisplayed, (ftl::SharedFuture<FenceResult>, ui::LayerStack),
                 (override));
 
+    MOCK_METHOD0(createReleaseFenceFuture, ftl::Future<FenceResult>());
+    MOCK_METHOD1(setReleaseFence, void(const FenceResult&));
+    MOCK_METHOD0(getReleaseFencePromiseStatus, LayerFE::ReleaseFencePromiseStatus());
     MOCK_CONST_METHOD0(getDebugName, const char*());
     MOCK_CONST_METHOD0(getSequence, int32_t());
     MOCK_CONST_METHOD0(hasRoundedCorners, bool());
diff --git a/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp b/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp
index b470208..4c77687 100644
--- a/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp
@@ -162,6 +162,7 @@
             future.get();
         }
     }
+    postComposition(args);
 }
 
 void CompositionEngine::updateCursorAsync(CompositionRefreshArgs& args) {
@@ -192,6 +193,34 @@
     mNeedsAnotherUpdate = needsAnotherUpdate;
 }
 
+// If a buffer is latched but the layer is not presented, such as when
+// obscured by another layer, the previous buffer needs to be released. We find
+// these buffers and fire a NO_FENCE to release it. This ensures that all
+// promises for buffer releases are fulfilled at the end of composition.
+void CompositionEngine::postComposition(CompositionRefreshArgs& args) {
+    if (FlagManager::getInstance().ce_fence_promise()) {
+        ATRACE_CALL();
+        ALOGV(__FUNCTION__);
+
+        for (auto& layerFE : args.layers) {
+            if (layerFE->getReleaseFencePromiseStatus() ==
+                LayerFE::ReleaseFencePromiseStatus::INITIALIZED) {
+                layerFE->setReleaseFence(Fence::NO_FENCE);
+            }
+        }
+
+        // List of layersWithQueuedFrames does not necessarily overlap with
+        // list of layers, so those layersWithQueuedFrames also need any
+        // unfulfilled promises to be resolved for completeness.
+        for (auto& layerFE : args.layersWithQueuedFrames) {
+            if (layerFE->getReleaseFencePromiseStatus() ==
+                LayerFE::ReleaseFencePromiseStatus::INITIALIZED) {
+                layerFE->setReleaseFence(Fence::NO_FENCE);
+            }
+        }
+    }
+}
+
 FeatureFlags CompositionEngine::getFeatureFlags() const {
     return {};
 }
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index 921e05d..7b5b49d 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -16,6 +16,7 @@
 
 #include <SurfaceFlingerProperties.sysprop.h>
 #include <android-base/stringprintf.h>
+#include <common/FlagManager.h>
 #include <compositionengine/CompositionEngine.h>
 #include <compositionengine/CompositionRefreshArgs.h>
 #include <compositionengine/DisplayColorProfile.h>
@@ -1621,9 +1622,13 @@
             releaseFence =
                     Fence::merge("LayerRelease", releaseFence, frame.clientTargetAcquireFence);
         }
-        layer->getLayerFE()
-                .onLayerDisplayed(ftl::yield<FenceResult>(std::move(releaseFence)).share(),
-                                  outputState.layerFilter.layerStack);
+        if (FlagManager::getInstance().ce_fence_promise()) {
+            layer->getLayerFE().setReleaseFence(releaseFence);
+        } else {
+            layer->getLayerFE()
+                    .onLayerDisplayed(ftl::yield<FenceResult>(std::move(releaseFence)).share(),
+                                      outputState.layerFilter.layerStack);
+        }
     }
 
     // We've got a list of layers needing fences, that are disjoint with
@@ -1631,8 +1636,12 @@
     // supply them with the present fence.
     for (auto& weakLayer : mReleasedLayers) {
         if (const auto layer = weakLayer.promote()) {
-            layer->onLayerDisplayed(ftl::yield<FenceResult>(frame.presentFence).share(),
-                                    outputState.layerFilter.layerStack);
+            if (FlagManager::getInstance().ce_fence_promise()) {
+                layer->setReleaseFence(frame.presentFence);
+            } else {
+                layer->onLayerDisplayed(ftl::yield<FenceResult>(frame.presentFence).share(),
+                                        outputState.layerFilter.layerStack);
+            }
         }
     }
 
diff --git a/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp b/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp
index 042010e..639164d 100644
--- a/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp
@@ -28,6 +28,7 @@
 
 #include "MockHWComposer.h"
 #include "TimeStats/TimeStats.h"
+#include "gmock/gmock.h"
 
 #include <variant>
 
@@ -90,14 +91,16 @@
         // These are the overridable functions CompositionEngine::present() may
         // call, and have separate test coverage.
         MOCK_METHOD1(preComposition, void(CompositionRefreshArgs&));
+        MOCK_METHOD1(postComposition, void(CompositionRefreshArgs&));
     };
 
     StrictMock<CompositionEnginePartialMock> mEngine;
 };
 
 TEST_F(CompositionEnginePresentTest, worksWithEmptyRequest) {
-    // present() always calls preComposition()
+    // present() always calls preComposition() and postComposition()
     EXPECT_CALL(mEngine, preComposition(Ref(mRefreshArgs)));
+    EXPECT_CALL(mEngine, postComposition(Ref(mRefreshArgs)));
 
     mEngine.present(mRefreshArgs);
 }
@@ -126,6 +129,9 @@
     EXPECT_CALL(*mOutput3, present(Ref(mRefreshArgs)))
             .WillOnce(Return(ftl::yield<std::monostate>({})));
 
+    // present() always calls postComposition()
+    EXPECT_CALL(mEngine, postComposition(Ref(mRefreshArgs)));
+
     mRefreshArgs.outputs = {mOutput1, mOutput2, mOutput3};
     mEngine.present(mRefreshArgs);
 }
@@ -481,5 +487,29 @@
     mEngine.present(mRefreshArgs);
 }
 
+struct CompositionEnginePostCompositionTest : public CompositionEngineTest {
+    sp<StrictMock<mock::LayerFE>> mLayer1FE = sp<StrictMock<mock::LayerFE>>::make();
+    sp<StrictMock<mock::LayerFE>> mLayer2FE = sp<StrictMock<mock::LayerFE>>::make();
+    sp<StrictMock<mock::LayerFE>> mLayer3FE = sp<StrictMock<mock::LayerFE>>::make();
+};
+
+TEST_F(CompositionEnginePostCompositionTest, postCompositionReleasesAllFences) {
+    SET_FLAG_FOR_TEST(com::android::graphics::surfaceflinger::flags::ce_fence_promise, true);
+    ASSERT_TRUE(FlagManager::getInstance().ce_fence_promise());
+
+    EXPECT_CALL(*mLayer1FE, getReleaseFencePromiseStatus)
+            .WillOnce(Return(LayerFE::ReleaseFencePromiseStatus::FULFILLED));
+    EXPECT_CALL(*mLayer2FE, getReleaseFencePromiseStatus)
+            .WillOnce(Return(LayerFE::ReleaseFencePromiseStatus::FULFILLED));
+    EXPECT_CALL(*mLayer3FE, getReleaseFencePromiseStatus)
+            .WillOnce(Return(LayerFE::ReleaseFencePromiseStatus::INITIALIZED));
+    mRefreshArgs.layers = {mLayer1FE, mLayer2FE, mLayer3FE};
+
+    EXPECT_CALL(*mLayer1FE, setReleaseFence(_)).Times(0);
+    EXPECT_CALL(*mLayer2FE, setReleaseFence(_)).Times(0);
+    EXPECT_CALL(*mLayer3FE, setReleaseFence(_)).Times(1);
+
+    mEngine.postComposition(mRefreshArgs);
+}
 } // namespace
 } // namespace android::compositionengine
diff --git a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
index 799c7ed..ea1d8e8 100644
--- a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
@@ -3164,6 +3164,8 @@
 }
 
 TEST_F(OutputPostFramebufferTest, releaseFencesAreSentToLayerFE) {
+    SET_FLAG_FOR_TEST(com::android::graphics::surfaceflinger::flags::ce_fence_promise, false);
+    ASSERT_FALSE(FlagManager::getInstance().ce_fence_promise());
     // Simulate getting release fences from each layer, and ensure they are passed to the
     // front-end layer interface for each layer correctly.
 
@@ -3205,7 +3207,51 @@
     mOutput.presentFrameAndReleaseLayers();
 }
 
+TEST_F(OutputPostFramebufferTest, releaseFencesAreSetInLayerFE) {
+    SET_FLAG_FOR_TEST(com::android::graphics::surfaceflinger::flags::ce_fence_promise, true);
+    ASSERT_TRUE(FlagManager::getInstance().ce_fence_promise());
+    // Simulate getting release fences from each layer, and ensure they are passed to the
+    // front-end layer interface for each layer correctly.
+
+    mOutput.mState.isEnabled = true;
+
+    // Create three unique fence instances
+    sp<Fence> layer1Fence = sp<Fence>::make();
+    sp<Fence> layer2Fence = sp<Fence>::make();
+    sp<Fence> layer3Fence = sp<Fence>::make();
+
+    Output::FrameFences frameFences;
+    frameFences.layerFences.emplace(&mLayer1.hwc2Layer, layer1Fence);
+    frameFences.layerFences.emplace(&mLayer2.hwc2Layer, layer2Fence);
+    frameFences.layerFences.emplace(&mLayer3.hwc2Layer, layer3Fence);
+
+    EXPECT_CALL(mOutput, presentFrame()).WillOnce(Return(frameFences));
+    EXPECT_CALL(*mRenderSurface, onPresentDisplayCompleted());
+
+    // Compare the pointers values of each fence to make sure the correct ones
+    // are passed. This happens to work with the current implementation, but
+    // would not survive certain calls like Fence::merge() which would return a
+    // new instance.
+    EXPECT_CALL(*mLayer1.layerFE, setReleaseFence(_))
+            .WillOnce([&layer1Fence](FenceResult releaseFence) {
+                EXPECT_EQ(FenceResult(layer1Fence), releaseFence);
+            });
+    EXPECT_CALL(*mLayer2.layerFE, setReleaseFence(_))
+            .WillOnce([&layer2Fence](FenceResult releaseFence) {
+                EXPECT_EQ(FenceResult(layer2Fence), releaseFence);
+            });
+    EXPECT_CALL(*mLayer3.layerFE, setReleaseFence(_))
+            .WillOnce([&layer3Fence](FenceResult releaseFence) {
+                EXPECT_EQ(FenceResult(layer3Fence), releaseFence);
+            });
+
+    mOutput.presentFrameAndReleaseLayers();
+}
+
 TEST_F(OutputPostFramebufferTest, releaseFencesIncludeClientTargetAcquireFence) {
+    SET_FLAG_FOR_TEST(com::android::graphics::surfaceflinger::flags::ce_fence_promise, false);
+    ASSERT_FALSE(FlagManager::getInstance().ce_fence_promise());
+
     mOutput.mState.isEnabled = true;
     mOutput.mState.usesClientComposition = true;
 
@@ -3228,7 +3274,35 @@
     mOutput.presentFrameAndReleaseLayers();
 }
 
+TEST_F(OutputPostFramebufferTest, setReleaseFencesIncludeClientTargetAcquireFence) {
+    SET_FLAG_FOR_TEST(com::android::graphics::surfaceflinger::flags::ce_fence_promise, true);
+    ASSERT_TRUE(FlagManager::getInstance().ce_fence_promise());
+
+    mOutput.mState.isEnabled = true;
+    mOutput.mState.usesClientComposition = true;
+
+    Output::FrameFences frameFences;
+    frameFences.clientTargetAcquireFence = sp<Fence>::make();
+    frameFences.layerFences.emplace(&mLayer1.hwc2Layer, sp<Fence>::make());
+    frameFences.layerFences.emplace(&mLayer2.hwc2Layer, sp<Fence>::make());
+    frameFences.layerFences.emplace(&mLayer3.hwc2Layer, sp<Fence>::make());
+
+    EXPECT_CALL(mOutput, presentFrame()).WillOnce(Return(frameFences));
+    EXPECT_CALL(*mRenderSurface, onPresentDisplayCompleted());
+
+    // Fence::merge is called, and since none of the fences are actually valid,
+    // Fence::NO_FENCE is returned and passed to each setReleaseFence() call.
+    // This is the best we can do without creating a real kernel fence object.
+    EXPECT_CALL(*mLayer1.layerFE, setReleaseFence).WillOnce(Return());
+    EXPECT_CALL(*mLayer2.layerFE, setReleaseFence).WillOnce(Return());
+    EXPECT_CALL(*mLayer3.layerFE, setReleaseFence).WillOnce(Return());
+    mOutput.presentFrameAndReleaseLayers();
+}
+
 TEST_F(OutputPostFramebufferTest, releasedLayersSentPresentFence) {
+    SET_FLAG_FOR_TEST(com::android::graphics::surfaceflinger::flags::ce_fence_promise, false);
+    ASSERT_FALSE(FlagManager::getInstance().ce_fence_promise());
+
     mOutput.mState.isEnabled = true;
     mOutput.mState.usesClientComposition = true;
 
@@ -3276,6 +3350,54 @@
     EXPECT_TRUE(mOutput.getReleasedLayersForTest().empty());
 }
 
+TEST_F(OutputPostFramebufferTest, setReleasedLayersSentPresentFence) {
+    SET_FLAG_FOR_TEST(com::android::graphics::surfaceflinger::flags::ce_fence_promise, true);
+    ASSERT_TRUE(FlagManager::getInstance().ce_fence_promise());
+
+    mOutput.mState.isEnabled = true;
+    mOutput.mState.usesClientComposition = true;
+
+    // This should happen even if there are no (current) output layers.
+    EXPECT_CALL(mOutput, getOutputLayerCount()).WillOnce(Return(0u));
+
+    // Load up the released layers with some mock instances
+    sp<StrictMock<mock::LayerFE>> releasedLayer1 = sp<StrictMock<mock::LayerFE>>::make();
+    sp<StrictMock<mock::LayerFE>> releasedLayer2 = sp<StrictMock<mock::LayerFE>>::make();
+    sp<StrictMock<mock::LayerFE>> releasedLayer3 = sp<StrictMock<mock::LayerFE>>::make();
+    Output::ReleasedLayers layers;
+    layers.push_back(releasedLayer1);
+    layers.push_back(releasedLayer2);
+    layers.push_back(releasedLayer3);
+    mOutput.setReleasedLayers(std::move(layers));
+
+    // Set up a fake present fence
+    sp<Fence> presentFence = sp<Fence>::make();
+    Output::FrameFences frameFences;
+    frameFences.presentFence = presentFence;
+
+    EXPECT_CALL(mOutput, presentFrame()).WillOnce(Return(frameFences));
+    EXPECT_CALL(*mRenderSurface, onPresentDisplayCompleted());
+
+    // Each released layer should be given the presentFence.
+    EXPECT_CALL(*releasedLayer1, setReleaseFence(_))
+            .WillOnce([&presentFence](FenceResult fenceResult) {
+                EXPECT_EQ(FenceResult(presentFence), fenceResult);
+            });
+    EXPECT_CALL(*releasedLayer2, setReleaseFence(_))
+            .WillOnce([&presentFence](FenceResult fenceResult) {
+                EXPECT_EQ(FenceResult(presentFence), fenceResult);
+            });
+    EXPECT_CALL(*releasedLayer3, setReleaseFence(_))
+            .WillOnce([&presentFence](FenceResult fenceResult) {
+                EXPECT_EQ(FenceResult(presentFence), fenceResult);
+            });
+
+    mOutput.presentFrameAndReleaseLayers();
+
+    // After the call the list of released layers should have been cleared.
+    EXPECT_TRUE(mOutput.getReleasedLayersForTest().empty());
+}
+
 /*
  * Output::composeSurfaces()
  */
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 736fec6..7e8ed48 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -15,6 +15,7 @@
  */
 
 // TODO(b/129481165): remove the #pragma below and fix conversion issues
+#include "TransactionCallbackInvoker.h"
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wconversion"
 
@@ -2912,9 +2913,7 @@
                               currentMaxAcquiredBufferCount);
 }
 
-void Layer::onLayerDisplayed(ftl::SharedFuture<FenceResult> futureFenceResult,
-                             ui::LayerStack layerStack,
-                             std::function<FenceResult(FenceResult)>&& continuation) {
+sp<CallbackHandle> Layer::findCallbackHandle() {
     // If we are displayed on multiple displays in a single composition cycle then we would
     // need to do careful tracking to enable the use of the mLastClientCompositionFence.
     //  For example we can only use it if all the displays are client comp, and we need
@@ -2949,6 +2948,53 @@
             break;
         }
     }
+    return ch;
+}
+
+void Layer::prepareReleaseCallbacks(ftl::Future<FenceResult> futureFenceResult,
+                                    ui::LayerStack layerStack) {
+    sp<CallbackHandle> ch = findCallbackHandle();
+
+    if (ch != nullptr) {
+        ch->previousReleaseCallbackId = mPreviousReleaseCallbackId;
+        ch->previousReleaseFences.emplace_back(std::move(futureFenceResult));
+        ch->name = mName;
+    } else {
+        // If we didn't get a release callback yet, e.g. some scenarios when capturing
+        // screenshots asynchronously, then make sure we don't drop the fence.
+        mAdditionalPreviousReleaseFences.emplace_back(std::move(futureFenceResult));
+        std::vector<ftl::Future<FenceResult>> mergedFences;
+        sp<Fence> prevFence = nullptr;
+        // For a layer that's frequently screenshotted, try to merge fences to make sure we
+        // don't grow unbounded.
+        for (auto& futureReleaseFence : mAdditionalPreviousReleaseFences) {
+            auto result = futureReleaseFence.wait_for(0s);
+            if (result != std::future_status::ready) {
+                mergedFences.emplace_back(std::move(futureReleaseFence));
+                continue;
+            }
+            mergeFence(getDebugName(), futureReleaseFence.get().value_or(Fence::NO_FENCE),
+                       prevFence);
+        }
+        if (prevFence != nullptr) {
+            mergedFences.emplace_back(ftl::yield(FenceResult(std::move(prevFence))));
+        }
+        mAdditionalPreviousReleaseFences.swap(mergedFences);
+    }
+
+    if (mBufferInfo.mBuffer) {
+        mPreviouslyPresentedLayerStacks.push_back(layerStack);
+    }
+
+    if (mDrawingState.frameNumber > 0) {
+        mDrawingState.previousFrameNumber = mDrawingState.frameNumber;
+    }
+}
+
+void Layer::onLayerDisplayed(ftl::SharedFuture<FenceResult> futureFenceResult,
+                             ui::LayerStack layerStack,
+                             std::function<FenceResult(FenceResult)>&& continuation) {
+    sp<CallbackHandle> ch = findCallbackHandle();
 
     if (!FlagManager::getInstance().screenshot_fence_preservation() && continuation) {
         futureFenceResult = ftl::Future(futureFenceResult).then(std::move(continuation)).share();
@@ -2956,32 +3002,32 @@
 
     if (ch != nullptr) {
         ch->previousReleaseCallbackId = mPreviousReleaseCallbackId;
-        ch->previousReleaseFences.emplace_back(std::move(futureFenceResult));
+        ch->previousSharedReleaseFences.emplace_back(std::move(futureFenceResult));
         ch->name = mName;
     } else if (FlagManager::getInstance().screenshot_fence_preservation()) {
         // If we didn't get a release callback yet, e.g. some scenarios when capturing screenshots
         // asynchronously, then make sure we don't drop the fence.
-        mAdditionalPreviousReleaseFences.emplace_back(std::move(futureFenceResult),
-                                                      std::move(continuation));
+        mPreviousReleaseFenceAndContinuations.emplace_back(std::move(futureFenceResult),
+                                                           std::move(continuation));
         std::vector<FenceAndContinuation> mergedFences;
         sp<Fence> prevFence = nullptr;
         // For a layer that's frequently screenshotted, try to merge fences to make sure we don't
         // grow unbounded.
-        for (const auto& futureAndContinution : mAdditionalPreviousReleaseFences) {
-            auto result = futureAndContinution.future.wait_for(0s);
+        for (const auto& futureAndContinuation : mPreviousReleaseFenceAndContinuations) {
+            auto result = futureAndContinuation.future.wait_for(0s);
             if (result != std::future_status::ready) {
-                mergedFences.emplace_back(futureAndContinution);
+                mergedFences.emplace_back(futureAndContinuation);
                 continue;
             }
 
-            mergeFence(getDebugName(), futureAndContinution.chain().get().value_or(Fence::NO_FENCE),
-                       prevFence);
+            mergeFence(getDebugName(),
+                       futureAndContinuation.chain().get().value_or(Fence::NO_FENCE), prevFence);
         }
         if (prevFence != nullptr) {
             mergedFences.emplace_back(ftl::yield(FenceResult(std::move(prevFence))).share());
         }
 
-        mAdditionalPreviousReleaseFences.swap(mergedFences);
+        mPreviousReleaseFenceAndContinuations.swap(mergedFences);
     }
 
     if (mBufferInfo.mBuffer) {
@@ -3481,16 +3527,23 @@
             handle->acquireTimeOrFence = mCallbackHandleAcquireTimeOrFence;
             handle->frameNumber = mDrawingState.frameNumber;
             handle->previousFrameNumber = mDrawingState.previousFrameNumber;
-            if (FlagManager::getInstance().screenshot_fence_preservation() &&
+            if (FlagManager::getInstance().ce_fence_promise() &&
                 mPreviousReleaseBufferEndpoint == handle->listener) {
                 // Add fences from previous screenshots now so that they can be dispatched to the
                 // client.
-                for (const auto& futureAndContinution : mAdditionalPreviousReleaseFences) {
-                    handle->previousReleaseFences.emplace_back(futureAndContinution.chain());
+                for (auto& futureReleaseFence : mAdditionalPreviousReleaseFences) {
+                    handle->previousReleaseFences.emplace_back(std::move(futureReleaseFence));
                 }
                 mAdditionalPreviousReleaseFences.clear();
+            } else if (FlagManager::getInstance().screenshot_fence_preservation() &&
+                       mPreviousReleaseBufferEndpoint == handle->listener) {
+                // Add fences from previous screenshots now so that they can be dispatched to the
+                // client.
+                for (const auto& futureAndContinution : mPreviousReleaseFenceAndContinuations) {
+                    handle->previousSharedReleaseFences.emplace_back(futureAndContinution.chain());
+                }
+                mPreviousReleaseFenceAndContinuations.clear();
             }
-
             // Store so latched time and release fence can be set
             mDrawingState.callbackHandles.push_back(handle);
 
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 0ceecec..9108869 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -559,6 +559,14 @@
     void onLayerDisplayed(ftl::SharedFuture<FenceResult>, ui::LayerStack layerStack,
                           std::function<FenceResult(FenceResult)>&& continuation = nullptr);
 
+    // Tracks mLastClientCompositionFence and gets the callback handle for this layer.
+    sp<CallbackHandle> findCallbackHandle();
+
+    // Adds the future release fence to a list of fences that are used to release the
+    // last presented buffer. Also keeps track of the layerstack in a list of previous
+    // layerstacks that have been presented.
+    void prepareReleaseCallbacks(ftl::Future<FenceResult>, ui::LayerStack layerStack);
+
     void setWasClientComposed(const sp<Fence>& fence) {
         mLastClientCompositionFence = fence;
         mClearClientCompositionFenceOnLayerDisplayed = false;
@@ -934,6 +942,7 @@
     // the release fences from the correct displays when we release the last buffer
     // from the layer.
     std::vector<ui::LayerStack> mPreviouslyPresentedLayerStacks;
+
     struct FenceAndContinuation {
         ftl::SharedFuture<FenceResult> future;
         std::function<FenceResult(FenceResult)> continuation;
@@ -946,7 +955,16 @@
             }
         }
     };
-    std::vector<FenceAndContinuation> mAdditionalPreviousReleaseFences;
+    std::vector<FenceAndContinuation> mPreviousReleaseFenceAndContinuations;
+
+    // Release fences for buffers that have not yet received a release
+    // callback. A release callback may not be given when capturing
+    // screenshots asynchronously. There may be no buffer update for the
+    // layer, but the layer will still be composited on the screen in every
+    // frame. Kepping track of these fences ensures that they are not dropped
+    // and can be dispatched to the client at a later time.
+    std::vector<ftl::Future<FenceResult>> mAdditionalPreviousReleaseFences;
+
     // Exposed so SurfaceFlinger can assert that it's held
     const sp<SurfaceFlinger> mFlinger;
 
diff --git a/services/surfaceflinger/LayerFE.cpp b/services/surfaceflinger/LayerFE.cpp
index 43a4397..620edca 100644
--- a/services/surfaceflinger/LayerFE.cpp
+++ b/services/surfaceflinger/LayerFE.cpp
@@ -27,6 +27,8 @@
 
 #include "LayerFE.h"
 #include "SurfaceFlinger.h"
+#include "ui/FenceResult.h"
+#include "ui/LayerStack.h"
 
 namespace android {
 
@@ -387,4 +389,29 @@
     return mSnapshot->externalTexture ? mSnapshot->externalTexture->getBuffer() : nullptr;
 }
 
+void LayerFE::setReleaseFence(const FenceResult& releaseFence) {
+    // Promises should not be fulfilled more than once. This case can occur if virtual
+    // displays with the same layerstack ID are being created and destroyed in quick
+    // succession, such as in tests. This would result in a race condition in which
+    // multiple displays have the same layerstack ID within the same vsync interval.
+    if (mReleaseFencePromiseStatus == ReleaseFencePromiseStatus::FULFILLED) {
+        return;
+    }
+    mReleaseFence.set_value(releaseFence);
+    mReleaseFencePromiseStatus = ReleaseFencePromiseStatus::FULFILLED;
+}
+
+// LayerFEs are reused and a new fence needs to be created whevever a buffer is latched.
+ftl::Future<FenceResult> LayerFE::createReleaseFenceFuture() {
+    if (mReleaseFencePromiseStatus == ReleaseFencePromiseStatus::INITIALIZED) {
+        LOG_ALWAYS_FATAL("Attempting to create a new promise while one is still unfulfilled.");
+    }
+    mReleaseFence = std::promise<FenceResult>();
+    mReleaseFencePromiseStatus = ReleaseFencePromiseStatus::INITIALIZED;
+    return mReleaseFence.get_future();
+}
+
+LayerFE::ReleaseFencePromiseStatus LayerFE::getReleaseFencePromiseStatus() {
+    return mReleaseFencePromiseStatus;
+}
 } // namespace android
diff --git a/services/surfaceflinger/LayerFE.h b/services/surfaceflinger/LayerFE.h
index 66cb88b..019fa22 100644
--- a/services/surfaceflinger/LayerFE.h
+++ b/services/surfaceflinger/LayerFE.h
@@ -22,6 +22,9 @@
 #include "compositionengine/LayerFE.h"
 #include "compositionengine/LayerFECompositionState.h"
 #include "renderengine/LayerSettings.h"
+#include "ui/LayerStack.h"
+
+#include <ftl/future.h>
 
 namespace android {
 
@@ -47,6 +50,9 @@
     std::optional<compositionengine::LayerFE::LayerSettings> prepareClientComposition(
             compositionengine::LayerFE::ClientCompositionTargetSettings&) const;
     CompositionResult&& stealCompositionResult();
+    ftl::Future<FenceResult> createReleaseFenceFuture() override;
+    void setReleaseFence(const FenceResult& releaseFence) override;
+    LayerFE::ReleaseFencePromiseStatus getReleaseFencePromiseStatus() override;
 
     std::unique_ptr<surfaceflinger::frontend::LayerSnapshot> mSnapshot;
 
@@ -76,6 +82,8 @@
 
     CompositionResult mCompositionResult;
     std::string mName;
+    std::promise<FenceResult> mReleaseFence;
+    ReleaseFencePromiseStatus mReleaseFencePromiseStatus = ReleaseFencePromiseStatus::UNINITIALIZED;
 };
 
 } // namespace android
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 9d07671..3ec5f21 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -40,6 +40,7 @@
 #include <binder/IPCThreadState.h>
 #include <binder/IServiceManager.h>
 #include <binder/PermissionCache.h>
+#include <common/FlagManager.h>
 #include <compositionengine/CompositionEngine.h>
 #include <compositionengine/CompositionRefreshArgs.h>
 #include <compositionengine/Display.h>
@@ -2719,10 +2720,12 @@
 
     refreshArgs.bufferIdsToUncache = std::move(mBufferIdsToUncache);
 
-    refreshArgs.layersWithQueuedFrames.reserve(mLayersWithQueuedFrames.size());
-    for (auto layer : mLayersWithQueuedFrames) {
-        if (auto layerFE = layer->getCompositionEngineLayerFE())
-            refreshArgs.layersWithQueuedFrames.push_back(layerFE);
+    if (!FlagManager::getInstance().ce_fence_promise()) {
+        refreshArgs.layersWithQueuedFrames.reserve(mLayersWithQueuedFrames.size());
+        for (auto& layer : mLayersWithQueuedFrames) {
+            if (const auto& layerFE = layer->getCompositionEngineLayerFE())
+                refreshArgs.layersWithQueuedFrames.push_back(layerFE);
+        }
     }
 
     refreshArgs.outputColorSetting = mDisplayColorSetting;
@@ -2784,22 +2787,56 @@
     }
 
     refreshArgs.refreshStartTime = systemTime(SYSTEM_TIME_MONOTONIC);
-    for (auto [layer, layerFE] : layers) {
+    for (auto& [layer, layerFE] : layers) {
         layer->onPreComposition(refreshArgs.refreshStartTime);
     }
 
-    mCompositionEngine->present(refreshArgs);
-    moveSnapshotsFromCompositionArgs(refreshArgs, layers);
-
-    for (auto [layer, layerFE] : layers) {
-        CompositionResult compositionResult{layerFE->stealCompositionResult()};
-        for (auto& [releaseFence, layerStack] : compositionResult.releaseFences) {
-            Layer* clonedFrom = layer->getClonedFrom().get();
-            auto owningLayer = clonedFrom ? clonedFrom : layer;
-            owningLayer->onLayerDisplayed(std::move(releaseFence), layerStack);
+    if (FlagManager::getInstance().ce_fence_promise()) {
+        for (auto& [layer, layerFE] : layers) {
+            attachReleaseFenceFutureToLayer(layer, layerFE,
+                                            layerFE->mSnapshot->outputFilter.layerStack);
         }
-        if (compositionResult.lastClientCompositionFence) {
-            layer->setWasClientComposed(compositionResult.lastClientCompositionFence);
+
+        refreshArgs.layersWithQueuedFrames.reserve(mLayersWithQueuedFrames.size());
+        for (auto& layer : mLayersWithQueuedFrames) {
+            if (const auto& layerFE = layer->getCompositionEngineLayerFE()) {
+                refreshArgs.layersWithQueuedFrames.push_back(layerFE);
+                // Some layers are not displayed and do not yet have a future release fence
+                if (layerFE->getReleaseFencePromiseStatus() ==
+                            LayerFE::ReleaseFencePromiseStatus::UNINITIALIZED ||
+                    layerFE->getReleaseFencePromiseStatus() ==
+                            LayerFE::ReleaseFencePromiseStatus::FULFILLED) {
+                    // layerStack is invalid because layer is not on a display
+                    attachReleaseFenceFutureToLayer(layer.get(), layerFE.get(),
+                                                    ui::INVALID_LAYER_STACK);
+                }
+            }
+        }
+
+        mCompositionEngine->present(refreshArgs);
+        moveSnapshotsFromCompositionArgs(refreshArgs, layers);
+
+        for (auto& [layer, layerFE] : layers) {
+            CompositionResult compositionResult{layerFE->stealCompositionResult()};
+            if (compositionResult.lastClientCompositionFence) {
+                layer->setWasClientComposed(compositionResult.lastClientCompositionFence);
+            }
+        }
+
+    } else {
+        mCompositionEngine->present(refreshArgs);
+        moveSnapshotsFromCompositionArgs(refreshArgs, layers);
+
+        for (auto [layer, layerFE] : layers) {
+            CompositionResult compositionResult{layerFE->stealCompositionResult()};
+            for (auto& [releaseFence, layerStack] : compositionResult.releaseFences) {
+                Layer* clonedFrom = layer->getClonedFrom().get();
+                auto owningLayer = clonedFrom ? clonedFrom : layer;
+                owningLayer->onLayerDisplayed(std::move(releaseFence), layerStack);
+            }
+            if (compositionResult.lastClientCompositionFence) {
+                layer->setWasClientComposed(compositionResult.lastClientCompositionFence);
+            }
         }
     }
 
@@ -3065,8 +3102,13 @@
             auto optDisplay = layerStackToDisplay.get(layerStack);
             if (optDisplay && !optDisplay->get()->isVirtual()) {
                 auto fence = getHwComposer().getPresentFence(optDisplay->get()->getPhysicalId());
-                layer->onLayerDisplayed(ftl::yield<FenceResult>(fence).share(),
-                                        ui::INVALID_LAYER_STACK);
+                if (FlagManager::getInstance().ce_fence_promise()) {
+                    layer->prepareReleaseCallbacks(ftl::yield<FenceResult>(fence),
+                                                   ui::INVALID_LAYER_STACK);
+                } else {
+                    layer->onLayerDisplayed(ftl::yield<FenceResult>(fence).share(),
+                                            ui::INVALID_LAYER_STACK);
+                }
             }
         }
         layer->releasePendingBuffer(presentTime.ns());
@@ -7999,7 +8041,7 @@
 
     // really small crop or frameScale
     if (reqSize.width <= 0 || reqSize.height <= 0) {
-        ALOGW("Failed to captureLayes: crop or scale too small");
+        ALOGW("Failed to captureLayers: crop or scale too small");
         invokeScreenCaptureError(BAD_VALUE, captureListener);
         return;
     }
@@ -8073,6 +8115,17 @@
                         args.allowProtected, args.grayscale, captureListener);
 }
 
+// Creates a Future release fence for a layer and keeps track of it in a list to
+// release the buffer when the Future is complete. Calls from composittion
+// involve needing to refresh the composition start time for stats.
+void SurfaceFlinger::attachReleaseFenceFutureToLayer(Layer* layer, LayerFE* layerFE,
+                                                     ui::LayerStack layerStack) {
+    ftl::Future<FenceResult> futureFence = layerFE->createReleaseFenceFuture();
+    Layer* clonedFrom = layer->getClonedFrom().get();
+    auto owningLayer = clonedFrom ? clonedFrom : layer;
+    owningLayer->prepareReleaseCallbacks(std::move(futureFence), layerStack);
+}
+
 bool SurfaceFlinger::layersHasProtectedLayer(
         const std::vector<std::pair<Layer*, sp<LayerFE>>>& layers) const {
     bool protectedLayerFound = false;
@@ -8108,7 +8161,6 @@
     const bool supportsProtected = getRenderEngine().supportsProtectedContent();
     bool hasProtectedLayer = false;
     if (allowProtected && supportsProtected) {
-        // Snapshots must be taken from the main thread.
         auto layers = mScheduler->schedule([=]() { return getLayerSnapshots(); }).get();
         hasProtectedLayer = layersHasProtectedLayer(layers);
     }
@@ -8149,6 +8201,14 @@
 
     auto takeScreenshotFn = [=, this, renderAreaFuture = std::move(renderAreaFuture)]() REQUIRES(
                                     kMainThreadContext) mutable -> ftl::SharedFuture<FenceResult> {
+        // LayerSnapshots must be obtained from the main thread.
+        auto layers = getLayerSnapshots();
+        if (FlagManager::getInstance().ce_fence_promise()) {
+            for (auto& [layer, layerFE] : layers) {
+                attachReleaseFenceFutureToLayer(layer, layerFE.get(), ui::INVALID_LAYER_STACK);
+            }
+        }
+
         ScreenCaptureResults captureResults;
         std::shared_ptr<RenderArea> renderArea = renderAreaFuture.get();
         if (!renderArea) {
@@ -8162,8 +8222,8 @@
 
         ftl::SharedFuture<FenceResult> renderFuture;
         renderArea->render([&]() FTL_FAKE_GUARD(kMainThreadContext) {
-            renderFuture = renderScreenImpl(renderArea, getLayerSnapshots, buffer, regionSampling,
-                                            grayscale, isProtected, captureResults);
+            renderFuture = renderScreenImpl(renderArea, buffer, regionSampling, grayscale,
+                                            isProtected, captureResults, layers);
         });
 
         if (captureListener) {
@@ -8180,6 +8240,10 @@
         return renderFuture;
     };
 
+    // TODO(b/294936197): Run takeScreenshotsFn() in a binder thread to reduce the number
+    // of calls on the main thread. renderAreaFuture runs on the main thread and should
+    // no longer be a future, so that it does not need to make an additional jump on the
+    // main thread whenever get() is called.
     auto future =
             mScheduler->schedule(FTL_FAKE_GUARD(kMainThreadContext, std::move(takeScreenshotFn)));
 
@@ -8195,9 +8259,17 @@
         std::shared_ptr<const RenderArea> renderArea, GetLayerSnapshotsFunction getLayerSnapshots,
         const std::shared_ptr<renderengine::ExternalTexture>& buffer, bool regionSampling,
         bool grayscale, bool isProtected, ScreenCaptureResults& captureResults) {
-    ATRACE_CALL();
-
     auto layers = getLayerSnapshots();
+    return renderScreenImpl(renderArea, buffer, regionSampling, grayscale, isProtected,
+                            captureResults, layers);
+}
+
+ftl::SharedFuture<FenceResult> SurfaceFlinger::renderScreenImpl(
+        std::shared_ptr<const RenderArea> renderArea,
+        const std::shared_ptr<renderengine::ExternalTexture>& buffer, bool regionSampling,
+        bool grayscale, bool isProtected, ScreenCaptureResults& captureResults,
+        std::vector<std::pair<Layer*, sp<android::LayerFE>>>& layers) {
+    ATRACE_CALL();
 
     for (auto& [_, layerFE] : layers) {
         frontend::LayerSnapshot* snapshot = layerFE->mSnapshot.get();
@@ -8351,24 +8423,26 @@
     auto presentFuture = mRenderEngine->isThreaded() ? ftl::defer(std::move(present)).share()
                                                      : ftl::yield(present()).share();
 
-    for (auto& [layer, layerFE] : layers) {
-        layer->onLayerDisplayed(presentFuture, ui::INVALID_LAYER_STACK,
-                                [layerFE = std::move(layerFE)](FenceResult) {
-                                    if (FlagManager::getInstance()
-                                                .screenshot_fence_preservation()) {
-                                        const auto compositionResult =
-                                                layerFE->stealCompositionResult();
-                                        const auto& fences = compositionResult.releaseFences;
-                                        // CompositionEngine may choose to cull layers that
-                                        // aren't visible, so pass a non-fence.
-                                        return fences.empty() ? Fence::NO_FENCE
-                                                              : fences.back().first.get();
-                                    } else {
-                                        return layerFE->stealCompositionResult()
-                                                .releaseFences.back()
-                                                .first.get();
-                                    }
-                                });
+    if (!FlagManager::getInstance().ce_fence_promise()) {
+        for (auto& [layer, layerFE] : layers) {
+            layer->onLayerDisplayed(presentFuture, ui::INVALID_LAYER_STACK,
+                                    [layerFE = std::move(layerFE)](FenceResult) {
+                                        if (FlagManager::getInstance()
+                                                    .screenshot_fence_preservation()) {
+                                            const auto compositionResult =
+                                                    layerFE->stealCompositionResult();
+                                            const auto& fences = compositionResult.releaseFences;
+                                            // CompositionEngine may choose to cull layers that
+                                            // aren't visible, so pass a non-fence.
+                                            return fences.empty() ? Fence::NO_FENCE
+                                                                  : fences.back().first.get();
+                                        } else {
+                                            return layerFE->stealCompositionResult()
+                                                    .releaseFences.back()
+                                                    .first.get();
+                                        }
+                                    });
+        }
     }
 
     return presentFuture;
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 34a7e7f..c106abd 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -881,6 +881,11 @@
     // Traverse through all the layers and compute and cache its bounds.
     void computeLayerBounds();
 
+    // Creates a promise for a future release fence for a layer. This allows for
+    // the layer to keep track of when its buffer can be released.
+    void attachReleaseFenceFutureToLayer(Layer* layer, LayerFE* layerFE, ui::LayerStack layerStack);
+
+    // Checks if a protected layer exists in a list of layers.
     bool layersHasProtectedLayer(const std::vector<std::pair<Layer*, sp<LayerFE>>>& layers) const;
 
     void captureScreenCommon(RenderAreaFuture, GetLayerSnapshotsFunction, ui::Size bufferSize,
@@ -892,12 +897,22 @@
             const std::shared_ptr<renderengine::ExternalTexture>&, bool regionSampling,
             bool grayscale, bool isProtected, const sp<IScreenCaptureListener>&);
 
+    // Overloaded version of renderScreenImpl that is used when layer snapshots have
+    // not yet been captured, and thus cannot yet be passed in as a parameter.
+    // Needed for TestableSurfaceFlinger.
     ftl::SharedFuture<FenceResult> renderScreenImpl(
             std::shared_ptr<const RenderArea>, GetLayerSnapshotsFunction,
             const std::shared_ptr<renderengine::ExternalTexture>&, bool regionSampling,
             bool grayscale, bool isProtected, ScreenCaptureResults&) EXCLUDES(mStateLock)
             REQUIRES(kMainThreadContext);
 
+    ftl::SharedFuture<FenceResult> renderScreenImpl(
+            std::shared_ptr<const RenderArea>,
+            const std::shared_ptr<renderengine::ExternalTexture>&, bool regionSampling,
+            bool grayscale, bool isProtected, ScreenCaptureResults&,
+            std::vector<std::pair<Layer*, sp<android::LayerFE>>>& layers) EXCLUDES(mStateLock)
+            REQUIRES(kMainThreadContext);
+
     // If the uid provided is not UNSET_UID, the traverse will skip any layers that don't have a
     // matching ownerUid
     void traverseLayersInLayerStack(ui::LayerStack, const int32_t uid,
diff --git a/services/surfaceflinger/TransactionCallbackInvoker.cpp b/services/surfaceflinger/TransactionCallbackInvoker.cpp
index 7b5298c..222ae30 100644
--- a/services/surfaceflinger/TransactionCallbackInvoker.cpp
+++ b/services/surfaceflinger/TransactionCallbackInvoker.cpp
@@ -30,6 +30,7 @@
 #include <cinttypes>
 
 #include <binder/IInterface.h>
+#include <common/FlagManager.h>
 #include <utils/RefBase.h>
 
 namespace android {
@@ -128,9 +129,17 @@
     sp<IBinder> surfaceControl = handle->surfaceControl.promote();
     if (surfaceControl) {
         sp<Fence> prevFence = nullptr;
-        for (const auto& future : handle->previousReleaseFences) {
-            mergeFence(handle->name.c_str(), future.get().value_or(Fence::NO_FENCE), prevFence);
+
+        if (FlagManager::getInstance().ce_fence_promise()) {
+            for (auto& future : handle->previousReleaseFences) {
+                mergeFence(handle->name.c_str(), future.get().value_or(Fence::NO_FENCE), prevFence);
+            }
+        } else {
+            for (const auto& future : handle->previousSharedReleaseFences) {
+                mergeFence(handle->name.c_str(), future.get().value_or(Fence::NO_FENCE), prevFence);
+            }
         }
+
         handle->previousReleaseFence = prevFence;
         handle->previousReleaseFences.clear();
 
diff --git a/services/surfaceflinger/TransactionCallbackInvoker.h b/services/surfaceflinger/TransactionCallbackInvoker.h
index 245398f..cb7150b 100644
--- a/services/surfaceflinger/TransactionCallbackInvoker.h
+++ b/services/surfaceflinger/TransactionCallbackInvoker.h
@@ -46,7 +46,8 @@
     bool releasePreviousBuffer = false;
     std::string name;
     sp<Fence> previousReleaseFence;
-    std::vector<ftl::SharedFuture<FenceResult>> previousReleaseFences;
+    std::vector<ftl::Future<FenceResult>> previousReleaseFences;
+    std::vector<ftl::SharedFuture<FenceResult>> previousSharedReleaseFences;
     std::variant<nsecs_t, sp<Fence>> acquireTimeOrFence = -1;
     nsecs_t latchTime = -1;
     std::optional<uint32_t> transformHint = std::nullopt;
diff --git a/services/surfaceflinger/common/FlagManager.cpp b/services/surfaceflinger/common/FlagManager.cpp
index 8276eed..4b34a55 100644
--- a/services/surfaceflinger/common/FlagManager.cpp
+++ b/services/surfaceflinger/common/FlagManager.cpp
@@ -136,6 +136,7 @@
     DUMP_READ_ONLY_FLAG(restore_blur_step);
     DUMP_READ_ONLY_FLAG(dont_skip_on_early_ro);
     DUMP_READ_ONLY_FLAG(protected_if_client);
+    DUMP_READ_ONLY_FLAG(ce_fence_promise);
 #undef DUMP_READ_ONLY_FLAG
 #undef DUMP_SERVER_FLAG
 #undef DUMP_FLAG_INTERVAL
@@ -220,6 +221,7 @@
 FLAG_MANAGER_READ_ONLY_FLAG(restore_blur_step, "debug.renderengine.restore_blur_step")
 FLAG_MANAGER_READ_ONLY_FLAG(dont_skip_on_early_ro, "")
 FLAG_MANAGER_READ_ONLY_FLAG(protected_if_client, "")
+FLAG_MANAGER_READ_ONLY_FLAG(ce_fence_promise, "");
 
 /// Trunk stable server flags ///
 FLAG_MANAGER_SERVER_FLAG(refresh_rate_overlay_on_external_display, "")
diff --git a/services/surfaceflinger/common/include/common/FlagManager.h b/services/surfaceflinger/common/include/common/FlagManager.h
index b55bd98..320e34b 100644
--- a/services/surfaceflinger/common/include/common/FlagManager.h
+++ b/services/surfaceflinger/common/include/common/FlagManager.h
@@ -75,6 +75,7 @@
     bool restore_blur_step() const;
     bool dont_skip_on_early_ro() const;
     bool protected_if_client() const;
+    bool ce_fence_promise() const;
 
 protected:
     // overridden for unit tests
diff --git a/services/surfaceflinger/surfaceflinger_flags_new.aconfig b/services/surfaceflinger/surfaceflinger_flags_new.aconfig
index e7bfb6c..0a5cde3 100644
--- a/services/surfaceflinger/surfaceflinger_flags_new.aconfig
+++ b/services/surfaceflinger/surfaceflinger_flags_new.aconfig
@@ -11,6 +11,17 @@
 } # adpf_gpu_sf
 
 flag {
+  name: "ce_fence_promise"
+  namespace: "window_surfaces"
+  description: "Moves logic for buffer release fences into LayerFE"
+  bug: "294936197"
+  is_fixed_read_only: true
+  metadata {
+    purpose: PURPOSE_BUGFIX
+  }
+}
+
+flag {
   name: "dont_skip_on_early_ro2"
   namespace: "core_graphics"
   description: "This flag is guarding the behaviour where SurfaceFlinger is trying to opportunistically present a frame when the configuration change from late to early"
diff --git a/services/surfaceflinger/tests/Android.bp b/services/surfaceflinger/tests/Android.bp
index 1fd7ae0..d60ef48 100644
--- a/services/surfaceflinger/tests/Android.bp
+++ b/services/surfaceflinger/tests/Android.bp
@@ -68,6 +68,7 @@
     static_libs: [
         "liblayers_proto",
         "android.hardware.graphics.composer@2.1",
+        "libsurfaceflinger_common",
     ],
     shared_libs: [
         "android.hardware.graphics.common@1.2",
@@ -83,6 +84,7 @@
         "libprotobuf-cpp-full",
         "libui",
         "libutils",
+        "server_configurable_flags",
     ],
     header_libs: [
         "libnativewindow_headers",
diff --git a/services/surfaceflinger/tests/LayerCallback_test.cpp b/services/surfaceflinger/tests/LayerCallback_test.cpp
index 79886bd..b4496d3 100644
--- a/services/surfaceflinger/tests/LayerCallback_test.cpp
+++ b/services/surfaceflinger/tests/LayerCallback_test.cpp
@@ -1295,4 +1295,74 @@
     }
 }
 
+TEST_F(LayerCallbackTest, OccludedLayerHasReleaseCallback) {
+    sp<SurfaceControl> layer1, layer2;
+    ASSERT_NO_FATAL_FAILURE(layer1 = createLayerWithBuffer());
+    ASSERT_NO_FATAL_FAILURE(layer2 = createLayerWithBuffer());
+
+    Transaction transaction1, transaction2;
+    CallbackHelper callback1a, callback1b, callback2a, callback2b;
+    int err = fillTransaction(transaction1, &callback1a, layer1);
+    if (err) {
+        GTEST_SUCCEED() << "test not supported";
+        return;
+    }
+    err = fillTransaction(transaction2, &callback2a, layer2);
+    if (err) {
+        GTEST_SUCCEED() << "test not supported";
+        return;
+    }
+
+    ui::Size bufferSize = getBufferSize();
+
+    // Occlude layer1 with layer2
+    TransactionUtils::setFrame(transaction1, layer1,
+                               Rect(0, 0, bufferSize.width, bufferSize.height), Rect(0, 0, 32, 32));
+    TransactionUtils::setFrame(transaction2, layer2,
+                               Rect(0, 0, bufferSize.width, bufferSize.height), Rect(0, 0, 32, 32));
+    transaction1.apply();
+    transaction2.apply();
+
+    ExpectedResult expected1a, expected1b, expected2a, expected2b;
+    expected1a.addSurface(ExpectedResult::Transaction::PRESENTED, {layer1},
+                          ExpectedResult::Buffer::ACQUIRED,
+                          ExpectedResult::PreviousBuffer::NOT_RELEASED);
+
+    expected2a.addSurface(ExpectedResult::Transaction::PRESENTED, {layer2},
+                          ExpectedResult::Buffer::ACQUIRED,
+                          ExpectedResult::PreviousBuffer::NOT_RELEASED);
+
+    EXPECT_NO_FATAL_FAILURE(waitForCallback(callback1a, expected1a, true));
+    EXPECT_NO_FATAL_FAILURE(waitForCallback(callback2a, expected2a, true));
+
+    // Submit new buffers so previous buffers can be released
+    err = fillTransaction(transaction1, &callback1b, layer1);
+    if (err) {
+        GTEST_SUCCEED() << "test not supported";
+        return;
+    }
+    err = fillTransaction(transaction2, &callback2b, layer2);
+    if (err) {
+        GTEST_SUCCEED() << "test not supported";
+        return;
+    }
+
+    TransactionUtils::setFrame(transaction1, layer1,
+                               Rect(0, 0, bufferSize.width, bufferSize.height), Rect(0, 0, 32, 32));
+    TransactionUtils::setFrame(transaction2, layer2,
+                               Rect(0, 0, bufferSize.width, bufferSize.height), Rect(0, 0, 32, 32));
+    transaction1.apply();
+    transaction2.apply();
+
+    expected1b.addSurface(ExpectedResult::Transaction::PRESENTED, {layer1},
+                          ExpectedResult::Buffer::ACQUIRED,
+                          ExpectedResult::PreviousBuffer::RELEASED);
+
+    expected2b.addSurface(ExpectedResult::Transaction::PRESENTED, {layer2},
+                          ExpectedResult::Buffer::ACQUIRED,
+                          ExpectedResult::PreviousBuffer::RELEASED);
+
+    EXPECT_NO_FATAL_FAILURE(waitForCallback(callback1b, expected1b, true));
+    EXPECT_NO_FATAL_FAILURE(waitForCallback(callback2b, expected2b, true));
+}
 } // namespace android
diff --git a/services/surfaceflinger/tests/MultiDisplayLayerBounds_test.cpp b/services/surfaceflinger/tests/MultiDisplayLayerBounds_test.cpp
index 15ff696..7fce7e9 100644
--- a/services/surfaceflinger/tests/MultiDisplayLayerBounds_test.cpp
+++ b/services/surfaceflinger/tests/MultiDisplayLayerBounds_test.cpp
@@ -18,9 +18,12 @@
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wconversion"
 
+#include <common/FlagManager.h>
 #include <ui/DisplayState.h>
 
 #include "LayerTransactionTest.h"
+#include "gui/SurfaceComposerClient.h"
+#include "ui/DisplayId.h"
 
 namespace android {
 
@@ -37,7 +40,8 @@
 
         const auto ids = SurfaceComposerClient::getPhysicalDisplayIds();
         ASSERT_FALSE(ids.empty());
-        mMainDisplay = SurfaceComposerClient::getPhysicalDisplayToken(ids.front());
+        mMainDisplayId = ids.front();
+        mMainDisplay = SurfaceComposerClient::getPhysicalDisplayToken(mMainDisplayId);
         SurfaceComposerClient::getDisplayState(mMainDisplay, &mMainDisplayState);
         SurfaceComposerClient::getActiveDisplayMode(mMainDisplay, &mMainDisplayMode);
 
@@ -85,6 +89,7 @@
     ui::DisplayState mMainDisplayState;
     ui::DisplayMode mMainDisplayMode;
     sp<IBinder> mMainDisplay;
+    PhysicalDisplayId mMainDisplayId;
     sp<IBinder> mVirtualDisplay;
     sp<IGraphicBufferProducer> mProducer;
     sp<SurfaceControl> mColorLayer;
@@ -119,6 +124,9 @@
     createDisplay(mMainDisplayState.layerStackSpaceRect, ui::DEFAULT_LAYER_STACK);
     createColorLayer(ui::DEFAULT_LAYER_STACK);
 
+    sp<SurfaceControl> mirrorSc =
+            SurfaceComposerClient::getDefault()->mirrorDisplay(mMainDisplayId);
+
     asTransaction([&](Transaction& t) { t.setPosition(mColorLayer, 10, 10); });
 
     // Verify color layer renders correctly on main display and it is mirrored on the
@@ -133,6 +141,37 @@
     sc->expectColor(Rect(0, 0, 9, 9), {0, 0, 0, 255});
 }
 
+TEST_F(MultiDisplayLayerBoundsTest, RenderLayerWithPromisedFenceInMirroredVirtualDisplay) {
+    // Create a display and use a unique layerstack ID for mirrorDisplay() so
+    // the contents of the main display are mirrored on to the virtual display.
+
+    // A unique layerstack ID must be used because sharing the same layerFE
+    // with more than one display is unsupported. A unique layerstack ensures
+    // that a different layerFE is used between displays.
+    constexpr ui::LayerStack layerStack{77687666}; // ASCII for MDLB (MultiDisplayLayerBounds)
+    createDisplay(mMainDisplayState.layerStackSpaceRect, layerStack);
+    createColorLayer(ui::DEFAULT_LAYER_STACK);
+
+    sp<SurfaceControl> mirrorSc =
+            SurfaceComposerClient::getDefault()->mirrorDisplay(mMainDisplayId);
+
+    asTransaction([&](Transaction& t) {
+        t.setPosition(mColorLayer, 10, 10);
+        t.setLayerStack(mirrorSc, layerStack);
+    });
+
+    // Verify color layer renders correctly on main display and it is mirrored on the
+    // virtual display.
+    std::unique_ptr<ScreenCapture> sc;
+    ScreenCapture::captureScreen(&sc, mMainDisplay);
+    sc->expectColor(Rect(10, 10, 40, 50), mExpectedColor);
+    sc->expectColor(Rect(0, 0, 9, 9), {0, 0, 0, 255});
+
+    ScreenCapture::captureScreen(&sc, mVirtualDisplay);
+    sc->expectColor(Rect(10, 10, 40, 50), mExpectedColor);
+    sc->expectColor(Rect(0, 0, 9, 9), {0, 0, 0, 255});
+}
+
 } // namespace android
 
 // TODO(b/129481165): remove the #pragma below and fix conversion issues
diff --git a/services/surfaceflinger/tests/TransactionTestHarnesses.h b/services/surfaceflinger/tests/TransactionTestHarnesses.h
index 797a64c..87e6d3e 100644
--- a/services/surfaceflinger/tests/TransactionTestHarnesses.h
+++ b/services/surfaceflinger/tests/TransactionTestHarnesses.h
@@ -16,9 +16,11 @@
 #ifndef ANDROID_TRANSACTION_TEST_HARNESSES
 #define ANDROID_TRANSACTION_TEST_HARNESSES
 
+#include <common/FlagManager.h>
 #include <ui/DisplayState.h>
 
 #include "LayerTransactionTest.h"
+#include "ui/LayerStack.h"
 
 namespace android {
 
@@ -36,9 +38,10 @@
             case RenderPath::VIRTUAL_DISPLAY:
 
                 const auto ids = SurfaceComposerClient::getPhysicalDisplayIds();
+                const PhysicalDisplayId displayId = ids.front();
                 const auto displayToken = ids.empty()
                         ? nullptr
-                        : SurfaceComposerClient::getPhysicalDisplayToken(ids.front());
+                        : SurfaceComposerClient::getPhysicalDisplayToken(displayId);
 
                 ui::DisplayState displayState;
                 SurfaceComposerClient::getDisplayState(displayToken, &displayState);
@@ -66,11 +69,21 @@
                 vDisplay = SurfaceComposerClient::createDisplay(String8("VirtualDisplay"),
                                                                 false /*secure*/);
 
+                constexpr ui::LayerStack layerStack{
+                        848472}; // ASCII for TTH (TransactionTestHarnesses)
+                sp<SurfaceControl> mirrorSc =
+                        SurfaceComposerClient::getDefault()->mirrorDisplay(displayId);
+
                 SurfaceComposerClient::Transaction t;
                 t.setDisplaySurface(vDisplay, producer);
-                t.setDisplayLayerStack(vDisplay, ui::DEFAULT_LAYER_STACK);
                 t.setDisplayProjection(vDisplay, displayState.orientation,
                                        Rect(displayState.layerStackSpaceRect), Rect(resolution));
+                if (FlagManager::getInstance().ce_fence_promise()) {
+                    t.setDisplayLayerStack(vDisplay, layerStack);
+                    t.setLayerStack(mirrorSc, layerStack);
+                } else {
+                    t.setDisplayLayerStack(vDisplay, ui::DEFAULT_LAYER_STACK);
+                }
                 t.apply();
                 SurfaceComposerClient::Transaction().apply(true);
 
@@ -85,6 +98,15 @@
                 constexpr bool kContainsHdr = false;
                 auto sc = std::make_unique<ScreenCapture>(item.mGraphicBuffer, kContainsHdr);
                 itemConsumer->releaseBuffer(item);
+
+                // Possible race condition with destroying virtual displays, in which
+                // CompositionEngine::present may attempt to be called on the same
+                // display multiple times. The layerStack is set to invalid here so
+                // that the display is ignored if that scenario occurs.
+                if (FlagManager::getInstance().ce_fence_promise()) {
+                    t.setLayerStack(mirrorSc, ui::INVALID_LAYER_STACK);
+                    t.apply(true);
+                }
                 SurfaceComposerClient::destroyDisplay(vDisplay);
                 return sc;
         }