Re: [PATCH v1 3/9] media: verisilicon: Save bit depth for AV1 decoder

[Benjamin Gaignard]

Le 19/12/2022 à 22:29, Ezequiel Garcia a écrit :
> Bonjour Nicolas,
>
> On Mon, Dec 19, 2022 at 5:37 PM Nicolas Dufresne <nicolas@xxxxxxxxxxxx> wrote:
> > Le lundi 19 décembre 2022 à 16:56 +0100, Benjamin Gaignard a écrit :
> > > Store bit depth information from AV1 sequence control.
> > >
> > > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> > > ---
> > >   .../media/platform/verisilicon/hantro_drv.c   | 26 +++++++++++++++++++
> > >   1 file changed, 26 insertions(+)
> > >
> > > diff --git a/drivers/media/platform/verisilicon/hantro_drv.c b/drivers/media/platform/verisilicon/hantro_drv.c
> > > index 4500e1fc0f2c..8e93710dcfed 100644
> > > --- a/drivers/media/platform/verisilicon/hantro_drv.c
> > > +++ b/drivers/media/platform/verisilicon/hantro_drv.c
> > > @@ -324,6 +324,25 @@ static int hantro_vp9_s_ctrl(struct v4l2_ctrl *ctrl)
> > >        return 0;
> > >   }
> > >
> > > +static int hantro_av1_s_ctrl(struct v4l2_ctrl *ctrl)
> > > +{
> > > +     struct hantro_ctx *ctx;
> > > +
> > > +     ctx = container_of(ctrl->handler,
> > > +                        struct hantro_ctx, ctrl_handler);
> > > +
> > > +     switch (ctrl->id) {
> > > +     case V4L2_CID_STATELESS_AV1_SEQUENCE:
> > > +             ctx->bit_depth = ctrl->p_new.p_av1_sequence->bit_depth;
> > That seems a little be weak, what happens if you change the bit_depth with a
> > non-request s_ctrl while its decoding ? To be this deserve a little bit of
> > protection, a something that validate and copy it at the start of the decoding.
> Oh, nice catch. We need to return EBUSY, see
> https://www.kernel.org/doc/html/v5.0/media/uapi/v4l/buffer.html#interactions-between-formats-controls-and-buffers.
>
> There's already an API in the V4L2 control framework for drivers to use,
> see v4l2_ctrl_grab in
> https://www.kernel.org/doc/html/v5.0/media/kapi/v4l2-controls.html#active-and-grabbed-controls.
>
> > p.s. I know, VP9 seems similar, though arguably that was copied from jpeg, for
> > which it seems totally save to change the quality at run-time.
> No, wasn't copied from JPEG :-) I just didn't realize this was an
> issue, but it is
> given the bit_depth affects the buffers so you are correct, it needs
> to be fixed for VP9 too.

I will use v4l2_ctrl_grab() in codecs->ops init() and exit() functions
but it will be on patch 7 because it where they appear for this codec.

Benjamin

> Thanks!
> Ezequiel
>
> > > +             break;
> > > +     default:
> > > +             return -EINVAL;
> > > +     }
> > > +
> > > +     return 0;
> > > +}
> > > +
> > > +
> > >   static const struct v4l2_ctrl_ops hantro_ctrl_ops = {
> > >        .try_ctrl = hantro_try_ctrl,
> > >   };
> > > @@ -336,6 +355,12 @@ static const struct v4l2_ctrl_ops hantro_vp9_ctrl_ops = {
> > >        .s_ctrl = hantro_vp9_s_ctrl,
> > >   };
> > >
> > > +static const struct v4l2_ctrl_ops hantro_av1_ctrl_ops = {
> > > +     .try_ctrl = hantro_try_ctrl,
> > > +     .s_ctrl = hantro_av1_s_ctrl,
> > > +};
> > > +
> > > +
> > >   #define HANTRO_JPEG_ACTIVE_MARKERS   (V4L2_JPEG_ACTIVE_MARKER_APP0 | \
> > >                                         V4L2_JPEG_ACTIVE_MARKER_COM | \
> > >                                         V4L2_JPEG_ACTIVE_MARKER_DQT | \
> > > @@ -513,6 +538,7 @@ static const struct hantro_ctrl controls[] = {
> > >                .codec = HANTRO_AV1_DECODER,
> > >                .cfg = {
> > >                        .id = V4L2_CID_STATELESS_AV1_SEQUENCE,
> > > +                     .ops = &hantro_av1_ctrl_ops,
> > >                },
> > >        }, {
> > >                .codec = HANTRO_AV1_DECODER,