Setting the display state to off when the default display is being changed
This fixes the issue of the display state change always being "in progress". PhotonicModulator thread fails to make any progress while waiting for a notify call to release the lock. This happensbecause the screenState is set to invalid when a device is being folded/unfolded, forcing it to wait until the screen state is recovered.
Bug: 262294651
Test: adb shell dumpsys display | grep "Photonic Modulator" -A 10 ->
Shows mStateChangeInProgress is false
Test: Manually folding/unfolding the device wont cause the display stuck
in the power off state
Change-Id: I903f6392cbe42031aab8ffdbfbe541463d6b5e01
diff --git a/services/core/java/com/android/server/display/DisplayPowerController.java b/services/core/java/com/android/server/display/DisplayPowerController.java
index d791c06..a648135 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 @@
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 f650b11..7d1396d 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 @@
}
/**
- * 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() {
