[libcamera-devel] [PATCH v2 17/17] v4l2: v4l2_camera_proxy: Fix buffer flags related to queueing

[Laurent Pinchart]

Hi Paul,

Thank you for the patch.

On Fri, Jun 19, 2020 at 02:41:23PM +0900, Paul Elder wrote:
> Fix buffer flags related to queueing and dequeueing:
> - don't allow a buffer with the same index that is already in the queue
>   to be enqueued again
> - don't set the done flag on dequeueing

Why ? V4L2_BUF_FLAG_DONE is never set anymore, that doesn't seem right.

> - set the mapped flag on enqueueing

Why ? Isn't it valid to queued an unmapped buffer ?

> - set the flags in V4L2CameraProxy's internal buffers, and not just in
>   the buffers returned from qbuf

It's really tempting to bundle multiple changes in the last patch, right
? :-) It would be nice to split this, especially given that for the
second and third fixes a rationale should be given in the commit message
(assuming the fixes are correct).

> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> 
> ---
> New in v2
> - split from "Fix v4l2-compliance streaming tests"
> ---
>  src/v4l2/v4l2_camera_proxy.cpp | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
> index 2eb2fcc..3e5fb7c 100644
> --- a/src/v4l2/v4l2_camera_proxy.cpp
> +++ b/src/v4l2/v4l2_camera_proxy.cpp
> @@ -221,7 +221,6 @@ void V4L2CameraProxy::updateBuffers()
>  			buf.timestamp.tv_usec = fmd.timestamp % 1000000;
>  			buf.sequence = fmd.sequence;
>  
> -			buf.flags |= V4L2_BUF_FLAG_DONE;
>  			break;
>  		case FrameMetadata::FrameError:
>  			buf.flags |= V4L2_BUF_FLAG_ERROR;
> @@ -569,6 +568,9 @@ int V4L2CameraProxy::vidioc_qbuf(V4L2CameraFile *cf, struct v4l2_buffer *arg)
>  	if (arg->index >= bufferCount_)
>  		return -EINVAL;
>  
> +	if (buffers_[arg->index].flags & V4L2_BUF_FLAG_QUEUED)
> +		return -EINVAL;
> +
>  	int ret = lock(cf);
>  	if (ret < 0)
>  		return ret;
> @@ -582,9 +584,12 @@ int V4L2CameraProxy::vidioc_qbuf(V4L2CameraFile *cf, struct v4l2_buffer *arg)
>  	if (ret < 0)
>  		return ret;
>  
> -	arg->flags |= V4L2_BUF_FLAG_QUEUED;
> +	arg->flags |= V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_MAPPED;
>  	arg->flags &= ~V4L2_BUF_FLAG_DONE;
>  
> +	buffers_[arg->index].flags |= V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_MAPPED;
> +	buffers_[arg->index].flags &= ~V4L2_BUF_FLAG_DONE;

Maybe

	buffers_[arg->index].flags |= V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_MAPPED;
	buffers_[arg->index].flags &= ~V4L2_BUF_FLAG_DONE;
  	arg->flags = buffers_[arg->index].flags;

to avoid duplicating the logic ?

> +
>  	return ret;
>  }
>  

-- 
Regards,

Laurent Pinchart