Re: [PATCH 2/2] media: rkvdec: Support dynamic resolution changes

[Nicolas Dufresne <nicolas@ndufresne.ca>]

Le vendredi 08 octobre 2021 à 18:04 +0800, Chen-Yu Tsai a écrit :
> The mem-to-mem stateless decoder API specifies support for dynamic
> resolution changes. In particular, the decoder should accept format
> changes on the OUTPUT queue even when buffers have been allocated,
> as long as it is not streaming.

As commented in the code, it also requires the CAPTURE side not to be busy, not
sure if its worth clarifying, I don't really mind.

> 
> Relax restrictions for S_FMT as described in the previous paragraph,
> and as long as the codec format remains the same. This aligns it with
> the Hantro and Cedrus decoders. This change was mostly based on commit
> ae02d49493b5 ("media: hantro: Fix s_fmt for dynamic resolution changes").
> 
> Since rkvdec_s_fmt() is now just a wrapper around the output/capture
> variants without any additional shared functionality, drop the wrapper
> and call the respective functions directly.
> 
> Fixes: cd33c830448b ("media: rkvdec: Add the rkvdec driver")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>

Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>

> ---
>  drivers/staging/media/rkvdec/rkvdec.c | 40 +++++++++++++--------------
>  1 file changed, 20 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/staging/media/rkvdec/rkvdec.c b/drivers/staging/media/rkvdec/rkvdec.c
> index 7131156c1f2c..3f3f96488d74 100644
> --- a/drivers/staging/media/rkvdec/rkvdec.c
> +++ b/drivers/staging/media/rkvdec/rkvdec.c
> @@ -280,31 +280,20 @@ static int rkvdec_try_output_fmt(struct file *file, void *priv,
>  	return 0;
>  }
>  
> -static int rkvdec_s_fmt(struct file *file, void *priv,
> -			struct v4l2_format *f,
> -			int (*try_fmt)(struct file *, void *,
> -				       struct v4l2_format *))
> +static int rkvdec_s_capture_fmt(struct file *file, void *priv,
> +				struct v4l2_format *f)
>  {
>  	struct rkvdec_ctx *ctx = fh_to_rkvdec_ctx(priv);
>  	struct vb2_queue *vq;
> +	int ret;
>  
> -	if (!try_fmt)
> -		return -EINVAL;
> -
> -	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, f->type);
> +	/* Change not allowed if queue is busy */
> +	vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx,
> +			     V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
>  	if (vb2_is_busy(vq))
>  		return -EBUSY;
>  
> -	return try_fmt(file, priv, f);
> -}
> -
> -static int rkvdec_s_capture_fmt(struct file *file, void *priv,
> -				struct v4l2_format *f)
> -{
> -	struct rkvdec_ctx *ctx = fh_to_rkvdec_ctx(priv);
> -	int ret;
> -
> -	ret = rkvdec_s_fmt(file, priv, f, rkvdec_try_capture_fmt);
> +	ret = rkvdec_try_capture_fmt(file, priv, f);
>  	if (ret)
>  		return ret;
>  
> @@ -319,9 +308,20 @@ static int rkvdec_s_output_fmt(struct file *file, void *priv,
>  	struct v4l2_m2m_ctx *m2m_ctx = ctx->fh.m2m_ctx;
>  	const struct rkvdec_coded_fmt_desc *desc;
>  	struct v4l2_format *cap_fmt;
> -	struct vb2_queue *peer_vq;
> +	struct vb2_queue *peer_vq, *vq;
>  	int ret;
>  
> +	/*
> +	 * In order to support dynamic resolution change, the decoder admits
> +	 * a resolution change, as long as the pixelformat remains. Can't be
> +	 * done if streaming.
> +	 */
> +	vq = v4l2_m2m_get_vq(m2m_ctx, V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE);
> +	if (vb2_is_streaming(vq) ||
> +	    (vb2_is_busy(vq) &&
> +	     f->fmt.pix_mp.pixelformat != ctx->coded_fmt.fmt.pix_mp.pixelformat))
> +		return -EBUSY;
> +
>  	/*
>  	 * Since format change on the OUTPUT queue will reset the CAPTURE
>  	 * queue, we can't allow doing so when the CAPTURE queue has buffers
> @@ -331,7 +331,7 @@ static int rkvdec_s_output_fmt(struct file *file, void *priv,
>  	if (vb2_is_busy(peer_vq))
>  		return -EBUSY;
>  
> -	ret = rkvdec_s_fmt(file, priv, f, rkvdec_try_output_fmt);
> +	ret = rkvdec_try_output_fmt(file, priv, f);
>  	if (ret)
>  		return ret;
>