Re: [RFC PATCH v6] media: mediatek: vcodec: support stateless AV1 decoder

[Andrzej Pietrasiewicz]

Hi again,

W dniu 17.11.2022 o 13:42, Andrzej Pietrasiewicz pisze:
> Hi Xiaoyong Lu,
>
> Sorry about chiming in only at v6. Please see inline below.
>
> Andrzej
>
> W dniu 17.11.2022 o 07:17, Xiaoyong Lu pisze:
> > Add mediatek av1 decoder linux driver which use the stateless API in
> > MT8195.
> >
> > Signed-off-by: Xiaoyong Lu<xiaoyong.lu@xxxxxxxxxxxx>
> > ---
> > Changes from v5:
> >
> > - change av1 PROFILE and LEVEL cfg
> > - test by av1 fluster, result is 173/239
> >
> > Changes from v4:
> >
> > - convert vb2_find_timestamp to vb2_find_buffer
> > - test by av1 fluster, result is 173/239
> >
> > Changes from v3:
> >
> > - modify comment for struct vdec_av1_slice_slot
> > - add define SEG_LVL_ALT_Q
> > - change use_lr/use_chroma_lr parse from av1 spec
> > - use ARRAY_SIZE to replace size for loop_filter_level and 
> > loop_filter_mode_deltas
> > - change array size of loop_filter_mode_deltas from 4 to 2
> > - add define SECONDARY_FILTER_STRENGTH_NUM_BITS
> > - change some hex values from upper case to lower case
> > - change *dpb_sz equal to V4L2_AV1_TOTAL_REFS_PER_FRAME + 1
> > - test by av1 fluster, result is 173/239
> >
> > Changes from v2:
> >
> > - Match with av1 uapi v3 modify
> > - test by av1 fluster, result is 173/239
> >
> > ---
> > Reference series:
> > [1]: v3 of this series is presend by Daniel Almeida.
> >       message-id: 20220825225312.564619-1-daniel.almeida@xxxxxxxxxxxxx
> >
> >   .../media/platform/mediatek/vcodec/Makefile   |    1 +
> >   .../vcodec/mtk_vcodec_dec_stateless.c         |   47 +-
> >   .../platform/mediatek/vcodec/mtk_vcodec_drv.h |    1 +
> >   .../vcodec/vdec/vdec_av1_req_lat_if.c         | 2234 +++++++++++++++++
> >   .../platform/mediatek/vcodec/vdec_drv_if.c    |    4 +
> >   .../platform/mediatek/vcodec/vdec_drv_if.h    |    1 +
> >   .../platform/mediatek/vcodec/vdec_msg_queue.c |   27 +
> >   .../platform/mediatek/vcodec/vdec_msg_queue.h |    4 +
> >   8 files changed, 2318 insertions(+), 1 deletion(-)
> >   create mode 100644 
> > drivers/media/platform/mediatek/vcodec/vdec/vdec_av1_req_lat_if.c

<snip>

> > +
> > +static void *vdec_av1_get_ctrl_ptr(struct mtk_vcodec_ctx *ctx, int id)
> > +{
> > +    struct v4l2_ctrl *ctrl = v4l2_ctrl_find(&ctx->ctrl_hdl, id);
> > +
> > +    if (!ctrl)
> > +        return ERR_PTR(-EINVAL);
> > +
> > +    return ctrl->p_cur.p;
> > +}
>
> I see we keep repeating this kind of a v4l2_ctrl_find() wrapper in drivers.
> The only reason this code cannot be factored out is the "context" struct pointer
> pointing at structs of different types. Maybe we could
>
> #define v4l2_get_ctrl_ptr(ctx, member, id) \
>      __v4l2_get_ctrl_ptr((ctx), offsetof(typeof(*ctx), (member)), (id))
>
> void *__v4l2_get_ctrl_ptr(void *ctx, size_t offset, u32 id)
> {
>      struct v4l2_ctrl_handler *hdl = (struct v4l2_ctrl_handler *)(ctx + offset);
>      struct v4l2_ctrl *ctrl = v4l2_ctrl_find(hdl, id);
>
>      if (!ctrl)
>          return ERR_PTR(-EINVAL);
>
>      return ctrl->p_cur.p;
> }
>
> and reuse v4l2_get_ctrl_ptr() in drivers?
>
> A similar kind of void* arithmetic happens in container_of, only with '-'.

When I think of it it seems a bit over-engineered to me now, it would
be better to give up the macro and simply pass struct v4l2_ctrl_handler *hdl.

Another second thought is that including such a wrapper in this patch
would make it too noisy if all potential users were to be updated.
A separate series would make more sense.

Regards,

Andrzej