pipeline: ipu3: Skip recording timestamp for cancelled buffers

There is no point in recording sensor's timestamp when V4L2VideoDevice
has marked the frame buffers with FrameMetadata::FrameCancelled
(happens when the streams are stopped). The metadata is mostly invalid
for cancelled buffers  hence, setting timestamp on invalid metadata
does not make sense (however some metadata can be considered valid
for e.g. returning cause of failure through metadata on cancelled
buffers).

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/libcamera/pipeline/ipu3/ipu3.cpp

@@ -1318,15 +1318,6 @@ void IPU3CameraData::cio2BufferReady(FrameBuffer *buffer)
 
 	Request *request = info->request;
 
-	/*
-	 * Record the sensor's timestamp in the request metadata.
-	 *
-	 * \todo The sensor timestamp should be better estimated by connecting
-	 * to the V4L2Device::frameStart signal.
-	 */
-	request->metadata().set(controls::SensorTimestamp,
-				buffer->metadata().timestamp);
-
 	/* If the buffer is cancelled force a complete of the whole request. */
 	if (buffer->metadata().status == FrameMetadata::FrameCancelled) {
 		for (auto it : request->buffers()) {
@@ -1340,6 +1331,15 @@ void IPU3CameraData::cio2BufferReady(FrameBuffer *buffer)
 		return;
 	}
 
+	/*
+	 * Record the sensor's timestamp in the request metadata.
+	 *
+	 * \todo The sensor timestamp should be better estimated by connecting
+	 * to the V4L2Device::frameStart signal.
+	 */
+	request->metadata().set(controls::SensorTimestamp,
+				buffer->metadata().timestamp);
+
 	if (request->findBuffer(&rawStream_))
 		pipe()->completeBuffer(request, buffer);