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From:   Tomasz Figa <tfiga@chromium.org>
Date:   Thu, 1 Aug 2019 16:12:43 +0900
Message-ID: <CAAFQd5BPFLqu0JvyxTfS9UAfWanFcXzFtuJ9jcPmHV+XSq6cvQ@mail.gmail.com>
Subject: Re: [PATCH 7/9] media: hantro: Add core bits to support H264 decoding
To:     Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Cc:     Boris Brezillon <boris.brezillon@collabora.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Sakari Ailus <sakari.ailus@iki.fi>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Nicolas Dufresne <nicolas@ndufresne.ca>, kernel@collabora.com,
        Ezequiel Garcia <ezequiel@collabora.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Heiko Stuebner <heiko@sntech.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Hertz Wong <hertz.wong@rock-chips.com>
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On Thu, Aug 1, 2019 at 4:04 PM Paul Kocialkowski
<paul.kocialkowski@bootlin.com> wrote:
>
> Hi,
>
> On Thu 01 Aug 19, 13:06, Tomasz Figa wrote:
> > Hi Boris,
> >
> > On Wed, Jun 19, 2019 at 9:15 PM Boris Brezillon
> > <boris.brezillon@collabora.com> 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?
>
> Does the extra size have to be allocated along with the buffer?
>
> On cedrus, we have a need for a similar side-buffer but give it a dedicated CMA
> allocation, which should allow dma-buf-imported buffers.

Yes, the decoder stores motion vectors (IIRC) after the image data.

Best regards,
Tomasz