Re: [PATCH v5 3/3] [media] s5p-mfc: Check and set 'v4l2_pix_format:field' field in try_fmt

[Thibault Saunier]

Hello,

On 02/22/2017 06:29 AM, Andrzej Hajda wrote:
> On 21.02.2017 20:20, Thibault Saunier wrote:
> > It is required by the standard that the field order is set by the
> > driver.
> >
> > Signed-off-by: Thibault Saunier <thibault.saunier@xxxxxxxxxxxxxxx>
> >
> > ---
> >
> > 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_dec.c | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c b/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
> > index 0976c3e0a5ce..44ed2afe0780 100644
> > --- a/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
> > +++ b/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
> > @@ -386,6 +386,9 @@ static int vidioc_try_fmt(struct file *file, void *priv, struct v4l2_format *f)
> >   	struct v4l2_pix_format_mplane *pix_mp = &f->fmt.pix_mp;
> >   	struct s5p_mfc_fmt *fmt;
> >   
> > +	if (f->fmt.pix.field == V4L2_FIELD_ANY)
> > +		f->fmt.pix.field = V4L2_FIELD_NONE;
> > +
> In previous version the only supported field type was NONE, here you
> support everything.
> If the only supported format is none you should set 'field'
> unconditionally to NONE, nothing more.
Afaict we  support 2 things:

  1. NONE
  2. INTERLACE

Until now we were not checking what was supported or not and basically 
ignoring that info, this patch
keeps the old behaviour making sure to be compliant.

I had a doubt and was pondering doing:

``` diff

+	if (f->fmt.pix.field != V4L2_FIELD_INTERLACED)
+		f->fmt.pix.field = V4L2_FIELD_NONE;
+

```

instead, it is probably more correct, do you think it is what should be 
done here?

Regards,

Thibault

> Regards
> Andrzej
>
> >   	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);