Re: [PATCH] media: amphion: return error if format is unsupported by vpu

From: Nicolas Dufresne <nicolas@ndufresne.ca>
To: Ming Qian <ming.qian@nxp.com>,
	mchehab@kernel.org, hverkuil-cisco@xs4all.nl
Cc: shawnguo@kernel.org, robh+dt@kernel.org, s.hauer@pengutronix.de,
	kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com,
	linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] media: amphion: return error if format is unsupported by vpu
Date: Thu, 19 May 2022 14:12:34 -0400	[thread overview]
Message-ID: <e03669333c20c07d40d0b1ce05eb771f5dbd4139.camel@ndufresne.ca> (raw)
In-Reply-To: <20220519072844.31792-1-ming.qian@nxp.com>

Hi Ming Qian,

Le jeudi 19 mai 2022 à 15:28 +0800, Ming Qian a écrit :
> return error if format is unsupported by vpu,
> otherwise the vpu will be stalled at decoding

I have a reasonable doubt about this patch. I don't think such a case should be
reachable by users. Normally, calls to S_FMT should ensure the driver format
state is valid on both ends but modifying the relevant structures. As an
example, for decoders, setting the CODEC (OUTPUT queue) format, may change the
raw format (CAPTURE queue) implicitly to prevent this situation. Are we certain
this change isn't papering around some missing format propagation ?

regards,
Nicolas

> 
> Signed-off-by: Ming Qian <ming.qian@nxp.com>
> ---
>  drivers/media/platform/amphion/vpu_malone.c | 2 ++
>  drivers/media/platform/amphion/vpu_v4l2.c   | 4 ++--
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/amphion/vpu_malone.c b/drivers/media/platform/amphion/vpu_malone.c
> index f29c223eefce..0930b6ba8c42 100644
> --- a/drivers/media/platform/amphion/vpu_malone.c
> +++ b/drivers/media/platform/amphion/vpu_malone.c
> @@ -610,6 +610,8 @@ static int vpu_malone_set_params(struct vpu_shared_addr *shared,
>  	enum vpu_malone_format malone_format;
>  
>  	malone_format = vpu_malone_format_remap(params->codec_format);
> +	if (malone_format == MALONE_FMT_NULL)
> +		return -EINVAL;
>  	iface->udata_buffer[instance].base = params->udata.base;
>  	iface->udata_buffer[instance].slot_size = params->udata.size;
>  
> diff --git a/drivers/media/platform/amphion/vpu_v4l2.c b/drivers/media/platform/amphion/vpu_v4l2.c
> index 446f07d09d0b..89b88e063e45 100644
> --- a/drivers/media/platform/amphion/vpu_v4l2.c
> +++ b/drivers/media/platform/amphion/vpu_v4l2.c
> @@ -500,10 +500,10 @@ static int vpu_vb2_start_streaming(struct vb2_queue *q, unsigned int count)
>  		  fmt->sizeimage[1], fmt->bytesperline[1],
>  		  fmt->sizeimage[2], fmt->bytesperline[2],
>  		  q->num_buffers);
> -	call_void_vop(inst, start, q->type);
> +	ret = call_vop(inst, start, q->type);
>  	vb2_clear_last_buffer_dequeued(q);
>  
> -	return 0;
> +	return ret;
>  }
>  
>  static void vpu_vb2_stop_streaming(struct vb2_queue *q)