[libcamera-devel] [PATCH v4 4/6] libcamera: pipeline: ipu3: Cancel unused buffers

[Jean-Michel Hautbois]

Hi Kieran,

Thanks for the patch !

On 20/04/2021 15:07, Kieran Bingham wrote:
> When the CIO2 returns a cancelled buffer, we will not queue buffers
> to the IMGU.

This is my personal preference: s/IMGU/ImgU but do what you want ;-p

> These buffers should be explicitly marked as cancelled to ensure
> the application knows there is no valid metadata or frame data
> provided in the buffer.
> 
> Provide a cancel() method on the FrameBuffer to allow explicitly
> cancelling a buffer.
> 
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
> ---
>  include/libcamera/buffer.h           | 2 ++
>  src/libcamera/buffer.cpp             | 8 ++++++++
>  src/libcamera/pipeline/ipu3/ipu3.cpp | 7 +++++--
>  3 files changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/include/libcamera/buffer.h b/include/libcamera/buffer.h
> index 620f8a66f6a2..e0af00900409 100644
> --- a/include/libcamera/buffer.h
> +++ b/include/libcamera/buffer.h
> @@ -53,6 +53,8 @@ public:
>  	unsigned int cookie() const { return cookie_; }
>  	void setCookie(unsigned int cookie) { cookie_ = cookie; }
>  
> +	void cancel() { metadata_.status = FrameMetadata::FrameCancelled; }
> +
>  private:
>  	LIBCAMERA_DISABLE_COPY_AND_MOVE(FrameBuffer)
>  
> diff --git a/src/libcamera/buffer.cpp b/src/libcamera/buffer.cpp
> index 75b2693281a7..7635226b9045 100644
> --- a/src/libcamera/buffer.cpp
> +++ b/src/libcamera/buffer.cpp
> @@ -226,6 +226,14 @@ FrameBuffer::FrameBuffer(const std::vector<Plane> &planes, unsigned int cookie)
>   * core never modifies the buffer cookie.
>   */
>  
> +/**
> + * \fn FrameBuffer::cancel()
> + * \brief Marks the buffer as cancelled
> + *
> + * If a buffer is not used by a request, it shall be marked as cancelled to
> + * indicate that the metadata is invalid.
> + */
> +
>  /**
>   * \class MappedBuffer
>   * \brief Provide an interface to support managing memory mapped buffers
> diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> index 51446fcf5bc1..73306cea6b37 100644
> --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> @@ -1257,8 +1257,11 @@ void IPU3CameraData::cio2BufferReady(FrameBuffer *buffer)
>  
>  	/* If the buffer is cancelled force a complete of the whole request. */
>  	if (buffer->metadata().status == FrameMetadata::FrameCancelled) {
> -		for (auto it : request->buffers())
> -			pipe_->completeBuffer(request, it.second);
> +		for (auto it : request->buffers()) {
> +			FrameBuffer *b = it.second;
> +			b->cancel();
> +			pipe_->completeBuffer(request, b);
> +		}
>  
>  		frameInfos_.remove(info);
>  		pipe_->completeRequest(request);
>