Support toggling layer caching at runtime

The use-case for this is dynamically enabling and disabling layer
caching when a bad layer state is encountered that is difficult to
reproduce.

Bug: 187448777
Test: adb shell service call SurfaceFlinger 1040 i32 1
Test: libcompositionengine_test
Change-Id: Id441a0894ff5a4c654db9fd706ceb1c0d1c343f0
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h
index 4976213..9fba7aa 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h
@@ -163,6 +163,9 @@
     // Enables (or disables) composition on this output
     virtual void setCompositionEnabled(bool) = 0;
 
+    // Enables (or disables) layer caching on this output
+    virtual void setLayerCachingEnabled(bool) = 0;
+
     // Sets the projection state to use
     virtual void setProjection(ui::Rotation orientation, const Rect& layerStackSpaceRect,
                                const Rect& orientedDisplaySpaceRect) = 0;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
index eeb20fc..2893c3f 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
@@ -20,6 +20,7 @@
 #include <compositionengine/Output.h>
 #include <compositionengine/impl/ClientCompositionRequestCache.h>
 #include <compositionengine/impl/OutputCompositionState.h>
+#include <compositionengine/impl/planner/Planner.h>
 #include <renderengine/DisplaySettings.h>
 #include <renderengine/LayerSettings.h>
 #include <memory>
@@ -28,21 +29,18 @@
 
 namespace android::compositionengine::impl {
 
-namespace planner {
-class Planner;
-} // namespace planner
-
 // The implementation class contains the common implementation, but does not
 // actually contain the final output state.
 class Output : public virtual compositionengine::Output {
 public:
-    Output();
+    Output() = default;
     ~Output() override;
 
     // compositionengine::Output overrides
     bool isValid() const override;
     std::optional<DisplayId> getDisplayId() const override;
     void setCompositionEnabled(bool) override;
+    void setLayerCachingEnabled(bool) override;
     void setProjection(ui::Rotation orientation, const Rect& layerStackSpaceRect,
                        const Rect& orientedDisplaySpaceRect) override;
     void setDisplaySize(const ui::Size&) override;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h
index 5aa53e5..749675d 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h
@@ -36,6 +36,7 @@
     MOCK_CONST_METHOD0(getDisplayId, std::optional<DisplayId>());
 
     MOCK_METHOD1(setCompositionEnabled, void(bool));
+    MOCK_METHOD1(setLayerCachingEnabled, void(bool));
     MOCK_METHOD3(setProjection, void(ui::Rotation, const Rect&, const Rect&));
     MOCK_METHOD1(setDisplaySize, void(const ui::Size&));
     MOCK_METHOD2(setLayerStackFilter, void(uint32_t, bool));
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index 297e687..796fe7d 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -55,18 +55,6 @@
 
 namespace impl {
 
-Output::Output() {
-    const bool enableLayerCaching = [] {
-        const bool enable =
-                android::sysprop::SurfaceFlingerProperties::enable_layer_caching().value_or(false);
-        return base::GetBoolProperty(std::string("debug.sf.enable_layer_caching"), enable);
-    }();
-
-    if (enableLayerCaching) {
-        mPlanner = std::make_unique<planner::Planner>();
-    }
-}
-
 namespace {
 
 template <typename T>
@@ -135,6 +123,21 @@
     dirtyEntireOutput();
 }
 
+void Output::setLayerCachingEnabled(bool enabled) {
+    if (enabled == (mPlanner != nullptr)) {
+        return;
+    }
+
+    if (enabled) {
+        mPlanner = std::make_unique<planner::Planner>();
+        if (mRenderSurface) {
+            mPlanner->setDisplaySize(mRenderSurface->getSize());
+        }
+    } else {
+        mPlanner.reset();
+    }
+}
+
 void Output::setProjection(ui::Rotation orientation, const Rect& layerStackSpaceRect,
                            const Rect& orientedDisplaySpaceRect) {
     auto& outputState = editState();
diff --git a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
index 27980a0..11736d1 100644
--- a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
@@ -238,6 +238,28 @@
 }
 
 /*
+ * Output::setLayerCachingEnabled()
+ */
+
+TEST_F(OutputTest, setLayerCachingEnabled_enablesCaching) {
+    const auto kSize = ui::Size(1, 1);
+    EXPECT_CALL(*mRenderSurface, getSize()).WillRepeatedly(ReturnRef(kSize));
+    mOutput->setLayerCachingEnabled(false);
+    mOutput->setLayerCachingEnabled(true);
+
+    EXPECT_TRUE(mOutput->plannerEnabled());
+}
+
+TEST_F(OutputTest, setLayerCachingEnabled_disablesCaching) {
+    const auto kSize = ui::Size(1, 1);
+    EXPECT_CALL(*mRenderSurface, getSize()).WillRepeatedly(ReturnRef(kSize));
+    mOutput->setLayerCachingEnabled(true);
+    mOutput->setLayerCachingEnabled(false);
+
+    EXPECT_FALSE(mOutput->plannerEnabled());
+}
+
+/*
  * Output::setProjection()
  */
 
@@ -972,9 +994,7 @@
     mOutput.editState().usesDeviceComposition = true;
 
     EXPECT_CALL(mOutput, chooseCompositionStrategy()).Times(1);
-    if (mOutput.plannerEnabled()) {
-        EXPECT_CALL(mOutput, getOutputLayerCount()).WillOnce(Return(0u));
-    }
+    EXPECT_CALL(mOutput, getOutputLayerCount()).WillRepeatedly(Return(0u));
     EXPECT_CALL(*mRenderSurface, prepareFrame(false, true));
 
     mOutput.prepareFrame();
diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index d8a7514..3397011 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -139,6 +139,10 @@
     getCompositionDisplay()->setCompositionEnabled(mPowerMode != hal::PowerMode::OFF);
 }
 
+void DisplayDevice::enableLayerCaching(bool enable) {
+    getCompositionDisplay()->setLayerCachingEnabled(enable);
+}
+
 hal::PowerMode DisplayDevice::getPowerMode() const {
     return mPowerMode;
 }
diff --git a/services/surfaceflinger/DisplayDevice.h b/services/surfaceflinger/DisplayDevice.h
index 68846d3..bf249cd 100644
--- a/services/surfaceflinger/DisplayDevice.h
+++ b/services/surfaceflinger/DisplayDevice.h
@@ -157,6 +157,9 @@
     void setPowerMode(hardware::graphics::composer::hal::PowerMode mode);
     bool isPoweredOn() const;
 
+    // Enables layer caching on this DisplayDevice
+    void enableLayerCaching(bool enable);
+
     ui::Dataspace getCompositionDataSpace() const;
 
     /* ------------------------------------------------------------------------
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 5bd43e1..1e39d05 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -381,6 +381,12 @@
     mColorSpaceAgnosticDataspace =
             static_cast<ui::Dataspace>(color_space_agnostic_dataspace(Dataspace::UNKNOWN));
 
+    mLayerCachingEnabled = [] {
+        const bool enable =
+                android::sysprop::SurfaceFlingerProperties::enable_layer_caching().value_or(false);
+        return base::GetBoolProperty(std::string("debug.sf.enable_layer_caching"), enable);
+    }();
+
     useContextPriority = use_context_priority(true);
 
     using Values = SurfaceFlingerProperties::primary_display_orientation_values;
@@ -2641,6 +2647,7 @@
     builder.setGpuVirtualDisplayIdGenerator(mGpuVirtualDisplayIdGenerator);
     builder.setName(state.displayName);
     const auto compositionDisplay = getCompositionEngine().createDisplay(builder.build());
+    compositionDisplay->setLayerCachingEnabled(mLayerCachingEnabled);
 
     sp<compositionengine::DisplaySurface> displaySurface;
     sp<IGraphicBufferProducer> producer;
@@ -5186,9 +5193,9 @@
         code == IBinder::SYSPROPS_TRANSACTION) {
         return OK;
     }
-    // Numbers from 1000 to 1038 are currently used for backdoors. The code
+    // Numbers from 1000 to 1040 are currently used for backdoors. The code
     // in onTransact verifies that the user is root, and has access to use SF.
-    if (code >= 1000 && code <= 1039) {
+    if (code >= 1000 && code <= 1040) {
         ALOGV("Accessing SurfaceFlinger through backdoor code: %u", code);
         return OK;
     }
@@ -5572,6 +5579,33 @@
                 mScheduler->onFrameRateOverridesChanged(mAppConnectionHandle, displayId);
                 return NO_ERROR;
             }
+            // Toggle caching feature
+            // First argument is an int32 - nonzero enables caching and zero disables caching
+            // Second argument is an optional uint64 - if present, then limits enabling/disabling
+            // caching to a particular physical display
+            case 1040: {
+                n = data.readInt32();
+                std::optional<PhysicalDisplayId> inputId = std::nullopt;
+                if (uint64_t inputDisplayId; data.readUint64(&inputDisplayId) == NO_ERROR) {
+                    inputId = DisplayId::fromValue<PhysicalDisplayId>(inputDisplayId);
+                    if (!inputId || getPhysicalDisplayToken(*inputId)) {
+                        ALOGE("No display with id: %" PRIu64, inputDisplayId);
+                        return NAME_NOT_FOUND;
+                    }
+                }
+                {
+                    Mutex::Autolock lock(mStateLock);
+                    mLayerCachingEnabled = n != 0;
+                    for (const auto& [_, display] : mDisplays) {
+                        if (!inputId || *inputId == display->getPhysicalId()) {
+                            display->enableLayerCaching(mLayerCachingEnabled);
+                        }
+                    }
+                }
+                invalidateHwcGeometry();
+                repaintEverything();
+                return NO_ERROR;
+            }
         }
     }
     return err;
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 0a6a8e7..4009baf 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -1244,6 +1244,7 @@
     int mDebugRegion = 0;
     bool mDebugDisableHWC = false;
     bool mDebugDisableTransformHint = false;
+    bool mLayerCachingEnabled = false;
     volatile nsecs_t mDebugInTransaction = 0;
     bool mForceFullDamage = false;
     bool mPropagateBackpressureClientComposition = false;