[PATCH v5 4/7] v4l2: extend the CSC API to subdevice.

[Tomasz Figa]

On Mon, Aug 17, 2020 at 12:24 PM Dafna Hirschfeld
<dafna.hirschfeld at collabora.com> wrote:
>
>
>
> Am 22.07.20 um 14:53 schrieb Tomasz Figa:
> > Hi Dafna,
> >
> > On Fri, Jul 03, 2020 at 07:10:16PM +0200, Dafna Hirschfeld wrote:
> >> This patch extends the CSC API in video devices to be supported
> >> also on sub-devices. The flag V4L2_MBUS_FRAMEFMT_SET_CSC set by
> >> the application when calling VIDIOC_SUBDEV_S_FMT ioctl.
> >> The flags:
> >>
> >> V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE, V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC,
> >> V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC,
> >>
> >> are set by the driver in the VIDIOC_SUBDEV_ENUM_MBUS_CODE ioctl.
> >>
> >> New 'flags' fields were added to the structs
> >> v4l2_subdev_mbus_code_enum, v4l2_mbus_framefmt which are borrowed
> >> from the 'reserved' field
> >>
> >> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld at collabora.com>
> >> ---
> >>   .../media/v4l/subdev-formats.rst              | 78 +++++++++++++++++--
> >>   .../v4l/vidioc-subdev-enum-mbus-code.rst      | 44 ++++++++++-
> >>   include/uapi/linux/v4l2-mediabus.h            |  9 ++-
> >>   include/uapi/linux/v4l2-subdev.h              |  8 +-
> >>   4 files changed, 129 insertions(+), 10 deletions(-)
> >>
> >
> > Thank you for the patch. Please see my comments inline.
> >
> >> diff --git a/Documentation/userspace-api/media/v4l/subdev-formats.rst b/Documentation/userspace-api/media/v4l/subdev-formats.rst
> >> index 9a4d61b0d76f..7362ee0b1e96 100644
> >> --- a/Documentation/userspace-api/media/v4l/subdev-formats.rst
> >> +++ b/Documentation/userspace-api/media/v4l/subdev-formats.rst
> >> @@ -41,32 +41,96 @@ Media Bus Formats
> >>      :ref:`field-order` for details.
> >>       * - __u32
> >>         - ``colorspace``
> >> -      - Image colorspace, from enum
> >> -    :c:type:`v4l2_colorspace`. See
> >> -    :ref:`colorspaces` for details.
> >> +      - Image colorspace, from enum :c:type:`v4l2_colorspace`.
> >> +        Must be set by the driver for capture streams and by the application
> >> +    for output streams, see :ref:`colorspaces`. If the application sets the
> >> +    flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
> >> +    this field for a capture stream to request a specific colorspace
> >
> > What is a "capture stream" in terms of the subdev API? Should this
> > perhaps refer to "source pads" instead?
>
> Hi, yes, I should change it to 'source pad'. I see that for the other colorimetry fields,
> the docs for v4l2_mbus_framefmt already writes
> "This information supplements the colorspace and must be set by the driver for capture streams and by the application for output streams,"
> I guess this should also change,

Right.

Best regards,
Tomasz