Re: [PATCH 7/9] media: hantro: Add core bits to support H264 decoding

[Boris Brezillon]

On Thu, 1 Aug 2019 13:06:10 +0900
Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote:

> Hi Boris,
> 
> On Wed, Jun 19, 2019 at 9:15 PM Boris Brezillon
> <boris.brezillon@xxxxxxxxxxxxx> wrote:
> [snip]
> > @@ -533,10 +535,21 @@ hantro_queue_setup(struct vb2_queue *vq, unsigned int *num_buffers,
> >                 return -EINVAL;
> >         }
> >
> > +       /* The H264 decoder needs extra size on the output buffer. */
> > +       if (ctx->vpu_src_fmt->fourcc == V4L2_PIX_FMT_H264_SLICE_RAW)
> > +               extra_size0 = 128 * DIV_ROUND_UP(pixfmt->width, 16) *
> > +                             DIV_ROUND_UP(pixfmt->height, 16);
> > +  
> 
> I wonder if this shouldn't be accounted for already in the sizeimage
> returned by TRY_/S_FMT, so that the application can know the required
> buffer size if it uses some external allocator and DMABUF memory type.
> I know we had it like this in our downstream code, but it wasn't the
> problem because we use minigbm, where we explicitly add the same
> padding in the rockchip backend. Any thoughts?

Actually, I was wondering why it was not counted in ->sizeimage. I
thought you had a good reason to not expose the extra size to userspace
so I kept it like that.