[libcamera-devel] [PATCH] libcamera: camera: Reset request sequence number on stop/start

[Kieran Bingham]

Quoting Umang Jain via libcamera-devel (2022-07-01 11:32:36)
> We now have V4L2VideoDevice ensuring that sensor sequence numbers
> start from zero [1], and we desire that these should match the Request
> sequence number as well.
> 
> [1] 1c9dc0fd89cf ("libcamera: v4l2_videodevice: Identify non-zero stream starts")
> 

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
> ---
>  src/libcamera/camera.cpp           | 4 +++-
>  src/libcamera/pipeline_handler.cpp | 2 ++
>  src/libcamera/request.cpp          | 4 ++--
>  3 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
> index 713543fd..f8150dcd 100644
> --- a/src/libcamera/camera.cpp
> +++ b/src/libcamera/camera.cpp
> @@ -497,7 +497,7 @@ Camera::Private::~Private()
>   * facilitate debugging of internal request usage.
>   *
>   * The requestSequence_ tracks the number of requests queued to a camera
> - * over its lifetime.
> + * over a single capture session.
>   */
>  
>  static const char *const camera_state_names[] = {
> @@ -1181,6 +1181,8 @@ int Camera::start(const ControlList *controls)
>  
>         LOG(Camera, Debug) << "Starting capture";
>  
> +       ASSERT(d->requestSequence_ == 0);
> +
>         ret = d->pipe_->invokeMethod(&PipelineHandler::start,
>                                      ConnectionTypeBlocking, this, controls);
>         if (ret)
> diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
> index 7ebd76ad..67540533 100644
> --- a/src/libcamera/pipeline_handler.cpp
> +++ b/src/libcamera/pipeline_handler.cpp
> @@ -312,6 +312,8 @@ void PipelineHandler::stop(Camera *camera)
>         /* Make sure no requests are pending. */
>         Camera::Private *data = camera->_d();
>         ASSERT(data->queuedRequests_.empty());
> +
> +       data->requestSequence_ = 0;
>  }
>  
>  /**
> diff --git a/src/libcamera/request.cpp b/src/libcamera/request.cpp
> index 51d74b29..07613cb3 100644
> --- a/src/libcamera/request.cpp
> +++ b/src/libcamera/request.cpp
> @@ -526,8 +526,8 @@ FrameBuffer *Request::findBuffer(const Stream *stream) const
>   *
>   * When requests are queued, they are given a sequential number to track the
>   * order in which requests are queued to a camera. This number counts all
> - * requests given to a camera through its lifetime, and is not reset to zero
> - * between camera stop/start sequences.
> + * requests given to a camera and is reset to zero between camera stop/start
> + * sequences.
>   *
>   * It can be used to support debugging and identifying the flow of requests
>   * through a pipeline, but does not guarantee to represent the sequence number
> -- 
> 2.31.1
>