Add leadDisplayAddress to display-layout-config

- If leadDisplayAddress is not specified in display-layout-config XML,
  no lead display is set.
- This CL will set a lead display according to leadDisplayAddress in
  display-layout-config.

Bug: 274391981
Test: atest DeviceStateToLayoutmapTest
Change-Id: I6f9272ff41429f64c8e55984182c55a9ccebd9f7

6 files changed, 248 insertions, 35 deletions

diff --git a/services/core/java/com/android/server/display/DeviceStateToLayoutMap.java b/services/core/java/com/android/server/display/DeviceStateToLayoutMap.java
index f84a58c5b06d..472c1f58dc8a 100644
--- a/services/core/java/com/android/server/display/DeviceStateToLayoutMap.java
+++ b/services/core/java/com/android/server/display/DeviceStateToLayoutMap.java
@@ -22,7 +22,6 @@ import android.os.Environment;
 import android.util.IndentingPrintWriter;
 import android.util.Slog;
 import android.util.SparseArray;
-import android.view.Display;
 import android.view.DisplayAddress;
 
 import com.android.internal.annotations.VisibleForTesting;
@@ -38,6 +37,7 @@ import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.math.BigInteger;
 
 import javax.xml.datatype.DatatypeConfigurationException;
 
@@ -115,13 +115,16 @@ class DeviceStateToLayoutMap {
                 Slog.i(TAG, "Display layout config not found: " + configFile);
                 return;
             }
-            int leadDisplayId = Display.DEFAULT_DISPLAY;
             for (com.android.server.display.config.layout.Layout l : layouts.getLayout()) {
                 final int state = l.getState().intValue();
                 final Layout layout = createLayout(state);
                 for (com.android.server.display.config.layout.Display d: l.getDisplay()) {
                     assert layout != null;
                     int position = getPosition(d.getPosition());
+                    BigInteger leadDisplayPhysicalId = d.getLeadDisplayAddress();
+                    DisplayAddress leadDisplayAddress = leadDisplayPhysicalId == null ? null
+                            : DisplayAddress.fromPhysicalDisplayId(
+                                    leadDisplayPhysicalId.longValue());
                     layout.createDisplayLocked(
                             DisplayAddress.fromPhysicalDisplayId(d.getAddress().longValue()),
                             d.isDefaultDisplay(),
@@ -129,11 +132,12 @@ class DeviceStateToLayoutMap {
                             d.getDisplayGroup(),
                             mIdProducer,
                             position,
-                            leadDisplayId,
+                            leadDisplayAddress,
                             d.getBrightnessThrottlingMapId(),
                             d.getRefreshRateZoneId(),
                             d.getRefreshRateThermalThrottlingMapId());
                 }
+                layout.postProcessLocked();
             }
         } catch (IOException | DatatypeConfigurationException | XmlPullParserException e) {
             Slog.e(TAG, "Encountered an error while reading/parsing display layout config file: "
diff --git a/services/core/java/com/android/server/display/layout/Layout.java b/services/core/java/com/android/server/display/layout/Layout.java
index b55d7d5d9d3c..d9ec3de46b0e 100644
--- a/services/core/java/com/android/server/display/layout/Layout.java
+++ b/services/core/java/com/android/server/display/layout/Layout.java
@@ -22,6 +22,8 @@ import static com.android.server.display.layout.Layout.Display.POSITION_UNKNOWN;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.text.TextUtils;
+import android.util.ArraySet;
 import android.util.Slog;
 import android.view.DisplayAddress;
 
@@ -77,7 +79,7 @@ public class Layout {
             DisplayIdProducer idProducer) {
         createDisplayLocked(address, /* isDefault= */ true, /* isEnabled= */ true,
                 DEFAULT_DISPLAY_GROUP_NAME, idProducer, POSITION_UNKNOWN,
-                NO_LEAD_DISPLAY, /* brightnessThrottlingMapId= */ null,
+                /* leadDisplayAddress= */ null, /* brightnessThrottlingMapId= */ null,
                 /* refreshRateZoneId= */ null, /* refreshRateThermalThrottlingMapId= */ null);
     }
 
@@ -90,19 +92,20 @@ public class Layout {
      * @param displayGroupName Name of the display group to which the display is assigned.
      * @param idProducer Produces the logical display id.
      * @param position Indicates the position this display is facing in this layout.
-     * @param leadDisplayId Display that this one follows (-1 if none).
+     * @param leadDisplayAddress Address of a display that this one follows ({@code null} if none).
      * @param brightnessThrottlingMapId Name of which brightness throttling policy should be used.
      * @param refreshRateZoneId Layout limited refresh rate zone name.
      * @param refreshRateThermalThrottlingMapId Name of which refresh rate throttling
      *                                          policy should be used.
-
+     *
      * @exception IllegalArgumentException When a default display owns a display group other than
      *            DEFAULT_DISPLAY_GROUP.
      */
     public void createDisplayLocked(
             @NonNull DisplayAddress address, boolean isDefault, boolean isEnabled,
-            String displayGroupName, DisplayIdProducer idProducer, int position, int leadDisplayId,
-            String brightnessThrottlingMapId, @Nullable String refreshRateZoneId,
+            String displayGroupName, DisplayIdProducer idProducer, int position,
+            @Nullable DisplayAddress leadDisplayAddress, String brightnessThrottlingMapId,
+            @Nullable String refreshRateZoneId,
             @Nullable String refreshRateThermalThrottlingMapId) {
         if (contains(address)) {
             Slog.w(TAG, "Attempting to add second definition for display-device: " + address);
@@ -115,21 +118,27 @@ public class Layout {
             return;
         }
 
-        // Assign a logical display ID and create the new display.
-        // Note that the logical display ID is saved into the layout, so when switching between
-        // different layouts, a logical display can be destroyed and later recreated with the
-        // same logical display ID.
         if (displayGroupName == null) {
             displayGroupName = DEFAULT_DISPLAY_GROUP_NAME;
         }
         if (isDefault && !displayGroupName.equals(DEFAULT_DISPLAY_GROUP_NAME)) {
             throw new IllegalArgumentException("Default display should own DEFAULT_DISPLAY_GROUP");
         }
+        if (isDefault && leadDisplayAddress != null) {
+            throw new IllegalArgumentException("Default display cannot have a lead display");
+        }
+        if (address.equals(leadDisplayAddress)) {
+            throw new IllegalArgumentException("Lead display address cannot be the same as display "
+                    + " address");
+        }
+        // Assign a logical display ID and create the new display.
+        // Note that the logical display ID is saved into the layout, so when switching between
+        // different layouts, a logical display can be destroyed and later recreated with the
+        // same logical display ID.
         final int logicalDisplayId = idProducer.getId(isDefault);
-        leadDisplayId = isDefault ? NO_LEAD_DISPLAY : leadDisplayId;
 
         final Display display = new Display(address, logicalDisplayId, isEnabled, displayGroupName,
-                brightnessThrottlingMapId, position, leadDisplayId, refreshRateZoneId,
+                brightnessThrottlingMapId, position, leadDisplayAddress, refreshRateZoneId,
                 refreshRateThermalThrottlingMapId);
 
         mDisplays.add(display);
@@ -146,6 +155,43 @@ public class Layout {
     }
 
     /**
+     * Applies post-processing to displays to make sure the information of each display is
+     * up-to-date.
+     *
+     * <p>At creation of a display, lead display is specified by display address. At post
+     * processing, we convert it to logical display ID.
+     */
+    public void postProcessLocked() {
+        for (int i = 0; i < mDisplays.size(); i++) {
+            Display display = mDisplays.get(i);
+            if (display.getLogicalDisplayId() == DEFAULT_DISPLAY) {
+                display.setLeadDisplayId(NO_LEAD_DISPLAY);
+                continue;
+            }
+            DisplayAddress leadDisplayAddress = display.getLeadDisplayAddress();
+            if (leadDisplayAddress == null) {
+                display.setLeadDisplayId(NO_LEAD_DISPLAY);
+                continue;
+            }
+            Display leadDisplay = getByAddress(leadDisplayAddress);
+            if (leadDisplay == null) {
+                throw new IllegalArgumentException("Cannot find a lead display whose address is "
+                        + leadDisplayAddress);
+            }
+            if (!TextUtils.equals(display.getDisplayGroupName(),
+                    leadDisplay.getDisplayGroupName())) {
+                throw new IllegalArgumentException("Lead display(" + leadDisplay + ") should be in "
+                        + "the same display group of the display(" + display + ")");
+            }
+            if (hasCyclicLeadDisplay(display)) {
+                throw new IllegalArgumentException("Display(" + display + ") has a cyclic lead "
+                        + "display");
+            }
+            display.setLeadDisplayId(leadDisplay.getLogicalDisplayId());
+        }
+    }
+
+    /**
      * @param address The address to check.
      *
      * @return True if the specified address is used in this layout.
@@ -208,6 +254,20 @@ public class Layout {
         return mDisplays.size();
     }
 
+    private boolean hasCyclicLeadDisplay(Display display) {
+        ArraySet<Display> visited = new ArraySet<>();
+
+        while (display != null) {
+            if (visited.contains(display)) {
+                return true;
+            }
+            visited.add(display);
+            DisplayAddress leadDisplayAddress = display.getLeadDisplayAddress();
+            display = leadDisplayAddress == null ? null : getByAddress(leadDisplayAddress);
+        }
+        return false;
+    }
+
     /**
      * Describes how a {@link LogicalDisplay} is built from {@link DisplayDevice}s.
      */
@@ -240,8 +300,9 @@ public class Layout {
         @Nullable
         private final String mThermalBrightnessThrottlingMapId;
 
-        // The ID of the lead display that this display will follow in a layout. -1 means no lead.
-        private final int mLeadDisplayId;
+        // The address of the lead display that is specified in display-layout-configuration.
+        @Nullable
+        private final DisplayAddress mLeadDisplayAddress;
 
         // Refresh rate zone id for specific layout
         @Nullable
@@ -250,9 +311,13 @@ public class Layout {
         @Nullable
         private final String mThermalRefreshRateThrottlingMapId;
 
+        // The ID of the lead display that this display will follow in a layout. -1 means no lead.
+        // This is determined using {@code mLeadDisplayAddress}.
+        private int mLeadDisplayId;
+
         private Display(@NonNull DisplayAddress address, int logicalDisplayId, boolean isEnabled,
                 @NonNull String displayGroupName, String brightnessThrottlingMapId, int position,
-                int leadDisplayId, @Nullable String refreshRateZoneId,
+                @Nullable DisplayAddress leadDisplayAddress, @Nullable String refreshRateZoneId,
                 @Nullable String refreshRateThermalThrottlingMapId) {
             mAddress = address;
             mLogicalDisplayId = logicalDisplayId;
@@ -260,9 +325,10 @@ public class Layout {
             mDisplayGroupName = displayGroupName;
             mPosition = position;
             mThermalBrightnessThrottlingMapId = brightnessThrottlingMapId;
+            mLeadDisplayAddress = leadDisplayAddress;
             mRefreshRateZoneId = refreshRateZoneId;
             mThermalRefreshRateThrottlingMapId = refreshRateThermalThrottlingMapId;
-            mLeadDisplayId = leadDisplayId;
+            mLeadDisplayId = NO_LEAD_DISPLAY;
         }
 
         @Override
@@ -276,6 +342,7 @@ public class Layout {
                     + ", mThermalBrightnessThrottlingMapId: " + mThermalBrightnessThrottlingMapId
                     + ", mRefreshRateZoneId: " + mRefreshRateZoneId
                     + ", mLeadDisplayId: " + mLeadDisplayId
+                    + ", mLeadDisplayAddress: " + mLeadDisplayAddress
                     + ", mThermalRefreshRateThrottlingMapId: " + mThermalRefreshRateThrottlingMapId
                     + "}";
         }
@@ -297,6 +364,7 @@ public class Layout {
                     otherDisplay.mThermalBrightnessThrottlingMapId)
                     && Objects.equals(otherDisplay.mRefreshRateZoneId, this.mRefreshRateZoneId)
                     && this.mLeadDisplayId == otherDisplay.mLeadDisplayId
+                    && Objects.equals(mLeadDisplayAddress, otherDisplay.mLeadDisplayAddress)
                     && Objects.equals(mThermalRefreshRateThrottlingMapId,
                     otherDisplay.mThermalRefreshRateThrottlingMapId);
         }
@@ -309,9 +377,10 @@ public class Layout {
             result = 31 * result + mLogicalDisplayId;
             result = 31 * result + mDisplayGroupName.hashCode();
             result = 31 * result + mAddress.hashCode();
-            result = 31 * result + mThermalBrightnessThrottlingMapId.hashCode();
+            result = 31 * result + Objects.hashCode(mThermalBrightnessThrottlingMapId);
             result = 31 * result + Objects.hashCode(mRefreshRateZoneId);
             result = 31 * result + mLeadDisplayId;
+            result = 31 * result + Objects.hashCode(mLeadDisplayAddress);
             result = 31 * result + Objects.hashCode(mThermalRefreshRateThrottlingMapId);
             return result;
         }
@@ -360,8 +429,20 @@ public class Layout {
             return mLeadDisplayId;
         }
 
+        /**
+         * @return Display address of the display that this one follows.
+         */
+        @Nullable
+        public DisplayAddress getLeadDisplayAddress() {
+            return mLeadDisplayAddress;
+        }
+
         public String getRefreshRateThermalThrottlingMapId() {
             return mThermalRefreshRateThrottlingMapId;
         }
+
+        private void setLeadDisplayId(int id) {
+            mLeadDisplayId = id;
+        }
     }
 }
diff --git a/services/core/xsd/display-layout-config/display-layout-config.xsd b/services/core/xsd/display-layout-config/display-layout-config.xsd
index ce022e9cb78d..57b5d00f75a0 100644
--- a/services/core/xsd/display-layout-config/display-layout-config.xsd
+++ b/services/core/xsd/display-layout-config/display-layout-config.xsd
@@ -53,6 +53,7 @@
             <xs:element name="position" type="xs:string" minOccurs="0" maxOccurs="1" />
             <xs:element name="brightnessThrottlingMapId" type="xs:string" minOccurs="0" maxOccurs="1" />
             <xs:element name="refreshRateThermalThrottlingMapId" type="xs:string" minOccurs="0" />
+            <xs:element name="leadDisplayAddress" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1" />
         </xs:sequence>
         <xs:attribute name="enabled" type="xs:boolean" use="optional" />
         <xs:attribute name="defaultDisplay" type="xs:boolean" use="optional" />
diff --git a/services/core/xsd/display-layout-config/schema/current.txt b/services/core/xsd/display-layout-config/schema/current.txt
index 42a800db1474..2d4f7a428db1 100644
--- a/services/core/xsd/display-layout-config/schema/current.txt
+++ b/services/core/xsd/display-layout-config/schema/current.txt
@@ -6,6 +6,7 @@ package com.android.server.display.config.layout {
     method public java.math.BigInteger getAddress();
     method public String getBrightnessThrottlingMapId();
     method public String getDisplayGroup();
+    method public java.math.BigInteger getLeadDisplayAddress();
     method public String getPosition();
     method public String getRefreshRateThermalThrottlingMapId();
     method public String getRefreshRateZoneId();
@@ -16,6 +17,7 @@ package com.android.server.display.config.layout {
     method public void setDefaultDisplay(boolean);
     method public void setDisplayGroup(String);
     method public void setEnabled(boolean);
+    method public void setLeadDisplayAddress(java.math.BigInteger);
     method public void setPosition(String);
     method public void setRefreshRateThermalThrottlingMapId(String);
     method public void setRefreshRateZoneId(String);
diff --git a/services/tests/displayservicetests/src/com/android/server/display/DeviceStateToLayoutMapTest.java b/services/tests/displayservicetests/src/com/android/server/display/DeviceStateToLayoutMapTest.java
index 130e6ad91b49..4b124caca7d6 100644
--- a/services/tests/displayservicetests/src/com/android/server/display/DeviceStateToLayoutMapTest.java
+++ b/services/tests/displayservicetests/src/com/android/server/display/DeviceStateToLayoutMapTest.java
@@ -19,8 +19,8 @@ package com.android.server.display;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThrows;
 
-import android.view.Display;
 import android.view.DisplayAddress;
 
 import androidx.test.filters.SmallTest;
@@ -65,9 +65,15 @@ public class DeviceStateToLayoutMapTest {
 
         Layout testLayout = new Layout();
         createDefaultDisplay(testLayout, 123456L);
-        createNonDefaultDisplay(testLayout, 78910L, /* enabled= */ false, /* group= */ null);
-        createNonDefaultDisplay(testLayout, 98765L, /* enabled= */ true, /* group= */ "group1");
-        createNonDefaultDisplay(testLayout, 786L, /* enabled= */ false, /* group= */ "group2");
+        createNonDefaultDisplay(testLayout, 78910L, /* enabled= */ false, /* group= */ null,
+                /* leadDisplayAddress= */ null);
+        createNonDefaultDisplay(testLayout, 98765L, /* enabled= */ true, /* group= */ "group1",
+                /* leadDisplayAddress= */ null);
+        createNonDefaultDisplay(testLayout, 786L, /* enabled= */ false, /* group= */ "group2",
+                /* leadDisplayAddress= */ null);
+        createNonDefaultDisplay(testLayout, 1092L, /* enabled= */ true, /* group= */ null,
+                DisplayAddress.fromPhysicalDisplayId(78910L));
+        testLayout.postProcessLocked();
 
         assertEquals(testLayout, configLayout);
     }
@@ -78,7 +84,9 @@ public class DeviceStateToLayoutMapTest {
 
         Layout testLayout = new Layout();
         createDefaultDisplay(testLayout, 78910L);
-        createNonDefaultDisplay(testLayout, 123456L, /* enabled= */ false, /* group= */ null);
+        createNonDefaultDisplay(testLayout, 123456L, /* enabled= */ false, /* group= */ null,
+                /* leadDisplayAddress= */ null);
+        testLayout.postProcessLocked();
 
         assertEquals(testLayout, configLayout);
     }
@@ -122,20 +130,132 @@ public class DeviceStateToLayoutMapTest {
         Layout testLayout = new Layout();
         testLayout.createDisplayLocked(DisplayAddress.fromPhysicalDisplayId(345L),
                 /* isDefault= */ true, /* isEnabled= */ true, /* displayGroupName= */ null,
-                mDisplayIdProducerMock,  Layout.Display.POSITION_FRONT, Display.DEFAULT_DISPLAY,
-                /* brightnessThrottlingMapId= */ "brightness1",
+                mDisplayIdProducerMock,  Layout.Display.POSITION_FRONT,
+                /* leadDisplayAddress= */ null, /* brightnessThrottlingMapId= */ "brightness1",
                 /* refreshRateZoneId= */ "zone1",
                 /* refreshRateThermalThrottlingMapId= */ "rr1");
         testLayout.createDisplayLocked(DisplayAddress.fromPhysicalDisplayId(678L),
                 /* isDefault= */ false, /* isEnabled= */ false, /* displayGroupName= */ "group1",
-                mDisplayIdProducerMock, Layout.Display.POSITION_REAR, Display.DEFAULT_DISPLAY,
-                /* brightnessThrottlingMapId= */ "brightness2",
+                mDisplayIdProducerMock, Layout.Display.POSITION_REAR,
+                /* leadDisplayAddress= */ null, /* brightnessThrottlingMapId= */ "brightness2",
                 /* refreshRateZoneId= */ "zone2",
                 /* refreshRateThermalThrottlingMapId= */ "rr2");
+        testLayout.postProcessLocked();
 
         assertEquals(testLayout, configLayout);
     }
 
+    @Test
+    public void testLeadDisplayAddress() {
+        Layout layout = new Layout();
+        createNonDefaultDisplay(layout, 111L, /* enabled= */ true, /* group= */ null,
+                /* leadDisplayAddress= */ null);
+        createNonDefaultDisplay(layout, 222L, /* enabled= */ true, /* group= */ null,
+                DisplayAddress.fromPhysicalDisplayId(111L));
+
+        layout.postProcessLocked();
+
+        com.android.server.display.layout.Layout.Display display111 =
+                layout.getByAddress(DisplayAddress.fromPhysicalDisplayId(111));
+        com.android.server.display.layout.Layout.Display display222 =
+                layout.getByAddress(DisplayAddress.fromPhysicalDisplayId(222));
+        assertEquals(display111.getLeadDisplayId(), layout.NO_LEAD_DISPLAY);
+        assertEquals(display222.getLeadDisplayId(), display111.getLogicalDisplayId());
+    }
+
+    @Test
+    public void testLeadDisplayAddress_defaultDisplay() {
+        Layout layout = new Layout();
+        createDefaultDisplay(layout, 123456L);
+
+        layout.postProcessLocked();
+
+        com.android.server.display.layout.Layout.Display display =
+                layout.getByAddress(DisplayAddress.fromPhysicalDisplayId(123456));
+        assertEquals(display.getLeadDisplayId(), layout.NO_LEAD_DISPLAY);
+    }
+
+    @Test
+    public void testLeadDisplayAddress_noLeadDisplay() {
+        Layout layout = new Layout();
+        createNonDefaultDisplay(layout, 222L, /* enabled= */ true, /* group= */ null,
+                /* leadDisplayAddress= */ null);
+
+        layout.postProcessLocked();
+
+        com.android.server.display.layout.Layout.Display display =
+                layout.getByAddress(DisplayAddress.fromPhysicalDisplayId(222));
+        assertEquals(display.getLeadDisplayId(), layout.NO_LEAD_DISPLAY);
+    }
+
+    @Test
+    public void testLeadDisplayAddress_selfLeadDisplayForNonDefaultDisplay() {
+        Layout layout = new Layout();
+
+        assertThrows("Expected Layout to throw IllegalArgumentException when the display points out"
+                + " itself as a lead display",
+                IllegalArgumentException.class,
+                () -> layout.createDisplayLocked(DisplayAddress.fromPhysicalDisplayId(123L),
+                    /* isDefault= */ true, /* isEnabled= */ true, /* displayGroupName= */ null,
+                    mDisplayIdProducerMock,  Layout.Display.POSITION_FRONT,
+                    DisplayAddress.fromPhysicalDisplayId(123L),
+                    /* brightnessThrottlingMapId= */ null, /* refreshRateZoneId= */ null,
+                    /* refreshRateThermalThrottlingMapId= */ null));
+    }
+
+    @Test
+    public void testLeadDisplayAddress_wrongLeadDisplayForDefaultDisplay() {
+        Layout layout = new Layout();
+
+        assertThrows("Expected Layout to throw IllegalArgumentException when the default display "
+                + "has a lead display",
+                IllegalArgumentException.class,
+                () -> layout.createDisplayLocked(DisplayAddress.fromPhysicalDisplayId(123L),
+                    /* isDefault= */ true, /* isEnabled= */ true, /* displayGroupName= */ null,
+                    mDisplayIdProducerMock,  Layout.Display.POSITION_FRONT,
+                    DisplayAddress.fromPhysicalDisplayId(987L),
+                    /* brightnessThrottlingMapId= */ null, /* refreshRateZoneId= */ null,
+                    /* refreshRateThermalThrottlingMapId= */ null));
+    }
+
+    @Test
+    public void testLeadDisplayAddress_notExistingLeadDisplayForNonDefaultDisplay() {
+        Layout layout = new Layout();
+        createNonDefaultDisplay(layout, 222L, /* enabled= */ true, /* group= */ null,
+                DisplayAddress.fromPhysicalDisplayId(111L));
+
+        assertThrows("Expected Layout to throw IllegalArgumentException when a lead display doesn't"
+                + " exist", IllegalArgumentException.class, () -> layout.postProcessLocked());
+    }
+
+    @Test
+    public void testLeadDisplayAddress_leadDisplayInDifferentDisplayGroup() {
+        Layout layout = new Layout();
+        createNonDefaultDisplay(layout, 111, /* enabled= */ true, /* group= */ "group1",
+                /* leadDisplayAddress= */ null);
+        createNonDefaultDisplay(layout, 222L, /* enabled= */ true, /* group= */ "group2",
+                DisplayAddress.fromPhysicalDisplayId(111L));
+
+        assertThrows("Expected Layout to throw IllegalArgumentException when pointing to a lead "
+                + "display in the different group",
+                IllegalArgumentException.class, () -> layout.postProcessLocked());
+    }
+
+    @Test
+    public void testLeadDisplayAddress_cyclicLeadDisplay() {
+        Layout layout = new Layout();
+        createNonDefaultDisplay(layout, 111, /* enabled= */ true, /* group= */ null,
+                DisplayAddress.fromPhysicalDisplayId(222L));
+        createNonDefaultDisplay(layout, 222L, /* enabled= */ true, /* group= */ null,
+                DisplayAddress.fromPhysicalDisplayId(333L));
+        createNonDefaultDisplay(layout, 333L, /* enabled= */ true, /* group= */ null,
+                DisplayAddress.fromPhysicalDisplayId(222L));
+
+        assertThrows("Expected Layout to throw IllegalArgumentException when pointing to a lead "
+                + "display in the different group",
+                IllegalArgumentException.class, () -> layout.postProcessLocked());
+    }
+
     ////////////////////
     // Helper Methods //
     ////////////////////
@@ -145,10 +265,11 @@ public class DeviceStateToLayoutMapTest {
                 mDisplayIdProducerMock);
     }
 
-    private void createNonDefaultDisplay(Layout layout, long id, boolean enabled, String group) {
+    private void createNonDefaultDisplay(Layout layout, long id, boolean enabled, String group,
+            DisplayAddress leadDisplayAddress) {
         layout.createDisplayLocked(DisplayAddress.fromPhysicalDisplayId(id), /* isDefault= */ false,
                 enabled, group, mDisplayIdProducerMock, Layout.Display.POSITION_UNKNOWN,
-                Display.DEFAULT_DISPLAY, /* brightnessThrottlingMapId= */ null,
+                leadDisplayAddress, /* brightnessThrottlingMapId= */ null,
                 /* refreshRateZoneId= */ null,
                 /* refreshRateThermalThrottlingMapId= */ null);
     }
@@ -177,6 +298,10 @@ public class DeviceStateToLayoutMapTest {
                 +      "<display enabled=\"false\" displayGroup=\"group2\">\n"
                 +        "<address>786</address>\n"
                 +      "</display>\n"
+                +      "<display enabled=\"true\">\n"
+                +        "<address>1092</address>\n"
+                +        "<leadDisplayAddress>78910</leadDisplayAddress>\n"
+                +      "</display>\n"
                 +    "</layout>\n"
 
                 +    "<layout>\n"
diff --git a/services/tests/displayservicetests/src/com/android/server/display/LogicalDisplayMapperTest.java b/services/tests/displayservicetests/src/com/android/server/display/LogicalDisplayMapperTest.java
index 1eec70da3d20..3e695c9407b6 100644
--- a/services/tests/displayservicetests/src/com/android/server/display/LogicalDisplayMapperTest.java
+++ b/services/tests/displayservicetests/src/com/android/server/display/LogicalDisplayMapperTest.java
@@ -604,13 +604,13 @@ public class LogicalDisplayMapperTest {
         layout.createDisplayLocked(device1.getDisplayDeviceInfoLocked().address,
                 /* isDefault= */ true, /* isEnabled= */ true, /* displayGroup= */ null,
                 mIdProducer, POSITION_UNKNOWN,
-                /* leadDisplayId= */ Display.DEFAULT_DISPLAY,
+                /* leadDisplayAddress= */ null,
                 /* brightnessThrottlingMapId= */ "concurrent",
                 /* refreshRateZoneId= */ null, /* refreshRateThermalThrottlingMapId= */ null);
         layout.createDisplayLocked(device2.getDisplayDeviceInfoLocked().address,
                 /* isDefault= */ false, /* isEnabled= */ true, /* displayGroup= */ null,
                 mIdProducer, POSITION_UNKNOWN,
-                /* leadDisplayId= */ Display.DEFAULT_DISPLAY,
+                /* leadDisplayAddress= */ null,
                 /* brightnessThrottlingMapId= */ "concurrent",
                 /* refreshRateZoneId= */ null, /* refreshRateThermalThrottlingMapId= */ null);
         when(mDeviceStateToLayoutMapSpy.get(0)).thenReturn(layout);
@@ -646,7 +646,7 @@ public class LogicalDisplayMapperTest {
         assertFalse(mLogicalDisplayMapper.getDisplayLocked(device2).isInTransitionLocked());
         assertEquals(-1, mLogicalDisplayMapper.getDisplayLocked(device1)
                 .getLeadDisplayIdLocked());
-        assertEquals(0, mLogicalDisplayMapper.getDisplayLocked(device2)
+        assertEquals(-1, mLogicalDisplayMapper.getDisplayLocked(device2)
                 .getLeadDisplayIdLocked());
         assertEquals("concurrent", mLogicalDisplayMapper.getDisplayLocked(device1)
                 .getDisplayInfoLocked().thermalBrightnessThrottlingDataId);
@@ -811,7 +811,7 @@ public class LogicalDisplayMapperTest {
                 mIdProducer);
         layout.createDisplayLocked(device2.getDisplayDeviceInfoLocked().address,
                 /* isDefault= */ false, /* isEnabled= */ true, /* displayGroupName= */ null,
-                mIdProducer, POSITION_REAR, Display.DEFAULT_DISPLAY,
+                mIdProducer, POSITION_REAR, /* leadDisplayAddress= */ null,
                 /* brightnessThrottlingMapId= */ null, /* refreshRateZoneId= */ null,
                 /* refreshRateThermalThrottlingMapId= */null);
         when(mDeviceStateToLayoutMapSpy.get(0)).thenReturn(layout);
@@ -861,7 +861,7 @@ public class LogicalDisplayMapperTest {
     private void createNonDefaultDisplay(Layout layout, DisplayAddress address, boolean enabled,
             String group) {
         layout.createDisplayLocked(address, /* isDefault= */ false, enabled, group, mIdProducer,
-                Layout.Display.POSITION_UNKNOWN, Display.DEFAULT_DISPLAY,
+                Layout.Display.POSITION_UNKNOWN, /* leadDisplayAddress= */ null,
                 /* brightnessThrottlingMapId= */ null, /* refreshRateZoneId= */ null,
                 /* refreshRateThermalThrottlingMapId= */ null);
     }