CameraHal: Fix preview not starting after surface is abdandoned

If an application gets backgrounded (HOME key) without stopping
preview and releasing camera, preview would previously not restart
when application is resumed. ANativeWindowDisplayAdapter would
detect that the preview surface was abandoned and stop sending
buffers to CameraAdapter.

We were previously not doing anything when CameraService called
setPreviewWindow when a display adapter was already created. To
fix this issue, we need to send the preview window and restart
preview.

Change-Id: I36089b0046f9861897d32c50b52128a41e2de2a5
Signed-off-by: Tyler Luu <tluu@ti.com>

2 files changed, 13 insertions, 6 deletions

diff --git a/camera/ANativeWindowDisplayAdapter.cpp b/camera/ANativeWindowDisplayAdapter.cpp
index a7b2e86..e6a4c87 100644
--- a/camera/ANativeWindowDisplayAdapter.cpp
+++ b/camera/ANativeWindowDisplayAdapter.cpp
@@ -269,6 +269,10 @@ int ANativeWindowDisplayAdapter::setPreviewWindow(preview_stream_ops_t* window)
         return BAD_VALUE;
     }
 
+    if ( window == mANativeWindow ) {
+        return ALREADY_EXISTS;
+    }
+
     ///Destroy the existing window object, if it exists
     destroy();
 
diff --git a/camera/CameraHal.cpp b/camera/CameraHal.cpp
index c7ba87f..c64b7e2 100644
--- a/camera/CameraHal.cpp
+++ b/camera/CameraHal.cpp
@@ -1713,12 +1713,15 @@ status_t CameraHal::setPreviewWindow(struct preview_stream_ops *window)
             // Start the preview since the window is now available
             ret = startPreview();
         }
-    }else
-    {
-        /* If mDisplayAdpater is already created. No need to do anything.
-         * We get a surface handle directly now, so we can reconfigure surface
-         * itself in DisplayAdapter if dimensions have changed
-         */
+    } else {
+        // Update the display adapter with the new window that is passed from CameraService
+        ret = mDisplayAdapter->setPreviewWindow(window);
+        if ( (NO_ERROR == ret) && previewEnabled() ) {
+            restartPreview();
+        } else if (ret == ALREADY_EXISTS) {
+            // ALREADY_EXISTS should be treated as a noop in this case
+            ret = NO_ERROR;
+        }
     }
     LOG_FUNCTION_NAME_EXIT;