diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFE.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFE.h
index 1fd07b0..791e7db 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFE.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFE.h
@@ -138,6 +138,9 @@
 
     // Gets the sequence number: a serial number that uniquely identifies a Layer
     virtual int32_t getSequence() const = 0;
+
+    // Whether the layer should be rendered with rounded corners.
+    virtual bool hasRoundedCorners() const = 0;
 };
 
 // TODO(b/121291683): Specialize std::hash<> for sp<T> so these and others can
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/OutputLayer.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/OutputLayer.h
index 3a84327..ead941d 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/OutputLayer.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/OutputLayer.h
@@ -16,6 +16,7 @@
 
 #pragma once
 
+#include <cstdint>
 #include <optional>
 #include <string>
 
@@ -90,8 +91,13 @@
     // Writes the geometry state to the HWC, or does nothing if this layer does
     // not use the HWC. If includeGeometry is false, the geometry state can be
     // skipped. If skipLayer is true, then the alpha of the layer is forced to
-    // 0 so that HWC will ignore it.
-    virtual void writeStateToHWC(bool includeGeometry, bool skipLayer) = 0;
+    // 0 so that HWC will ignore it. z specifies the order to draw the layer in
+    // (starting with 0 for the back layer, and increasing for each following
+    // layer). zIsOverridden specifies whether the layer has been reordered.
+    // isPeekingThrough specifies whether this layer will be shown through a
+    // hole punch in a layer above it.
+    virtual void writeStateToHWC(bool includeGeometry, bool skipLayer, uint32_t z,
+                                 bool zIsOverridden, bool isPeekingThrough) = 0;
 
     // Updates the cursor position with the HWC
     virtual void writeCursorPositionToHWC() const = 0;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputLayer.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputLayer.h
index ae88e78..2488c66 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputLayer.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputLayer.h
@@ -16,6 +16,7 @@
 
 #pragma once
 
+#include <cstdint>
 #include <memory>
 #include <string>
 
@@ -42,7 +43,8 @@
 
     void updateCompositionState(bool includeGeometry, bool forceClientComposition,
                                 ui::Transform::RotationFlags) override;
-    void writeStateToHWC(bool includeGeometry, bool skipLayer) override;
+    void writeStateToHWC(bool includeGeometry, bool skipLayer, uint32_t z, bool zIsOverridden,
+                         bool isPeekingThrough) override;
     void writeCursorPositionToHWC() const override;
 
     HWC2::Layer* getHwcLayer() const override;
@@ -66,7 +68,8 @@
 
 private:
     Rect calculateInitialCrop() const;
-    void writeOutputDependentGeometryStateToHWC(HWC2::Layer*, Hwc2::IComposerClient::Composition);
+    void writeOutputDependentGeometryStateToHWC(HWC2::Layer*, Hwc2::IComposerClient::Composition,
+                                                uint32_t z);
     void writeOutputIndependentGeometryStateToHWC(HWC2::Layer*, const LayerFECompositionState&,
                                                   bool skipLayer);
     void writeOutputDependentPerFrameStateToHWC(HWC2::Layer*);
@@ -74,7 +77,8 @@
     void writeSolidColorStateToHWC(HWC2::Layer*, const LayerFECompositionState&);
     void writeSidebandStateToHWC(HWC2::Layer*, const LayerFECompositionState&);
     void writeBufferStateToHWC(HWC2::Layer*, const LayerFECompositionState&);
-    void writeCompositionTypeToHWC(HWC2::Layer*, Hwc2::IComposerClient::Composition);
+    void writeCompositionTypeToHWC(HWC2::Layer*, Hwc2::IComposerClient::Composition,
+                                   bool isPeekingThrough);
     void detectDisallowedCompositionTypeChange(Hwc2::IComposerClient::Composition from,
                                                Hwc2::IComposerClient::Composition to) const;
 };
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputLayerCompositionState.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputLayerCompositionState.h
index c61ec59..356965c 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputLayerCompositionState.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputLayerCompositionState.h
@@ -46,6 +46,10 @@
 
 class HWComposer;
 
+namespace compositionengine {
+class OutputLayer;
+} // namespace compositionengine
+
 namespace compositionengine::impl {
 
 // Note that fields that affect HW composer state may need to be mirrored into
@@ -84,9 +88,6 @@
     // The dataspace for this layer
     ui::Dataspace dataspace{ui::Dataspace::UNKNOWN};
 
-    // The Z order index of this layer on this output
-    uint32_t z{0};
-
     // Overrides the buffer, acquire fence, and display frame stored in LayerFECompositionState
     struct {
         std::shared_ptr<renderengine::ExternalTexture> buffer = nullptr;
@@ -96,6 +97,12 @@
         ProjectionSpace displaySpace;
         Region damageRegion = Region::INVALID_REGION;
         Region visibleRegion;
+
+        // The OutputLayer pointed to by this field will be rearranged to draw
+        // behind the OutputLayer represented by this CompositionState and will
+        // be visible through it. Unowned - the OutputLayer's lifetime will
+        // outlast this.)
+        OutputLayer* peekThroughLayer = nullptr;
     } overrideInfo;
 
     /*
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/CachedSet.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/CachedSet.h
index 53f4a30..1ee0e2f 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/CachedSet.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/CachedSet.h
@@ -105,12 +105,32 @@
 
     void dump(std::string& result) const;
 
+    // Whether this represents a single layer with a buffer and rounded corners.
+    // If it is, we may be able to draw it by placing it behind another
+    // CachedSet and punching a hole.
+    bool requiresHolePunch() const;
+
+    // Add a layer that will be drawn behind this one. ::render() will render a
+    // hole in this CachedSet's buffer, allowing the supplied layer to peek
+    // through. Must be called before ::render().
+    // Will do nothing if this CachedSet is not opaque where the hole punch
+    // layer is displayed.
+    // If isFirstLayer is true, this CachedSet can be considered opaque because
+    // nothing (besides the hole punch layer) will be drawn behind it.
+    void addHolePunchLayerIfFeasible(const CachedSet&, bool isFirstLayer);
+
+    // Retrieve the layer that will be drawn behind this one.
+    OutputLayer* getHolePunchLayer() const;
+
 private:
     CachedSet() = default;
 
     const NonBufferHash mFingerprint;
     std::chrono::steady_clock::time_point mLastUpdate = std::chrono::steady_clock::now();
     std::vector<Layer> mLayers;
+
+    // Unowned.
+    const LayerState* mHolePunchLayer = nullptr;
     Rect mBounds = Rect::EMPTY_RECT;
     Region mVisibleRegion;
     size_t mAge = 0;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h
index 2f2ad4c..942592a 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h
@@ -36,7 +36,8 @@
 
 class Flattener {
 public:
-    Flattener(Predictor& predictor) : mPredictor(predictor) {}
+    Flattener(Predictor& predictor, bool enableHolePunch = false)
+          : mEnableHolePunch(enableHolePunch), mPredictor(predictor) {}
 
     void setDisplaySize(ui::Size size) { mDisplaySize = size; }
 
@@ -61,6 +62,7 @@
 
     void buildCachedSets(std::chrono::steady_clock::time_point now);
 
+    const bool mEnableHolePunch;
     Predictor& mPredictor;
 
     ui::Size mDisplaySize;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/LayerState.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/LayerState.h
index f2f6c0b..3391273 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/LayerState.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/LayerState.h
@@ -53,20 +53,19 @@
     Name            = 1u << 1,
     DisplayFrame    = 1u << 2,
     SourceCrop      = 1u << 3,
-    ZOrder          = 1u << 4,
-    BufferTransform = 1u << 5,
-    BlendMode       = 1u << 6,
-    Alpha           = 1u << 7,
-    LayerMetadata   = 1u << 8,
-    VisibleRegion   = 1u << 9,
-    Dataspace       = 1u << 10,
-    PixelFormat     = 1u << 11,
-    ColorTransform  = 1u << 12,
-    SurfaceDamage   = 1u << 13,
-    CompositionType = 1u << 14,
-    SidebandStream  = 1u << 15,
-    Buffer          = 1u << 16,
-    SolidColor      = 1u << 17,
+    BufferTransform = 1u << 4,
+    BlendMode       = 1u << 5,
+    Alpha           = 1u << 6,
+    LayerMetadata   = 1u << 7,
+    VisibleRegion   = 1u << 8,
+    Dataspace       = 1u << 9,
+    PixelFormat     = 1u << 10,
+    ColorTransform  = 1u << 11,
+    SurfaceDamage   = 1u << 12,
+    CompositionType = 1u << 13,
+    SidebandStream  = 1u << 14,
+    Buffer          = 1u << 15,
+    SolidColor      = 1u << 16,
 };
 // clang-format on
 
@@ -271,9 +270,6 @@
                                                        rect.top, rect.right, rect.bottom)};
                         }};
 
-    OutputLayerState<uint32_t, LayerStateField::ZOrder> mZOrder{
-            [](auto layer) { return layer->getState().z; }};
-
     using BufferTransformState = OutputLayerState<hardware::graphics::composer::hal::Transform,
                                                   LayerStateField::BufferTransform>;
     BufferTransformState mBufferTransform{[](auto layer) {
@@ -402,7 +398,7 @@
                             return std::vector<std::string>{stream.str()};
                         }};
 
-    static const constexpr size_t kNumNonUniqueFields = 15;
+    static const constexpr size_t kNumNonUniqueFields = 14;
 
     std::array<StateInterface*, kNumNonUniqueFields> getNonUniqueFields() {
         std::array<const StateInterface*, kNumNonUniqueFields> constFields =
@@ -417,10 +413,10 @@
 
     std::array<const StateInterface*, kNumNonUniqueFields> getNonUniqueFields() const {
         return {
-                &mDisplayFrame,    &mSourceCrop,     &mZOrder,         &mBufferTransform,
-                &mBlendMode,       &mAlpha,          &mLayerMetadata,  &mVisibleRegion,
-                &mOutputDataspace, &mPixelFormat,    &mColorTransform, &mCompositionType,
-                &mSidebandStream,  &mBuffer,         &mSolidColor,
+                &mDisplayFrame, &mSourceCrop,     &mBufferTransform, &mBlendMode,
+                &mAlpha,        &mLayerMetadata,  &mVisibleRegion,   &mOutputDataspace,
+                &mPixelFormat,  &mColorTransform, &mCompositionType, &mSidebandStream,
+                &mBuffer,       &mSolidColor,
         };
     }
 };
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Planner.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Planner.h
index e6d2b63..c2037a8 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Planner.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Planner.h
@@ -41,7 +41,7 @@
 // as a more efficient representation of parts of the layer stack.
 class Planner {
 public:
-    Planner() : mFlattener(mPredictor) {}
+    Planner();
 
     void setDisplaySize(ui::Size);
 
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/LayerFE.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/LayerFE.h
index dde8999..d215bda 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/LayerFE.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/LayerFE.h
@@ -43,6 +43,7 @@
 
     MOCK_CONST_METHOD0(getDebugName, const char*());
     MOCK_CONST_METHOD0(getSequence, int32_t());
+    MOCK_CONST_METHOD0(hasRoundedCorners, bool());
 };
 
 } // namespace android::compositionengine::mock
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/OutputLayer.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/OutputLayer.h
index 2454ff7..358ed5a 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/OutputLayer.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/OutputLayer.h
@@ -22,6 +22,7 @@
 #include <compositionengine/OutputLayer.h>
 #include <compositionengine/impl/OutputLayerCompositionState.h>
 #include <gmock/gmock.h>
+#include <cstdint>
 
 namespace android::compositionengine::mock {
 
@@ -39,7 +40,7 @@
     MOCK_METHOD0(editState, impl::OutputLayerCompositionState&());
 
     MOCK_METHOD3(updateCompositionState, void(bool, bool, ui::Transform::RotationFlags));
-    MOCK_METHOD2(writeStateToHWC, void(bool, bool));
+    MOCK_METHOD5(writeStateToHWC, void(bool, bool, uint32_t, bool, bool));
     MOCK_CONST_METHOD0(writeCursorPositionToHWC, void());
 
     MOCK_CONST_METHOD0(getHwcLayer, HWC2::Layer*());
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index faa4b74..c809e1a 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -455,12 +455,6 @@
     setReleasedLayers(refreshArgs);
 
     finalizePendingOutputLayers();
-
-    // Generate a simple Z-order values to each visible output layer
-    uint32_t zOrder = 0;
-    for (auto* outputLayer : getOutputLayersOrderedByZ()) {
-        outputLayer->editState().z = zOrder++;
-    }
 }
 
 void Output::ensureOutputLayerIfVisible(sp<compositionengine::LayerFE>& layerFE,
@@ -713,20 +707,45 @@
 
     editState().earliestPresentTime = refreshArgs.earliestPresentTime;
 
+    OutputLayer* peekThroughLayer = nullptr;
     sp<GraphicBuffer> previousOverride = nullptr;
+    bool includeGeometry = refreshArgs.updatingGeometryThisFrame;
+    uint32_t z = 0;
+    bool overrideZ = false;
     for (auto* layer : getOutputLayersOrderedByZ()) {
+        if (layer == peekThroughLayer) {
+            // No longer needed, although it should not show up again, so
+            // resetting it is not truly needed either.
+            peekThroughLayer = nullptr;
+
+            // peekThroughLayer was already drawn ahead of its z order.
+            continue;
+        }
         bool skipLayer = false;
-        if (layer->getState().overrideInfo.buffer != nullptr) {
-            if (previousOverride != nullptr &&
-                layer->getState().overrideInfo.buffer->getBuffer() == previousOverride) {
+        const auto& overrideInfo = layer->getState().overrideInfo;
+        if (overrideInfo.buffer != nullptr) {
+            if (previousOverride && overrideInfo.buffer->getBuffer() == previousOverride) {
                 ALOGV("Skipping redundant buffer");
                 skipLayer = true;
+            } else {
+                // First layer with the override buffer.
+                if (overrideInfo.peekThroughLayer) {
+                    peekThroughLayer = overrideInfo.peekThroughLayer;
+
+                    // Draw peekThroughLayer first.
+                    overrideZ = true;
+                    includeGeometry = true;
+                    constexpr bool isPeekingThrough = true;
+                    peekThroughLayer->writeStateToHWC(includeGeometry, false, z++, overrideZ,
+                                                      isPeekingThrough);
+                }
+
+                previousOverride = overrideInfo.buffer->getBuffer();
             }
-            previousOverride = layer->getState().overrideInfo.buffer->getBuffer();
         }
 
-        const bool includeGeometry = refreshArgs.updatingGeometryThisFrame;
-        layer->writeStateToHWC(includeGeometry, skipLayer);
+        constexpr bool isPeekingThrough = false;
+        layer->writeStateToHWC(includeGeometry, skipLayer, z++, overrideZ, isPeekingThrough);
     }
 }
 
diff --git a/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp b/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
index 9ca8914..d3e2c25 100644
--- a/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
@@ -21,6 +21,7 @@
 #include <compositionengine/impl/OutputCompositionState.h>
 #include <compositionengine/impl/OutputLayer.h>
 #include <compositionengine/impl/OutputLayerCompositionState.h>
+#include <cstdint>
 
 // TODO(b/129481165): remove the #pragma below and fix conversion issues
 #pragma clang diagnostic push
@@ -312,7 +313,8 @@
     }
 }
 
-void OutputLayer::writeStateToHWC(bool includeGeometry, bool skipLayer) {
+void OutputLayer::writeStateToHWC(bool includeGeometry, bool skipLayer, uint32_t z,
+                                  bool zIsOverridden, bool isPeekingThrough) {
     const auto& state = getState();
     // Skip doing this if there is no HWC interface
     if (!state.hwc) {
@@ -335,10 +337,11 @@
 
     // TODO(b/181172795): We now update geometry for all flattened layers. We should update it
     // only when the geometry actually changes
-    const bool isOverridden = state.overrideInfo.buffer != nullptr;
+    const bool isOverridden =
+            state.overrideInfo.buffer != nullptr || isPeekingThrough || zIsOverridden;
     const bool prevOverridden = state.hwc->stateOverridden;
     if (isOverridden || prevOverridden || skipLayer || includeGeometry) {
-        writeOutputDependentGeometryStateToHWC(hwcLayer.get(), requestedCompositionType);
+        writeOutputDependentGeometryStateToHWC(hwcLayer.get(), requestedCompositionType, z);
         writeOutputIndependentGeometryStateToHWC(hwcLayer.get(), *outputIndependentState,
                                                  skipLayer);
     }
@@ -346,7 +349,7 @@
     writeOutputDependentPerFrameStateToHWC(hwcLayer.get());
     writeOutputIndependentPerFrameStateToHWC(hwcLayer.get(), *outputIndependentState);
 
-    writeCompositionTypeToHWC(hwcLayer.get(), requestedCompositionType);
+    writeCompositionTypeToHWC(hwcLayer.get(), requestedCompositionType, isPeekingThrough);
 
     // Always set the layer color after setting the composition type.
     writeSolidColorStateToHWC(hwcLayer.get(), *outputIndependentState);
@@ -354,8 +357,9 @@
     editState().hwc->stateOverridden = isOverridden;
 }
 
-void OutputLayer::writeOutputDependentGeometryStateToHWC(
-        HWC2::Layer* hwcLayer, hal::Composition requestedCompositionType) {
+void OutputLayer::writeOutputDependentGeometryStateToHWC(HWC2::Layer* hwcLayer,
+                                                         hal::Composition requestedCompositionType,
+                                                         uint32_t z) {
     const auto& outputDependentState = getState();
 
     Rect displayFrame = outputDependentState.displayFrame;
@@ -382,9 +386,9 @@
               sourceCrop.bottom, to_string(error).c_str(), static_cast<int32_t>(error));
     }
 
-    if (auto error = hwcLayer->setZOrder(outputDependentState.z); error != hal::Error::NONE) {
-        ALOGE("[%s] Failed to set Z %u: %s (%d)", getLayerFE().getDebugName(),
-              outputDependentState.z, to_string(error).c_str(), static_cast<int32_t>(error));
+    if (auto error = hwcLayer->setZOrder(z); error != hal::Error::NONE) {
+        ALOGE("[%s] Failed to set Z %u: %s (%d)", getLayerFE().getDebugName(), z,
+              to_string(error).c_str(), static_cast<int32_t>(error));
     }
 
     // Solid-color layers and overridden buffers should always use an identity transform.
@@ -403,7 +407,10 @@
 void OutputLayer::writeOutputIndependentGeometryStateToHWC(
         HWC2::Layer* hwcLayer, const LayerFECompositionState& outputIndependentState,
         bool skipLayer) {
-    const auto blendMode = getState().overrideInfo.buffer
+    // If there is a peekThroughLayer, then this layer has a hole in it. We need to use
+    // PREMULTIPLIED so it will peek through.
+    const auto& overrideInfo = getState().overrideInfo;
+    const auto blendMode = overrideInfo.buffer || overrideInfo.peekThroughLayer
             ? hardware::graphics::composer::hal::BlendMode::PREMULTIPLIED
             : outputIndependentState.blendMode;
     if (auto error = hwcLayer->setBlendMode(blendMode); error != hal::Error::NONE) {
@@ -558,11 +565,13 @@
 }
 
 void OutputLayer::writeCompositionTypeToHWC(HWC2::Layer* hwcLayer,
-                                            hal::Composition requestedCompositionType) {
+                                            hal::Composition requestedCompositionType,
+                                            bool isPeekingThrough) {
     auto& outputDependentState = editState();
 
     // If we are forcing client composition, we need to tell the HWC
-    if (outputDependentState.forceClientComposition) {
+    if (outputDependentState.forceClientComposition ||
+        (!isPeekingThrough && getLayerFE().hasRoundedCorners())) {
         requestedCompositionType = hal::Composition::CLIENT;
     }
 
diff --git a/services/surfaceflinger/CompositionEngine/src/OutputLayerCompositionState.cpp b/services/surfaceflinger/CompositionEngine/src/OutputLayerCompositionState.cpp
index efd23dc..b4c314c 100644
--- a/services/surfaceflinger/CompositionEngine/src/OutputLayerCompositionState.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/OutputLayerCompositionState.cpp
@@ -67,7 +67,6 @@
     dumpVal(out, "sourceCrop", sourceCrop);
     dumpVal(out, "bufferTransform", toString(bufferTransform), bufferTransform);
     dumpVal(out, "dataspace", toString(dataspace), dataspace);
-    dumpVal(out, "z-index", z);
     dumpVal(out, "override buffer", overrideInfo.buffer.get());
     dumpVal(out, "override acquire fence", overrideInfo.acquireFence.get());
     dumpVal(out, "override display frame", overrideInfo.displayFrame);
diff --git a/services/surfaceflinger/CompositionEngine/src/planner/CachedSet.cpp b/services/surfaceflinger/CompositionEngine/src/planner/CachedSet.cpp
index 9955e29..b31e89e 100644
--- a/services/surfaceflinger/CompositionEngine/src/planner/CachedSet.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/planner/CachedSet.cpp
@@ -193,6 +193,23 @@
     std::transform(layerSettings.cbegin(), layerSettings.cend(),
                    std::back_inserter(layerSettingsPointers),
                    [](const renderengine::LayerSettings& settings) { return &settings; });
+    renderengine::LayerSettings holePunchSettings;
+    if (mHolePunchLayer) {
+        auto clientCompositionList =
+                mHolePunchLayer->getOutputLayer()->getLayerFE().prepareClientCompositionList(
+                        targetSettings);
+        // Assume that the final layer contains the buffer that we want to
+        // replace with a hole punch.
+        holePunchSettings = clientCompositionList.back();
+        LOG_ALWAYS_FATAL_IF(!holePunchSettings.source.buffer.buffer, "Expected to have a buffer!");
+        // This mimics Layer::prepareClearClientComposition
+        holePunchSettings.source.buffer.buffer = nullptr;
+        holePunchSettings.source.solidColor = half3(0.0f, 0.0f, 0.0f);
+        holePunchSettings.disableBlending = true;
+        holePunchSettings.alpha = 0.0f;
+        holePunchSettings.name = std::string("hole punch layer");
+        layerSettingsPointers.push_back(&holePunchSettings);
+    }
 
     if (sDebugHighlighLayers) {
         highlight = {
@@ -241,6 +258,56 @@
     }
 }
 
+bool CachedSet::requiresHolePunch() const {
+    // In order for the hole punch to be beneficial, the layer must be updating
+    // regularly, meaning  it should not have been merged with other layers.
+    if (getLayerCount() != 1) {
+        return false;
+    }
+
+    // There is no benefit to a hole punch unless the layer has a buffer.
+    if (!mLayers[0].getBuffer()) {
+        return false;
+    }
+
+    const auto& layerFE = mLayers[0].getState()->getOutputLayer()->getLayerFE();
+    if (layerFE.getCompositionState()->forceClientComposition) {
+        return false;
+    }
+
+    return layerFE.hasRoundedCorners();
+}
+
+namespace {
+bool contains(const Rect& outer, const Rect& inner) {
+    return outer.left <= inner.left && outer.right >= inner.right && outer.top <= inner.top &&
+            outer.bottom >= inner.bottom;
+}
+}; // namespace
+
+void CachedSet::addHolePunchLayerIfFeasible(const CachedSet& holePunchLayer, bool isFirstLayer) {
+    // Verify that this CachedSet is opaque where the hole punch layer
+    // will draw.
+    const Rect& holePunchBounds = holePunchLayer.getBounds();
+    for (const auto& layer : mLayers) {
+        // The first layer is considered opaque because nothing is behind it.
+        // Note that isOpaque is always false for a layer with rounded
+        // corners, even if the interior is opaque. In theory, such a layer
+        // could be used for a hole punch, but this is unlikely to happen in
+        // practice.
+        const auto* outputLayer = layer.getState()->getOutputLayer();
+        if (contains(outputLayer->getState().displayFrame, holePunchBounds) &&
+            (isFirstLayer || outputLayer->getLayerFE().getCompositionState()->isOpaque)) {
+            mHolePunchLayer = holePunchLayer.getFirstLayer().getState();
+            return;
+        }
+    }
+}
+
+OutputLayer* CachedSet::getHolePunchLayer() const {
+    return mHolePunchLayer ? mHolePunchLayer->getOutputLayer() : nullptr;
+}
+
 void CachedSet::dump(std::string& result) const {
     const auto now = std::chrono::steady_clock::now();
 
@@ -248,6 +315,11 @@
             std::chrono::duration_cast<std::chrono::milliseconds>(now - mLastUpdate);
     base::StringAppendF(&result, "  + Fingerprint %016zx, last update %sago, age %zd\n",
                         mFingerprint, durationString(lastUpdate).c_str(), mAge);
+    {
+        const auto b = mTexture ? mTexture->getBuffer().get() : nullptr;
+        base::StringAppendF(&result, "    Override buffer: %p\n", b);
+    }
+    base::StringAppendF(&result, "    HolePunchLayer: %p\n", mHolePunchLayer);
 
     if (mLayers.size() == 1) {
         base::StringAppendF(&result, "    Layer [%s]\n", mLayers[0].getName().c_str());
diff --git a/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp b/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp
index 9c9649c..13de622 100644
--- a/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp
@@ -209,6 +209,7 @@
                 ALOGV("[%s] Found ready buffer", __func__);
                 size_t skipCount = mNewCachedSet->getLayerCount();
                 while (skipCount != 0) {
+                    auto* peekThroughLayer = mNewCachedSet->getHolePunchLayer();
                     const size_t layerCount = currentLayerIter->getLayerCount();
                     for (size_t i = 0; i < layerCount; ++i) {
                         OutputLayer::CompositionState& state =
@@ -221,6 +222,7 @@
                                 .displaySpace = mNewCachedSet->getOutputSpace(),
                                 .damageRegion = Region::INVALID_REGION,
                                 .visibleRegion = mNewCachedSet->getVisibleRegion(),
+                                .peekThroughLayer = peekThroughLayer,
                         };
                         ++incomingLayerIter;
                     }
@@ -244,6 +246,7 @@
 
             // Skip the incoming layers corresponding to this valid current layer
             const size_t layerCount = currentLayerIter->getLayerCount();
+            auto* peekThroughLayer = currentLayerIter->getHolePunchLayer();
             for (size_t i = 0; i < layerCount; ++i) {
                 OutputLayer::CompositionState& state =
                         (*incomingLayerIter)->getOutputLayer()->editState();
@@ -255,6 +258,7 @@
                         .displaySpace = currentLayerIter->getOutputSpace(),
                         .damageRegion = Region(),
                         .visibleRegion = currentLayerIter->getVisibleRegion(),
+                        .peekThroughLayer = peekThroughLayer,
                 };
                 ++incomingLayerIter;
             }
@@ -298,6 +302,11 @@
 
     std::vector<Run> runs;
     bool isPartOfRun = false;
+
+    // Keep track of the layer that follows a run. It's possible that we will
+    // render it with a hole-punch.
+    const CachedSet* holePunchLayer = nullptr;
+
     for (auto currentSet = mLayers.cbegin(); currentSet != mLayers.cend(); ++currentSet) {
         if (now - currentSet->getLastUpdate() > kActiveLayerTimeout) {
             // Layer is inactive
@@ -312,10 +321,20 @@
                     isPartOfRun = true;
                 }
             }
-        } else {
+        } else if (isPartOfRun) {
             // Runs must be at least 2 sets long or there's nothing to combine
-            if (isPartOfRun && runs.back().start->getLayerCount() == runs.back().length) {
+            if (runs.back().start->getLayerCount() == runs.back().length) {
                 runs.pop_back();
+            } else {
+                // The prior run contained at least two sets. Currently, we'll
+                // only possibly merge a single run, so only keep track of a
+                // holePunchLayer if this is the first run.
+                if (runs.size() == 1) {
+                    holePunchLayer = &(*currentSet);
+                }
+
+                // TODO(b/185114532: Break out of the loop? We may find more runs, but we
+                // won't do anything with them.
             }
 
             isPartOfRun = false;
@@ -341,6 +360,13 @@
         mNewCachedSet->append(*currentSet);
     }
 
+    if (mEnableHolePunch && holePunchLayer && holePunchLayer->requiresHolePunch()) {
+        // Add the pip layer to mNewCachedSet, but in a special way - it should
+        // replace the buffer with a clear round rect.
+        mNewCachedSet->addHolePunchLayerIfFeasible(*holePunchLayer,
+                                                   runs[0].start == mLayers.cbegin());
+    }
+
     // TODO(b/181192467): Actually compute new LayerState vector and corresponding hash for each run
     mPredictor.getPredictedPlan({}, 0);
 
diff --git a/services/surfaceflinger/CompositionEngine/src/planner/LayerState.cpp b/services/surfaceflinger/CompositionEngine/src/planner/LayerState.cpp
index ab85997..8423a12 100644
--- a/services/surfaceflinger/CompositionEngine/src/planner/LayerState.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/planner/LayerState.cpp
@@ -155,10 +155,9 @@
 
 bool operator==(const LayerState& lhs, const LayerState& rhs) {
     return lhs.mId == rhs.mId && lhs.mName == rhs.mName && lhs.mDisplayFrame == rhs.mDisplayFrame &&
-            lhs.mSourceCrop == rhs.mSourceCrop && lhs.mZOrder == rhs.mZOrder &&
-            lhs.mBufferTransform == rhs.mBufferTransform && lhs.mBlendMode == rhs.mBlendMode &&
-            lhs.mAlpha == rhs.mAlpha && lhs.mLayerMetadata == rhs.mLayerMetadata &&
-            lhs.mVisibleRegion == rhs.mVisibleRegion &&
+            lhs.mSourceCrop == rhs.mSourceCrop && lhs.mBufferTransform == rhs.mBufferTransform &&
+            lhs.mBlendMode == rhs.mBlendMode && lhs.mAlpha == rhs.mAlpha &&
+            lhs.mLayerMetadata == rhs.mLayerMetadata && lhs.mVisibleRegion == rhs.mVisibleRegion &&
             lhs.mOutputDataspace == rhs.mOutputDataspace && lhs.mPixelFormat == rhs.mPixelFormat &&
             lhs.mColorTransform == rhs.mColorTransform &&
             lhs.mCompositionType == rhs.mCompositionType &&
diff --git a/services/surfaceflinger/CompositionEngine/src/planner/Planner.cpp b/services/surfaceflinger/CompositionEngine/src/planner/Planner.cpp
index 3a2534b..7d2bf06 100644
--- a/services/surfaceflinger/CompositionEngine/src/planner/Planner.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/planner/Planner.cpp
@@ -19,12 +19,17 @@
 #undef LOG_TAG
 #define LOG_TAG "Planner"
 
+#include <android-base/properties.h>
 #include <compositionengine/LayerFECompositionState.h>
 #include <compositionengine/impl/OutputLayerCompositionState.h>
 #include <compositionengine/impl/planner/Planner.h>
 
 namespace android::compositionengine::impl::planner {
 
+Planner::Planner()
+      : mFlattener(mPredictor,
+                   base::GetBoolProperty(std::string("debug.sf.enable_hole_punch_pip"), false)) {}
+
 void Planner::setDisplaySize(ui::Size size) {
     mFlattener.setDisplaySize(size);
 }
diff --git a/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp b/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
index 4c3f494..5a92f26 100644
--- a/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
@@ -689,7 +689,6 @@
 struct OutputLayerWriteStateToHWCTest : public OutputLayerTest {
     static constexpr hal::Error kError = hal::Error::UNSUPPORTED;
     static constexpr FloatRect kSourceCrop{11.f, 12.f, 13.f, 14.f};
-    static constexpr uint32_t kZOrder = 21u;
     static constexpr Hwc2::Transform kBufferTransform = static_cast<Hwc2::Transform>(31);
     static constexpr Hwc2::Transform kOverrideBufferTransform = static_cast<Hwc2::Transform>(0);
     static constexpr Hwc2::IComposerClient::BlendMode kBlendMode =
@@ -735,7 +734,6 @@
 
         outputLayerState.displayFrame = kDisplayFrame;
         outputLayerState.sourceCrop = kSourceCrop;
-        outputLayerState.z = kZOrder;
         outputLayerState.bufferTransform = static_cast<Hwc2::Transform>(kBufferTransform);
         outputLayerState.outputSpaceVisibleRegion = kOutputSpaceVisibleRegion;
         outputLayerState.dataspace = kDataspace;
@@ -785,7 +783,7 @@
                                    float alpha = kAlpha) {
         EXPECT_CALL(*mHwcLayer, setDisplayFrame(displayFrame)).WillOnce(Return(kError));
         EXPECT_CALL(*mHwcLayer, setSourceCrop(sourceCrop)).WillOnce(Return(kError));
-        EXPECT_CALL(*mHwcLayer, setZOrder(kZOrder)).WillOnce(Return(kError));
+        EXPECT_CALL(*mHwcLayer, setZOrder(_)).WillOnce(Return(kError));
         EXPECT_CALL(*mHwcLayer, setTransform(bufferTransform)).WillOnce(Return(kError));
 
         EXPECT_CALL(*mHwcLayer, setBlendMode(blendMode)).WillOnce(Return(kError));
@@ -878,19 +876,22 @@
 TEST_F(OutputLayerWriteStateToHWCTest, doesNothingIfNoFECompositionState) {
     EXPECT_CALL(*mLayerFE, getCompositionState()).WillOnce(Return(nullptr));
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false);
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, doesNothingIfNoHWCState) {
     mOutputLayer.editState().hwc.reset();
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false);
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, doesNothingIfNoHWCLayer) {
     mOutputLayer.editState().hwc = impl::OutputLayerCompositionState::Hwc(nullptr);
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false);
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, canSetAllState) {
@@ -898,8 +899,10 @@
     expectPerFrameCommonCalls();
 
     expectNoSetCompositionTypeCall();
+    EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillOnce(Return(false));
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false);
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerTest, displayInstallOrientationBufferTransformSetTo90) {
@@ -921,6 +924,7 @@
     mLayerFEState.compositionType = Hwc2::IComposerClient::Composition::SOLID_COLOR;
 
     expectPerFrameCommonCalls();
+    EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillOnce(Return(false));
 
     // Setting the composition type should happen before setting the color. We
     // check this in this test only by setting up an testing::InSeqeuence
@@ -929,7 +933,8 @@
     expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::SOLID_COLOR);
     expectSetColorCall();
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false);
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, canSetPerFrameStateForSideband) {
@@ -939,7 +944,10 @@
     expectSetSidebandHandleCall();
     expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::SIDEBAND);
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false);
+    EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillOnce(Return(false));
+
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, canSetPerFrameStateForCursor) {
@@ -949,7 +957,10 @@
     expectSetHdrMetadataAndBufferCalls();
     expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::CURSOR);
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false);
+    EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillOnce(Return(false));
+
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, canSetPerFrameStateForDevice) {
@@ -959,7 +970,10 @@
     expectSetHdrMetadataAndBufferCalls();
     expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::DEVICE);
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false);
+    EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillOnce(Return(false));
+
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, compositionTypeIsNotSetIfUnchanged) {
@@ -972,7 +986,10 @@
     expectSetColorCall();
     expectNoSetCompositionTypeCall();
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false);
+    EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillOnce(Return(false));
+
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, compositionTypeIsSetToClientIfColorTransformNotSupported) {
@@ -982,7 +999,8 @@
     expectSetColorCall();
     expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::CLIENT);
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false);
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, compositionTypeIsSetToClientIfClientCompositionForced) {
@@ -994,7 +1012,8 @@
     expectSetColorCall();
     expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::CLIENT);
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false);
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, allStateIncludesMetadataIfPresent) {
@@ -1007,7 +1026,10 @@
     expectGenericLayerMetadataCalls();
     expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::DEVICE);
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false);
+    EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillOnce(Return(false));
+
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, perFrameStateDoesNotIncludeMetadataIfPresent) {
@@ -1018,7 +1040,10 @@
     expectSetHdrMetadataAndBufferCalls();
     expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::DEVICE);
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false);
+    EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillOnce(Return(false));
+
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 TEST_F(OutputLayerWriteStateToHWCTest, includesOverrideInfoIfPresent) {
@@ -1032,7 +1057,10 @@
     expectSetHdrMetadataAndBufferCalls(kOverrideBuffer->getBuffer(), kOverrideFence);
     expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::DEVICE);
 
-    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false);
+    EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillOnce(Return(false));
+
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
 /*
diff --git a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
index e80100c..7b71957 100644
--- a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
@@ -30,6 +30,7 @@
 #include <ui/Region.h>
 
 #include <cmath>
+#include <cstdint>
 
 #include "CallOrderStateMachineHelper.h"
 #include "MockHWC2.h"
@@ -783,15 +784,19 @@
     InjectedLayer layer2;
     InjectedLayer layer3;
 
+    uint32_t z = 0;
     EXPECT_CALL(*layer1.outputLayer, updateCompositionState(false, false, ui::Transform::ROT_180));
     EXPECT_CALL(*layer1.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
     EXPECT_CALL(*layer2.outputLayer, updateCompositionState(false, false, ui::Transform::ROT_180));
     EXPECT_CALL(*layer2.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
     EXPECT_CALL(*layer3.outputLayer, updateCompositionState(false, false, ui::Transform::ROT_180));
     EXPECT_CALL(*layer3.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
 
     injectOutputLayer(layer1);
     injectOutputLayer(layer2);
@@ -813,15 +818,19 @@
     InjectedLayer layer2;
     InjectedLayer layer3;
 
+    uint32_t z = 0;
     EXPECT_CALL(*layer1.outputLayer, updateCompositionState(true, false, ui::Transform::ROT_0));
     EXPECT_CALL(*layer1.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
     EXPECT_CALL(*layer2.outputLayer, updateCompositionState(true, false, ui::Transform::ROT_0));
     EXPECT_CALL(*layer2.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
     EXPECT_CALL(*layer3.outputLayer, updateCompositionState(true, false, ui::Transform::ROT_0));
     EXPECT_CALL(*layer3.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
 
     injectOutputLayer(layer1);
     injectOutputLayer(layer2);
@@ -842,15 +851,19 @@
     InjectedLayer layer2;
     InjectedLayer layer3;
 
+    uint32_t z = 0;
     EXPECT_CALL(*layer1.outputLayer, updateCompositionState(false, true, ui::Transform::ROT_0));
     EXPECT_CALL(*layer1.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
     EXPECT_CALL(*layer2.outputLayer, updateCompositionState(false, true, ui::Transform::ROT_0));
     EXPECT_CALL(*layer2.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
     EXPECT_CALL(*layer3.outputLayer, updateCompositionState(false, true, ui::Transform::ROT_0));
     EXPECT_CALL(*layer3.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
 
     injectOutputLayer(layer1);
     injectOutputLayer(layer2);
@@ -1144,11 +1157,6 @@
     EXPECT_CALL(mOutput, finalizePendingOutputLayers());
 
     mOutput.collectVisibleLayers(mRefreshArgs, mCoverageState);
-
-    // Ensure all output layers have been assigned a simple/flattened z-order.
-    EXPECT_EQ(0u, mLayer1.outputLayerState.z);
-    EXPECT_EQ(1u, mLayer2.outputLayerState.z);
-    EXPECT_EQ(2u, mLayer3.outputLayerState.z);
 }
 
 /*
@@ -3501,7 +3509,8 @@
 
         EXPECT_CALL(mLayer.outputLayer, updateCompositionState(false, true, ui::Transform::ROT_0));
         EXPECT_CALL(mLayer.outputLayer,
-                    writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                    writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, 0,
+                                    /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
         EXPECT_CALL(mOutput, generateClientCompositionRequests(_, _, kDefaultOutputDataspace))
                 .WillOnce(Return(std::vector<LayerFE::LayerSettings>{}));
         EXPECT_CALL(mRenderEngine, drawLayers(_, _, _, false, _, _)).WillOnce(Return(NO_ERROR));
@@ -4080,16 +4089,20 @@
     InjectedLayer layer2;
     InjectedLayer layer3;
 
+    uint32_t z = 0;
     // Layer requesting blur, or below, should request client composition.
     EXPECT_CALL(*layer1.outputLayer, updateCompositionState(false, true, ui::Transform::ROT_0));
     EXPECT_CALL(*layer1.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
     EXPECT_CALL(*layer2.outputLayer, updateCompositionState(false, true, ui::Transform::ROT_0));
     EXPECT_CALL(*layer2.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
     EXPECT_CALL(*layer3.outputLayer, updateCompositionState(false, false, ui::Transform::ROT_0));
     EXPECT_CALL(*layer3.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
 
     layer2.layerFEState.backgroundBlurRadius = 10;
 
@@ -4112,16 +4125,20 @@
     InjectedLayer layer2;
     InjectedLayer layer3;
 
+    uint32_t z = 0;
     // Layer requesting blur, or below, should request client composition.
     EXPECT_CALL(*layer1.outputLayer, updateCompositionState(false, true, ui::Transform::ROT_0));
     EXPECT_CALL(*layer1.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
     EXPECT_CALL(*layer2.outputLayer, updateCompositionState(false, true, ui::Transform::ROT_0));
     EXPECT_CALL(*layer2.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
     EXPECT_CALL(*layer3.outputLayer, updateCompositionState(false, false, ui::Transform::ROT_0));
     EXPECT_CALL(*layer3.outputLayer,
-                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false));
+                writeStateToHWC(/*includeGeometry*/ false, /*skipLayer*/ false, z++,
+                                /*zIsOverridden*/ false, /*isPeekingThrough*/ false));
 
     BlurRegion region;
     layer2.layerFEState.blurRegions.push_back(region);
diff --git a/services/surfaceflinger/CompositionEngine/tests/planner/LayerStateTest.cpp b/services/surfaceflinger/CompositionEngine/tests/planner/LayerStateTest.cpp
index 83cc19b..948c850 100644
--- a/services/surfaceflinger/CompositionEngine/tests/planner/LayerStateTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/planner/LayerStateTest.cpp
@@ -41,8 +41,6 @@
 const Rect sRectTwo = Rect(40, 30, 20, 10);
 const FloatRect sFloatRectOne = FloatRect(100.f, 200.f, 300.f, 400.f);
 const FloatRect sFloatRectTwo = FloatRect(400.f, 300.f, 200.f, 100.f);
-const constexpr int32_t sZOne = 100;
-const constexpr int32_t sZTwo = 101;
 const constexpr float sAlphaOne = 0.25f;
 const constexpr float sAlphaTwo = 0.5f;
 const Region sRegionOne = Region(sRectOne);
@@ -408,45 +406,6 @@
     EXPECT_TRUE(otherLayerState->compare(*mLayerState));
 }
 
-TEST_F(LayerStateTest, updateZOrder) {
-    OutputLayerCompositionState outputLayerCompositionState;
-    outputLayerCompositionState.z = sZOne;
-    LayerFECompositionState layerFECompositionState;
-    setupMocksForLayer(mOutputLayer, mLayerFE, outputLayerCompositionState,
-                       layerFECompositionState);
-    mLayerState = std::make_unique<LayerState>(&mOutputLayer);
-
-    mock::OutputLayer newOutputLayer;
-    mock::LayerFE newLayerFE;
-    OutputLayerCompositionState outputLayerCompositionStateTwo;
-    outputLayerCompositionStateTwo.z = sZTwo;
-    setupMocksForLayer(newOutputLayer, newLayerFE, outputLayerCompositionStateTwo,
-                       layerFECompositionState);
-    Flags<LayerStateField> updates = mLayerState->update(&newOutputLayer);
-    EXPECT_EQ(Flags<LayerStateField>(LayerStateField::ZOrder), updates);
-}
-
-TEST_F(LayerStateTest, compareZOrder) {
-    OutputLayerCompositionState outputLayerCompositionState;
-    outputLayerCompositionState.z = sZOne;
-    LayerFECompositionState layerFECompositionState;
-    setupMocksForLayer(mOutputLayer, mLayerFE, outputLayerCompositionState,
-                       layerFECompositionState);
-    mLayerState = std::make_unique<LayerState>(&mOutputLayer);
-    mock::OutputLayer newOutputLayer;
-    mock::LayerFE newLayerFE;
-    OutputLayerCompositionState outputLayerCompositionStateTwo;
-    outputLayerCompositionStateTwo.z = sZTwo;
-    setupMocksForLayer(newOutputLayer, newLayerFE, outputLayerCompositionStateTwo,
-                       layerFECompositionState);
-    auto otherLayerState = std::make_unique<LayerState>(&newOutputLayer);
-
-    verifyNonUniqueDifferingFields(*mLayerState, *otherLayerState, LayerStateField::ZOrder);
-
-    EXPECT_TRUE(mLayerState->compare(*otherLayerState));
-    EXPECT_TRUE(otherLayerState->compare(*mLayerState));
-}
-
 TEST_F(LayerStateTest, updateBufferTransform) {
     OutputLayerCompositionState outputLayerCompositionState;
     outputLayerCompositionState.bufferTransform = Hwc2::Transform::FLIP_H;
@@ -954,4 +913,4 @@
 }
 
 } // namespace
-} // namespace android::compositionengine::impl::planner
\ No newline at end of file
+} // namespace android::compositionengine::impl::planner
diff --git a/services/surfaceflinger/CompositionEngine/tests/planner/PredictorTest.cpp b/services/surfaceflinger/CompositionEngine/tests/planner/PredictorTest.cpp
index 43e119f..1492707 100644
--- a/services/surfaceflinger/CompositionEngine/tests/planner/PredictorTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/planner/PredictorTest.cpp
@@ -31,8 +31,6 @@
 const FloatRect sFloatRectTwo = FloatRect(400.f, 300.f, 200.f, 100.f);
 const Rect sRectOne = Rect(1, 2, 3, 4);
 const Rect sRectTwo = Rect(4, 3, 2, 1);
-const constexpr int32_t sZOne = 100;
-const constexpr int32_t sZTwo = 101;
 const constexpr float sAlphaOne = 0.25f;
 const constexpr float sAlphaTwo = 0.5f;
 const Region sRegionOne = Region(sRectOne);
@@ -194,11 +192,11 @@
             .displayFrame = sRectOne,
             .sourceCrop = sFloatRectOne,
             .dataspace = ui::Dataspace::SRGB,
-            .z = sZOne,
     };
     LayerFECompositionState layerFECompositionStateOne;
     layerFECompositionStateOne.alpha = sAlphaOne;
     layerFECompositionStateOne.colorTransformIsIdentity = true;
+    layerFECompositionStateOne.blendMode = hal::BlendMode::NONE;
     setupMocksForLayer(outputLayerOne, layerFEOne, outputLayerCompositionStateOne,
                        layerFECompositionStateOne);
     LayerState layerStateOne(&outputLayerOne);
@@ -210,12 +208,12 @@
             .displayFrame = sRectTwo,
             .sourceCrop = sFloatRectTwo,
             .dataspace = ui::Dataspace::DISPLAY_P3,
-            .z = sZTwo,
     };
     LayerFECompositionState layerFECompositionStateTwo;
     layerFECompositionStateTwo.alpha = sAlphaTwo;
     layerFECompositionStateTwo.colorTransformIsIdentity = false;
     layerFECompositionStateTwo.colorTransform = sMat4One;
+    layerFECompositionStateTwo.blendMode = hal::BlendMode::PREMULTIPLIED;
     setupMocksForLayer(outputLayerTwo, layerFETwo, outputLayerCompositionStateTwo,
                        layerFECompositionStateTwo);
     LayerState layerStateTwo(&outputLayerTwo);
@@ -264,7 +262,6 @@
             .displayFrame = sRectOne,
             .sourceCrop = sFloatRectOne,
             .dataspace = ui::Dataspace::SRGB,
-            .z = sZOne,
     };
     LayerFECompositionState layerFECompositionStateOne;
     layerFECompositionStateOne.buffer = new GraphicBuffer();
@@ -282,7 +279,6 @@
             .displayFrame = sRectTwo,
             .sourceCrop = sFloatRectTwo,
             .dataspace = ui::Dataspace::DISPLAY_P3,
-            .z = sZTwo,
     };
     LayerFECompositionState layerFECompositionStateTwo;
     layerFECompositionStateTwo.buffer = new GraphicBuffer();
@@ -346,6 +342,32 @@
     }
 };
 
+TEST_F(LayerStackTest, reorderingChangesNonBufferHash) {
+    mock::OutputLayer outputLayerOne;
+    mock::LayerFE layerFEOne;
+    OutputLayerCompositionState outputLayerCompositionStateOne{
+            .sourceCrop = sFloatRectOne,
+    };
+    LayerFECompositionState layerFECompositionStateOne;
+    setupMocksForLayer(outputLayerOne, layerFEOne, outputLayerCompositionStateOne,
+                       layerFECompositionStateOne);
+    LayerState layerStateOne(&outputLayerOne);
+
+    mock::OutputLayer outputLayerTwo;
+    mock::LayerFE layerFETwo;
+    OutputLayerCompositionState outputLayerCompositionStateTwo{
+            .sourceCrop = sFloatRectTwo,
+    };
+    LayerFECompositionState layerFECompositionStateTwo;
+    setupMocksForLayer(outputLayerTwo, layerFETwo, outputLayerCompositionStateTwo,
+                       layerFECompositionStateTwo);
+    LayerState layerStateTwo(&outputLayerTwo);
+
+    NonBufferHash hash = getNonBufferHash({&layerStateOne, &layerStateTwo});
+    NonBufferHash hashReverse = getNonBufferHash({&layerStateTwo, &layerStateOne});
+    EXPECT_NE(hash, hashReverse);
+}
+
 TEST_F(PredictionTest, constructPrediction) {
     Plan plan;
     plan.addLayerType(hal::Composition::DEVICE);
@@ -525,4 +547,4 @@
 }
 
 } // namespace
-} // namespace android::compositionengine::impl::planner
\ No newline at end of file
+} // namespace android::compositionengine::impl::planner
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index cf215ad..4461420 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -531,7 +531,9 @@
             isOpaque(drawingState) && !usesRoundedCorners && getAlpha() == 1.0_hf;
 
     // Force client composition for special cases known only to the front-end.
-    if (isHdrY410() || usesRoundedCorners || drawShadows() || drawingState.blurRegions.size() > 0 ||
+    // Rounded corners no longer force client composition, since we may use a
+    // hole punch so that the layer will appear to have rounded corners.
+    if (isHdrY410() || drawShadows() || drawingState.blurRegions.size() > 0 ||
         compositionState->stretchEffect.hasEffect()) {
         compositionState->forceClientComposition = true;
     }
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 9f3ea9a..688a2c3 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -600,6 +600,8 @@
     // ignored.
     virtual RoundedCornerState getRoundedCornerState() const;
 
+    bool hasRoundedCorners() const override { return getRoundedCornerState().radius > .0f; }
+
     virtual PixelFormat getPixelFormat() const { return PIXEL_FORMAT_NONE; }
     /**
      * Return whether this layer needs an input info. For most layer types