Re: [PATCH v11 40/56] sample: v4l: Stop direct calls to queue num_buffers field

[Hans Verkuil <hverkuil-cisco@xs4all.nl>]

On 12/10/2023 13:46, Benjamin Gaignard wrote:
> Use vb2_get_num_buffers() to avoid using queue num_buffers field directly.
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> ---
>  samples/v4l/v4l2-pci-skeleton.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/samples/v4l/v4l2-pci-skeleton.c b/samples/v4l/v4l2-pci-skeleton.c
> index a61f94db18d9..a65aa9d1e9da 100644
> --- a/samples/v4l/v4l2-pci-skeleton.c
> +++ b/samples/v4l/v4l2-pci-skeleton.c
> @@ -155,6 +155,7 @@ static int queue_setup(struct vb2_queue *vq,
>  		       unsigned int sizes[], struct device *alloc_devs[])
>  {
>  	struct skeleton *skel = vb2_get_drv_priv(vq);
> +	unsigned int q_num_bufs = vb2_get_num_buffers(vq);
>  
>  	skel->field = skel->format.field;
>  	if (skel->field == V4L2_FIELD_ALTERNATE) {
> @@ -167,8 +168,8 @@ static int queue_setup(struct vb2_queue *vq,
>  		skel->field = V4L2_FIELD_TOP;
>  	}
>  
> -	if (vq->num_buffers + *nbuffers < 3)
> -		*nbuffers = 3 - vq->num_buffers;
> +	if (q_num_bufs + *nbuffers < 3)
> +		*nbuffers = 3 - q_num_bufs;

This should be dropped, and instead update q->min_buffers_needed from
2 to 3.

Regards,

	Hans

>  
>  	if (*nplanes)
>  		return sizes[0] < skel->format.sizeimage ? -EINVAL : 0;