diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h
index 2d00f0c..69b5728 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/Output.h
@@ -52,11 +52,9 @@
     // Sets the bounds to use
     virtual void setBounds(const ui::Size&) = 0;
 
-    // Sets the layer stack filter for this output. If singleLayerStack is true,
-    // this output displays just the single layer stack specified by
-    // singleLayerStackId. Otherwise all layer stacks will be visible on this
-    // output.
-    virtual void setLayerStackFilter(bool singleLayerStack, uint32_t singleLayerStackId) = 0;
+    // Sets the layer stack filtering settings for this output. See
+    // belongsInOutput for full details.
+    virtual void setLayerStackFilter(uint32_t layerStackId, bool isInternal) = 0;
 
     // Sets the color transform matrix to use
     virtual void setColorTransform(const mat4&) = 0;
@@ -96,8 +94,14 @@
     // logical (aka layer stack) space.
     virtual Region getPhysicalSpaceDirtyRegion(bool repaintEverything) const = 0;
 
-    // Tests whether a given layerStackId belongs in this output
-    virtual bool belongsInOutput(uint32_t layerStackId) const = 0;
+    // Tests whether a given layerStackId belongs in this output.
+    // A layer belongs to the output if its layerStackId matches the of the output layerStackId,
+    // unless the layer should display on the primary output only and this is not the primary output
+
+    // A layer belongs to the output if its layerStackId matches. Additionally
+    // if the layer should only show in the internal (primary) display only and
+    // this output allows that.
+    virtual bool belongsInOutput(uint32_t layerStackId, bool internalOnly) const = 0;
 
 protected:
     ~Output() = default;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
index 521e1d7..180c40b 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
@@ -38,7 +38,7 @@
     void setProjection(const ui::Transform&, int32_t orientation, const Rect& frame,
                        const Rect& viewport, const Rect& scissor, bool needsFiltering) override;
     void setBounds(const ui::Size&) override;
-    void setLayerStackFilter(bool singleLayerStack, uint32_t singleLayerStackId) override;
+    void setLayerStackFilter(uint32_t layerStackId, bool isInternal) override;
 
     void setColorTransform(const mat4&) override;
     void setColorMode(ui::ColorMode, ui::Dataspace, ui::RenderIntent) override;
@@ -58,7 +58,7 @@
     OutputCompositionState& editState() override;
 
     Region getPhysicalSpaceDirtyRegion(bool repaintEverything) const override;
-    bool belongsInOutput(uint32_t) const override;
+    bool belongsInOutput(uint32_t, bool) const override;
 
     // Testing
     void setDisplayColorProfileForTest(std::unique_ptr<compositionengine::DisplayColorProfile>);
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h
index 96a0e0f..024ed45 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/OutputCompositionState.h
@@ -34,12 +34,11 @@
     // If false, this output is not considered secure
     bool isSecure{false};
 
-    // If true, only layer stacks with a matching layerStack value will be
-    // displayed. If false, all layer stacks will be displayed.
-    bool singleLayerStack{true};
+    // If true, this output displays layers that are internal-only
+    bool layerStackInternal{false};
 
     // The layer stack to display on this display
-    uint32_t singleLayerStackId{~0u};
+    uint32_t layerStackId{~0u};
 
     // The physical space screen bounds
     Rect bounds;
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h
index 37f7007..445f0bb 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/mock/Output.h
@@ -35,7 +35,7 @@
     MOCK_METHOD6(setProjection,
                  void(const ui::Transform&, int32_t, const Rect&, const Rect&, const Rect&, bool));
     MOCK_METHOD1(setBounds, void(const ui::Size&));
-    MOCK_METHOD2(setLayerStackFilter, void(bool, uint32_t));
+    MOCK_METHOD2(setLayerStackFilter, void(uint32_t, bool));
 
     MOCK_METHOD1(setColorTransform, void(const mat4&));
     MOCK_METHOD3(setColorMode, void(ui::ColorMode, ui::Dataspace, ui::RenderIntent));
@@ -54,7 +54,7 @@
     MOCK_METHOD0(editState, OutputCompositionState&());
 
     MOCK_CONST_METHOD1(getPhysicalSpaceDirtyRegion, Region(bool));
-    MOCK_CONST_METHOD1(belongsInOutput, bool(uint32_t));
+    MOCK_CONST_METHOD2(belongsInOutput, bool(uint32_t, bool));
 };
 
 } // namespace android::compositionengine::mock
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index dbf77b0..7fb67bd 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -75,9 +75,9 @@
     dirtyEntireOutput();
 }
 
-void Output::setLayerStackFilter(bool singleLayerStack, uint32_t singleLayerStackId) {
-    mState.singleLayerStack = singleLayerStack;
-    mState.singleLayerStackId = singleLayerStackId;
+void Output::setLayerStackFilter(uint32_t layerStackId, bool isInternal) {
+    mState.layerStackId = layerStackId;
+    mState.layerStackInternal = isInternal;
 
     dirtyEntireOutput();
 }
@@ -175,8 +175,10 @@
     return dirty;
 }
 
-bool Output::belongsInOutput(uint32_t layerStackId) const {
-    return !mState.singleLayerStack || (layerStackId == mState.singleLayerStackId);
+bool Output::belongsInOutput(uint32_t layerStackId, bool internalOnly) const {
+    // The layerStackId's must match, and also the layer must not be internal
+    // only when not on an internal output.
+    return (layerStackId == mState.layerStackId) && (!internalOnly || mState.layerStackInternal);
 }
 
 void Output::dirtyEntireOutput() {
diff --git a/services/surfaceflinger/CompositionEngine/src/OutputCompositionState.cpp b/services/surfaceflinger/CompositionEngine/src/OutputCompositionState.cpp
index 7d8765f..78807ff 100644
--- a/services/surfaceflinger/CompositionEngine/src/OutputCompositionState.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/OutputCompositionState.cpp
@@ -22,11 +22,9 @@
 void OutputCompositionState::dump(std::string& out) const {
     dumpVal(out, "isEnabled", isEnabled);
     dumpVal(out, "isSecure", isSecure);
-    if (singleLayerStack) {
-        out.append("layerStack=<any>");
-    } else {
-        dumpVal(out, "layerStack", singleLayerStackId);
-    }
+
+    dumpVal(out, "layerStack", layerStackId);
+    dumpVal(out, "layerStackInternal", layerStackInternal);
 
     out.append("\n   ");
 
diff --git a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
index f060cff..fe12825 100644
--- a/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/OutputTest.cpp
@@ -153,10 +153,10 @@
     mOutput.editState().bounds = displaySize;
 
     const uint32_t layerStack = 123u;
-    mOutput.setLayerStackFilter(true, layerStack);
+    mOutput.setLayerStackFilter(layerStack, true);
 
-    EXPECT_TRUE(mOutput.getState().singleLayerStack);
-    EXPECT_EQ(layerStack, mOutput.getState().singleLayerStackId);
+    EXPECT_TRUE(mOutput.getState().layerStackInternal);
+    EXPECT_EQ(layerStack, mOutput.getState().layerStackId);
 
     EXPECT_THAT(mOutput.getState().dirtyRegion, RegionEq(Region(displaySize)));
 }
@@ -260,5 +260,32 @@
     }
 }
 
+/* ------------------------------------------------------------------------
+ * Output::belongsInOutput()
+ */
+
+TEST_F(OutputTest, belongsInOutputFiltersAsExpected) {
+    const uint32_t layerStack1 = 123u;
+    const uint32_t layerStack2 = 456u;
+
+    // If the output accepts layerStack1 and internal-only layers....
+    mOutput.setLayerStackFilter(layerStack1, true);
+
+    // Any layer with layerStack1 belongs to it, internal-only or not.
+    EXPECT_TRUE(mOutput.belongsInOutput(layerStack1, false));
+    EXPECT_TRUE(mOutput.belongsInOutput(layerStack1, true));
+    EXPECT_FALSE(mOutput.belongsInOutput(layerStack2, true));
+    EXPECT_FALSE(mOutput.belongsInOutput(layerStack2, false));
+
+    // If the output accepts layerStack21 but not internal-only layers...
+    mOutput.setLayerStackFilter(layerStack1, false);
+
+    // Only non-internal layers with layerStack1 belong to it.
+    EXPECT_TRUE(mOutput.belongsInOutput(layerStack1, false));
+    EXPECT_FALSE(mOutput.belongsInOutput(layerStack1, true));
+    EXPECT_FALSE(mOutput.belongsInOutput(layerStack2, true));
+    EXPECT_FALSE(mOutput.belongsInOutput(layerStack2, false));
+}
+
 } // namespace
 } // namespace android::compositionengine