diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
index 8bcb1e5..4dd4f79 100644
--- a/PREUPLOAD.cfg
+++ b/PREUPLOAD.cfg
@@ -1,5 +1,6 @@
 [Builtin Hooks]
 clang_format = true
+bpfmt = true
 
 [Builtin Hooks Options]
 # Only turn on clang-format check for the following subfolders.
@@ -26,6 +27,7 @@
                services/vibratorservice/
                services/vr/
                vulkan/
+bpfmt = -d
 
 [Hook Scripts]
 owners_hook = ${REPO_ROOT}/frameworks/base/tools/aosp/aosp_sha.sh ${PREUPLOAD_COMMIT} "OWNERS$"
diff --git a/libs/battery/Android.bp b/libs/battery/Android.bp
new file mode 100644
index 0000000..c860324
--- /dev/null
+++ b/libs/battery/Android.bp
@@ -0,0 +1,37 @@
+package {
+    // See: http://go/android-license-faq
+    default_applicable_licenses: ["frameworks_native_license"],
+}
+
+cc_library {
+    name: "libbattery",
+    srcs: [
+        "LongArrayMultiStateCounter.cpp",
+    ],
+    shared_libs: [
+        "liblog",
+    ],
+    cflags: [
+        "-Werror",
+        "-Wall",
+        "-Wextra",
+    ],
+    export_include_dirs: ["."],
+}
+
+cc_test {
+    name: "libbattery_test",
+    srcs: [
+        "MultiStateCounterTest.cpp",
+        "LongArrayMultiStateCounterTest.cpp",
+    ],
+    static_libs: ["libbattery"],
+    shared_libs: [
+        "liblog",
+    ],
+    cflags: [
+        "-Werror",
+        "-Wall",
+        "-Wextra",
+    ],
+}
diff --git a/libs/battery/LongArrayMultiStateCounter.cpp b/libs/battery/LongArrayMultiStateCounter.cpp
new file mode 100644
index 0000000..68e0883
--- /dev/null
+++ b/libs/battery/LongArrayMultiStateCounter.cpp
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ * Android BPF library - public API
+ *
+ * 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.
+ */
+
+#include "LongArrayMultiStateCounter.h"
+#include <log/log.h>
+
+namespace android {
+namespace battery {
+
+template <>
+bool LongArrayMultiStateCounter::delta(const std::vector<uint64_t>& previousValue,
+                                       const std::vector<uint64_t>& newValue,
+                                       std::vector<uint64_t>* outValue) const {
+    size_t size = previousValue.size();
+    if (newValue.size() != size) {
+        ALOGE("Incorrect array size: %d, should be %d", (int)newValue.size(), (int)size);
+        return false;
+    }
+
+    bool is_delta_valid = true;
+    for (int i = size - 1; i >= 0; i--) {
+        if (newValue[i] >= previousValue[i]) {
+            (*outValue)[i] = newValue[i] - previousValue[i];
+        } else {
+            (*outValue)[i] = 0;
+            is_delta_valid = false;
+        }
+    }
+    return is_delta_valid;
+}
+
+template <>
+void LongArrayMultiStateCounter::add(std::vector<uint64_t>* value1,
+                                     const std::vector<uint64_t>& value2, const uint64_t numerator,
+                                     const uint64_t denominator) const {
+    if (numerator != denominator) {
+        for (int i = value2.size() - 1; i >= 0; i--) {
+            // The caller ensures that denominator != 0
+            (*value1)[i] += value2[i] * numerator / denominator;
+        }
+    } else {
+        for (int i = value2.size() - 1; i >= 0; i--) {
+            (*value1)[i] += value2[i];
+        }
+    }
+}
+
+template <>
+std::string LongArrayMultiStateCounter::valueToString(const std::vector<uint64_t>& v) const {
+    std::stringstream s;
+    s << "{ ";
+    bool first = true;
+    for (uint64_t n : v) {
+        if (!first) {
+            s << ", ";
+        }
+        s << n;
+        first = false;
+    }
+    s << "}";
+    return s.str();
+}
+
+} // namespace battery
+} // namespace android
diff --git a/libs/battery/LongArrayMultiStateCounter.h b/libs/battery/LongArrayMultiStateCounter.h
new file mode 100644
index 0000000..f3439f6
--- /dev/null
+++ b/libs/battery/LongArrayMultiStateCounter.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ * Android BPF library - public API
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <vector>
+#include "MultiStateCounter.h"
+
+namespace android {
+namespace battery {
+
+typedef MultiStateCounter<std::vector<uint64_t>> LongArrayMultiStateCounter;
+
+} // namespace battery
+} // namespace android
diff --git a/libs/battery/LongArrayMultiStateCounterTest.cpp b/libs/battery/LongArrayMultiStateCounterTest.cpp
new file mode 100644
index 0000000..24cb437
--- /dev/null
+++ b/libs/battery/LongArrayMultiStateCounterTest.cpp
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ * Android BPF library - public API
+ *
+ * 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.
+ */
+
+#include <gtest/gtest.h>
+#include "LongArrayMultiStateCounter.h"
+
+namespace android {
+namespace battery {
+
+class LongArrayMultiStateCounterTest : public testing::Test {};
+
+TEST_F(LongArrayMultiStateCounterTest, stateChange) {
+    LongArrayMultiStateCounter testCounter(2, 0, std::vector<uint64_t>(4), 1000);
+    testCounter.setState(1, 2000);
+    testCounter.updateValue(std::vector<uint64_t>({100, 200, 300, 400}), 3000);
+
+    // Time was split in half between the two states, so the counts will be split 50:50 too
+    EXPECT_EQ(std::vector<uint64_t>({50, 100, 150, 200}), testCounter.getCount(0));
+    EXPECT_EQ(std::vector<uint64_t>({50, 100, 150, 200}), testCounter.getCount(1));
+}
+
+TEST_F(LongArrayMultiStateCounterTest, accumulation) {
+    LongArrayMultiStateCounter testCounter(2, 0, std::vector<uint64_t>(4), 1000);
+    testCounter.setState(1, 2000);
+    testCounter.updateValue(std::vector<uint64_t>({100, 200, 300, 400}), 3000);
+    testCounter.setState(0, 4000);
+    testCounter.updateValue(std::vector<uint64_t>({200, 300, 400, 500}), 8000);
+
+    // The first delta is split 50:50:
+    //   0: {50, 100, 150, 200}
+    //   1: {50, 100, 150, 200}
+    // The second delta is split 4:1
+    //   0: {80, 80, 80, 80}
+    //   1: {20, 20, 20, 20}
+    EXPECT_EQ(std::vector<uint64_t>({130, 180, 230, 280}), testCounter.getCount(0));
+    EXPECT_EQ(std::vector<uint64_t>({70, 120, 170, 220}), testCounter.getCount(1));
+}
+
+} // namespace battery
+} // namespace android
diff --git a/libs/battery/MultiStateCounter.h b/libs/battery/MultiStateCounter.h
new file mode 100644
index 0000000..9f56b29
--- /dev/null
+++ b/libs/battery/MultiStateCounter.h
@@ -0,0 +1,182 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ * Android BPF library - public API
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <inttypes.h>
+#include <log/log.h>
+#include <time.h>
+#include <sstream>
+#include <string>
+
+/**
+ * An object that can track changes of some value over time, taking into account an additional
+ * dimension: the object's state.  As the tracked value changes, the deltas are distributed
+ * among the object states in accordance with the time spent in those states.
+ */
+namespace android {
+namespace battery {
+
+typedef uint16_t state_t;
+
+template <class T>
+class MultiStateCounter {
+    uint16_t stateCount;
+    state_t currentState;
+    time_t lastStateChangeTimestamp;
+    T emptyValue;
+    T lastValue;
+    time_t lastUpdateTimestamp;
+    T deltaValue;
+
+    struct State {
+        time_t timeInStateSinceUpdate;
+        T counter;
+    };
+
+    State* states;
+
+public:
+    MultiStateCounter(uint16_t stateCount, state_t initialState, const T& emptyValue,
+                      time_t timestamp);
+
+    virtual ~MultiStateCounter();
+
+    void setState(state_t state, time_t timestamp);
+
+    void updateValue(const T& value, time_t timestamp);
+
+    const T& getCount(state_t state);
+
+    std::string toString();
+
+private:
+    /**
+     * Subtracts previousValue from newValue and returns the result in outValue.
+     * Returns true iff the combination of previousValue and newValue is valid
+     * (newValue >= prevValue)
+     */
+    bool delta(const T& previousValue, const T& newValue, T* outValue) const;
+
+    /**
+     * Adds value2 to value1 and stores the result in value1.  Denominator is
+     * guaranteed to be non-zero.
+     */
+    void add(T* value1, const T& value2, const uint64_t numerator,
+             const uint64_t denominator) const;
+
+    std::string valueToString(const T& value) const;
+};
+
+// ---------------------- MultiStateCounter Implementation -------------------------
+// Since MultiStateCounter is a template, the implementation must be inlined.
+
+template <class T>
+MultiStateCounter<T>::MultiStateCounter(uint16_t stateCount, state_t initialState,
+                                        const T& emptyValue, time_t timestamp)
+      : stateCount(stateCount),
+        currentState(initialState),
+        lastStateChangeTimestamp(timestamp),
+        emptyValue(emptyValue),
+        lastValue(emptyValue),
+        lastUpdateTimestamp(timestamp),
+        deltaValue(emptyValue) {
+    states = new State[stateCount];
+    for (int i = 0; i < stateCount; i++) {
+        states[i].timeInStateSinceUpdate = 0;
+        states[i].counter = emptyValue;
+    }
+}
+
+template <class T>
+MultiStateCounter<T>::~MultiStateCounter() {
+    delete[] states;
+};
+
+template <class T>
+void MultiStateCounter<T>::setState(state_t state, time_t timestamp) {
+    if (timestamp >= lastStateChangeTimestamp) {
+        states[currentState].timeInStateSinceUpdate += timestamp - lastStateChangeTimestamp;
+    } else {
+        ALOGE("setState is called with an earlier timestamp: %lu, previous timestamp: %lu\n",
+              (unsigned long)timestamp, (unsigned long)lastStateChangeTimestamp);
+        // The accumulated durations have become unreliable. For example, if the timestamp
+        // sequence was 1000, 2000, 1000, 3000, if we accumulated the positive deltas,
+        // we would get 4000, which is greater than (last - first). This could lead to
+        // counts exceeding 100%.
+        for (int i = 0; i < stateCount; i++) {
+            states[i].timeInStateSinceUpdate = 0;
+        }
+    }
+    currentState = state;
+    lastStateChangeTimestamp = timestamp;
+}
+
+template <class T>
+void MultiStateCounter<T>::updateValue(const T& value, time_t timestamp) {
+    // Confirm the current state for the side-effect of updating the time-in-state
+    // counter for the current state.
+    setState(currentState, timestamp);
+
+    if (timestamp > lastUpdateTimestamp) {
+        if (delta(lastValue, value, &deltaValue)) {
+            time_t timeSinceUpdate = timestamp - lastUpdateTimestamp;
+            for (int i = 0; i < stateCount; i++) {
+                time_t timeInState = states[i].timeInStateSinceUpdate;
+                if (timeInState) {
+                    add(&states[i].counter, deltaValue, timeInState, timeSinceUpdate);
+                    states[i].timeInStateSinceUpdate = 0;
+                }
+            }
+        } else {
+            std::stringstream str;
+            str << "updateValue is called with a value " << valueToString(value)
+                << ", which is lower than the previous value " << valueToString(lastValue) << "\n";
+            ALOGE("%s", str.str().c_str());
+        }
+    } else if (timestamp < lastUpdateTimestamp) {
+        ALOGE("updateValue is called with an earlier timestamp: %lu, previous timestamp: %lu\n",
+              (unsigned long)timestamp, (unsigned long)lastUpdateTimestamp);
+    }
+    lastValue = value;
+    lastUpdateTimestamp = timestamp;
+}
+
+template <class T>
+const T& MultiStateCounter<T>::getCount(state_t state) {
+    return states[state].counter;
+}
+
+template <class T>
+std::string MultiStateCounter<T>::toString() {
+    std::stringstream str;
+    str << "currentState: " << currentState
+        << " lastStateChangeTimestamp: " << lastStateChangeTimestamp
+        << " lastUpdateTimestamp: " << lastUpdateTimestamp << " states: [";
+    for (int i = 0; i < stateCount; i++) {
+        if (i != 0) {
+            str << ", ";
+        }
+        str << i << ": time: " << states[i].timeInStateSinceUpdate
+            << " counter: " << valueToString(states[i].counter);
+    }
+    str << "]";
+    return str.str();
+}
+
+} // namespace battery
+} // namespace android
diff --git a/libs/battery/MultiStateCounterTest.cpp b/libs/battery/MultiStateCounterTest.cpp
new file mode 100644
index 0000000..942d5ca
--- /dev/null
+++ b/libs/battery/MultiStateCounterTest.cpp
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ * Android BPF library - public API
+ *
+ * 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.
+ */
+
+#include <gtest/gtest.h>
+#include "MultiStateCounter.h"
+
+namespace android {
+namespace battery {
+
+typedef MultiStateCounter<double> DoubleMultiStateCounter;
+
+template <>
+bool DoubleMultiStateCounter::delta(const double& previousValue, const double& newValue,
+                                    double* outValue) const {
+    *outValue = newValue - previousValue;
+    return *outValue >= 0;
+}
+
+template <>
+void DoubleMultiStateCounter::add(double* value1, const double& value2, const uint64_t numerator,
+                                  const uint64_t denominator) const {
+    if (numerator != denominator) {
+        // The caller ensures that denominator != 0
+        *value1 += value2 * numerator / denominator;
+    } else {
+        *value1 += value2;
+    }
+}
+
+template <>
+std::string DoubleMultiStateCounter::valueToString(const double& v) const {
+    return std::to_string(v);
+}
+
+class MultiStateCounterTest : public testing::Test {};
+
+TEST_F(MultiStateCounterTest, constructor) {
+    DoubleMultiStateCounter testCounter(3, 1, 0, 1000);
+    testCounter.setState(1, 2000);
+    testCounter.updateValue(3.14, 3000);
+
+    EXPECT_DOUBLE_EQ(0, testCounter.getCount(0));
+    EXPECT_DOUBLE_EQ(3.14, testCounter.getCount(1));
+    EXPECT_DOUBLE_EQ(0, testCounter.getCount(2));
+}
+
+TEST_F(MultiStateCounterTest, stateChange) {
+    DoubleMultiStateCounter testCounter(3, 1, 0, 0);
+    testCounter.setState(2, 1000);
+    testCounter.updateValue(6.0, 3000);
+
+    EXPECT_DOUBLE_EQ(0, testCounter.getCount(0));
+    EXPECT_DOUBLE_EQ(2.0, testCounter.getCount(1));
+    EXPECT_DOUBLE_EQ(4.0, testCounter.getCount(2));
+}
+
+TEST_F(MultiStateCounterTest, timeAdjustment_setState) {
+    DoubleMultiStateCounter testCounter(3, 1, 0, 0);
+    testCounter.setState(2, 2000);
+
+    // Time moves back
+    testCounter.setState(1, 1000);
+    testCounter.updateValue(6.0, 3000);
+
+    EXPECT_DOUBLE_EQ(0, testCounter.getCount(0));
+
+    // We were in state 1 from 0 to 2000, which was erased because the time moved back.
+    // Then from 1000 to 3000, so we expect the count to be 6 * (2000/3000)
+    EXPECT_DOUBLE_EQ(4.0, testCounter.getCount(1));
+
+    // No time was effectively accumulated for state 2, because the timestamp moved back
+    // while we were in state 2.
+    EXPECT_DOUBLE_EQ(0, testCounter.getCount(2));
+}
+
+TEST_F(MultiStateCounterTest, timeAdjustment_updateValue) {
+    DoubleMultiStateCounter testCounter(1, 0, 0, 0);
+    testCounter.updateValue(6.0, 2000);
+
+    // Time moves back. The negative delta from 2000 to 1000 is ignored
+    testCounter.updateValue(8.0, 1000);
+    testCounter.updateValue(11.0, 3000);
+
+    // The total accumulated count is:
+    //  6.0          // For the period 0-2000
+    //  +(11.0-8.0)  // For the period 1000-3000
+    EXPECT_DOUBLE_EQ(9.0, testCounter.getCount(0));
+}
+
+} // namespace battery
+} // namespace android
diff --git a/libs/input/VelocityControl.cpp b/libs/input/VelocityControl.cpp
index 2c04d42..6e991e9 100644
--- a/libs/input/VelocityControl.cpp
+++ b/libs/input/VelocityControl.cpp
@@ -18,7 +18,7 @@
 //#define LOG_NDEBUG 0
 
 // Log debug messages about acceleration.
-#define DEBUG_ACCELERATION 0
+static constexpr bool DEBUG_ACCELERATION = false;
 
 #include <math.h>
 #include <limits.h>
@@ -52,10 +52,10 @@
 void VelocityControl::move(nsecs_t eventTime, float* deltaX, float* deltaY) {
     if ((deltaX && *deltaX) || (deltaY && *deltaY)) {
         if (eventTime >= mLastMovementTime + STOP_TIME) {
-#if DEBUG_ACCELERATION
-            ALOGD("VelocityControl: stopped, last movement was %0.3fms ago",
-                    (eventTime - mLastMovementTime) * 0.000001f);
-#endif
+            if (DEBUG_ACCELERATION && mLastMovementTime != LLONG_MIN) {
+                ALOGD("VelocityControl: stopped, last movement was %0.3fms ago",
+                           (eventTime - mLastMovementTime) * 0.000001f);
+            }
             reset();
         }
 
@@ -83,19 +83,20 @@
                         * (mParameters.acceleration - 1);
             }
 
-#if DEBUG_ACCELERATION
-            ALOGD("VelocityControl(%0.3f, %0.3f, %0.3f, %0.3f): "
-                    "vx=%0.3f, vy=%0.3f, speed=%0.3f, accel=%0.3f",
-                    mParameters.scale, mParameters.lowThreshold, mParameters.highThreshold,
-                    mParameters.acceleration,
-                    vx, vy, speed, scale / mParameters.scale);
-#endif
+            if (DEBUG_ACCELERATION) {
+                ALOGD("VelocityControl(%0.3f, %0.3f, %0.3f, %0.3f): "
+                        "vx=%0.3f, vy=%0.3f, speed=%0.3f, accel=%0.3f",
+                        mParameters.scale, mParameters.lowThreshold, mParameters.highThreshold,
+                        mParameters.acceleration,
+                        vx, vy, speed, scale / mParameters.scale);
+            }
+
         } else {
-#if DEBUG_ACCELERATION
-            ALOGD("VelocityControl(%0.3f, %0.3f, %0.3f, %0.3f): unknown velocity",
-                    mParameters.scale, mParameters.lowThreshold, mParameters.highThreshold,
-                    mParameters.acceleration);
-#endif
+            if (DEBUG_ACCELERATION) {
+                ALOGD("VelocityControl(%0.3f, %0.3f, %0.3f, %0.3f): unknown velocity",
+                        mParameters.scale, mParameters.lowThreshold, mParameters.highThreshold,
+                        mParameters.acceleration);
+            }
         }
 
         if (deltaX) {
diff --git a/libs/renderengine/OWNERS b/libs/renderengine/OWNERS
index c478506..5d23a5e 100644
--- a/libs/renderengine/OWNERS
+++ b/libs/renderengine/OWNERS
@@ -1,3 +1,4 @@
+adyabr@google.com
 alecmouri@google.com
 djsollen@google.com
 jreck@google.com
diff --git a/libs/renderengine/RenderEngine.cpp b/libs/renderengine/RenderEngine.cpp
index 0c5a851..2174df5 100644
--- a/libs/renderengine/RenderEngine.cpp
+++ b/libs/renderengine/RenderEngine.cpp
@@ -95,5 +95,16 @@
                         "output buffer not gpu writeable");
 }
 
+std::future<RenderEngineResult> RenderEngine::drawLayers(
+        const DisplaySettings& display, const std::vector<const LayerSettings*>& layers,
+        const std::shared_ptr<ExternalTexture>& buffer, const bool useFramebufferCache,
+        base::unique_fd&& bufferFence) {
+    const auto resultPromise = std::make_shared<std::promise<RenderEngineResult>>();
+    std::future<RenderEngineResult> resultFuture = resultPromise->get_future();
+    drawLayersInternal(std::move(resultPromise), display, layers, buffer, useFramebufferCache,
+                       std::move(bufferFence));
+    return resultFuture;
+}
+
 } // namespace renderengine
 } // namespace android
diff --git a/libs/renderengine/gl/GLESRenderEngine.cpp b/libs/renderengine/gl/GLESRenderEngine.cpp
index b1e1014..2375cb7 100644
--- a/libs/renderengine/gl/GLESRenderEngine.cpp
+++ b/libs/renderengine/gl/GLESRenderEngine.cpp
@@ -1078,15 +1078,16 @@
     return image;
 }
 
-status_t GLESRenderEngine::drawLayers(const DisplaySettings& display,
-                                      const std::vector<const LayerSettings*>& layers,
-                                      const std::shared_ptr<ExternalTexture>& buffer,
-                                      const bool useFramebufferCache, base::unique_fd&& bufferFence,
-                                      base::unique_fd* drawFence) {
+void GLESRenderEngine::drawLayersInternal(
+        const std::shared_ptr<std::promise<RenderEngineResult>>&& resultPromise,
+        const DisplaySettings& display, const std::vector<const LayerSettings*>& layers,
+        const std::shared_ptr<ExternalTexture>& buffer, const bool useFramebufferCache,
+        base::unique_fd&& bufferFence) {
     ATRACE_CALL();
     if (layers.empty()) {
         ALOGV("Drawing empty layer stack");
-        return NO_ERROR;
+        resultPromise->set_value({NO_ERROR, base::unique_fd()});
+        return;
     }
 
     if (bufferFence.get() >= 0) {
@@ -1100,7 +1101,8 @@
 
     if (buffer == nullptr) {
         ALOGE("No output buffer provided. Aborting GPU composition.");
-        return BAD_VALUE;
+        resultPromise->set_value({BAD_VALUE, base::unique_fd()});
+        return;
     }
 
     validateOutputBufferUsage(buffer->getBuffer());
@@ -1128,7 +1130,8 @@
             ALOGE("Failed to bind framebuffer! Aborting GPU composition for buffer (%p).",
                   buffer->getBuffer()->handle);
             checkErrors();
-            return fbo->getStatus();
+            resultPromise->set_value({fbo->getStatus(), base::unique_fd()});
+            return;
         }
         setViewportAndProjection(display.physicalDisplay, display.clip);
     } else {
@@ -1139,7 +1142,8 @@
             ALOGE("Failed to prepare blur filter! Aborting GPU composition for buffer (%p).",
                   buffer->getBuffer()->handle);
             checkErrors();
-            return status;
+            resultPromise->set_value({status, base::unique_fd()});
+            return;
         }
     }
 
@@ -1172,7 +1176,8 @@
                 ALOGE("Failed to render blur effect! Aborting GPU composition for buffer (%p).",
                       buffer->getBuffer()->handle);
                 checkErrors("Can't render first blur pass");
-                return status;
+                resultPromise->set_value({status, base::unique_fd()});
+                return;
             }
 
             if (blurLayers.size() == 0) {
@@ -1194,7 +1199,8 @@
                 ALOGE("Failed to bind framebuffer! Aborting GPU composition for buffer (%p).",
                       buffer->getBuffer()->handle);
                 checkErrors("Can't bind native framebuffer");
-                return status;
+                resultPromise->set_value({status, base::unique_fd()});
+                return;
             }
 
             status = mBlurFilter->render(blurLayersSize > 1);
@@ -1202,7 +1208,8 @@
                 ALOGE("Failed to render blur effect! Aborting GPU composition for buffer (%p).",
                       buffer->getBuffer()->handle);
                 checkErrors("Can't render blur filter");
-                return status;
+                resultPromise->set_value({status, base::unique_fd()});
+                return;
             }
         }
 
@@ -1289,30 +1296,31 @@
         }
     }
 
-    if (drawFence != nullptr) {
-        *drawFence = flush();
-    }
+    base::unique_fd drawFence = flush();
+
     // If flush failed or we don't support native fences, we need to force the
     // gl command stream to be executed.
-    if (drawFence == nullptr || drawFence->get() < 0) {
+    if (drawFence.get() < 0) {
         bool success = finish();
         if (!success) {
             ALOGE("Failed to flush RenderEngine commands");
             checkErrors();
             // Chances are, something illegal happened (either the caller passed
             // us bad parameters, or we messed up our shader generation).
-            return INVALID_OPERATION;
+            resultPromise->set_value({INVALID_OPERATION, std::move(drawFence)});
+            return;
         }
         mLastDrawFence = nullptr;
     } else {
         // The caller takes ownership of drawFence, so we need to duplicate the
         // fd here.
-        mLastDrawFence = new Fence(dup(drawFence->get()));
+        mLastDrawFence = new Fence(dup(drawFence.get()));
     }
     mPriorResourcesCleaned = false;
 
     checkErrors();
-    return NO_ERROR;
+    resultPromise->set_value({NO_ERROR, std::move(drawFence)});
+    return;
 }
 
 void GLESRenderEngine::setViewportAndProjection(Rect viewport, Rect clip) {
diff --git a/libs/renderengine/gl/GLESRenderEngine.h b/libs/renderengine/gl/GLESRenderEngine.h
index 14627ce..c4adfdf 100644
--- a/libs/renderengine/gl/GLESRenderEngine.h
+++ b/libs/renderengine/gl/GLESRenderEngine.h
@@ -63,11 +63,6 @@
     bool isProtected() const override { return mInProtectedContext; }
     bool supportsProtectedContent() const override;
     void useProtectedContext(bool useProtectedContext) override;
-    status_t drawLayers(const DisplaySettings& display,
-                        const std::vector<const LayerSettings*>& layers,
-                        const std::shared_ptr<ExternalTexture>& buffer,
-                        const bool useFramebufferCache, base::unique_fd&& bufferFence,
-                        base::unique_fd* drawFence) override;
     void cleanupPostRender() override;
     int getContextPriority() override;
     bool supportsBackgroundBlur() override { return mBlurFilter != nullptr; }
@@ -107,6 +102,11 @@
             EXCLUDES(mRenderingMutex);
     void unmapExternalTextureBuffer(const sp<GraphicBuffer>& buffer) EXCLUDES(mRenderingMutex);
     bool canSkipPostRenderCleanup() const override;
+    void drawLayersInternal(const std::shared_ptr<std::promise<RenderEngineResult>>&& resultPromise,
+                            const DisplaySettings& display,
+                            const std::vector<const LayerSettings*>& layers,
+                            const std::shared_ptr<ExternalTexture>& buffer,
+                            const bool useFramebufferCache, base::unique_fd&& bufferFence) override;
 
 private:
     friend class BindNativeBufferAsFramebuffer;
diff --git a/libs/renderengine/include/renderengine/RenderEngine.h b/libs/renderengine/include/renderengine/RenderEngine.h
index 967cf5d..701c1f2 100644
--- a/libs/renderengine/include/renderengine/RenderEngine.h
+++ b/libs/renderengine/include/renderengine/RenderEngine.h
@@ -68,6 +68,7 @@
 class Mesh;
 class Texture;
 struct RenderEngineCreationArgs;
+struct RenderEngineResult;
 
 namespace threaded {
 class RenderEngineThreaded;
@@ -156,17 +157,12 @@
     // parameter does nothing.
     // @param bufferFence Fence signalling that the buffer is ready to be drawn
     // to.
-    // @param drawFence A pointer to a fence, which will fire when the buffer
-    // has been drawn to and is ready to be examined. The fence will be
-    // initialized by this method. The caller will be responsible for owning the
-    // fence.
-    // @return An error code indicating whether drawing was successful. For
-    // now, this always returns NO_ERROR.
-    virtual status_t drawLayers(const DisplaySettings& display,
-                                const std::vector<const LayerSettings*>& layers,
-                                const std::shared_ptr<ExternalTexture>& buffer,
-                                const bool useFramebufferCache, base::unique_fd&& bufferFence,
-                                base::unique_fd* drawFence) = 0;
+    // @return A future object of RenderEngineResult struct indicating whether
+    // drawing was successful in async mode.
+    virtual std::future<RenderEngineResult> drawLayers(
+            const DisplaySettings& display, const std::vector<const LayerSettings*>& layers,
+            const std::shared_ptr<ExternalTexture>& buffer, const bool useFramebufferCache,
+            base::unique_fd&& bufferFence);
 
     // Clean-up method that should be called on the main thread after the
     // drawFence returned by drawLayers fires. This method will free up
@@ -232,6 +228,12 @@
     friend class threaded::RenderEngineThreaded;
     friend class RenderEngineTest_cleanupPostRender_cleansUpOnce_Test;
     const RenderEngineType mRenderEngineType;
+
+    virtual void drawLayersInternal(
+            const std::shared_ptr<std::promise<RenderEngineResult>>&& resultPromise,
+            const DisplaySettings& display, const std::vector<const LayerSettings*>& layers,
+            const std::shared_ptr<ExternalTexture>& buffer, const bool useFramebufferCache,
+            base::unique_fd&& bufferFence) = 0;
 };
 
 struct RenderEngineCreationArgs {
@@ -318,6 +320,13 @@
             RenderEngine::RenderEngineType::SKIA_GL_THREADED;
 };
 
+struct RenderEngineResult {
+    // status indicates if drawing is successful
+    status_t status;
+    // drawFence will fire when the buffer has been drawn to and is ready to be examined.
+    base::unique_fd drawFence;
+};
+
 } // namespace renderengine
 } // namespace android
 
diff --git a/libs/renderengine/include/renderengine/mock/RenderEngine.h b/libs/renderengine/include/renderengine/mock/RenderEngine.h
index 0be3ba6..a7e6809 100644
--- a/libs/renderengine/include/renderengine/mock/RenderEngine.h
+++ b/libs/renderengine/include/renderengine/mock/RenderEngine.h
@@ -47,10 +47,15 @@
     MOCK_METHOD1(useProtectedContext, void(bool));
     MOCK_METHOD0(cleanupPostRender, void());
     MOCK_CONST_METHOD0(canSkipPostRenderCleanup, bool());
-    MOCK_METHOD6(drawLayers,
-                 status_t(const DisplaySettings&, const std::vector<const LayerSettings*>&,
-                          const std::shared_ptr<ExternalTexture>&, const bool, base::unique_fd&&,
-                          base::unique_fd*));
+    MOCK_METHOD5(drawLayers,
+                 std::future<RenderEngineResult>(const DisplaySettings&,
+                                                 const std::vector<const LayerSettings*>&,
+                                                 const std::shared_ptr<ExternalTexture>&,
+                                                 const bool, base::unique_fd&&));
+    MOCK_METHOD6(drawLayersInternal,
+                 void(const std::shared_ptr<std::promise<RenderEngineResult>>&&,
+                      const DisplaySettings&, const std::vector<const LayerSettings*>&,
+                      const std::shared_ptr<ExternalTexture>&, const bool, base::unique_fd&&));
     MOCK_METHOD0(cleanFramebufferCache, void());
     MOCK_METHOD0(getContextPriority, int());
     MOCK_METHOD0(supportsBackgroundBlur, bool());
diff --git a/libs/renderengine/skia/Cache.cpp b/libs/renderengine/skia/Cache.cpp
index 01df6a6..c4fa1bb 100644
--- a/libs/renderengine/skia/Cache.cpp
+++ b/libs/renderengine/skia/Cache.cpp
@@ -95,7 +95,6 @@
             .alpha = 1,
     };
 
-    base::unique_fd drawFence;
     auto layers = std::vector<const LayerSettings*>{&layer, &caster};
     // Four combinations of settings are used (two transforms here, and drawShadowLayers is
     // called with two different destination data spaces) They're all rounded rect.
@@ -116,7 +115,7 @@
         layer.geometry.positionTransform = transform;
         caster.geometry.positionTransform = transform;
         renderengine->drawLayers(display, layers, dstTexture, kUseFrameBufferCache,
-                                base::unique_fd(), &drawFence);
+                                 base::unique_fd());
     }
 }
 
@@ -141,7 +140,6 @@
                                           }},
     };
 
-    base::unique_fd drawFence;
     auto layers = std::vector<const LayerSettings*>{&layer};
     for (auto dataspace : {kDestDataSpace, kOtherDataSpace}) {
         layer.sourceDataspace = dataspace;
@@ -155,7 +153,7 @@
                 for (auto alpha : {half(.2f), half(1.0f)}) {
                     layer.alpha = alpha;
                     renderengine->drawLayers(display, layers, dstTexture, kUseFrameBufferCache,
-                                             base::unique_fd(), &drawFence);
+                                             base::unique_fd());
                 }
             }
         }
@@ -178,14 +176,13 @@
             .alpha = 0.5,
     };
 
-    base::unique_fd drawFence;
     auto layers = std::vector<const LayerSettings*>{&layer};
     for (auto transform : {mat4(), kScaleAndTranslate}) {
         layer.geometry.positionTransform = transform;
         for (float roundedCornersRadius : {0.0f, 50.f}) {
             layer.geometry.roundedCornersRadius = roundedCornersRadius;
             renderengine->drawLayers(display, layers, dstTexture, kUseFrameBufferCache,
-                                     base::unique_fd(), &drawFence);
+                                     base::unique_fd());
         }
     }
 }
@@ -204,13 +201,12 @@
             .skipContentDraw = true,
     };
 
-    base::unique_fd drawFence;
     auto layers = std::vector<const LayerSettings*>{&layer};
     // Different blur code is invoked for radii less and greater than 30 pixels
     for (int radius : {9, 60}) {
         layer.backgroundBlurRadius = radius;
         renderengine->drawLayers(display, layers, dstTexture, kUseFrameBufferCache,
-                                 base::unique_fd(), &drawFence);
+                                 base::unique_fd());
     }
 }
 
@@ -246,7 +242,6 @@
                     },
     };
 
-    base::unique_fd drawFence;
     auto layers = std::vector<const LayerSettings*>{&layer};
     for (auto pixelSource : {bufferSource, bufferOpaque, colorSource}) {
         layer.source = pixelSource;
@@ -258,7 +253,7 @@
                 for (float alpha : {0.5f, 1.f}) {
                     layer.alpha = alpha,
                     renderengine->drawLayers(display, layers, dstTexture, kUseFrameBufferCache,
-                                             base::unique_fd(), &drawFence);
+                                             base::unique_fd());
                 }
             }
         }
@@ -294,10 +289,8 @@
 
     };
 
-    base::unique_fd drawFence;
     auto layers = std::vector<const LayerSettings*>{&layer};
-    renderengine->drawLayers(display, layers, dstTexture, kUseFrameBufferCache,
-                             base::unique_fd(), &drawFence);
+    renderengine->drawLayers(display, layers, dstTexture, kUseFrameBufferCache, base::unique_fd());
 }
 
 static void drawHolePunchLayer(SkiaRenderEngine* renderengine, const DisplaySettings& display,
@@ -324,10 +317,8 @@
 
     };
 
-    base::unique_fd drawFence;
     auto layers = std::vector<const LayerSettings*>{&layer};
-    renderengine->drawLayers(display, layers, dstTexture, kUseFrameBufferCache,
-                            base::unique_fd(), &drawFence);
+    renderengine->drawLayers(display, layers, dstTexture, kUseFrameBufferCache, base::unique_fd());
 }
 
 //
@@ -398,7 +389,10 @@
             drawBlurLayers(renderengine, display, dstTexture);
         }
 
-        // should be the same as AHARDWAREBUFFER_USAGE_GPU_SAMPLED_IMAGE;
+        // The majority of skia shaders needed by RenderEngine are related to sampling images.
+        // These need to be generated with various source textures.
+        // Make a list of applicable sources.
+        // GRALLOC_USAGE_HW_TEXTURE should be the same as AHARDWAREBUFFER_USAGE_GPU_SAMPLED_IMAGE.
         const int64_t usageExternal = GRALLOC_USAGE_HW_TEXTURE;
         sp<GraphicBuffer> externalBuffer =
                 new GraphicBuffer(displayRect.width(), displayRect.height(), PIXEL_FORMAT_RGBA_8888,
@@ -406,24 +400,24 @@
         const auto externalTexture =
                 std::make_shared<ExternalTexture>(externalBuffer, *renderengine,
                                                   ExternalTexture::Usage::READABLE);
+        std::vector<const std::shared_ptr<ExternalTexture>> textures =
+            {srcTexture, externalTexture};
 
-        // Another external texture with a different pixel format triggers useIsOpaqueWorkaround
+        // Another external texture with a different pixel format triggers useIsOpaqueWorkaround.
+        // It doesn't have to be f16, but it can't be the usual 8888.
         sp<GraphicBuffer> f16ExternalBuffer =
                 new GraphicBuffer(displayRect.width(), displayRect.height(), PIXEL_FORMAT_RGBA_FP16,
                                   1, usageExternal, "primeShaderCache_external_f16");
-        const auto f16ExternalTexture =
+        // The F16 texture may not be usable on all devices, so check first that it was created.
+        status_t error = f16ExternalBuffer->initCheck();
+        if (!error) {
+            const auto f16ExternalTexture =
                 std::make_shared<ExternalTexture>(f16ExternalBuffer, *renderengine,
                                                   ExternalTexture::Usage::READABLE);
+            textures.push_back(f16ExternalTexture);
+        }
 
-        // The majority of shaders are related to sampling images.
-        // These need to be generated with various source textures
-        // The F16 texture may not be usable on all devices, so check first that it was created with
-        // the requested usage bit.
-        auto textures = {srcTexture, externalTexture};
-        auto texturesWithF16 = {srcTexture, externalTexture, f16ExternalTexture};
-        bool canUsef16 = f16ExternalBuffer->getUsage() & GRALLOC_USAGE_HW_TEXTURE;
-
-        for (auto texture : canUsef16 ? texturesWithF16 : textures) {
+        for (auto texture : textures) {
             drawImageLayers(renderengine, display, dstTexture, texture);
             // Draw layers for b/185569240.
             drawClippedLayers(renderengine, display, dstTexture, texture);
@@ -436,8 +430,10 @@
                 .source = PixelSource{.solidColor = half3(0.f, 0.f, 0.f)},
         };
         auto layers = std::vector<const LayerSettings*>{&layer};
-        renderengine->drawLayers(display, layers, dstTexture, kUseFrameBufferCache,
-                             base::unique_fd(), nullptr); // null drawFence makes it synchronous
+        // call get() to make it synchronous
+        renderengine
+                ->drawLayers(display, layers, dstTexture, kUseFrameBufferCache, base::unique_fd())
+                .get();
 
         const nsecs_t timeAfter = systemTime();
         const float compileTimeMs = static_cast<float>(timeAfter - timeBefore) / 1.0E6;
diff --git a/libs/renderengine/skia/SkiaGLRenderEngine.cpp b/libs/renderengine/skia/SkiaGLRenderEngine.cpp
index 9fbbdc3..052c61f 100644
--- a/libs/renderengine/skia/SkiaGLRenderEngine.cpp
+++ b/libs/renderengine/skia/SkiaGLRenderEngine.cpp
@@ -713,17 +713,18 @@
     return roundedRect;
 }
 
-status_t SkiaGLRenderEngine::drawLayers(const DisplaySettings& display,
-                                        const std::vector<const LayerSettings*>& layers,
-                                        const std::shared_ptr<ExternalTexture>& buffer,
-                                        const bool /*useFramebufferCache*/,
-                                        base::unique_fd&& bufferFence, base::unique_fd* drawFence) {
+void SkiaGLRenderEngine::drawLayersInternal(
+        const std::shared_ptr<std::promise<RenderEngineResult>>&& resultPromise,
+        const DisplaySettings& display, const std::vector<const LayerSettings*>& layers,
+        const std::shared_ptr<ExternalTexture>& buffer, const bool /*useFramebufferCache*/,
+        base::unique_fd&& bufferFence) {
     ATRACE_NAME("SkiaGL::drawLayers");
 
     std::lock_guard<std::mutex> lock(mRenderingMutex);
     if (layers.empty()) {
         ALOGV("Drawing empty layer stack");
-        return NO_ERROR;
+        resultPromise->set_value({NO_ERROR, base::unique_fd()});
+        return;
     }
 
     if (bufferFence.get() >= 0) {
@@ -736,7 +737,8 @@
     }
     if (buffer == nullptr) {
         ALOGE("No output buffer provided. Aborting GPU composition.");
-        return BAD_VALUE;
+        resultPromise->set_value({BAD_VALUE, base::unique_fd()});
+        return;
     }
 
     validateOutputBufferUsage(buffer->getBuffer());
@@ -765,7 +767,8 @@
     SkCanvas* dstCanvas = mCapture->tryCapture(dstSurface.get());
     if (dstCanvas == nullptr) {
         ALOGE("Cannot acquire canvas from Skia.");
-        return BAD_VALUE;
+        resultPromise->set_value({BAD_VALUE, base::unique_fd()});
+        return;
     }
 
     // setup color filter if necessary
@@ -1094,13 +1097,11 @@
         activeSurface->flush();
     }
 
-    if (drawFence != nullptr) {
-        *drawFence = flush();
-    }
+    base::unique_fd drawFence = flush();
 
     // If flush failed or we don't support native fences, we need to force the
     // gl command stream to be executed.
-    bool requireSync = drawFence == nullptr || drawFence->get() < 0;
+    bool requireSync = drawFence.get() < 0;
     if (requireSync) {
         ATRACE_BEGIN("Submit(sync=true)");
     } else {
@@ -1112,11 +1113,13 @@
         ALOGE("Failed to flush RenderEngine commands");
         // Chances are, something illegal happened (either the caller passed
         // us bad parameters, or we messed up our shader generation).
-        return INVALID_OPERATION;
+        resultPromise->set_value({INVALID_OPERATION, std::move(drawFence)});
+        return;
     }
 
     // checkErrors();
-    return NO_ERROR;
+    resultPromise->set_value({NO_ERROR, std::move(drawFence)});
+    return;
 }
 
 inline SkRect SkiaGLRenderEngine::getSkRect(const FloatRect& rect) {
diff --git a/libs/renderengine/skia/SkiaGLRenderEngine.h b/libs/renderengine/skia/SkiaGLRenderEngine.h
index cc91948..0b46705 100644
--- a/libs/renderengine/skia/SkiaGLRenderEngine.h
+++ b/libs/renderengine/skia/SkiaGLRenderEngine.h
@@ -54,11 +54,6 @@
     ~SkiaGLRenderEngine() override EXCLUDES(mRenderingMutex);
 
     std::future<void> primeCache() override;
-    status_t drawLayers(const DisplaySettings& display,
-                        const std::vector<const LayerSettings*>& layers,
-                        const std::shared_ptr<ExternalTexture>& buffer,
-                        const bool useFramebufferCache, base::unique_fd&& bufferFence,
-                        base::unique_fd* drawFence) override;
     void cleanupPostRender() override;
     void cleanFramebufferCache() override{};
     int getContextPriority() override;
@@ -77,6 +72,11 @@
     void mapExternalTextureBuffer(const sp<GraphicBuffer>& buffer, bool isRenderable) override;
     void unmapExternalTextureBuffer(const sp<GraphicBuffer>& buffer) override;
     bool canSkipPostRenderCleanup() const override;
+    void drawLayersInternal(const std::shared_ptr<std::promise<RenderEngineResult>>&& resultPromise,
+                            const DisplaySettings& display,
+                            const std::vector<const LayerSettings*>& layers,
+                            const std::shared_ptr<ExternalTexture>& buffer,
+                            const bool useFramebufferCache, base::unique_fd&& bufferFence) override;
 
 private:
     static EGLConfig chooseEglConfig(EGLDisplay display, int format, bool logConfig);
diff --git a/libs/renderengine/skia/SkiaRenderEngine.h b/libs/renderengine/skia/SkiaRenderEngine.h
index 7cd9eca..f61653b 100644
--- a/libs/renderengine/skia/SkiaRenderEngine.h
+++ b/libs/renderengine/skia/SkiaRenderEngine.h
@@ -44,14 +44,6 @@
     virtual void deleteTextures(size_t /*count*/, uint32_t const* /*names*/) override{};
     virtual bool isProtected() const override { return false; } // mInProtectedContext; }
     virtual bool supportsProtectedContent() const override { return false; };
-    virtual status_t drawLayers(const DisplaySettings& /*display*/,
-                                const std::vector<const LayerSettings*>& /*layers*/,
-                                const std::shared_ptr<ExternalTexture>& /*buffer*/,
-                                const bool /*useFramebufferCache*/,
-                                base::unique_fd&& /*bufferFence*/,
-                                base::unique_fd* /*drawFence*/) override {
-        return 0;
-    };
     virtual int getContextPriority() override { return 0; }
     virtual void assertShadersCompiled(int numShaders) {}
     virtual int reportShadersCompiled() { return 0; }
@@ -60,6 +52,14 @@
     virtual void mapExternalTextureBuffer(const sp<GraphicBuffer>& /*buffer*/,
                                           bool /*isRenderable*/) override = 0;
     virtual void unmapExternalTextureBuffer(const sp<GraphicBuffer>& /*buffer*/) override = 0;
+
+    virtual void drawLayersInternal(
+            const std::shared_ptr<std::promise<RenderEngineResult>>&& resultPromise,
+            const DisplaySettings& display, const std::vector<const LayerSettings*>& layers,
+            const std::shared_ptr<ExternalTexture>& buffer, const bool useFramebufferCache,
+            base::unique_fd&& bufferFence) override {
+        resultPromise->set_value({NO_ERROR, base::unique_fd()});
+    };
 };
 
 } // namespace skia
diff --git a/libs/renderengine/tests/RenderEngineTest.cpp b/libs/renderengine/tests/RenderEngineTest.cpp
index 33053a0..b3b726d 100644
--- a/libs/renderengine/tests/RenderEngineTest.cpp
+++ b/libs/renderengine/tests/RenderEngineTest.cpp
@@ -419,9 +419,10 @@
 
     void invokeDraw(renderengine::DisplaySettings settings,
                     std::vector<const renderengine::LayerSettings*> layers) {
-        base::unique_fd fence;
-        status_t status =
-                mRE->drawLayers(settings, layers, mBuffer, true, base::unique_fd(), &fence);
+        std::future<renderengine::RenderEngineResult> result =
+                mRE->drawLayers(settings, layers, mBuffer, true, base::unique_fd());
+        ASSERT_TRUE(result.valid());
+        auto [status, fence] = result.get();
 
         int fd = fence.release();
         if (fd >= 0) {
@@ -1312,9 +1313,11 @@
     layer.geometry.boundaries = fullscreenRect().toFloatRect();
     BufferSourceVariant<ForceOpaqueBufferVariant>::fillColor(layer, 1.0f, 0.0f, 0.0f, this);
     layers.push_back(&layer);
-    base::unique_fd fence;
-    status_t status = mRE->drawLayers(settings, layers, nullptr, true, base::unique_fd(), &fence);
+    std::future<renderengine::RenderEngineResult> result =
+            mRE->drawLayers(settings, layers, nullptr, true, base::unique_fd());
 
+    ASSERT_TRUE(result.valid());
+    auto [status, _] = result.get();
     ASSERT_EQ(BAD_VALUE, status);
 }
 
@@ -1333,7 +1336,10 @@
     layer.alpha = 1.0;
     layers.push_back(&layer);
 
-    status_t status = mRE->drawLayers(settings, layers, mBuffer, true, base::unique_fd(), nullptr);
+    std::future<renderengine::RenderEngineResult> result =
+            mRE->drawLayers(settings, layers, mBuffer, true, base::unique_fd());
+    ASSERT_TRUE(result.valid());
+    auto [status, _] = result.get();
     ASSERT_EQ(NO_ERROR, status);
     expectBufferColor(fullscreenRect(), 255, 0, 0, 255);
 }
@@ -1360,7 +1366,10 @@
     layer.alpha = 1.0;
     layers.push_back(&layer);
 
-    status_t status = mRE->drawLayers(settings, layers, mBuffer, false, base::unique_fd(), nullptr);
+    std::future<renderengine::RenderEngineResult> result =
+            mRE->drawLayers(settings, layers, mBuffer, false, base::unique_fd());
+    ASSERT_TRUE(result.valid());
+    auto [status, _] = result.get();
     ASSERT_EQ(NO_ERROR, status);
     ASSERT_FALSE(mGLESRE->isFramebufferImageCachedForTesting(mBuffer->getBuffer()->getId()));
     expectBufferColor(fullscreenRect(), 255, 0, 0, 255);
@@ -1760,10 +1769,17 @@
     layer.alpha = 1.0;
     layers.push_back(&layer);
 
-    base::unique_fd fenceOne;
-    mRE->drawLayers(settings, layers, mBuffer, true, base::unique_fd(), &fenceOne);
-    base::unique_fd fenceTwo;
-    mRE->drawLayers(settings, layers, mBuffer, true, std::move(fenceOne), &fenceTwo);
+    std::future<renderengine::RenderEngineResult> resultOne =
+            mRE->drawLayers(settings, layers, mBuffer, true, base::unique_fd());
+    ASSERT_TRUE(resultOne.valid());
+    auto [statusOne, fenceOne] = resultOne.get();
+    ASSERT_EQ(NO_ERROR, statusOne);
+
+    std::future<renderengine::RenderEngineResult> resultTwo =
+            mRE->drawLayers(settings, layers, mBuffer, true, std::move(fenceOne));
+    ASSERT_TRUE(resultTwo.valid());
+    auto [statusTwo, fenceTwo] = resultTwo.get();
+    ASSERT_EQ(NO_ERROR, statusTwo);
 
     const int fd = fenceTwo.get();
     if (fd >= 0) {
diff --git a/libs/renderengine/tests/RenderEngineThreadedTest.cpp b/libs/renderengine/tests/RenderEngineThreadedTest.cpp
index 830f463..99250c1 100644
--- a/libs/renderengine/tests/RenderEngineThreadedTest.cpp
+++ b/libs/renderengine/tests/RenderEngineThreadedTest.cpp
@@ -169,6 +169,7 @@
     status_t result = mThreadedRE->supportsBackgroundBlur();
     ASSERT_EQ(true, result);
 }
+
 TEST_F(RenderEngineThreadedTest, drawLayers) {
     renderengine::DisplaySettings settings;
     std::vector<const renderengine::LayerSettings*> layers;
@@ -177,17 +178,22 @@
                                            renderengine::ExternalTexture::Usage::READABLE |
                                                    renderengine::ExternalTexture::Usage::WRITEABLE);
     base::unique_fd bufferFence;
-    base::unique_fd drawFence;
 
-    EXPECT_CALL(*mRenderEngine, drawLayers)
-            .WillOnce([](const renderengine::DisplaySettings&,
-                         const std::vector<const renderengine::LayerSettings*>&,
-                         const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
-                         base::unique_fd&&, base::unique_fd*) -> status_t { return NO_ERROR; });
+    EXPECT_CALL(*mRenderEngine, drawLayersInternal)
+            .WillOnce([&](const std::shared_ptr<std::promise<renderengine::RenderEngineResult>>&&
+                                  resultPromise,
+                          const renderengine::DisplaySettings&,
+                          const std::vector<const renderengine::LayerSettings*>&,
+                          const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                          base::unique_fd &&) -> void {
+                resultPromise->set_value({NO_ERROR, base::unique_fd()});
+            });
 
-    status_t result = mThreadedRE->drawLayers(settings, layers, buffer, false,
-                                              std::move(bufferFence), &drawFence);
-    ASSERT_EQ(NO_ERROR, result);
+    std::future<renderengine::RenderEngineResult> result =
+            mThreadedRE->drawLayers(settings, layers, buffer, false, std::move(bufferFence));
+    ASSERT_TRUE(result.valid());
+    auto [status, _] = result.get();
+    ASSERT_EQ(NO_ERROR, status);
 }
 
 } // namespace android
diff --git a/libs/renderengine/threaded/RenderEngineThreaded.cpp b/libs/renderengine/threaded/RenderEngineThreaded.cpp
index 8e666d5..9a8201f 100644
--- a/libs/renderengine/threaded/RenderEngineThreaded.cpp
+++ b/libs/renderengine/threaded/RenderEngineThreaded.cpp
@@ -304,27 +304,33 @@
     return mRenderEngine->canSkipPostRenderCleanup();
 }
 
-status_t RenderEngineThreaded::drawLayers(const DisplaySettings& display,
-                                          const std::vector<const LayerSettings*>& layers,
-                                          const std::shared_ptr<ExternalTexture>& buffer,
-                                          const bool useFramebufferCache,
-                                          base::unique_fd&& bufferFence,
-                                          base::unique_fd* drawFence) {
+void RenderEngineThreaded::drawLayersInternal(
+        const std::shared_ptr<std::promise<RenderEngineResult>>&& resultPromise,
+        const DisplaySettings& display, const std::vector<const LayerSettings*>& layers,
+        const std::shared_ptr<ExternalTexture>& buffer, const bool useFramebufferCache,
+        base::unique_fd&& bufferFence) {
+    resultPromise->set_value({NO_ERROR, base::unique_fd()});
+    return;
+}
+
+std::future<RenderEngineResult> RenderEngineThreaded::drawLayers(
+        const DisplaySettings& display, const std::vector<const LayerSettings*>& layers,
+        const std::shared_ptr<ExternalTexture>& buffer, const bool useFramebufferCache,
+        base::unique_fd&& bufferFence) {
     ATRACE_CALL();
-    std::promise<status_t> resultPromise;
-    std::future<status_t> resultFuture = resultPromise.get_future();
+    const auto resultPromise = std::make_shared<std::promise<RenderEngineResult>>();
+    std::future<RenderEngineResult> resultFuture = resultPromise->get_future();
     {
         std::lock_guard lock(mThreadMutex);
-        mFunctionCalls.push([&resultPromise, &display, &layers, &buffer, useFramebufferCache,
-                             &bufferFence, &drawFence](renderengine::RenderEngine& instance) {
+        mFunctionCalls.push([resultPromise, &display, &layers, &buffer, useFramebufferCache,
+                             &bufferFence](renderengine::RenderEngine& instance) {
             ATRACE_NAME("REThreaded::drawLayers");
-            status_t status = instance.drawLayers(display, layers, buffer, useFramebufferCache,
-                                                  std::move(bufferFence), drawFence);
-            resultPromise.set_value(status);
+            instance.drawLayersInternal(std::move(resultPromise), display, layers, buffer,
+                                        useFramebufferCache, std::move(bufferFence));
         });
     }
     mCondition.notify_one();
-    return resultFuture.get();
+    return resultFuture;
 }
 
 void RenderEngineThreaded::cleanFramebufferCache() {
diff --git a/libs/renderengine/threaded/RenderEngineThreaded.h b/libs/renderengine/threaded/RenderEngineThreaded.h
index b197df7..2303caa 100644
--- a/libs/renderengine/threaded/RenderEngineThreaded.h
+++ b/libs/renderengine/threaded/RenderEngineThreaded.h
@@ -56,11 +56,11 @@
     void useProtectedContext(bool useProtectedContext) override;
     void cleanupPostRender() override;
 
-    status_t drawLayers(const DisplaySettings& display,
-                        const std::vector<const LayerSettings*>& layers,
-                        const std::shared_ptr<ExternalTexture>& buffer,
-                        const bool useFramebufferCache, base::unique_fd&& bufferFence,
-                        base::unique_fd* drawFence) override;
+    std::future<RenderEngineResult> drawLayers(const DisplaySettings& display,
+                                               const std::vector<const LayerSettings*>& layers,
+                                               const std::shared_ptr<ExternalTexture>& buffer,
+                                               const bool useFramebufferCache,
+                                               base::unique_fd&& bufferFence) override;
 
     void cleanFramebufferCache() override;
     int getContextPriority() override;
@@ -71,6 +71,11 @@
     void mapExternalTextureBuffer(const sp<GraphicBuffer>& buffer, bool isRenderable) override;
     void unmapExternalTextureBuffer(const sp<GraphicBuffer>& buffer) override;
     bool canSkipPostRenderCleanup() const override;
+    void drawLayersInternal(const std::shared_ptr<std::promise<RenderEngineResult>>&& resultPromise,
+                            const DisplaySettings& display,
+                            const std::vector<const LayerSettings*>& layers,
+                            const std::shared_ptr<ExternalTexture>& buffer,
+                            const bool useFramebufferCache, base::unique_fd&& bufferFence) override;
 
 private:
     void threadMain(CreateInstanceFactory factory);
diff --git a/services/surfaceflinger/Android.bp b/services/surfaceflinger/Android.bp
index eeb3f3a..af012cd 100644
--- a/services/surfaceflinger/Android.bp
+++ b/services/surfaceflinger/Android.bp
@@ -66,6 +66,7 @@
         "libinput",
         "libutils",
         "libSurfaceFlingerProp",
+        "server_configurable_flags",
     ],
     static_libs: [
         "libcompositionengine",
@@ -154,6 +155,7 @@
         "DisplayRenderArea.cpp",
         "Effects/Daltonizer.cpp",
         "EventLog/EventLog.cpp",
+        "FlagManager.cpp",
         "FpsReporter.cpp",
         "FrameTracer/FrameTracer.cpp",
         "FrameTracker.cpp",
diff --git a/services/surfaceflinger/BufferLayer.cpp b/services/surfaceflinger/BufferLayer.cpp
index b600fad..d805294 100644
--- a/services/surfaceflinger/BufferLayer.cpp
+++ b/services/surfaceflinger/BufferLayer.cpp
@@ -287,7 +287,7 @@
 
     // Sideband layers
     auto* compositionState = editCompositionState();
-    if (compositionState->sidebandStream.get()) {
+    if (compositionState->sidebandStream.get() && !compositionState->sidebandStreamHasFrame) {
         compositionState->compositionType = Hwc2::IComposerClient::Composition::SIDEBAND;
         return;
     } else {
@@ -303,6 +303,7 @@
             ? 0
             : mBufferInfo.mBufferSlot;
     compositionState->acquireFence = mBufferInfo.mFence;
+    compositionState->sidebandStreamHasFrame = false;
 }
 
 bool BufferLayer::onPreComposition(nsecs_t refreshStartTime) {
diff --git a/services/surfaceflinger/BufferQueueLayer.cpp b/services/surfaceflinger/BufferQueueLayer.cpp
index 81254ac..e4f642e 100644
--- a/services/surfaceflinger/BufferQueueLayer.cpp
+++ b/services/surfaceflinger/BufferQueueLayer.cpp
@@ -197,11 +197,10 @@
 
 bool BufferQueueLayer::latchSidebandStream(bool& recomputeVisibleRegions) {
     // We need to update the sideband stream if the layer has both a buffer and a sideband stream.
-    const bool updateSidebandStream = hasFrameUpdate() && mSidebandStream.get();
+    editCompositionState()->sidebandStreamHasFrame = hasFrameUpdate() && mSidebandStream.get();
 
     bool sidebandStreamChanged = true;
-    if (mSidebandStreamChanged.compare_exchange_strong(sidebandStreamChanged, false) ||
-        updateSidebandStream) {
+    if (mSidebandStreamChanged.compare_exchange_strong(sidebandStreamChanged, false)) {
         // mSidebandStreamChanged was changed to false
         mSidebandStream = mConsumer->getSidebandStream();
         auto* layerCompositionState = editCompositionState();
diff --git a/services/surfaceflinger/BufferStateLayer.cpp b/services/surfaceflinger/BufferStateLayer.cpp
index 4d86598..7466c06 100644
--- a/services/surfaceflinger/BufferStateLayer.cpp
+++ b/services/surfaceflinger/BufferStateLayer.cpp
@@ -697,9 +697,9 @@
 
 bool BufferStateLayer::latchSidebandStream(bool& recomputeVisibleRegions) {
     // We need to update the sideband stream if the layer has both a buffer and a sideband stream.
-    const bool updateSidebandStream = hasFrameUpdate() && mSidebandStream.get();
+    editCompositionState()->sidebandStreamHasFrame = hasFrameUpdate() && mSidebandStream.get();
 
-    if (mSidebandStreamChanged.exchange(false) || updateSidebandStream) {
+    if (mSidebandStreamChanged.exchange(false)) {
         const State& s(getDrawingState());
         // mSidebandStreamChanged was true
         mSidebandStream = s.sidebandStream;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFECompositionState.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFECompositionState.h
index ecb4e6d..a000661 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFECompositionState.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFECompositionState.h
@@ -166,6 +166,8 @@
 
     // The handle to use for a sideband stream for this layer
     sp<NativeHandle> sidebandStream;
+    // If true, this sideband layer has a frame update
+    bool sidebandStreamHasFrame{false};
 
     // The color for this layer
     half4 color;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h
index 8ec15ed..cff6527 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h
@@ -38,35 +38,56 @@
 
 class Flattener {
 public:
-    struct CachedSetRenderSchedulingTunables {
-        // This default assumes that rendering a cached set takes about 3ms. That time is then cut
-        // in half - the next frame using the cached set would have the same workload, meaning that
-        // composition cost is the same. This is best illustrated with the following example:
-        //
-        // Suppose we're at a 120hz cadence so SurfaceFlinger is budgeted 8.3ms per-frame. If
-        // renderCachedSets costs 3ms, then two consecutive frames have timings:
-        //
-        // First frame: Start at 0ms, end at 6.8ms.
-        // renderCachedSets: Start at 6.8ms, end at 9.8ms.
-        // Second frame: Start at 9.8ms, end at 16.6ms.
-        //
-        // Now the second frame won't render a cached set afterwards, but the first frame didn't
-        // really steal time from the second frame.
-        static const constexpr std::chrono::nanoseconds kDefaultCachedSetRenderDuration = 1500us;
+    // Collection of tunables which are backed by sysprops
+    struct Tunables {
+        // Tunables that are specific to scheduling when a cached set should be rendered
+        struct RenderScheduling {
+            // This default assumes that rendering a cached set takes about 3ms. That time is then
+            // cut in half - the next frame using the cached set would have the same workload,
+            // meaning that composition cost is the same. This is best illustrated with the
+            // following example:
+            //
+            // Suppose we're at a 120hz cadence so SurfaceFlinger is budgeted 8.3ms per-frame. If
+            // renderCachedSets costs 3ms, then two consecutive frames have timings:
+            //
+            // First frame: Start at 0ms, end at 6.8ms.
+            // renderCachedSets: Start at 6.8ms, end at 9.8ms.
+            // Second frame: Start at 9.8ms, end at 16.6ms.
+            //
+            // Now the second frame won't render a cached set afterwards, but the first frame didn't
+            // really steal time from the second frame.
+            static const constexpr std::chrono::nanoseconds kDefaultCachedSetRenderDuration =
+                    1500us;
 
-        static const constexpr size_t kDefaultMaxDeferRenderAttempts = 240;
+            static const constexpr size_t kDefaultMaxDeferRenderAttempts = 240;
 
-        // Duration allocated for rendering a cached set. If we don't have enough time for rendering
-        // a cached set, then rendering is deferred to another frame.
-        const std::chrono::nanoseconds cachedSetRenderDuration;
-        // Maximum of times that we defer rendering a cached set. If we defer rendering a cached set
-        // too many times, then render it anyways so that future frames would benefit from the
-        // flattened cached set.
-        const size_t maxDeferRenderAttempts;
+            // Duration allocated for rendering a cached set. If we don't have enough time for
+            // rendering a cached set, then rendering is deferred to another frame.
+            const std::chrono::nanoseconds cachedSetRenderDuration;
+            // Maximum of times that we defer rendering a cached set. If we defer rendering a cached
+            // set too many times, then render it anyways so that future frames would benefit from
+            // the flattened cached set.
+            const size_t maxDeferRenderAttempts;
+        };
+
+        static const constexpr std::chrono::milliseconds kDefaultActiveLayerTimeout = 150ms;
+
+        static const constexpr bool kDefaultEnableHolePunch = true;
+
+        // Threshold for determing whether a layer is active. A layer whose properties, including
+        // the buffer, have not changed in at least this time is considered inactive and is
+        // therefore a candidate for flattening.
+        const std::chrono::milliseconds mActiveLayerTimeout;
+
+        // Toggles for scheduling when it's safe to render a cached set.
+        // See: RenderScheduling
+        const std::optional<RenderScheduling> mRenderScheduling;
+
+        // True if the hole punching feature should be enabled.
+        const bool mEnableHolePunch;
     };
-    Flattener(renderengine::RenderEngine& renderEngine, bool enableHolePunch = false,
-              std::optional<CachedSetRenderSchedulingTunables> cachedSetRenderSchedulingTunables =
-                      std::nullopt);
+
+    Flattener(renderengine::RenderEngine& renderEngine, const Tunables& tunables);
 
     void setDisplaySize(ui::Size size) {
         mDisplaySize = size;
@@ -98,8 +119,8 @@
                              std::chrono::steady_clock::time_point now);
 
     // A Run is a sequence of CachedSets, which is a candidate for flattening into a single
-    // CachedSet. Because it is wasteful to flatten 1 CachedSet, a Run must contain more than 1
-    // CachedSet
+    // CachedSet. Because it is wasteful to flatten 1 CachedSet, a run must contain more than
+    // 1 CachedSet or be used for a hole punch.
     class Run {
     public:
         // A builder for a Run, to aid in construction
@@ -133,7 +154,13 @@
 
             // Builds a Run instance, if a valid Run may be built.
             std::optional<Run> validateAndBuild() {
-                if (mLengths.size() <= 1) {
+                if (mLengths.size() == 0) {
+                    return std::nullopt;
+                }
+                // Runs of length 1 which are hole punch candidates are allowed if the candidate is
+                // going to be used.
+                if (mLengths.size() == 1 &&
+                    (!mHolePunchCandidate || !(mHolePunchCandidate->requiresHolePunch()))) {
                     return std::nullopt;
                 }
 
@@ -177,8 +204,7 @@
     void buildCachedSets(std::chrono::steady_clock::time_point now);
 
     renderengine::RenderEngine& mRenderEngine;
-    const bool mEnableHolePunch;
-    const std::optional<CachedSetRenderSchedulingTunables> mCachedSetRenderSchedulingTunables;
+    const Tunables mTunables;
 
     TexturePool mTexturePool;
 
@@ -202,9 +228,6 @@
     size_t mCachedSetCreationCount = 0;
     size_t mCachedSetCreationCost = 0;
     std::unordered_map<size_t, size_t> mInvalidatedCachedSetAges;
-    std::chrono::nanoseconds mActiveLayerTimeout = kActiveLayerTimeout;
-
-    static constexpr auto kActiveLayerTimeout = std::chrono::nanoseconds(150ms);
 };
 
 } // namespace compositionengine::impl::planner
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Planner.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Planner.h
index 76d5e81..b7ebca6 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Planner.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Planner.h
@@ -39,6 +39,9 @@
 // heuristically determining the composition strategy of the current layer stack,
 // and flattens inactive layers into an override buffer so it can be used
 // as a more efficient representation of parts of the layer stack.
+// Implicitly, layer caching must also be enabled for the Planner to have any effect
+// E.g., setprop debug.sf.enable_layer_caching 1, or
+// adb shell service call SurfaceFlinger 1040 i32 1 [i64 <display ID>]
 class Planner {
 public:
     Planner(renderengine::RenderEngine& renderengine);
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index 0ff5eca..1747294 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -1030,10 +1030,9 @@
         }
     }
 
-    base::unique_fd readyFence;
     if (!hasClientComposition) {
         setExpensiveRenderingExpected(false);
-        return readyFence;
+        return base::unique_fd();
     }
 
     ALOGV("hasClientComposition");
@@ -1073,7 +1072,7 @@
                                                    clientCompositionLayers)) {
             outputCompositionState.reusedClientComposition = true;
             setExpensiveRenderingExpected(false);
-            return readyFence;
+            return base::unique_fd();
         }
         mClientCompositionRequestCache->add(tex->getBuffer()->getId(), clientCompositionDisplay,
                                             clientCompositionLayers);
@@ -1107,9 +1106,11 @@
     // probably to encapsulate the output buffer into a structure that dispatches resource cleanup
     // over to RenderEngine, in which case this flag can be removed from the drawLayers interface.
     const bool useFramebufferCache = outputState.layerFilter.toInternalDisplay;
-    status_t status =
-            renderEngine.drawLayers(clientCompositionDisplay, clientCompositionLayerPointers, tex,
-                                    useFramebufferCache, std::move(fd), &readyFence);
+    auto [status, drawFence] =
+            renderEngine
+                    .drawLayers(clientCompositionDisplay, clientCompositionLayerPointers, tex,
+                                useFramebufferCache, std::move(fd))
+                    .get();
 
     if (status != NO_ERROR && mClientCompositionRequestCache) {
         // If rendering was not successful, remove the request from the cache.
@@ -1117,15 +1118,15 @@
     }
 
     auto& timeStats = getCompositionEngine().getTimeStats();
-    if (readyFence.get() < 0) {
+    if (drawFence.get() < 0) {
         timeStats.recordRenderEngineDuration(renderEngineStart, systemTime());
     } else {
         timeStats.recordRenderEngineDuration(renderEngineStart,
                                              std::make_shared<FenceTime>(
-                                                     new Fence(dup(readyFence.get()))));
+                                                     new Fence(dup(drawFence.get()))));
     }
 
-    return readyFence;
+    return std::move(drawFence);
 }
 
 std::vector<LayerFE::LayerSettings> Output::generateClientCompositionRequests(
diff --git a/services/surfaceflinger/CompositionEngine/src/planner/CachedSet.cpp b/services/surfaceflinger/CompositionEngine/src/planner/CachedSet.cpp
index ccacdfb..5bbd58e 100644
--- a/services/surfaceflinger/CompositionEngine/src/planner/CachedSet.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/planner/CachedSet.cpp
@@ -272,12 +272,12 @@
         bufferFence.reset(texture->getReadyFence()->dup());
     }
 
-    base::unique_fd drawFence;
-    status_t result =
-            renderEngine.drawLayers(displaySettings, layerSettingsPointers, texture->get(), false,
-                                    std::move(bufferFence), &drawFence);
+    auto [status, drawFence] = renderEngine
+                                       .drawLayers(displaySettings, layerSettingsPointers,
+                                                   texture->get(), false, std::move(bufferFence))
+                                       .get();
 
-    if (result == NO_ERROR) {
+    if (status == NO_ERROR) {
         mDrawFence = new Fence(drawFence.release());
         mOutputSpace = outputState.framebufferSpace;
         mTexture = texture;
diff --git a/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp b/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp
index 8e2c182..ad5e931 100644
--- a/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp
@@ -60,19 +60,8 @@
 
 } // namespace
 
-Flattener::Flattener(
-        renderengine::RenderEngine& renderEngine, bool enableHolePunch,
-        std::optional<CachedSetRenderSchedulingTunables> cachedSetRenderSchedulingTunables)
-      : mRenderEngine(renderEngine),
-        mEnableHolePunch(enableHolePunch),
-        mCachedSetRenderSchedulingTunables(cachedSetRenderSchedulingTunables),
-        mTexturePool(mRenderEngine) {
-    const int timeoutInMs =
-            base::GetIntProperty(std::string("debug.sf.layer_caching_active_layer_timeout_ms"), 0);
-    if (timeoutInMs != 0) {
-        mActiveLayerTimeout = std::chrono::milliseconds(timeoutInMs);
-    }
-}
+Flattener::Flattener(renderengine::RenderEngine& renderEngine, const Tunables& tunables)
+      : mRenderEngine(renderEngine), mTunables(tunables), mTexturePool(mRenderEngine) {}
 
 NonBufferHash Flattener::flattenLayers(const std::vector<const LayerState*>& layers,
                                        NonBufferHash hash, time_point now) {
@@ -128,14 +117,14 @@
     // If we have a render deadline, and the flattener is configured to skip rendering if we don't
     // have enough time, then we skip rendering the cached set if we think that we'll steal too much
     // time from the next frame.
-    if (renderDeadline && mCachedSetRenderSchedulingTunables) {
+    if (renderDeadline && mTunables.mRenderScheduling) {
         if (const auto estimatedRenderFinish =
-                    now + mCachedSetRenderSchedulingTunables->cachedSetRenderDuration;
+                    now + mTunables.mRenderScheduling->cachedSetRenderDuration;
             estimatedRenderFinish > *renderDeadline) {
             mNewCachedSet->incrementSkipCount();
 
             if (mNewCachedSet->getSkipCount() <=
-                mCachedSetRenderSchedulingTunables->maxDeferRenderAttempts) {
+                mTunables.mRenderScheduling->maxDeferRenderAttempts) {
                 ATRACE_FORMAT("DeadlinePassed: exceeded deadline by: %d us",
                               std::chrono::duration_cast<std::chrono::microseconds>(
                                       estimatedRenderFinish - *renderDeadline)
@@ -420,8 +409,10 @@
     bool runHasFirstLayer = false;
 
     for (auto currentSet = mLayers.cbegin(); currentSet != mLayers.cend(); ++currentSet) {
-        const bool layerIsInactive = now - currentSet->getLastUpdate() > mActiveLayerTimeout;
+        const bool layerIsInactive =
+                now - currentSet->getLastUpdate() > mTunables.mActiveLayerTimeout;
         const bool layerHasBlur = currentSet->hasBlurBehind();
+
         if (layerIsInactive && (firstLayer || runHasFirstLayer || !layerHasBlur) &&
             !currentSet->hasUnsupportedDataspace()) {
             if (isPartOfRun) {
@@ -522,7 +513,7 @@
         mNewCachedSet->addBackgroundBlurLayer(*bestRun->getBlurringLayer());
     }
 
-    if (mEnableHolePunch && bestRun->getHolePunchCandidate() &&
+    if (mTunables.mEnableHolePunch && bestRun->getHolePunchCandidate() &&
         bestRun->getHolePunchCandidate()->requiresHolePunch()) {
         // Add the pip layer to mNewCachedSet, but in a special way - it should
         // replace the buffer with a clear round rect.
diff --git a/services/surfaceflinger/CompositionEngine/src/planner/Planner.cpp b/services/surfaceflinger/CompositionEngine/src/planner/Planner.cpp
index f077470..f5b1cee 100644
--- a/services/surfaceflinger/CompositionEngine/src/planner/Planner.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/planner/Planner.cpp
@@ -32,36 +32,46 @@
 
 namespace {
 
-std::optional<Flattener::CachedSetRenderSchedulingTunables> buildFlattenerTuneables() {
+std::optional<Flattener::Tunables::RenderScheduling> buildRenderSchedulingTunables() {
     if (!base::GetBoolProperty(std::string("debug.sf.enable_cached_set_render_scheduling"), true)) {
         return std::nullopt;
     }
 
-    auto renderDuration = std::chrono::nanoseconds(
+    const auto renderDuration = std::chrono::nanoseconds(
             base::GetUintProperty<uint64_t>(std::string("debug.sf.cached_set_render_duration_ns"),
-                                            Flattener::CachedSetRenderSchedulingTunables::
+                                            Flattener::Tunables::RenderScheduling::
                                                     kDefaultCachedSetRenderDuration.count()));
 
-    auto maxDeferRenderAttempts = base::GetUintProperty<
+    const auto maxDeferRenderAttempts = base::GetUintProperty<
             size_t>(std::string("debug.sf.cached_set_max_defer_render_attmpts"),
-                    Flattener::CachedSetRenderSchedulingTunables::kDefaultMaxDeferRenderAttempts);
+                    Flattener::Tunables::RenderScheduling::kDefaultMaxDeferRenderAttempts);
 
-    return std::make_optional<Flattener::CachedSetRenderSchedulingTunables>(
-            Flattener::CachedSetRenderSchedulingTunables{
+    return std::make_optional<Flattener::Tunables::RenderScheduling>(
+            Flattener::Tunables::RenderScheduling{
                     .cachedSetRenderDuration = renderDuration,
                     .maxDeferRenderAttempts = maxDeferRenderAttempts,
             });
 }
 
+Flattener::Tunables buildFlattenerTuneables() {
+    const auto activeLayerTimeout = std::chrono::milliseconds(
+            base::GetIntProperty<int32_t>(std::string(
+                                                  "debug.sf.layer_caching_active_layer_timeout_ms"),
+                                          Flattener::Tunables::kDefaultActiveLayerTimeout.count()));
+    const auto enableHolePunch =
+            base::GetBoolProperty(std::string("debug.sf.enable_hole_punch_pip"),
+                                  Flattener::Tunables::kDefaultEnableHolePunch);
+    return Flattener::Tunables{
+            .mActiveLayerTimeout = activeLayerTimeout,
+            .mRenderScheduling = buildRenderSchedulingTunables(),
+            .mEnableHolePunch = enableHolePunch,
+    };
+}
+
 } // namespace
 
 Planner::Planner(renderengine::RenderEngine& renderEngine)
-      // Implicitly, layer caching must also be enabled for the hole punch or
-      // predictor to have any effect.
-      // E.g., setprop debug.sf.enable_layer_caching 1, or
-      // adb shell service call SurfaceFlinger 1040 i32 1 [i64 <display ID>]
       : mFlattener(renderEngine,
-                   base::GetBoolProperty(std::string("debug.sf.enable_hole_punch_pip"), true),
                    buildFlattenerTuneables()) {
     mPredictorEnabled =
             base::GetBoolProperty(std::string("debug.sf.enable_planner_prediction"), false);
diff --git a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
index 6c510eb..a904c7d 100644
--- a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
@@ -35,6 +35,7 @@
 #include "CallOrderStateMachineHelper.h"
 #include "MockHWC2.h"
 #include "RegionMatcher.h"
+#include "TestUtils.h"
 #include "renderengine/ExternalTexture.h"
 
 namespace android::compositionengine {
@@ -3119,9 +3120,14 @@
             .WillRepeatedly(Return());
 
     EXPECT_CALL(*mRenderSurface, dequeueBuffer(_)).WillRepeatedly(Return(mOutputBuffer));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, IsEmpty(), _, false, _, _))
-            .WillRepeatedly(Return(NO_ERROR));
-
+    EXPECT_CALL(mRenderEngine, drawLayers(_, IsEmpty(), _, false, _))
+            .WillRepeatedly([&](const renderengine::DisplaySettings&,
+                                const std::vector<const renderengine::LayerSettings*>&,
+                                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                                base::unique_fd &&)
+                                    -> std::future<renderengine::RenderEngineResult> {
+                return futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()});
+            });
     verify().execute().expectAFenceWasReturned();
 }
 
@@ -3146,8 +3152,14 @@
                     }));
 
     EXPECT_CALL(*mRenderSurface, dequeueBuffer(_)).WillRepeatedly(Return(mOutputBuffer));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, false, _, _))
-            .WillRepeatedly(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, false, _))
+            .WillRepeatedly([&](const renderengine::DisplaySettings&,
+                                const std::vector<const renderengine::LayerSettings*>&,
+                                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                                base::unique_fd &&)
+                                    -> std::future<renderengine::RenderEngineResult> {
+                return futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()});
+            });
 
     verify().execute().expectAFenceWasReturned();
 }
@@ -3175,8 +3187,14 @@
                     }));
 
     EXPECT_CALL(*mRenderSurface, dequeueBuffer(_)).WillRepeatedly(Return(mOutputBuffer));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, true, _, _))
-            .WillRepeatedly(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, true, _))
+            .WillRepeatedly([&](const renderengine::DisplaySettings&,
+                                const std::vector<const renderengine::LayerSettings*>&,
+                                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                                base::unique_fd &&)
+                                    -> std::future<renderengine::RenderEngineResult> {
+                return futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()});
+            });
 
     verify().execute().expectAFenceWasReturned();
 }
@@ -3199,9 +3217,12 @@
             .WillRepeatedly(Return());
 
     EXPECT_CALL(*mRenderSurface, dequeueBuffer(_)).WillRepeatedly(Return(mOutputBuffer));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, false, _, _))
+    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, false, _))
             .Times(2)
-            .WillOnce(Return(NO_ERROR));
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
 
     verify().execute().expectAFenceWasReturned();
     EXPECT_FALSE(mOutput.mState.reusedClientComposition);
@@ -3228,8 +3249,9 @@
             .WillRepeatedly(Return());
 
     EXPECT_CALL(*mRenderSurface, dequeueBuffer(_)).WillRepeatedly(Return(mOutputBuffer));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, false, _, _))
-            .WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, false, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     EXPECT_CALL(mOutput, setExpensiveRenderingExpected(false));
 
     verify().execute().expectAFenceWasReturned();
@@ -3263,8 +3285,14 @@
     EXPECT_CALL(*mRenderSurface, dequeueBuffer(_))
             .WillOnce(Return(mOutputBuffer))
             .WillOnce(Return(otherOutputBuffer));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, false, _, _))
-            .WillRepeatedly(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, false, _))
+            .WillRepeatedly([&](const renderengine::DisplaySettings&,
+                                const std::vector<const renderengine::LayerSettings*>&,
+                                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                                base::unique_fd &&)
+                                    -> std::future<renderengine::RenderEngineResult> {
+                return futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()});
+            });
 
     verify().execute().expectAFenceWasReturned();
     EXPECT_FALSE(mOutput.mState.reusedClientComposition);
@@ -3293,10 +3321,12 @@
             .WillRepeatedly(Return());
 
     EXPECT_CALL(*mRenderSurface, dequeueBuffer(_)).WillRepeatedly(Return(mOutputBuffer));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, false, _, _))
-            .WillOnce(Return(NO_ERROR));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r3)), _, false, _, _))
-            .WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r2)), _, false, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, ElementsAre(Pointee(r1), Pointee(r3)), _, false, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
 
     verify().execute().expectAFenceWasReturned();
     EXPECT_FALSE(mOutput.mState.reusedClientComposition);
@@ -3345,8 +3375,9 @@
     struct ExpectDisplaySettingsState
           : public CallOrderStateMachineHelper<TestType, ExpectDisplaySettingsState> {
         auto thenExpectDisplaySettingsUsed(renderengine::DisplaySettings settings) {
-            EXPECT_CALL(getInstance()->mRenderEngine, drawLayers(settings, _, _, false, _, _))
-                    .WillOnce(Return(NO_ERROR));
+            EXPECT_CALL(getInstance()->mRenderEngine, drawLayers(settings, _, _, false, _))
+                    .WillOnce(Return(ByMove(futureOf<renderengine::RenderEngineResult>(
+                            {NO_ERROR, base::unique_fd()}))));
             return nextState<ExecuteState>();
         }
     };
@@ -3444,8 +3475,15 @@
         EXPECT_CALL(mOutput, appendRegionFlashRequests(RegionEq(kDebugRegion), _))
                 .WillRepeatedly(Return());
         EXPECT_CALL(*mRenderSurface, dequeueBuffer(_)).WillRepeatedly(Return(mOutputBuffer));
-        EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, false, _, _))
-                .WillRepeatedly(Return(NO_ERROR));
+        EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, false, _))
+                .WillRepeatedly(
+                        [&](const renderengine::DisplaySettings&,
+                            const std::vector<const renderengine::LayerSettings*>&,
+                            const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                            base::unique_fd &&) -> std::future<renderengine::RenderEngineResult> {
+                            return futureOf<renderengine::RenderEngineResult>(
+                                    {NO_ERROR, base::unique_fd()});
+                        });
     }
 
     Layer mLayer1;
@@ -3497,7 +3535,9 @@
     EXPECT_CALL(*mRenderSurface, setProtected(true));
     // Must happen after setting the protected content state.
     EXPECT_CALL(*mRenderSurface, dequeueBuffer(_)).WillRepeatedly(Return(mOutputBuffer));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, false, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, false, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
 
     mOutput.composeSurfaces(kDebugRegion, kDefaultRefreshArgs);
 }
@@ -3567,7 +3607,9 @@
     InSequence seq;
 
     EXPECT_CALL(mOutput, setExpensiveRenderingExpected(true));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, false, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, false, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
 
     mOutput.composeSurfaces(kDebugRegion, kDefaultRefreshArgs);
 }
@@ -3584,7 +3626,9 @@
                                     /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
         EXPECT_CALL(mOutput, generateClientCompositionRequests(_, kDefaultOutputDataspace))
                 .WillOnce(Return(std::vector<LayerFE::LayerSettings>{}));
-        EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, false, _, _)).WillOnce(Return(NO_ERROR));
+        EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, false, _))
+                .WillOnce(Return(ByMove(futureOf<renderengine::RenderEngineResult>(
+                        {NO_ERROR, base::unique_fd()}))));
         EXPECT_CALL(mOutput, getOutputLayerCount()).WillRepeatedly(Return(1u));
         EXPECT_CALL(mOutput, getOutputLayerOrderedByZByIndex(0u))
                 .WillRepeatedly(Return(&mLayer.outputLayer));
diff --git a/services/surfaceflinger/CompositionEngine/tests/TestUtils.h b/services/surfaceflinger/CompositionEngine/tests/TestUtils.h
new file mode 100644
index 0000000..c80fde6
--- /dev/null
+++ b/services/surfaceflinger/CompositionEngine/tests/TestUtils.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+#pragma once
+
+#include <future>
+
+namespace android::compositionengine {
+namespace {
+
+template <class T>
+std::future<T> futureOf(T obj) {
+    std::promise<T> resultPromise;
+    std::future<T> resultFuture = resultPromise.get_future();
+    resultPromise.set_value(std::move(obj));
+    return resultFuture;
+}
+} // namespace
+} // namespace android::compositionengine
diff --git a/services/surfaceflinger/CompositionEngine/tests/planner/CachedSetTest.cpp b/services/surfaceflinger/CompositionEngine/tests/planner/CachedSetTest.cpp
index ec81322..818334d 100644
--- a/services/surfaceflinger/CompositionEngine/tests/planner/CachedSetTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/planner/CachedSetTest.cpp
@@ -27,6 +27,8 @@
 #include <utils/Errors.h>
 #include <memory>
 
+#include "tests/TestUtils.h"
+
 namespace android::compositionengine {
 using namespace std::chrono_literals;
 
@@ -342,10 +344,11 @@
     clientCompList2.push_back({});
     clientCompList2[0].alpha = 0.75f;
 
-    const auto drawLayers = [&](const renderengine::DisplaySettings& displaySettings,
-                                const std::vector<const renderengine::LayerSettings*>& layers,
-                                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
-                                base::unique_fd&&, base::unique_fd*) -> size_t {
+    const auto drawLayers =
+            [&](const renderengine::DisplaySettings& displaySettings,
+                const std::vector<const renderengine::LayerSettings*>& layers,
+                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                base::unique_fd &&) -> std::future<renderengine::RenderEngineResult> {
         EXPECT_EQ(mOutputState.framebufferSpace.content, displaySettings.physicalDisplay);
         EXPECT_EQ(mOutputState.layerStackSpace.content, displaySettings.clip);
         EXPECT_EQ(ui::Transform::toRotationFlags(mOutputState.framebufferSpace.orientation),
@@ -353,8 +356,7 @@
         EXPECT_EQ(0.5f, layers[0]->alpha);
         EXPECT_EQ(0.75f, layers[1]->alpha);
         EXPECT_EQ(ui::Dataspace::SRGB, displaySettings.outputDataspace);
-
-        return NO_ERROR;
+        return futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()});
     };
 
     EXPECT_CALL(*layerFE1,
@@ -363,7 +365,7 @@
     EXPECT_CALL(*layerFE2,
                 prepareClientCompositionList(ClientCompositionTargetSettingsSecureEq(false)))
             .WillOnce(Return(clientCompList2));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Invoke(drawLayers));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).WillOnce(Invoke(drawLayers));
     mOutputState.isSecure = false;
     cachedSet.render(mRenderEngine, mTexturePool, mOutputState);
     expectReadyBuffer(cachedSet);
@@ -394,10 +396,11 @@
     clientCompList2.push_back({});
     clientCompList2[0].alpha = 0.75f;
 
-    const auto drawLayers = [&](const renderengine::DisplaySettings& displaySettings,
-                                const std::vector<const renderengine::LayerSettings*>& layers,
-                                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
-                                base::unique_fd&&, base::unique_fd*) -> size_t {
+    const auto drawLayers =
+            [&](const renderengine::DisplaySettings& displaySettings,
+                const std::vector<const renderengine::LayerSettings*>& layers,
+                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                base::unique_fd &&) -> std::future<renderengine::RenderEngineResult> {
         EXPECT_EQ(mOutputState.framebufferSpace.content, displaySettings.physicalDisplay);
         EXPECT_EQ(mOutputState.layerStackSpace.content, displaySettings.clip);
         EXPECT_EQ(ui::Transform::toRotationFlags(mOutputState.framebufferSpace.orientation),
@@ -406,7 +409,7 @@
         EXPECT_EQ(0.75f, layers[1]->alpha);
         EXPECT_EQ(ui::Dataspace::SRGB, displaySettings.outputDataspace);
 
-        return NO_ERROR;
+        return futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()});
     };
 
     EXPECT_CALL(*layerFE1,
@@ -415,7 +418,7 @@
     EXPECT_CALL(*layerFE2,
                 prepareClientCompositionList(ClientCompositionTargetSettingsSecureEq(true)))
             .WillOnce(Return(clientCompList2));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Invoke(drawLayers));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).WillOnce(Invoke(drawLayers));
     mOutputState.isSecure = true;
     cachedSet.render(mRenderEngine, mTexturePool, mOutputState);
     expectReadyBuffer(cachedSet);
@@ -448,10 +451,11 @@
 
     mOutputState.framebufferSpace = ProjectionSpace(ui::Size(10, 20), Rect(2, 3, 10, 5));
 
-    const auto drawLayers = [&](const renderengine::DisplaySettings& displaySettings,
-                                const std::vector<const renderengine::LayerSettings*>& layers,
-                                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
-                                base::unique_fd&&, base::unique_fd*) -> size_t {
+    const auto drawLayers =
+            [&](const renderengine::DisplaySettings& displaySettings,
+                const std::vector<const renderengine::LayerSettings*>& layers,
+                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                base::unique_fd &&) -> std::future<renderengine::RenderEngineResult> {
         EXPECT_EQ(mOutputState.framebufferSpace.content, displaySettings.physicalDisplay);
         EXPECT_EQ(mOutputState.layerStackSpace.content, displaySettings.clip);
         EXPECT_EQ(ui::Transform::toRotationFlags(mOutputState.framebufferSpace.orientation),
@@ -460,12 +464,12 @@
         EXPECT_EQ(0.75f, layers[1]->alpha);
         EXPECT_EQ(ui::Dataspace::SRGB, displaySettings.outputDataspace);
 
-        return NO_ERROR;
+        return futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()});
     };
 
     EXPECT_CALL(*layerFE1, prepareClientCompositionList(_)).WillOnce(Return(clientCompList1));
     EXPECT_CALL(*layerFE2, prepareClientCompositionList(_)).WillOnce(Return(clientCompList2));
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Invoke(drawLayers));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).WillOnce(Invoke(drawLayers));
     cachedSet.render(mRenderEngine, mTexturePool, mOutputState);
     expectReadyBuffer(cachedSet);
 
@@ -650,10 +654,11 @@
     EXPECT_CALL(*layerFE2, prepareClientCompositionList(_)).WillOnce(Return(clientCompList2));
     EXPECT_CALL(*layerFE3, prepareClientCompositionList(_)).WillOnce(Return(clientCompList3));
 
-    const auto drawLayers = [&](const renderengine::DisplaySettings&,
-                                const std::vector<const renderengine::LayerSettings*>& layers,
-                                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
-                                base::unique_fd&&, base::unique_fd*) -> size_t {
+    const auto drawLayers =
+            [&](const renderengine::DisplaySettings&,
+                const std::vector<const renderengine::LayerSettings*>& layers,
+                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                base::unique_fd &&) -> std::future<renderengine::RenderEngineResult> {
         // If the highlight layer is enabled, it will increase the size by 1.
         // We're interested in the third layer either way.
         EXPECT_GE(layers.size(), 4u);
@@ -673,10 +678,10 @@
             EXPECT_EQ(1.0f, holePunchBackgroundSettings->alpha);
         }
 
-        return NO_ERROR;
+        return futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()});
     };
 
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Invoke(drawLayers));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).WillOnce(Invoke(drawLayers));
     cachedSet.render(mRenderEngine, mTexturePool, mOutputState);
 }
 
@@ -710,10 +715,11 @@
     EXPECT_CALL(*layerFE2, prepareClientCompositionList(_)).WillOnce(Return(clientCompList2));
     EXPECT_CALL(*layerFE3, prepareClientCompositionList(_)).WillOnce(Return(clientCompList3));
 
-    const auto drawLayers = [&](const renderengine::DisplaySettings&,
-                                const std::vector<const renderengine::LayerSettings*>& layers,
-                                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
-                                base::unique_fd&&, base::unique_fd*) -> size_t {
+    const auto drawLayers =
+            [&](const renderengine::DisplaySettings&,
+                const std::vector<const renderengine::LayerSettings*>& layers,
+                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                base::unique_fd &&) -> std::future<renderengine::RenderEngineResult> {
         // If the highlight layer is enabled, it will increase the size by 1.
         // We're interested in the third layer either way.
         EXPECT_GE(layers.size(), 4u);
@@ -734,10 +740,10 @@
             EXPECT_EQ(1.0f, holePunchBackgroundSettings->alpha);
         }
 
-        return NO_ERROR;
+        return futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()});
     };
 
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Invoke(drawLayers));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).WillOnce(Invoke(drawLayers));
     cachedSet.render(mRenderEngine, mTexturePool, mOutputState);
 }
 
@@ -859,10 +865,11 @@
                                 BackgroundBlurOnly)))
             .WillOnce(Return(clientCompList3));
 
-    const auto drawLayers = [&](const renderengine::DisplaySettings&,
-                                const std::vector<const renderengine::LayerSettings*>& layers,
-                                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
-                                base::unique_fd&&, base::unique_fd*) -> int32_t {
+    const auto drawLayers =
+            [&](const renderengine::DisplaySettings&,
+                const std::vector<const renderengine::LayerSettings*>& layers,
+                const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                base::unique_fd &&) -> std::future<renderengine::RenderEngineResult> {
         // If the highlight layer is enabled, it will increase the size by 1.
         // We're interested in the third layer either way.
         EXPECT_GE(layers.size(), 3u);
@@ -871,10 +878,10 @@
         EXPECT_EQ(half3(0.0f, 0.0f, 0.0f), blurSettings->source.solidColor);
         EXPECT_EQ(0.0f, blurSettings->alpha);
 
-        return NO_ERROR;
+        return futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()});
     };
 
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Invoke(drawLayers));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).WillOnce(Invoke(drawLayers));
     cachedSet.render(mRenderEngine, mTexturePool, mOutputState);
 }
 
diff --git a/services/surfaceflinger/CompositionEngine/tests/planner/FlattenerTest.cpp b/services/surfaceflinger/CompositionEngine/tests/planner/FlattenerTest.cpp
index f5cfd2f..0d5e362 100644
--- a/services/surfaceflinger/CompositionEngine/tests/planner/FlattenerTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/planner/FlattenerTest.cpp
@@ -26,6 +26,8 @@
 #include <renderengine/mock/RenderEngine.h>
 #include <chrono>
 
+#include "tests/TestUtils.h"
+
 namespace android::compositionengine {
 using namespace std::chrono_literals;
 using impl::planner::CachedSet;
@@ -47,23 +49,24 @@
 
 class TestableFlattener : public Flattener {
 public:
-    TestableFlattener(renderengine::RenderEngine& renderEngine, bool enableHolePunch,
-                      std::optional<Flattener::CachedSetRenderSchedulingTunables>
-                              cachedSetRenderSchedulingTunables = std::nullopt)
-          : Flattener(renderEngine, enableHolePunch, cachedSetRenderSchedulingTunables) {}
+    TestableFlattener(renderengine::RenderEngine& renderEngine, const Tunables& tunables)
+          : Flattener(renderEngine, tunables) {}
     const std::optional<CachedSet>& getNewCachedSetForTesting() const { return mNewCachedSet; }
 };
 
 class FlattenerTest : public testing::Test {
 public:
-    FlattenerTest() : FlattenerTest(std::nullopt) {}
+    FlattenerTest()
+          : FlattenerTest(Flattener::Tunables{
+                    .mActiveLayerTimeout = 100ms,
+                    .mRenderScheduling = std::nullopt,
+                    .mEnableHolePunch = true,
+            }) {}
     void SetUp() override;
 
 protected:
-    FlattenerTest(std::optional<Flattener::CachedSetRenderSchedulingTunables>
-                          cachedSetRenderSchedulingTunables)
-          : mFlattener(std::make_unique<TestableFlattener>(mRenderEngine, true,
-                                                           cachedSetRenderSchedulingTunables)) {}
+    FlattenerTest(const Flattener::Tunables& tunables)
+          : mFlattener(std::make_unique<TestableFlattener>(mRenderEngine, tunables)) {}
     void initializeOverrideBuffer(const std::vector<const LayerState*>& layers);
     void initializeFlattener(const std::vector<const LayerState*>& layers);
     void expectAllLayersFlattened(const std::vector<const LayerState*>& layers);
@@ -166,7 +169,9 @@
 
 void FlattenerTest::expectAllLayersFlattened(const std::vector<const LayerState*>& layers) {
     // layers would be flattened but the buffer would not be overridden
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
 
     initializeOverrideBuffer(layers);
     EXPECT_EQ(getNonBufferHash(layers),
@@ -400,7 +405,9 @@
     // caleed for Layer2 and Layer3
     layerState1->resetFramesSinceBufferUpdate();
 
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     initializeOverrideBuffer(layers);
     EXPECT_EQ(getNonBufferHash(layers),
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
@@ -422,7 +429,9 @@
     layerState1->incrementFramesSinceBufferUpdate();
     mTime += 200ms;
 
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     initializeOverrideBuffer(layers);
     EXPECT_NE(getNonBufferHash(layers),
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
@@ -473,7 +482,9 @@
     // called for Layer1 and Layer2
     layerState3->resetFramesSinceBufferUpdate();
 
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     initializeOverrideBuffer(layers);
     EXPECT_EQ(getNonBufferHash(layers),
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
@@ -486,7 +497,9 @@
     EXPECT_EQ(nullptr, overrideBuffer5);
 
     // Layers 1 and 2 will be flattened a new drawFrame would be called for Layer4 and Layer5
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     initializeOverrideBuffer(layers);
     EXPECT_NE(getNonBufferHash(layers),
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
@@ -514,8 +527,9 @@
 
     layerState3->incrementFramesSinceBufferUpdate();
     mTime += 200ms;
-
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     initializeOverrideBuffer(layers);
     EXPECT_NE(getNonBufferHash(layers),
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
@@ -569,7 +583,9 @@
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
 
     // This will render a CachedSet.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     mFlattener->renderCachedSets(mOutputState, std::nullopt);
 
     // We've rendered a CachedSet, but we haven't merged it in.
@@ -579,7 +595,7 @@
 
     // This time we merge the CachedSet in, so we have a new hash, and we should
     // only have two sets.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).Times(0);
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).Times(0);
     initializeOverrideBuffer(layers);
     EXPECT_NE(getNonBufferHash(layers),
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
@@ -631,7 +647,9 @@
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
 
     // This will render a CachedSet.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     mFlattener->renderCachedSets(mOutputState, std::nullopt);
 
     // We've rendered a CachedSet, but we haven't merged it in.
@@ -641,7 +659,7 @@
 
     // This time we merge the CachedSet in, so we have a new hash, and we should
     // only have two sets.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).Times(0);
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).Times(0);
     initializeOverrideBuffer(layers);
     EXPECT_NE(getNonBufferHash(layers),
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
@@ -659,6 +677,75 @@
     EXPECT_EQ(peekThroughLayer1, peekThroughLayer2);
 }
 
+// A test that verifies the hole puch optimization can be done on a single layer.
+TEST_F(FlattenerTest, flattenLayers_holePunchSingleLayer) {
+    mTestLayers[0]->outputLayerCompositionState.displayFrame = Rect(0, 0, 5, 5);
+
+    // An opaque static background
+    auto& layerState0 = mTestLayers[0]->layerState;
+    const auto& overrideBuffer0 = layerState0->getOutputLayer()->getState().overrideInfo.buffer;
+
+    // a rounded updating layer
+    auto& layerState1 = mTestLayers[1]->layerState;
+    const auto& overrideBuffer1 = layerState1->getOutputLayer()->getState().overrideInfo.buffer;
+
+    EXPECT_CALL(*mTestLayers[1]->layerFE, hasRoundedCorners()).WillRepeatedly(Return(true));
+
+    std::vector<LayerFE::LayerSettings> clientCompositionList = {
+            LayerFE::LayerSettings{},
+    };
+    clientCompositionList[0].source.buffer.buffer = std::make_shared<
+            renderengine::ExternalTexture>(mTestLayers[1]->layerFECompositionState.buffer,
+                                           mRenderEngine,
+                                           renderengine::ExternalTexture::Usage::READABLE);
+    EXPECT_CALL(*mTestLayers[1]->layerFE, prepareClientCompositionList(_))
+            .WillOnce(Return(clientCompositionList));
+
+    const std::vector<const LayerState*> layers = {
+            layerState0.get(),
+            layerState1.get(),
+    };
+
+    initializeFlattener(layers);
+
+    // layer 1 satisfies every condition in CachedSet::requiresHolePunch()
+    mTime += 200ms;
+    layerState1->resetFramesSinceBufferUpdate(); // it is updating
+
+    initializeOverrideBuffer(layers);
+    // Expect no cache invalidation the first time (there's no cache yet)
+    EXPECT_EQ(getNonBufferHash(layers),
+              mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
+
+    // This will render a CachedSet of layer 0. Though it is just one layer, it satisfies the
+    // exception that there would be a hole punch above it.
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
+    mFlattener->renderCachedSets(mOutputState, std::nullopt);
+
+    // We've rendered a CachedSet, but we haven't merged it in.
+    EXPECT_EQ(nullptr, overrideBuffer0);
+
+    // This time we merge the CachedSet in and we should still have only two sets.
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).Times(0);
+    initializeOverrideBuffer(layers);
+    EXPECT_EQ(getNonBufferHash(layers),
+              mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
+    mFlattener->renderCachedSets(mOutputState, std::nullopt);
+
+    EXPECT_NE(nullptr, overrideBuffer0); // got overridden
+    EXPECT_EQ(nullptr, overrideBuffer1); // did not
+
+    // expect 0's peek though layer to be 1's output layer
+    const auto* peekThroughLayer0 =
+            layerState0->getOutputLayer()->getState().overrideInfo.peekThroughLayer;
+    const auto* peekThroughLayer1 =
+            layerState1->getOutputLayer()->getState().overrideInfo.peekThroughLayer;
+    EXPECT_EQ(&mTestLayers[1]->outputLayer, peekThroughLayer0);
+    EXPECT_EQ(nullptr, peekThroughLayer1);
+}
+
 TEST_F(FlattenerTest, flattenLayers_flattensBlurBehindRunIfFirstRun) {
     auto& layerState1 = mTestLayers[0]->layerState;
 
@@ -684,7 +771,9 @@
     layerState3->resetFramesSinceBufferUpdate();
 
     // layers would be flattened but the buffer would not be overridden
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
 
     initializeOverrideBuffer(layers);
     EXPECT_EQ(getNonBufferHash(layers),
@@ -728,7 +817,9 @@
     layerState1->resetFramesSinceBufferUpdate();
 
     // layers would be flattened but the buffer would not be overridden
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillRepeatedly(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillRepeatedly(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
 
     initializeOverrideBuffer(layers);
     EXPECT_EQ(getNonBufferHash(layers),
@@ -780,7 +871,9 @@
     layerState1->resetFramesSinceBufferUpdate();
 
     // layers would be flattened but the buffer would not be overridden
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
 
     initializeOverrideBuffer(layers);
     EXPECT_EQ(getNonBufferHash(layers),
@@ -827,7 +920,9 @@
     layerStateWithBlurBehind->resetFramesSinceBufferUpdate();
 
     // layers would be flattened but the buffer would not be overridden
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
 
     initializeOverrideBuffer(layers);
     EXPECT_EQ(getNonBufferHash(layers),
@@ -868,7 +963,9 @@
     // Mark the layers inactive
     mTime += 200ms;
     // layers would be flattened but the buffer would not be overridden
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
 
     initializeOverrideBuffer(layers);
     EXPECT_EQ(getNonBufferHash(layers),
@@ -880,7 +977,7 @@
 
     // Simulate attempting to render prior to merging the new cached set with the layer stack.
     // Here we should not try to re-render.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).Times(0);
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).Times(0);
     mFlattener->renderCachedSets(mOutputState, std::nullopt);
 
     // We provide the override buffer now that it's rendered
@@ -899,11 +996,13 @@
 public:
     FlattenerRenderSchedulingTest()
           : FlattenerTest(
-                    Flattener::CachedSetRenderSchedulingTunables{.cachedSetRenderDuration =
+                    Flattener::Tunables{.mActiveLayerTimeout = 100ms,
+                                        .mRenderScheduling = Flattener::Tunables::
+                                                RenderScheduling{.cachedSetRenderDuration =
                                                                          kCachedSetRenderDuration,
                                                                  .maxDeferRenderAttempts =
-                                                                         kMaxDeferRenderAttempts}) {
-    }
+                                                                         kMaxDeferRenderAttempts},
+                                        .mEnableHolePunch = true}) {}
 };
 
 TEST_F(FlattenerRenderSchedulingTest, flattenLayers_renderCachedSets_defersUpToMaxAttempts) {
@@ -925,13 +1024,15 @@
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
 
     for (size_t i = 0; i < kMaxDeferRenderAttempts; i++) {
-        EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).Times(0);
+        EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).Times(0);
         mFlattener->renderCachedSets(mOutputState,
                                      std::chrono::steady_clock::now() -
                                              (kCachedSetRenderDuration + 10ms));
     }
 
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     mFlattener->renderCachedSets(mOutputState,
                                  std::chrono::steady_clock::now() -
                                          (kCachedSetRenderDuration + 10ms));
@@ -965,7 +1066,9 @@
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
 
     // This will render a CachedSet.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     mFlattener->renderCachedSets(mOutputState, std::nullopt);
 
     // We've rendered a CachedSet, but we haven't merged it in.
@@ -975,7 +1078,7 @@
 
     // This time we merge the CachedSet in, so we have a new hash, and we should
     // only have two sets.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).Times(0);
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).Times(0);
     initializeOverrideBuffer(layers);
     EXPECT_NE(getNonBufferHash(layers),
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
@@ -1014,7 +1117,9 @@
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
 
     // This will render a CachedSet.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     mFlattener->renderCachedSets(mOutputState, std::nullopt);
 
     // We've rendered a CachedSet, but we haven't merged it in.
@@ -1024,7 +1129,7 @@
 
     // This time we merge the CachedSet in, so we have a new hash, and we should
     // only have two sets.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).Times(0);
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).Times(0);
     initializeOverrideBuffer(layers);
     EXPECT_NE(getNonBufferHash(layers),
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
@@ -1063,7 +1168,9 @@
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
 
     // This will render a CachedSet.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).WillOnce(Return(NO_ERROR));
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _))
+            .WillOnce(Return(ByMove(
+                    futureOf<renderengine::RenderEngineResult>({NO_ERROR, base::unique_fd()}))));
     mFlattener->renderCachedSets(mOutputState, std::nullopt);
 
     // We've rendered a CachedSet, but we haven't merged it in.
@@ -1073,7 +1180,7 @@
 
     // This time we merge the CachedSet in, so we have a new hash, and we should
     // only have two sets.
-    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _, _)).Times(0);
+    EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, _, _)).Times(0);
     initializeOverrideBuffer(layers);
     EXPECT_NE(getNonBufferHash(layers),
               mFlattener->flattenLayers(layers, getNonBufferHash(layers), mTime));
diff --git a/services/surfaceflinger/FlagManager.cpp b/services/surfaceflinger/FlagManager.cpp
new file mode 100644
index 0000000..f0c5b58
--- /dev/null
+++ b/services/surfaceflinger/FlagManager.cpp
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#include "FlagManager.h"
+
+#include <SurfaceFlingerProperties.sysprop.h>
+#include <android-base/parsebool.h>
+#include <android-base/parseint.h>
+#include <android-base/stringprintf.h>
+#include <log/log.h>
+#include <server_configurable_flags/get_flags.h>
+#include <cinttypes>
+
+namespace android {
+static constexpr const char* kExperimentNamespace = "surface_flinger_native_boot";
+static constexpr const int64_t kDemoFlag = -1;
+
+FlagManager::~FlagManager() = default;
+
+void FlagManager::dump(std::string& result) const {
+    base::StringAppendF(&result, "FlagManager values: \n");
+    base::StringAppendF(&result, "demo_flag: %" PRId64 "\n", demo_flag());
+}
+
+namespace {
+template <typename T>
+std::optional<T> doParse(const char* str);
+
+template <>
+[[maybe_unused]] std::optional<int32_t> doParse(const char* str) {
+    int32_t ret;
+    return base::ParseInt(str, &ret) ? std::make_optional(ret) : std::nullopt;
+}
+
+template <>
+[[maybe_unused]] std::optional<int64_t> doParse(const char* str) {
+    int64_t ret;
+    return base::ParseInt(str, &ret) ? std::make_optional(ret) : std::nullopt;
+}
+
+template <>
+[[maybe_unused]] std::optional<bool> doParse(const char* str) {
+    base::ParseBoolResult parseResult = base::ParseBool(str);
+    switch (parseResult) {
+        case base::ParseBoolResult::kTrue:
+            return std::make_optional(true);
+        case base::ParseBoolResult::kFalse:
+            return std::make_optional(false);
+        case base::ParseBoolResult::kError:
+            return std::nullopt;
+    }
+}
+} // namespace
+
+std::string FlagManager::getServerConfigurableFlag(const std::string& experimentFlagName) const {
+    return server_configurable_flags::GetServerConfigurableFlag(kExperimentNamespace,
+                                                                experimentFlagName, "");
+}
+
+template int32_t FlagManager::getValue<int32_t>(const std::string&, std::optional<int32_t>,
+                                                int32_t) const;
+template int64_t FlagManager::getValue<int64_t>(const std::string&, std::optional<int64_t>,
+                                                int64_t) const;
+template bool FlagManager::getValue<bool>(const std::string&, std::optional<bool>, bool) const;
+template <typename T>
+T FlagManager::getValue(const std::string& experimentFlagName, std::optional<T> systemPropertyOpt,
+                        T defaultValue) const {
+    // System property takes precedence over the experiment config server value.
+    if (systemPropertyOpt.has_value()) {
+        return *systemPropertyOpt;
+    }
+    std::string str = getServerConfigurableFlag(experimentFlagName);
+    return str.empty() ? defaultValue : doParse<T>(str.c_str()).value_or(defaultValue);
+}
+
+int64_t FlagManager::demo_flag() const {
+    std::optional<int64_t> sysPropVal = std::nullopt;
+    return getValue("DemoFeature__demo_flag", sysPropVal, kDemoFlag);
+}
+} // namespace android
diff --git a/services/surfaceflinger/FlagManager.h b/services/surfaceflinger/FlagManager.h
new file mode 100644
index 0000000..65e30a4
--- /dev/null
+++ b/services/surfaceflinger/FlagManager.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include <string>
+
+namespace android {
+// Manages flags for SurfaceFlinger, including default values, system properties, and Mendel
+// experiment configuration values.
+class FlagManager {
+public:
+    FlagManager() = default;
+    virtual ~FlagManager();
+    void dump(std::string& result) const;
+
+    int64_t demo_flag() const;
+
+private:
+    friend class FlagManagerTest;
+
+    // Wrapper for mocking in test.
+    virtual std::string getServerConfigurableFlag(const std::string& experimentFlagName) const;
+
+    template <typename T>
+    T getValue(const std::string& experimentFlagName, std::optional<T> systemPropertyOpt,
+               T defaultValue) const;
+};
+} // namespace android
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 5d8d79b..15db2ed 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -6328,12 +6328,14 @@
     // Use an empty fence for the buffer fence, since we just created the buffer so
     // there is no need for synchronization with the GPU.
     base::unique_fd bufferFence;
-    base::unique_fd drawFence;
     getRenderEngine().useProtectedContext(useProtected);
 
     const constexpr bool kUseFramebufferCache = false;
-    getRenderEngine().drawLayers(clientCompositionDisplay, clientCompositionLayerPointers, buffer,
-                                 kUseFramebufferCache, std::move(bufferFence), &drawFence);
+    auto [status, drawFence] =
+            getRenderEngine()
+                    .drawLayers(clientCompositionDisplay, clientCompositionLayerPointers, buffer,
+                                kUseFramebufferCache, std::move(bufferFence))
+                    .get();
 
     if (drawFence >= 0) {
         sp<Fence> releaseFence = new Fence(dup(drawFence));
@@ -6346,7 +6348,7 @@
     // Always switch back to unprotected context.
     getRenderEngine().useProtectedContext(false);
 
-    return NO_ERROR;
+    return status;
 }
 
 void SurfaceFlinger::windowInfosReported() {
diff --git a/services/surfaceflinger/TimeStats/OWNERS b/services/surfaceflinger/TimeStats/OWNERS
index ded3ebb..d78f5e2 100644
--- a/services/surfaceflinger/TimeStats/OWNERS
+++ b/services/surfaceflinger/TimeStats/OWNERS
@@ -1 +1,2 @@
+adyabr@google.com
 alecmouri@google.com
diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index 200ecbd..078b0d4 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -57,6 +57,7 @@
         "DisplayDevice_InitiateModeChange.cpp",
         "DisplayDevice_SetProjectionTest.cpp",
         "EventThreadTest.cpp",
+        "FlagManagerTest.cpp",
         "FpsReporterTest.cpp",
         "FpsTest.cpp",
         "FramebufferSurfaceTest.cpp",
@@ -164,6 +165,7 @@
         "libsync",
         "libui",
         "libutils",
+        "server_configurable_flags",
     ],
     header_libs: [
         "android.hardware.graphics.composer@2.1-command-buffer",
diff --git a/services/surfaceflinger/tests/unittests/CompositionTest.cpp b/services/surfaceflinger/tests/unittests/CompositionTest.cpp
index 93a4ce2..5135ff9 100644
--- a/services/surfaceflinger/tests/unittests/CompositionTest.cpp
+++ b/services/surfaceflinger/tests/unittests/CompositionTest.cpp
@@ -255,6 +255,14 @@
     LayerCase::cleanup(this);
 }
 
+template <class T>
+std::future<T> futureOf(T obj) {
+    std::promise<T> resultPromise;
+    std::future<T> resultFuture = resultPromise.get_future();
+    resultPromise.set_value(std::move(obj));
+    return resultFuture;
+}
+
 /* ------------------------------------------------------------------------
  * Variants for each display configuration which can be tested
  */
@@ -337,16 +345,18 @@
     template <typename Case>
     static void setupCommonScreensCaptureCallExpectations(CompositionTest* test) {
         EXPECT_CALL(*test->mRenderEngine, drawLayers)
-                .WillRepeatedly([](const renderengine::DisplaySettings& displaySettings,
-                                   const std::vector<const renderengine::LayerSettings*>&,
-                                   const std::shared_ptr<renderengine::ExternalTexture>&,
-                                   const bool, base::unique_fd&&, base::unique_fd*) -> status_t {
+                .WillRepeatedly([&](const renderengine::DisplaySettings& displaySettings,
+                                    const std::vector<const renderengine::LayerSettings*>&,
+                                    const std::shared_ptr<renderengine::ExternalTexture>&,
+                                    const bool, base::unique_fd &&)
+                                        -> std::future<renderengine::RenderEngineResult> {
                     EXPECT_EQ(DEFAULT_DISPLAY_MAX_LUMINANCE, displaySettings.maxLuminance);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.physicalDisplay);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.clip);
-                    return NO_ERROR;
+                    return futureOf<renderengine::RenderEngineResult>(
+                            {NO_ERROR, base::unique_fd()});
                 });
     }
 
@@ -386,17 +396,19 @@
                 .WillOnce(DoAll(SetArgPointee<0>(test->mNativeWindowBuffer), SetArgPointee<1>(-1),
                                 Return(0)));
         EXPECT_CALL(*test->mRenderEngine, drawLayers)
-                .WillRepeatedly([](const renderengine::DisplaySettings& displaySettings,
-                                   const std::vector<const renderengine::LayerSettings*>&,
-                                   const std::shared_ptr<renderengine::ExternalTexture>&,
-                                   const bool, base::unique_fd&&, base::unique_fd*) -> status_t {
+                .WillRepeatedly([&](const renderengine::DisplaySettings& displaySettings,
+                                    const std::vector<const renderengine::LayerSettings*>&,
+                                    const std::shared_ptr<renderengine::ExternalTexture>&,
+                                    const bool, base::unique_fd &&)
+                                        -> std::future<renderengine::RenderEngineResult> {
                     EXPECT_EQ(DEFAULT_DISPLAY_MAX_LUMINANCE, displaySettings.maxLuminance);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.physicalDisplay);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.clip);
                     EXPECT_EQ(ui::Dataspace::UNKNOWN, displaySettings.outputDataspace);
-                    return NO_ERROR;
+                    return futureOf<renderengine::RenderEngineResult>(
+                            {NO_ERROR, base::unique_fd()});
                 });
     }
 
@@ -620,10 +632,10 @@
 
     static void setupREBufferCompositionCommonCallExpectations(CompositionTest* test) {
         EXPECT_CALL(*test->mRenderEngine, drawLayers)
-                .WillOnce([](const renderengine::DisplaySettings& displaySettings,
-                             const std::vector<const renderengine::LayerSettings*>& layerSettings,
-                             const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
-                             base::unique_fd&&, base::unique_fd*) -> status_t {
+                .WillOnce([&](const renderengine::DisplaySettings& displaySettings,
+                              const std::vector<const renderengine::LayerSettings*>& layerSettings,
+                              const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                              base::unique_fd &&) -> std::future<renderengine::RenderEngineResult> {
                     EXPECT_EQ(DEFAULT_DISPLAY_MAX_LUMINANCE, displaySettings.maxLuminance);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.physicalDisplay);
@@ -631,11 +643,14 @@
                               displaySettings.clip);
                     // screen capture adds an additional color layer as an alpha
                     // prefill, so gtet the back layer.
+                    std::future<renderengine::RenderEngineResult> resultFuture =
+                            futureOf<renderengine::RenderEngineResult>(
+                                    {NO_ERROR, base::unique_fd()});
                     if (layerSettings.empty()) {
                         ADD_FAILURE() << "layerSettings was not expected to be empty in "
                                          "setupREBufferCompositionCommonCallExpectations "
                                          "verification lambda";
-                        return NO_ERROR;
+                        return resultFuture;
                     }
                     const renderengine::LayerSettings* layer = layerSettings.back();
                     EXPECT_THAT(layer->source.buffer.buffer, Not(IsNull()));
@@ -647,7 +662,7 @@
                     EXPECT_EQ(0.0, layer->geometry.roundedCornersRadius);
                     EXPECT_EQ(ui::Dataspace::UNKNOWN, layer->sourceDataspace);
                     EXPECT_EQ(LayerProperties::COLOR[3], layer->alpha);
-                    return NO_ERROR;
+                    return resultFuture;
                 });
     }
 
@@ -669,10 +684,10 @@
 
     static void setupREColorCompositionCallExpectations(CompositionTest* test) {
         EXPECT_CALL(*test->mRenderEngine, drawLayers)
-                .WillOnce([](const renderengine::DisplaySettings& displaySettings,
-                             const std::vector<const renderengine::LayerSettings*>& layerSettings,
-                             const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
-                             base::unique_fd&&, base::unique_fd*) -> status_t {
+                .WillOnce([&](const renderengine::DisplaySettings& displaySettings,
+                              const std::vector<const renderengine::LayerSettings*>& layerSettings,
+                              const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                              base::unique_fd &&) -> std::future<renderengine::RenderEngineResult> {
                     EXPECT_EQ(DEFAULT_DISPLAY_MAX_LUMINANCE, displaySettings.maxLuminance);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.physicalDisplay);
@@ -680,11 +695,14 @@
                               displaySettings.clip);
                     // screen capture adds an additional color layer as an alpha
                     // prefill, so get the back layer.
+                    std::future<renderengine::RenderEngineResult> resultFuture =
+                            futureOf<renderengine::RenderEngineResult>(
+                                    {NO_ERROR, base::unique_fd()});
                     if (layerSettings.empty()) {
                         ADD_FAILURE()
                                 << "layerSettings was not expected to be empty in "
                                    "setupREColorCompositionCallExpectations verification lambda";
-                        return NO_ERROR;
+                        return resultFuture;
                     }
                     const renderengine::LayerSettings* layer = layerSettings.back();
                     EXPECT_THAT(layer->source.buffer.buffer, IsNull());
@@ -694,7 +712,7 @@
                     EXPECT_EQ(0.0, layer->geometry.roundedCornersRadius);
                     EXPECT_EQ(ui::Dataspace::UNKNOWN, layer->sourceDataspace);
                     EXPECT_EQ(LayerProperties::COLOR[3], layer->alpha);
-                    return NO_ERROR;
+                    return resultFuture;
                 });
     }
 
@@ -746,10 +764,10 @@
 
     static void setupInsecureREBufferCompositionCommonCallExpectations(CompositionTest* test) {
         EXPECT_CALL(*test->mRenderEngine, drawLayers)
-                .WillOnce([](const renderengine::DisplaySettings& displaySettings,
-                             const std::vector<const renderengine::LayerSettings*>& layerSettings,
-                             const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
-                             base::unique_fd&&, base::unique_fd*) -> status_t {
+                .WillOnce([&](const renderengine::DisplaySettings& displaySettings,
+                              const std::vector<const renderengine::LayerSettings*>& layerSettings,
+                              const std::shared_ptr<renderengine::ExternalTexture>&, const bool,
+                              base::unique_fd &&) -> std::future<renderengine::RenderEngineResult> {
                     EXPECT_EQ(DEFAULT_DISPLAY_MAX_LUMINANCE, displaySettings.maxLuminance);
                     EXPECT_EQ(Rect(DEFAULT_DISPLAY_WIDTH, DEFAULT_DISPLAY_HEIGHT),
                               displaySettings.physicalDisplay);
@@ -757,11 +775,14 @@
                               displaySettings.clip);
                     // screen capture adds an additional color layer as an alpha
                     // prefill, so get the back layer.
+                    std::future<renderengine::RenderEngineResult> resultFuture =
+                            futureOf<renderengine::RenderEngineResult>(
+                                    {NO_ERROR, base::unique_fd()});
                     if (layerSettings.empty()) {
                         ADD_FAILURE() << "layerSettings was not expected to be empty in "
                                          "setupInsecureREBufferCompositionCommonCallExpectations "
                                          "verification lambda";
-                        return NO_ERROR;
+                        return resultFuture;
                     }
                     const renderengine::LayerSettings* layer = layerSettings.back();
                     EXPECT_THAT(layer->source.buffer.buffer, IsNull());
@@ -769,7 +790,7 @@
                     EXPECT_EQ(0.0, layer->geometry.roundedCornersRadius);
                     EXPECT_EQ(ui::Dataspace::UNKNOWN, layer->sourceDataspace);
                     EXPECT_EQ(1.0f, layer->alpha);
-                    return NO_ERROR;
+                    return resultFuture;
                 });
     }
 
diff --git a/services/surfaceflinger/tests/unittests/FlagManagerTest.cpp b/services/surfaceflinger/tests/unittests/FlagManagerTest.cpp
new file mode 100644
index 0000000..0905cd1
--- /dev/null
+++ b/services/surfaceflinger/tests/unittests/FlagManagerTest.cpp
@@ -0,0 +1,143 @@
+/*
+ * Copyright 2021 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.
+ */
+
+#include <cstdint>
+#undef LOG_TAG
+#define LOG_TAG "FlagManagerTest"
+
+#include "FlagManager.h"
+
+#include <android-base/properties.h>
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <log/log.h>
+#include <server_configurable_flags/get_flags.h>
+#include <optional>
+
+namespace android {
+
+using testing::Return;
+
+class MockFlagManager : public FlagManager {
+public:
+    MockFlagManager() = default;
+    ~MockFlagManager() = default;
+
+    MOCK_METHOD(std::string, getServerConfigurableFlag, (const std::string& experimentFlagName),
+                (const, override));
+};
+
+class FlagManagerTest : public testing::Test {
+public:
+    FlagManagerTest();
+    ~FlagManagerTest() override;
+    std::unique_ptr<MockFlagManager> mFlagManager;
+
+    template <typename T>
+    T getValue(const std::string& experimentFlagName, std::optional<T> systemPropertyOpt,
+               T defaultValue);
+};
+
+FlagManagerTest::FlagManagerTest() {
+    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());
+    mFlagManager = std::make_unique<MockFlagManager>();
+}
+
+FlagManagerTest::~FlagManagerTest() {
+    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());
+}
+
+template <typename T>
+T FlagManagerTest::getValue(const std::string& experimentFlagName,
+                            std::optional<T> systemPropertyOpt, T defaultValue) {
+    return mFlagManager->getValue(experimentFlagName, systemPropertyOpt, defaultValue);
+}
+
+namespace {
+TEST_F(FlagManagerTest, getValue_bool_default) {
+    EXPECT_CALL(*mFlagManager, getServerConfigurableFlag).Times(1).WillOnce(Return(""));
+    const bool defaultValue = false;
+    std::optional<bool> systemPropertyValue = std::nullopt;
+    const bool result = FlagManagerTest::getValue("test_flag", systemPropertyValue, defaultValue);
+    ASSERT_EQ(result, defaultValue);
+}
+
+TEST_F(FlagManagerTest, getValue_bool_sysprop) {
+    const bool defaultValue = false;
+    std::optional<bool> systemPropertyValue = std::make_optional(true);
+    const bool result = FlagManagerTest::getValue("test_flag", systemPropertyValue, defaultValue);
+    ASSERT_EQ(result, true);
+}
+
+TEST_F(FlagManagerTest, getValue_bool_experiment) {
+    EXPECT_CALL(*mFlagManager, getServerConfigurableFlag).Times(1).WillOnce(Return("1"));
+    const bool defaultValue = false;
+    std::optional<bool> systemPropertyValue = std::nullopt;
+    const bool result = FlagManagerTest::getValue("test_flag", systemPropertyValue, defaultValue);
+    ASSERT_EQ(result, true);
+}
+
+TEST_F(FlagManagerTest, getValue_int32_default) {
+    EXPECT_CALL(*mFlagManager, getServerConfigurableFlag).Times(1).WillOnce(Return(""));
+    int32_t defaultValue = 30;
+    std::optional<int32_t> systemPropertyValue = std::nullopt;
+    int32_t result = FlagManagerTest::getValue("test_flag", systemPropertyValue, defaultValue);
+    ASSERT_EQ(result, defaultValue);
+}
+
+TEST_F(FlagManagerTest, getValue_int32_sysprop) {
+    int32_t defaultValue = 30;
+    std::optional<int32_t> systemPropertyValue = std::make_optional(10);
+    int32_t result = FlagManagerTest::getValue("test_flag", systemPropertyValue, defaultValue);
+    ASSERT_EQ(result, 10);
+}
+
+TEST_F(FlagManagerTest, getValue_int32_experiment) {
+    EXPECT_CALL(*mFlagManager, getServerConfigurableFlag).Times(1).WillOnce(Return("50"));
+    std::int32_t defaultValue = 30;
+    std::optional<std::int32_t> systemPropertyValue = std::nullopt;
+    std::int32_t result = FlagManagerTest::getValue("test_flag", systemPropertyValue, defaultValue);
+    ASSERT_EQ(result, 50);
+}
+
+TEST_F(FlagManagerTest, getValue_int64_default) {
+    EXPECT_CALL(*mFlagManager, getServerConfigurableFlag).Times(1).WillOnce(Return(""));
+    int64_t defaultValue = 30;
+    std::optional<int64_t> systemPropertyValue = std::nullopt;
+    int64_t result = getValue("flag_name", systemPropertyValue, defaultValue);
+    ASSERT_EQ(result, defaultValue);
+}
+
+TEST_F(FlagManagerTest, getValue_int64_sysprop) {
+    int64_t defaultValue = 30;
+    std::optional<int64_t> systemPropertyValue = std::make_optional(10);
+    int64_t result = getValue("flag_name", systemPropertyValue, defaultValue);
+    ASSERT_EQ(result, 10);
+}
+
+TEST_F(FlagManagerTest, getValue_int64_experiment) {
+    EXPECT_CALL(*mFlagManager, getServerConfigurableFlag).Times(1).WillOnce(Return("50"));
+    int64_t defaultValue = 30;
+    std::optional<int64_t> systemPropertyValue = std::nullopt;
+    int64_t result = getValue("flag_name", systemPropertyValue, defaultValue);
+    ASSERT_EQ(result, 50);
+}
+} // namespace
+} // namespace android