diff --git a/libs/gui/ISurfaceComposer.cpp b/libs/gui/ISurfaceComposer.cpp
index 2a27a9a..e62a61f 100644
--- a/libs/gui/ISurfaceComposer.cpp
+++ b/libs/gui/ISurfaceComposer.cpp
@@ -691,8 +691,7 @@
         return result;
     }
 
-    virtual status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const
-    {
+    virtual status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) {
         if (!outLayers) {
             return UNEXPECTED_NULL;
         }
diff --git a/libs/gui/include/gui/ISurfaceComposer.h b/libs/gui/include/gui/ISurfaceComposer.h
index 0d33b3f..b49fa1b 100644
--- a/libs/gui/include/gui/ISurfaceComposer.h
+++ b/libs/gui/include/gui/ISurfaceComposer.h
@@ -354,7 +354,7 @@
      *
      * Requires the ACCESS_SURFACE_FLINGER permission.
      */
-    virtual status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const = 0;
+    virtual status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) = 0;
 
     virtual status_t getColorManagement(bool* outGetColorManagement) const = 0;
 
diff --git a/libs/gui/tests/Surface_test.cpp b/libs/gui/tests/Surface_test.cpp
index a1d12a5..c2b4ef9 100644
--- a/libs/gui/tests/Surface_test.cpp
+++ b/libs/gui/tests/Surface_test.cpp
@@ -785,7 +785,7 @@
         return NO_ERROR;
     }
     status_t injectVSync(nsecs_t /*when*/) override { return NO_ERROR; }
-    status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* /*layers*/) const override {
+    status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* /*layers*/) override {
         return NO_ERROR;
     }
     status_t getCompositionPreference(
diff --git a/services/inputflinger/dispatcher/InputDispatcher.cpp b/services/inputflinger/dispatcher/InputDispatcher.cpp
index e6e3347..8dddd6d 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.cpp
+++ b/services/inputflinger/dispatcher/InputDispatcher.cpp
@@ -3640,7 +3640,8 @@
             continue;
         }
 
-        if (oldHandlesById.find(handle->getId()) != oldHandlesById.end()) {
+        if ((oldHandlesById.find(handle->getId()) != oldHandlesById.end()) &&
+                (oldHandlesById.at(handle->getId())->getToken() == handle->getToken())) {
             const sp<InputWindowHandle>& oldHandle = oldHandlesById.at(handle->getId());
             oldHandle->updateFrom(handle);
             newHandles.push_back(oldHandle);
diff --git a/services/surfaceflinger/BufferLayer.h b/services/surfaceflinger/BufferLayer.h
index 97ffe6f..0e69f60 100644
--- a/services/surfaceflinger/BufferLayer.h
+++ b/services/surfaceflinger/BufferLayer.h
@@ -148,6 +148,11 @@
     virtual status_t updateActiveBuffer() = 0;
     virtual status_t updateFrameNumber(nsecs_t latchTime) = 0;
 
+    // We generate InputWindowHandles for all buffered layers regardless of whether they
+    // have an InputChannel. This is to enable the InputDispatcher to do PID based occlusion
+    // detection.
+    bool needsInputInfo() const override { return true; }
+
 protected:
     struct BufferInfo {
         nsecs_t mDesiredPresentTime;
diff --git a/services/surfaceflinger/BufferStateLayer.cpp b/services/surfaceflinger/BufferStateLayer.cpp
index 4f8fc41..790f2ec 100644
--- a/services/surfaceflinger/BufferStateLayer.cpp
+++ b/services/surfaceflinger/BufferStateLayer.cpp
@@ -33,7 +33,6 @@
 #include <renderengine/Image.h>
 
 #include "EffectLayer.h"
-#include "FrameTracer/FrameTracer.h"
 #include "TimeStats/TimeStats.h"
 
 namespace android {
@@ -98,9 +97,6 @@
 
     // Prevent tracing the same release multiple times.
     if (mPreviousFrameNumber != mPreviousReleasedFrameNumber) {
-        mFlinger->mFrameTracer->traceFence(getSequence(), mPreviousBufferId, mPreviousFrameNumber,
-                                           std::make_shared<FenceTime>(releaseFence),
-                                           FrameTracer::FrameEvent::RELEASE_FENCE);
         mPreviousReleasedFrameNumber = mPreviousFrameNumber;
     }
 }
@@ -277,9 +273,6 @@
     const int32_t layerId = getSequence();
     mFlinger->mTimeStats->setPostTime(layerId, mCurrentState.frameNumber, getName().c_str(),
                                       postTime);
-    mFlinger->mFrameTracer->traceNewLayer(layerId, getName().c_str());
-    mFlinger->mFrameTracer->traceTimestamp(layerId, buffer->getId(), mCurrentState.frameNumber,
-                                           postTime, FrameTracer::FrameEvent::POST);
     desiredPresentTime = desiredPresentTime <= 0 ? 0 : desiredPresentTime;
     mCurrentState.desiredPresentTime = desiredPresentTime;
 
@@ -580,20 +573,13 @@
         status_t err = bindTextureImage();
         if (err != NO_ERROR) {
             mFlinger->mTimeStats->onDestroy(layerId);
-            mFlinger->mFrameTracer->onDestroy(layerId);
             return BAD_VALUE;
         }
     }
 
-    const uint64_t bufferID = getCurrentBufferId();
     mFlinger->mTimeStats->setAcquireFence(layerId, mDrawingState.frameNumber,
-                                          mBufferInfo.mFenceTime);
-    mFlinger->mFrameTracer->traceFence(layerId, bufferID, mDrawingState.frameNumber,
-                                       mBufferInfo.mFenceTime,
-                                       FrameTracer::FrameEvent::ACQUIRE_FENCE);
+                                          std::make_shared<FenceTime>(mDrawingState.acquireFence));
     mFlinger->mTimeStats->setLatchTime(layerId, mDrawingState.frameNumber, latchTime);
-    mFlinger->mFrameTracer->traceTimestamp(layerId, bufferID, mDrawingState.frameNumber, latchTime,
-                                           FrameTracer::FrameEvent::LATCH);
 
     mCurrentStateModified = false;
 
diff --git a/services/surfaceflinger/DisplayHardware/HWC2.cpp b/services/surfaceflinger/DisplayHardware/HWC2.cpp
index af76b81..8ac0561 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2.cpp
@@ -208,13 +208,17 @@
         *outVsyncPeriod = static_cast<nsecs_t>(vsyncPeriodNanos);
     } else {
         // Get the default vsync period
-        HWConfigId configId = 0;
-        auto intError_2_1 = mComposer.getActiveConfig(mId, &configId);
-        error = static_cast<Error>(intError_2_1);
-        if (error == Error::NONE) {
-            auto config = mConfigs.at(configId);
-            *outVsyncPeriod = config->getVsyncPeriod();
+        std::shared_ptr<const Display::Config> config;
+        error = getActiveConfig(&config);
+        if (error != Error::NONE) {
+            return error;
         }
+        if (!config) {
+            // HWC has updated the display modes and hasn't notified us yet.
+            return Error::BAD_CONFIG;
+        }
+
+        *outVsyncPeriod = config->getVsyncPeriod();
     }
 
     return error;
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index dcc213f..3255aac 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -229,13 +229,23 @@
     mFlinger->markLayerPendingRemovalLocked(this);
 }
 
+sp<Layer> Layer::getRootLayer() {
+    sp<Layer> parent = getParent();
+    if (parent == nullptr) {
+        return this;
+    }
+    return parent->getRootLayer();
+}
+
 void Layer::onRemovedFromCurrentState() {
-    auto layersInTree = getLayersInTree(LayerVector::StateSet::Current);
+    // Use the root layer since we want to maintain the hierarchy for the entire subtree.
+    auto layersInTree = getRootLayer()->getLayersInTree(LayerVector::StateSet::Current);
     std::sort(layersInTree.begin(), layersInTree.end());
-    for (const auto& layer : layersInTree) {
+
+    traverse(LayerVector::StateSet::Current, [&](Layer* layer) {
         layer->removeFromCurrentState();
         layer->removeRelativeZ(layersInTree);
-    }
+    });
 }
 
 void Layer::addToCurrentState() {
@@ -1501,7 +1511,7 @@
     LayerDebugInfo info;
     const State& ds = getDrawingState();
     info.mName = getName();
-    sp<Layer> parent = getParent();
+    sp<Layer> parent = mDrawingParent.promote();
     info.mParentName = parent ? parent->getName() : "none"s;
     info.mType = getType();
     info.mTransparentRegion = ds.activeTransparentRegion_legacy;
@@ -2343,6 +2353,16 @@
 }
 
 InputWindowInfo Layer::fillInputInfo() {
+    if (!hasInputInfo()) {
+        mDrawingState.inputInfo.name = getName();
+        mDrawingState.inputInfo.ownerUid = mCallingUid;
+        mDrawingState.inputInfo.ownerPid = mCallingPid;
+        mDrawingState.inputInfo.inputFeatures =
+            InputWindowInfo::INPUT_FEATURE_NO_INPUT_CHANNEL;
+        mDrawingState.inputInfo.layoutParamsFlags = InputWindowInfo::FLAG_NOT_TOUCH_MODAL;
+        mDrawingState.inputInfo.displayId = getLayerStack();
+    }
+
     InputWindowInfo info = mDrawingState.inputInfo;
     info.id = sequence;
 
@@ -2424,7 +2444,7 @@
     return mDrawingParent.promote()->getClonedRoot();
 }
 
-bool Layer::hasInput() const {
+bool Layer::hasInputInfo() const {
     return mDrawingState.inputInfo.token != nullptr;
 }
 
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 3fa935f..068424b 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -947,7 +947,17 @@
     void setInputInfo(const InputWindowInfo& info);
 
     InputWindowInfo fillInputInfo();
-    bool hasInput() const;
+    /**
+     * Returns whether this layer has an explicitly set input-info.
+     */
+    bool hasInputInfo() const;
+    /**
+     * Return whether this layer needs an input info. For most layer types
+     * this is only true if they explicitly set an input-info but BufferLayer
+     * overrides this so we can generate input-info for Buffered layers that don't
+     * have them (for input occlusion detection checks).
+     */
+    virtual bool needsInputInfo() const { return hasInputInfo(); }
 
 protected:
     compositionengine::OutputLayer* findOutputLayerForDisplay(const DisplayDevice*) const;
@@ -1088,6 +1098,10 @@
     // Find the root of the cloned hierarchy, this means the first non cloned parent.
     // This will return null if first non cloned parent is not found.
     sp<Layer> getClonedRoot();
+
+    // Finds the top most layer in the hierarchy. This will find the root Layer where the parent is
+    // null.
+    sp<Layer> getRootLayer();
 };
 
 } // namespace android
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 68dec66..9152571 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1449,17 +1449,14 @@
     return mScheduler->injectVSync(when, calculateExpectedPresentTime(when)) ? NO_ERROR : BAD_VALUE;
 }
 
-status_t SurfaceFlinger::getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const {
-    TimedLock lock(mStateLock, s2ns(1), __FUNCTION__);
-    if (!lock.locked()) {
-        return TIMED_OUT;
-    }
-
-    const auto display = getDefaultDisplayDeviceLocked();
+status_t SurfaceFlinger::getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) {
     outLayers->clear();
-    mCurrentState.traverseInZOrder(
-            [&](Layer* layer) { outLayers->push_back(layer->getLayerDebugInfo(display.get())); });
-
+    schedule([=] {
+        const auto display = ON_MAIN_THREAD(getDefaultDisplayDeviceLocked());
+        mDrawingState.traverseInZOrder([&](Layer* layer) {
+            outLayers->push_back(layer->getLayerDebugInfo(display.get()));
+        });
+    }).wait();
     return NO_ERROR;
 }
 
@@ -2904,7 +2901,7 @@
     std::vector<InputWindowInfo> inputHandles;
 
     mDrawingState.traverseInReverseZOrder([&](Layer* layer) {
-        if (layer->hasInput()) {
+        if (layer->needsInputInfo()) {
             // When calculating the screen bounds we ignore the transparent region since it may
             // result in an unwanted offset.
             inputHandles.push_back(layer->fillInputInfo());
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 113b035..f5be8a8 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -466,7 +466,7 @@
                                 HdrCapabilities* outCapabilities) const override;
     status_t enableVSyncInjections(bool enable) override;
     status_t injectVSync(nsecs_t when) override;
-    status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const override;
+    status_t getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) override;
     status_t getColorManagement(bool* outGetColorManagement) const override;
     status_t getCompositionPreference(ui::Dataspace* outDataspace, ui::PixelFormat* outPixelFormat,
                                       ui::Dataspace* outWideColorGamutDataspace,
diff --git a/services/surfaceflinger/tests/RelativeZ_test.cpp b/services/surfaceflinger/tests/RelativeZ_test.cpp
index 1180cac..3e0b3c6 100644
--- a/services/surfaceflinger/tests/RelativeZ_test.cpp
+++ b/services/surfaceflinger/tests/RelativeZ_test.cpp
@@ -207,6 +207,71 @@
         sc->checkPixel(1, 1, Color::BLUE.r, Color::BLUE.g, Color::BLUE.b);
     }
 }
+
+// Preserve the relative z order when a layer is reparented to a layer that's already offscreen
+TEST_F(RelativeZTest, LayerWithRelativeReparentedToOffscreen) {
+    std::unique_ptr<ScreenCapture> sc;
+
+    Color testLayerColor = {255, 100, 0, 255};
+
+    // Background layer (RED)
+    // Foregroud layer (GREEN)
+    //   child level 1a (testLayerColor) (relative to child level 2b)
+    //   child level 1b (WHITE)
+    //     child level 2a (BLUE)
+    //     child level 2b (BLACK)
+    sp<SurfaceControl> childLevel1a =
+            createColorLayer("child level 1a", testLayerColor, mForegroundLayer.get());
+    sp<SurfaceControl> childLevel1b =
+            createColorLayer("child level 1b", Color::WHITE, mForegroundLayer.get());
+    sp<SurfaceControl> childLevel2a =
+            createColorLayer("child level 2a", Color::BLUE, childLevel1b.get());
+    sp<SurfaceControl> childLevel2b =
+            createColorLayer("child level 2b", Color::BLACK, childLevel1b.get());
+
+    Transaction{}
+            .setRelativeLayer(childLevel1a, childLevel2b->getHandle(), 1)
+            .show(childLevel1a)
+            .show(childLevel1b)
+            .show(childLevel2a)
+            .show(childLevel2b)
+            .apply();
+
+    {
+        // The childLevel1a should be in front of childLevel2b.
+        ScreenCapture::captureScreen(&sc);
+        sc->expectColor(Rect(0, 0, mDisplayWidth, mDisplayHeight), testLayerColor);
+    }
+
+    // Background layer (RED)
+    // Foregroud layer (GREEN)
+    //   child level 1a (testLayerColor) (relative to child level 2b)
+    Transaction{}.reparent(childLevel1b, nullptr).apply();
+
+    // // Background layer (RED)
+    // // Foregroud layer (GREEN)
+    Transaction{}.reparent(childLevel1a, childLevel2a->getHandle()).apply();
+
+    {
+        // The childLevel1a and childLevel1b are no longer on screen
+        ScreenCapture::captureScreen(&sc);
+        sc->expectColor(Rect(0, 0, mDisplayWidth, mDisplayHeight), Color::GREEN);
+    }
+
+    // Background layer (RED)
+    // Foregroud layer (GREEN)
+    //   child level 1b (WHITE)
+    //     child level 2a (BLUE)
+    //       child level 1a (testLayerColor) (relative to child level 2b)
+    //     child level 2b (BLACK)
+    Transaction{}.reparent(childLevel1b, mForegroundLayer->getHandle()).apply();
+
+    {
+        // Nothing should change at this point since relative z info was preserved.
+        ScreenCapture::captureScreen(&sc);
+        sc->expectColor(Rect(0, 0, mDisplayWidth, mDisplayHeight), testLayerColor);
+    }
+}
 } // namespace android
 
 // TODO(b/129481165): remove the #pragma below and fix conversion issues