Merge "Setting the display state to off when the default display is being changed" into tm-qpr-dev

2 files changed, 13 insertions, 5 deletions

diff --git a/services/core/java/com/android/server/display/DisplayPowerController.java b/services/core/java/com/android/server/display/DisplayPowerController.java
index b43d830e7935..d6e78a195be4 100644
--- a/services/core/java/com/android/server/display/DisplayPowerController.java
+++ b/services/core/java/com/android/server/display/DisplayPowerController.java
@@ -818,8 +818,8 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
                 loadFromDisplayDeviceConfig(token, info);
 
                 // Since the underlying display-device changed, we really don't know the
-                // last command that was sent to change it's state. Lets assume it is unknown so
-                // that we trigger a change immediately.
+                // last command that was sent to change it's state. Lets assume it is off and we
+                // trigger a change immediately.
                 mPowerState.resetScreenState();
             }
             if (mIsEnabled != isEnabled || mIsInTransition != isInTransition) {
diff --git a/services/core/java/com/android/server/display/DisplayPowerState.java b/services/core/java/com/android/server/display/DisplayPowerState.java
index f650b118b815..7d1396d7e413 100644
--- a/services/core/java/com/android/server/display/DisplayPowerState.java
+++ b/services/core/java/com/android/server/display/DisplayPowerState.java
@@ -340,12 +340,20 @@ final class DisplayPowerState {
     }
 
     /**
-     * Resets the screen state to unknown. Useful when the underlying display-device changes for the
-     * LogicalDisplay and we do not know the last state that was sent to it.
+     * Resets the screen state to {@link Display#STATE_OFF}. Even though we do not know the last
+     * state that was sent to the underlying display-device, we assume it is off.
+     *
+     * We do not set the screen state to {@link Display#STATE_UNKNOWN} to avoid getting in the state
+     * where PhotonicModulator holds onto the lock. This happens because we currently try to keep
+     * the mScreenState and mPendingState in sync, however if the screenState is set to
+     * {@link Display#STATE_UNKNOWN} here, mPendingState will get progressed to this, which will
+     * force the PhotonicModulator thread to wait onto the lock to take it out of that state.
+     * b/262294651 for more info.
      */
     void resetScreenState() {
-        mScreenState = Display.STATE_UNKNOWN;
+        mScreenState = Display.STATE_OFF;
         mScreenReady = false;
+        scheduleScreenUpdate();
     }
 
     private void scheduleScreenUpdate() {