[libcamera-devel] [PATCH 2/2] android: Post-pone fences reset in result

[Jacopo Mondi]

When a request has been completed and a new capture_result is created
to be sent to the framework through the process_capture_result()
callback we assumed all fences had been waited on, hence we set both
the release and acquisition fences to -1.

Now that the acquisition fence of streams generated through
post-processing are handled by CameraStream::process(), resetting fences
too early would invalidate them before they get handled.

Post-pone setting fences to -1 for successful capture results, and
correct the release_fence handling for failed captures, as the framework
requires the release fences to be set to the acquire fence value if the
acquire fence has not been waited on.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/android/camera_device.cpp | 44 ++++++++++++++++++++++++-----------
 1 file changed, 31 insertions(+), 13 deletions(-)

diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index db35947afc2f..8ca2353e5f33 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -1098,22 +1098,10 @@ void CameraDevice::requestComplete(Request *request)
 	}
 	Camera3RequestDescriptor &descriptor = node.mapped();
 
-	/*
-	 * Prepare the capture result for the Android camera stack.
-	 *
-	 * The buffer status is set to OK and later changed to ERROR if
-	 * post-processing/compression fails.
-	 */
 	camera3_capture_result_t captureResult = {};
 	captureResult.frame_number = descriptor.frameNumber_;
 	captureResult.num_output_buffers = descriptor.buffers_.size();
-	for (camera3_stream_buffer_t &buffer : descriptor.buffers_) {
-		buffer.acquire_fence = -1;
-		buffer.release_fence = -1;
-		buffer.status = CAMERA3_BUFFER_STATUS_OK;
-	}
 	captureResult.output_buffers = descriptor.buffers_.data();
-	captureResult.partial_result = 1;
 
 	/*
 	 * If the Request has failed, abort the request by notifying the error
@@ -1128,8 +1116,27 @@ void CameraDevice::requestComplete(Request *request)
 			    CAMERA3_MSG_ERROR_REQUEST);
 
 		captureResult.partial_result = 0;
-		for (camera3_stream_buffer_t &buffer : descriptor.buffers_)
+		for (camera3_stream_buffer_t &buffer : descriptor.buffers_) {
+			CameraStream *cameraStream =
+				static_cast<CameraStream *>(buffer.stream->priv);
+
+			/*
+			 * Streams of type Direct have been queued to the
+			 * libcamera::Camera and their acquisition fences has
+			 * already been waited on by the CameraWorker.
+			 *
+			 * For other stream types signal to the framework the
+			 * acquisition fence has not been waited on, by setting
+			 * the release fence to its value.
+			 */
+			if (cameraStream->type() == CameraStream::Type::Direct)
+				buffer.release_fence = -1;
+			else
+				buffer.release_fence = buffer.acquire_fence;
+
+			buffer.acquire_fence = -1;
 			buffer.status = CAMERA3_BUFFER_STATUS_ERROR;
+		}
 		callbacks_->process_capture_result(callbacks_, &captureResult);
 
 		return;
@@ -1196,6 +1203,17 @@ void CameraDevice::requestComplete(Request *request)
 		}
 	}
 
+	/*
+	 * Finalize the capture result by setting fences and buffer status
+	 * before executing the callback.
+	 */
+	for (camera3_stream_buffer_t &buffer : descriptor.buffers_) {
+		buffer.acquire_fence = -1;
+		buffer.release_fence = -1;
+		buffer.status = CAMERA3_BUFFER_STATUS_OK;
+	}
+	captureResult.partial_result = 1;
+
 	captureResult.result = resultMetadata->get();
 	callbacks_->process_capture_result(callbacks_, &captureResult);
 }
-- 
2.32.0