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Message-ID: <5056559927df64d8cac8831a13db0c266e5fff65.camel@ndufresne.ca>
Subject: Re: [PATCH v3 4/5] media: Add HEXTILE compressed format
From:   Nicolas Dufresne <nicolas@ndufresne.ca>
To:     Marvin Lin <milkfafa@gmail.com>, mchehab@kernel.org,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     openbmc@lists.ozlabs.org, avifishman70@gmail.com,
        tmaimon77@gmail.com, tali.perry1@gmail.com, kwliu@nuvoton.com,
        kflin@nuvoton.com
Date:   Fri, 20 May 2022 14:43:22 -0400
In-Reply-To: <20220520024744.25655-5-milkfafa@gmail.com>
References: <20220520024744.25655-1-milkfafa@gmail.com>
         <20220520024744.25655-5-milkfafa@gmail.com>
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Le vendredi 20 mai 2022 =C3=A0 10:47 +0800, Marvin Lin a =C3=A9crit=C2=A0:
> Add HEXTILE compressed format. This format is defined in Remote Framebuff=
er
> 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 pa=
rt of
FFMPEG and GStreamer VMNC (VMWare CODECs) and also a decoder in GStreamer R=
FB
plugin. It is though an obsolete format for all of these technology, thanks=
 for
identifying clearly.

Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>

>=20
> Signed-off-by: Marvin Lin <milkfafa@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(+)
>=20
> 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 li=
st.
>  	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
> =20
>      \normalsize
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-co=
re/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 *f=
mt)
>  		case V4L2_PIX_FMT_SE401:	descr =3D "GSPCA SE401"; break;
>  		case V4L2_PIX_FMT_S5C_UYVY_JPG:	descr =3D "S5C73MX interleaved UYVY/JP=
EG"; break;
>  		case V4L2_PIX_FMT_MT21C:	descr =3D "Mediatek Compressed Format"; break=
;
> +		case V4L2_PIX_FMT_HEXTILE:	descr =3D "Hextile Compressed Format"; brea=
k;
>  		default:
>  			if (fmt->description[0])
>  				return;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev=
2.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 P=
lanar 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 */
> =20
>  /* 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') /* IPU=
3 packed 10-bit BGGR bayer */