Snapdragon Camera: Avoid possible race condition

 Camera open and preview start are currently
 executed in a separate thread different from the
 main handler thread. If the main thread tries to
 switch the camera immediately after the open camera
 thread starts a race condition is possible. This
 race condition can lead to a failing assert in
 CameraHolder which can receive two camera open
 requests one after another. To resolve this
 the main handler thread needs to check whether
 an open camera thread got initialized and started
 previously. If the check is positive, it needs
 to wait until the separate thread finishes before
 proceeding with the camera switch sequence.

Change-Id: I409e3158bc976120de31540351ea8e55fddbca46

1 files changed, 9 insertions, 0 deletions

diff --git a/src/com/android/camera/PhotoModule.java b/src/com/android/camera/PhotoModule.java
index da6278d08..2d2662eb3 100644
--- a/src/com/android/camera/PhotoModule.java
+++ b/src/com/android/camera/PhotoModule.java
@@ -640,6 +640,15 @@ public class PhotoModule
         mPendingSwitchCameraId = -1;
         setCameraId(mCameraId);
 
+        try {
+            if (mOpenCameraThread != null) {
+                mOpenCameraThread.join();
+            }
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        mOpenCameraThread = null;
+
         // from onPause
         try {
             if (mOpenCameraThread != null) {