In order to prepare to handle synchronization fences at Request queueing time, split the PipelineHandler::queueRequest() function in two, by creating a list of waiting requests and introducing the doQueueRequest() function that queues requests to the device in the order the pipeline has received them. Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>