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Message-ID: <6da7faf329128312f0862f555d1a855437ae99f3.camel@ndufresne.ca>
Subject: Re: [PATCH 2/2] [WIP]: media: Add Synaptics compressed tiled format
From:   Nicolas Dufresne <nicolas@ndufresne.ca>
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Hsia-Jun Li <Randy.Li@synaptics.com>
Cc:     Tomasz Figa <tfiga@chromium.org>, dri-devel@lists.freedesktop.org,
        maarten.lankhorst@linux.intel.com, mripard@kernel.org,
        tzimmermann@suse.de, airlied@linux.ie, daniel@ffwll.ch,
        mchehab@kernel.org, hverkuil-cisco@xs4all.nl,
        ezequiel@vanguardiasur.com.ar, sakari.ailus@linux.intel.com,
        ribalda@chromium.org, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org, sebastian.hesselbarth@gmail.com,
        jszhang@kernel.org, linux-arm-kernel@lists.infradead.org
Date:   Fri, 19 Aug 2022 11:28:04 -0400
In-Reply-To: <Yv7HnHE7bLmgq5D0@pendragon.ideasonboard.com>
References: <20220808162750.828001-1-randy.li@synaptics.com>
         <20220808162750.828001-3-randy.li@synaptics.com>
         <CAAFQd5AKjpJ+fPAeCqdNnJbS4R7SdaHkfyW4qG1xXr-sE801pQ@mail.gmail.com>
         <13d37c15-79f3-4e16-8cf4-fc37846f4a04@synaptics.com>
         <Yv7HnHE7bLmgq5D0@pendragon.ideasonboard.com>
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Le vendredi 19 ao=C3=BBt 2022 =C3=A0 02:13 +0300, Laurent Pinchart a =C3=A9=
crit=C2=A0:
> On Thu, Aug 18, 2022 at 02:33:42PM +0800, Hsia-Jun Li wrote:
> > On 8/18/22 14:06, Tomasz Figa wrote:
> > > On Tue, Aug 9, 2022 at 1:28 AM Hsia-Jun Li <randy.li@synaptics.com> w=
rote:
> > > >=20
> > > > From: "Hsia-Jun(Randy) Li" <randy.li@synaptics.com>
> > > >=20
> > > > The most of detail has been written in the drm.
>=20
> This patch still needs a description of the format, which should go to
> Documentation/userspace-api/media/v4l/.
>=20
> > > > Please notice that the tiled formats here request
> > > > one more plane for storing the motion vector metadata.
> > > > This buffer won't be compressed, so you can't append
> > > > it to luma or chroma plane.
> > >=20
> > > Does the motion vector buffer need to be exposed to userspace? Is the
> > > decoder stateless (requires userspace to specify the reference frames=
)
> > > or stateful (manages the entire decoding process internally)?
> >=20
> > No, users don't need to access them at all. Just they need a different=
=20
> > dma-heap.
> >=20
> > You would only get the stateful version of both encoder and decoder.
>=20
> Shouldn't the motion vectors be stored in a separate V4L2 buffer,
> submitted through a different queue then ?

Imho, I believe these should be invisible to users and pooled separately to
reduce the overhead. The number of reference is usually lower then the numb=
er of
allocated display buffers.

>=20
> > > > Signed-off-by: Hsia-Jun(Randy) Li <randy.li@synaptics.com>
> > > > ---
> > > >   drivers/media/v4l2-core/v4l2-common.c | 1 +
> > > >   drivers/media/v4l2-core/v4l2-ioctl.c  | 2 ++
> > > >   include/uapi/linux/videodev2.h        | 2 ++
> > > >   3 files changed, 5 insertions(+)
> > > >=20
> > > > diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/=
v4l2-core/v4l2-common.c
> > > > index e0fbe6ba4b6c..f645278b3055 100644
> > > > --- a/drivers/media/v4l2-core/v4l2-common.c
> > > > +++ b/drivers/media/v4l2-core/v4l2-common.c
> > > > @@ -314,6 +314,7 @@ const struct v4l2_format_info *v4l2_format_info=
(u32 format)
> > > >                  { .format =3D V4L2_PIX_FMT_SGBRG12,       .pixel_e=
nc =3D V4L2_PIXEL_ENC_BAYER, .mem_planes =3D 1, .comp_planes =3D 1, .bpp =
=3D { 2, 0, 0, 0 }, .hdiv =3D 1, .vdiv =3D 1 },
> > > >                  { .format =3D V4L2_PIX_FMT_SGRBG12,       .pixel_e=
nc =3D V4L2_PIXEL_ENC_BAYER, .mem_planes =3D 1, .comp_planes =3D 1, .bpp =
=3D { 2, 0, 0, 0 }, .hdiv =3D 1, .vdiv =3D 1 },
> > > >                  { .format =3D V4L2_PIX_FMT_SRGGB12,       .pixel_e=
nc =3D V4L2_PIXEL_ENC_BAYER, .mem_planes =3D 1, .comp_planes =3D 1, .bpp =
=3D { 2, 0, 0, 0 }, .hdiv =3D 1, .vdiv =3D 1 },
> > > > +               { .format =3D V4L2_PIX_FMT_NV12M_V4H1C, .pixel_enc =
=3D V4L2_PIXEL_ENC_YUV, .mem_planes =3D 5, .comp_planes =3D 2, .bpp =3D { 1=
, 2, 0, 0 }, .hdiv =3D 2, .vdiv =3D 2, .block_w =3D { 128, 128 }, .block_h =
=3D { 128, 128 } },
> > > >          };
> > > >          unsigned int i;
> > > >=20
> > > > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v=
4l2-core/v4l2-ioctl.c
> > > > index e6fd355a2e92..8f65964aff08 100644
> > > > --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> > > > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> > > > @@ -1497,6 +1497,8 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtd=
esc *fmt)
> > > >                  case V4L2_PIX_FMT_MT21C:        descr =3D "Mediate=
k Compressed Format"; break;
> > > >                  case V4L2_PIX_FMT_QC08C:        descr =3D "QCOM Co=
mpressed 8-bit Format"; break;
> > > >                  case V4L2_PIX_FMT_QC10C:        descr =3D "QCOM Co=
mpressed 10-bit Format"; break;
> > > > +               case V4L2_PIX_FMT_NV12M_V4H1C:  descr =3D "Synaptic=
s Compressed 8-bit tiled Format";break;
> > > > +               case V4L2_PIX_FMT_NV12M_10_V4H3P8C:     descr =3D "=
Synaptics Compressed 10-bit tiled Format";break;
> > > >                  default:
> > > >                          if (fmt->description[0])
> > > >                                  return;
> > > > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/vi=
deodev2.h
> > > > index 01e630f2ec78..7e928cb69e7c 100644
> > > > --- a/include/uapi/linux/videodev2.h
> > > > +++ b/include/uapi/linux/videodev2.h
> > > > @@ -661,6 +661,8 @@ struct v4l2_pix_format {
> > > >   #define V4L2_PIX_FMT_NV12MT_16X16 v4l2_fourcc('V', 'M', '1', '2')=
 /* 12  Y/CbCr 4:2:0 16x16 tiles */
> > > >   #define V4L2_PIX_FMT_NV12M_8L128      v4l2_fourcc('N', 'A', '1', =
'2') /* Y/CbCr 4:2:0 8x128 tiles */
> > > >   #define V4L2_PIX_FMT_NV12M_10BE_8L128 v4l2_fourcc_be('N', 'T', '1=
', '2') /* Y/CbCr 4:2:0 10-bit 8x128 tiles */
> > > > +#define V4L2_PIX_FMT_NV12M_V4H1C v4l2_fourcc('S', 'Y', '1', '2')  =
 /* 12  Y/CbCr 4:2:0 tiles */
> > > > +#define V4L2_PIX_FMT_NV12M_10_V4H3P8C v4l2_fourcc('S', 'Y', '1', '=
0')   /* 12  Y/CbCr 4:2:0 10-bits tiles */
> > > >=20
> > > >   /* Bayer formats - see http://www.siliconimaging.com/RGB%20Bayer.=
htm */
> > > >   #define V4L2_PIX_FMT_SBGGR8  v4l2_fourcc('B', 'A', '8', '1') /*  =
8  BGBG.. GRGR.. */
>=20