Re: [PATCH] media: rcar-vin: Update crop and compose settings for every s_fmt call

["Lad, Prabhakar" <prabhakar.csengg@gmail.com>]

Hi Hans and Laurent,

On Mon, Aug 3, 2020 at 8:21 PM Niklas <niklas.soderlund@ragnatech.se> wrote:
>
> Hi Lad, Hans,
>
> On 2020-08-03 19:11:32 +0100, Lad, Prabhakar wrote:
> > Hi Hans,
> >
> > On Sat, Aug 1, 2020 at 10:04 AM Niklas <niklas.soderlund@ragnatech.se> wrote:
> > >
> > > Hi Lad,
> > >
> > > Thanks for your work.
> > >
> > > On 2020-07-31 10:29:05 +0100, Lad Prabhakar wrote:
> > > > The crop and compose settings for VIN in non mc mode werent updated
> > > > in s_fmt call this resulted in captured images being clipped.
> > > >
> > > > With the below sequence on the third capture where size is set to
> > > > 640x480 resulted in clipped image of size 320x240.
> > > >
> > > > high(640x480) -> low (320x240) -> high (640x480)
> > > >
> > > > This patch makes sure the VIN crop and compose settings are updated.
> > >
> > > This is clearly an inconsistency in the VIN driver that should be fixed.
> > > But I think the none-mc mode implements the correct behavior. That is
> > > that S_FMT should not modify the crop/compose rectangles other then make
> > > sure they don't go out of bounds. This is an area we tried to clarify in
> > > the past but I'm still not sure what the correct answer to.
> > >
> > What should be the exact behaviour of the bridge driver  for s_fmt
> > call. Should the crop/compose settings be updated for every s_fmt
> > callback or should they be only updated on s_selection callback.
> > Currently the non-mc rcar-vin doesnt update the crop/compose setting
> > in s_fmt callback due to which I see the above issue as mentioned.
>
> This is not entirely correct. It does update the crop and compose
> rectangles on s_fmt, it makes sure they are not out-of-bounds for the
> new format if it's accepted by s_fmt. See v4l2_rect_map_inside() calls
> in the snippet bellow.
>
> That being said there is a difference how this is handled in the VIN
> driver between it's MC and non-MC modes and I would love to learn the
> correct mode of operation and seeing VIN being updated to doing it
> correct in both cases. Thanks Lad for dealing with this!
>
Can I have your feedback on this please.

Cheers,
Prabhakar
> >
> > Cheers,
> > Prabhakar
> >
> > > >
> > > > Fixes: 104464f573d ("media: rcar-vin: Do not reset the crop and compose rectangles in s_fmt")
> > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
> > > > ---
> > > >  drivers/media/platform/rcar-vin/rcar-v4l2.c | 6 ++++++
> > > >  1 file changed, 6 insertions(+)
> > > >
> > > > diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c b/drivers/media/platform/rcar-vin/rcar-v4l2.c
> > > > index f421e25..a9b13d9 100644
> > > > --- a/drivers/media/platform/rcar-vin/rcar-v4l2.c
> > > > +++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c
> > > > @@ -319,6 +319,12 @@ static int rvin_s_fmt_vid_cap(struct file *file, void *priv,
> > > >       fmt_rect.width = vin->format.width;
> > > >       fmt_rect.height = vin->format.height;
> > > >
> > > > +     vin->crop.top = 0;
> > > > +     vin->crop.left = 0;
> > > > +     vin->crop.width = vin->format.width;
> > > > +     vin->crop.height = vin->format.height;
> > > > +     vin->compose = vin->crop;
> > > > +
> > > >       v4l2_rect_map_inside(&vin->crop, &src_rect);
> > > >       v4l2_rect_map_inside(&vin->compose, &fmt_rect);
> > > >       vin->src_rect = src_rect;
> > > > --
> > > > 2.7.4
> > > >
> > >
> > > --
> > > Regards,
> > > Niklas Söderlund
>
> --
> Regards,
> Niklas Söderlund