Hi Sakari,
On Mon, Aug 14, 2023 at 11:02:40AM +0000, Sakari Ailus wrote:
> On Thu, Aug 10, 2023 at 05:24:14PM +0200, Jacopo Mondi wrote:
> > On Tue, Aug 08, 2023 at 10:55:36AM +0300, Sakari Ailus wrote:
> > > many camera sensors, among other devices, transmit embedded data and image
s/many/Many/
> > > data for each CSI-2 frame. This embedded data typically contains register
> > > configuration of the sensor that has been used to capture the image data
> > > of the same frame.
> > >
> > > The embedded data is received by the CSI-2 receiver and has the same
> > > properties as the image data, including that it is line based: it has
> > > width, height and bytesperline (stride).
> > >
> > > Add these fields to struct v4l2_meta_format and document them.
> > >
> > > Also add V4L2_FMT_FLAG_META_LINE_BASED to tell a given format is
> > > line-based i.e. these fields of struct v4l2_meta_format are valid for it.
> > >
> > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > > ---
> > > .../userspace-api/media/v4l/dev-meta.rst | 15 +++++++++++++++
> > > .../userspace-api/media/v4l/vidioc-enum-fmt.rst | 7 +++++++
> > > .../media/videodev2.h.rst.exceptions | 1 +
> > > drivers/media/v4l2-core/v4l2-ioctl.c | 5 +++--
> > > include/uapi/linux/videodev2.h | 10 ++++++++++
> > > 5 files changed, 36 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/Documentation/userspace-api/media/v4l/dev-meta.rst b/Documentation/userspace-api/media/v4l/dev-meta.rst
> > > index 0e7e1ee1471a..4b24bae6e171 100644
> > > --- a/Documentation/userspace-api/media/v4l/dev-meta.rst
> > > +++ b/Documentation/userspace-api/media/v4l/dev-meta.rst
> > > @@ -65,3 +65,18 @@ to 0.
> > > - ``buffersize``
> > > - Maximum buffer size in bytes required for data. The value is set by the
> > > driver.
> > > + * - __u32
> > > + - ``width``
> > > + - Width of a line of metadata in samples. Valid when :c:type`v4l2_fmtdesc`
> > > + flag ``V4L2_FMT_FLAG_META_LINE_BASED`` is set, otherwise zero. See
> > > + :c:func:`VIDIOC_ENUM_FMT`.
> > > + * - __u32
> > > + - ``height``
> > > + - Number of rows of metadata. Valid when :c:type`v4l2_fmtdesc` flag
> > > + ``V4L2_FMT_FLAG_META_LINE_BASED`` is set, otherwise zero. See
> > > + :c:func:`VIDIOC_ENUM_FMT`.
> > > + * - __u32
> > > + - ``bytesperline``
> > > + - Offset in bytes between the beginning of two consecutive lines. Valid
> > > + when :c:type`v4l2_fmtdesc` flag ``V4L2_FMT_FLAG_META_LINE_BASED`` is
> > > + set, otherwise zero. See :c:func:`VIDIOC_ENUM_FMT`.
> > > diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> > > index 000c154b0f98..6d7664345a4e 100644
> > > --- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> > > +++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> > > @@ -227,6 +227,13 @@ the ``mbus_code`` field is handled differently:
> > > The application can ask to configure the quantization of the capture
> > > device when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
> > > :ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
> > > + * - ``V4L2_FMT_FLAG_META_LINE_BASED``
> > > + - 0x0200
> > > + - The metadata format is line-based. In this case the ``width``,
> > > + ``height`` and ``bytesperline`` fields of :c:type:`v4l2_meta_format` are
> > > + valid. The buffer consists of ``height`` lines, each having ``width``
> > > + bytes of data and offset between the beginning of each two consecutive
> >
> > Isn't ``width`` in samples ?
>
> Indeed, it's better to refer to samples for clarity. I'll fix for v4.
How do you define a "sample" in this case ? I wonder if it wouldn't be
simpler for both userspace and kernel drivers if the width was specified
in bytes, including the padding bytes.
We need an implementation here to test it out. The good news is that I'm
working on it, the bad news is that I'm also busy with other things.
> I'll also add bytesperline is in bytes (and not in samples).
Thanks for not messing up (more than needed) with my mental health by
not specifying bytesperline in something else than bytes :-)
> > > + lines is ``bytesperline``.
> > >
> > > Return Value
> > > ============
> > > diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > > index 3e58aac4ef0b..bdc628e8c1d6 100644
> > > --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > > +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > > @@ -215,6 +215,7 @@ replace define V4L2_FMT_FLAG_CSC_XFER_FUNC fmtdesc-flags
> > > replace define V4L2_FMT_FLAG_CSC_YCBCR_ENC fmtdesc-flags
> > > replace define V4L2_FMT_FLAG_CSC_HSV_ENC fmtdesc-flags
> > > replace define V4L2_FMT_FLAG_CSC_QUANTIZATION fmtdesc-flags
> > > +replace define V4L2_FMT_FLAG_META_LINE_BASED fmtdesc-flags
> > >
> > > # V4L2 timecode types
> > > replace define V4L2_TC_TYPE_24FPS timecode-type
> > > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> > > index fbbddc333a30..971d784e7429 100644
> > > --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> > > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> > > @@ -343,8 +343,9 @@ static void v4l_print_format(const void *arg, bool write_only)
> > > case V4L2_BUF_TYPE_META_OUTPUT:
> > > meta = &p->fmt.meta;
> > > pixelformat = meta->dataformat;
> > > - pr_cont(", dataformat=%p4cc, buffersize=%u\n",
> > > - &pixelformat, meta->buffersize);
> > > + pr_cont(", dataformat=%p4cc, buffersize=%u, width=%u, height=%u, bytesperline=%u\n",
> > > + &pixelformat, meta->buffersize, meta->width,
> > > + meta->height, meta->bytesperline);
> > > break;
> > > }
> > > }
> > > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> > > index b4284a564025..d26c0650c6a7 100644
> > > --- a/include/uapi/linux/videodev2.h
> > > +++ b/include/uapi/linux/videodev2.h
> > > @@ -877,6 +877,7 @@ struct v4l2_fmtdesc {
> > > #define V4L2_FMT_FLAG_CSC_YCBCR_ENC 0x0080
> > > #define V4L2_FMT_FLAG_CSC_HSV_ENC V4L2_FMT_FLAG_CSC_YCBCR_ENC
> > > #define V4L2_FMT_FLAG_CSC_QUANTIZATION 0x0100
> > > +#define V4L2_FMT_FLAG_META_LINE_BASED 0x0200
> > >
> > > /* Frame Size and frame rate enumeration */
> > > /*
> > > @@ -2420,10 +2421,19 @@ struct v4l2_sdr_format {
> > > * struct v4l2_meta_format - metadata format definition
> > > * @dataformat: little endian four character code (fourcc)
> > > * @buffersize: maximum size in bytes required for data
> > > + * @width: number of bytes of data per line (valid for line based
> >
> > I'm a bit confused here as well, isn't width in samples ?
>
> I'll change this one as well.
>
> > > + * formats only, see format documentation)
> > > + * @height: number of lines of data per buffer (valid for line based
> > > + * formats only)
> > > + * @bytesperline: offset between the beginnings of two adjacent lines in
> > > + * bytes (valid for line based formats only)
> > > */
> > > struct v4l2_meta_format {
> > > __u32 dataformat;
> > > __u32 buffersize;
> > > + __u32 width;
> > > + __u32 height;
> > > + __u32 bytesperline;
> > > } __attribute__ ((packed));
> > >
> > > /**
--
Regards,
Laurent Pinchart
