Re: [PATCH v6 2/2] [media] s5p-mfc: Handle 'v4l2_pix_format:field' in try_fmt and g_fmt

[Andrzej Hajda <a.hajda@samsung.com>]

On 01.03.2017 12:51, Thibault Saunier wrote:
> It is required by the standard that the field order is set by the
> driver, default to NONE in case any is provided, but we can basically
> accept any value provided by the userspace as we will anyway not
> be able to do any deinterlacing.
>
> In this patch we also make sure to pass the interlacing mode provided
> by userspace from the output to the capture side of the device so
> that the information is given back to userspace. This way it can
> handle it and potentially deinterlace afterward.

As I wrote previously:
- on output side you have encoded bytestream - you cannot say about
interlacing in such case, so the only valid value is NONE,
- on capture side you have decoded frames, and in this case it depends
on the device and driver capabilities, if the driver/device does not
support (de-)interlacing (I suppose this is MFC case), interlace type
field should be filled according to decoded bytestream header (on output
side), but no direct copying from output side!!!

Regards
Andrzej

>
> Signed-off-by: Thibault Saunier <thibault.saunier@osg.samsung.com>
>
> ---
>
> Changes in v6:
> - Pass user output field value to the capture as the device is not
>   doing any deinterlacing and thus decoded content will still be
>   interlaced on the output.
>
> Changes in v5:
> - Just adapt the field and never error out.
>
> Changes in v4: None
> Changes in v3:
> - Do not check values in the g_fmt functions as Andrzej explained in previous review
>
> Changes in v2:
> - Fix a silly build error that slipped in while rebasing the patches
>
>  drivers/media/platform/s5p-mfc/s5p_mfc_common.h | 2 ++
>  drivers/media/platform/s5p-mfc/s5p_mfc_dec.c    | 6 +++++-
>  2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_common.h b/drivers/media/platform/s5p-mfc/s5p_mfc_common.h
> index ab23236aa942..3816a37de4bc 100644
> --- a/drivers/media/platform/s5p-mfc/s5p_mfc_common.h
> +++ b/drivers/media/platform/s5p-mfc/s5p_mfc_common.h
> @@ -652,6 +652,8 @@ struct s5p_mfc_ctx {
>  	size_t me_buffer_size;
>  	size_t tmv_buffer_size;
>  
> +	enum v4l2_field field;
> +
>  	enum v4l2_mpeg_mfc51_video_force_frame_type force_frame_type;
>  
>  	struct list_head ref_queue;
> diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c b/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
> index 367ef8e8dbf0..6e5ca86fb331 100644
> --- a/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
> +++ b/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
> @@ -345,7 +345,7 @@ static int vidioc_g_fmt(struct file *file, void *priv, struct v4l2_format *f)
>  		   rectangle. */
>  		pix_mp->width = ctx->buf_width;
>  		pix_mp->height = ctx->buf_height;
> -		pix_mp->field = V4L2_FIELD_NONE;
> +		pix_mp->field = ctx->field;
>  		pix_mp->num_planes = 2;
>  		/* Set pixelformat to the format in which MFC
>  		   outputs the decoded frame */
> @@ -380,6 +380,9 @@ static int vidioc_try_fmt(struct file *file, void *priv, struct v4l2_format *f)
>  	struct s5p_mfc_dev *dev = video_drvdata(file);
>  	struct s5p_mfc_fmt *fmt;
>  
> +	if (f->fmt.pix.field == V4L2_FIELD_ANY)
> +		f->fmt.pix.field = V4L2_FIELD_NONE;
> +
>  	mfc_debug(2, "Type is %d\n", f->type);
>  	if (f->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE) {
>  		fmt = find_format(f, MFC_FMT_DEC);
> @@ -436,6 +439,7 @@ static int vidioc_s_fmt(struct file *file, void *priv, struct v4l2_format *f)
>  		goto out;
>  	} else if (f->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE) {
>  		/* src_fmt is validated by call to vidioc_try_fmt */
> +		ctx->field = f->fmt.pix.field;
>  		ctx->src_fmt = find_format(f, MFC_FMT_DEC);
>  		ctx->codec_mode = ctx->src_fmt->codec_mode;
>  		mfc_debug(2, "The codec number is: %d\n", ctx->codec_mode);