[PATCH v3 4/5] media: Add HEXTILE compressed format

[Kun-Fa Lin]

Hi Nicolas,

Thanks for your review!

Regards,
Marvin

Nicolas Dufresne <nicolas at ndufresne.ca> 於 2022年5月21日 週六 上午2:43寫道：
>
> Le vendredi 20 mai 2022 à 10:47 +0800, Marvin Lin a écrit :
> > Add HEXTILE compressed format. This format is defined in Remote Framebuffer
> > Protocol (RFC 6143) and is used by Encoding Compression Engine present on
> > Nuvoton NPCM SoCs.
>
> Ah, ancient RFB compression. I also found that there is encoder/decoders part of
> FFMPEG and GStreamer VMNC (VMWare CODECs) and also a decoder in GStreamer RFB
> plugin. It is though an obsolete format for all of these technology, thanks for
> identifying clearly.
>
> Reviewed-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>
>
> >
> > Signed-off-by: Marvin Lin <milkfafa at gmail.com>
> > ---
> >  Documentation/userspace-api/media/v4l/pixfmt-reserved.rst | 7 +++++++
> >  drivers/media/v4l2-core/v4l2-ioctl.c                      | 1 +
> >  include/uapi/linux/videodev2.h                            | 1 +
> >  3 files changed, 9 insertions(+)
> >
> > diff --git a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
> > index cabfa34b7db5..bad2b9a2f16e 100644
> > --- a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
> > +++ b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
> > @@ -239,6 +239,13 @@ please make a proposal on the linux-media mailing list.
> >       It remains an opaque intermediate format and the MDP hardware must be
> >       used to convert ``V4L2_PIX_FMT_MT21C`` to ``V4L2_PIX_FMT_NV12M``,
> >       ``V4L2_PIX_FMT_YUV420M`` or ``V4L2_PIX_FMT_YVU420``.
> > +    * .. _V4L2-PIX-FMT-HEXTILE:
> > +
> > +      - ``V4L2_PIX_FMT_HEXTILE``
> > +      - 'HXTL'
> > +      - Compressed format used by Nuvoton NPCM video driver. This format is
> > +        defined in Remote Framebuffer Protocol (RFC 6143, chapter 7.7.4 Hextile
> > +        Encoding).
> >  .. raw:: latex
> >
> >      \normalsize
> > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> > index 96e307fe3aab..9365519d65bb 100644
> > --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> > @@ -1441,6 +1441,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
> >               case V4L2_PIX_FMT_SE401:        descr = "GSPCA SE401"; break;
> >               case V4L2_PIX_FMT_S5C_UYVY_JPG: descr = "S5C73MX interleaved UYVY/JPEG"; break;
> >               case V4L2_PIX_FMT_MT21C:        descr = "Mediatek Compressed Format"; break;
> > +             case V4L2_PIX_FMT_HEXTILE:      descr = "Hextile Compressed Format"; break;
> >               default:
> >                       if (fmt->description[0])
> >                               return;
> > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> > index 3768a0a80830..1c7af015b43b 100644
> > --- a/include/uapi/linux/videodev2.h
> > +++ b/include/uapi/linux/videodev2.h
> > @@ -746,6 +746,7 @@ struct v4l2_pix_format {
> >  #define V4L2_PIX_FMT_INZI     v4l2_fourcc('I', 'N', 'Z', 'I') /* Intel Planar Greyscale 10-bit and Depth 16-bit */
> >  #define V4L2_PIX_FMT_CNF4     v4l2_fourcc('C', 'N', 'F', '4') /* Intel 4-bit packed depth confidence information */
> >  #define V4L2_PIX_FMT_HI240    v4l2_fourcc('H', 'I', '2', '4') /* BTTV 8-bit dithered RGB */
> > +#define V4L2_PIX_FMT_HEXTILE  v4l2_fourcc('H', 'X', 'T', 'L') /* Hextile compression */
> >
> >  /* 10bit raw bayer packed, 32 bytes for every 25 pixels, last LSB 6 bits unused */
> >  #define V4L2_PIX_FMT_IPU3_SBGGR10    v4l2_fourcc('i', 'p', '3', 'b') /* IPU3 packed 10-bit BGGR bayer */
>