Fix deadlock conditions in Camera3Device.

Potential deadlock conditions this addresses, include:
- Not waking up waiting threads for several situations where
  the status had been updated.
- Not waking up all waiting thread when status had been updated
  (only one thread was awoken due to use of signal).
- Threads clear status transitions before other waiting threads
  have a chance to examine them.

Bug: 22448586
Change-Id: I53ba669d333a83d2bfa1ca3170d34acc6d8fe6e3

1 files changed, 11 insertions, 0 deletions

diff --git a/services/camera/libcameraservice/device3/Camera3Device.h b/services/camera/libcameraservice/device3/Camera3Device.h
index eea34af..0ea9b8b 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.h
+++ b/services/camera/libcameraservice/device3/Camera3Device.h
@@ -205,7 +205,11 @@ class Camera3Device :
         STATUS_CONFIGURED,
         STATUS_ACTIVE
     }                          mStatus;
+
+    // Only clear mRecentStatusUpdates, mStatusWaiters from waitUntilStateThenRelock
     Vector<Status>             mRecentStatusUpdates;
+    int                        mStatusWaiters;
+
     Condition                  mStatusChanged;
 
     // Tracking cause of fatal errors when in STATUS_ERROR
@@ -276,6 +280,13 @@ class Camera3Device :
     virtual CameraMetadata getLatestRequestLocked();
 
     /**
+     * Update the current device status and wake all waiting threads.
+     *
+     * Must be called with mLock held.
+     */
+    void internalUpdateStatusLocked(Status status);
+
+    /**
      * Pause processing and flush everything, but don't tell the clients.
      * This is for reconfiguring outputs transparently when according to the
      * CameraDeviceBase interface we shouldn't need to.