Re: [PATCH 2/4] media: rcar_vin: Ensure all in-flight buffers are returned to error state before sto

[Hans Verkuil <hverkuil@xs4all.nl>]

On 07/08/2014 11:41 AM, Ian Molton wrote:
> Videobuf2 complains about buffers that are still marked ACTIVE (in use by the driver) following a call to stop_streaming().
> 
> This patch returns all active buffers to state ERROR prior to stopping.
> 
> Note: this introduces a (non fatal) race condition as the stream is not guaranteed to be stopped at this point.
> 
> Signed-off-by: Ian Molton <ian.molton@codethink.co.uk>
> Signed-off-by: William Towle <william.towle@codethink.co.uk>
> ---
>  drivers/media/platform/soc_camera/rcar_vin.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/media/platform/soc_camera/rcar_vin.c b/drivers/media/platform/soc_camera/rcar_vin.c
> index 7154500..06ce705 100644
> --- a/drivers/media/platform/soc_camera/rcar_vin.c
> +++ b/drivers/media/platform/soc_camera/rcar_vin.c
> @@ -513,8 +513,14 @@ static void rcar_vin_stop_streaming(struct vb2_queue *vq)
>  	struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
>  	struct rcar_vin_priv *priv = ici->priv;
>  	struct list_head *buf_head, *tmp;
> +	int i;
>  
>  	spin_lock_irq(&priv->lock);
> +
> +	for (i = 0; i < vq->num_buffers; ++i)
> +		if (vq->bufs[i]->state = VB2_BUF_STATE_ACTIVE)
> +			vb2_buffer_done(vq->bufs[i], VB2_BUF_STATE_ERROR);
> +
>  	list_for_each_safe(buf_head, tmp, &priv->capture)
>  		list_del_init(buf_head);

I'm assuming all buffers that are queued to the driver via buf_queue() are
linked into priv->capture. So you would typically call vb2_buffer_done
when you are walking that list:

  	list_for_each_safe(buf_head, tmp, &priv->capture) {
		// usually you go from buf_head to the real buffer struct
		// containing a vb2_buffer struct
		vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR);
  		list_del_init(buf_head);
	}

Please use this rather than looking into internal vb2_queue datastructures.

Regards,

	Hans

>  	spin_unlock_irq(&priv->lock);
>