On 22/07/2024 17:05, Benjamin Gaignard wrote:
> When the index field is ORed with V4L2_FMT_FLAG_ENUM_ALL the driver
> will ignore any configuration and enumerate all the possible formats.
> Drivers which do not support this flag yet always return an EINVAL
> error code.
>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> ---
> changes in version 5:
> - Reset the proposal to follow Hans's advices
> - Add new flag to be used with index field.
>
> .../userspace-api/media/v4l/vidioc-enum-fmt.rst | 12 +++++++++++-
> .../userspace-api/media/videodev2.h.rst.exceptions | 1 +
> include/uapi/linux/videodev2.h | 3 +++
> 3 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> index 3adb3d205531..12e1e65e6a71 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> @@ -85,7 +85,11 @@ the ``mbus_code`` field is handled differently:
> * - __u32
> - ``index``
> - Number of the format in the enumeration, set by the application.
> - This is in no way related to the ``pixelformat`` field.
> + This is in no way related to the ``pixelformat`` field. When the
You need to start a new paragraph before 'When'. Otherwise you might read
that the 'When' sentence is somehow related to the previous sentence.
> + index is ORed with V4L2_FMT_FLAG_ENUM_ALL the driver will ignore
> + any configuration and enumerate all the possible formats. Drivers
I'd rephrase this a little bit:
the driver will enumerate all the possible formats, ignoring any limitations
from the current configuration.
And after that I would like to see an example of a use-case.
> + which do not support this flag yet always return an ``EINVAL``
> + error code.
> * - __u32
> - ``type``
> - Type of the data stream, set by the application. Only these types
> @@ -234,6 +238,12 @@ the ``mbus_code`` field is handled differently:
> valid. The buffer consists of ``height`` lines, each having ``width``
> Data Units of data and the offset (in bytes) between the beginning of
> each two consecutive lines is ``bytesperline``.
> + * - ``V4L2_FMT_FLAG_ENUM_ALL``
I am not really happy with this name since the prefix is identical to that
of other V4L2_FMT_FLAG_ defines. How about: V4L2_FMTDESC_FLAG_ENUM_ALL?
Or V4L2_FMT_IDX_ENUM_ALL?
> + - 0x80000000
> + - When the applications ORs ``index`` with ``V4L2_FMT_FLAG_ENUM_ALL`` flag
> + the driver enumerates all the possible pixel formats without taking care
> + of any already set configuration. Drivers which do not support this flag
> + yet always return ``EINVAL``.
>
> Return Value
> ============
> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> index bdc628e8c1d6..8dc10a500fc6 100644
> --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> @@ -216,6 +216,7 @@ 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
> +replace define V4L2_FMT_FLAG_ENUM_ALL fmtdesc-flags
>
> # V4L2 timecode types
> replace define V4L2_TC_TYPE_24FPS timecode-type
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 4e91362da6da..3d11f91273a1 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -904,6 +904,9 @@ struct v4l2_fmtdesc {
> #define V4L2_FMT_FLAG_CSC_QUANTIZATION 0x0100
> #define V4L2_FMT_FLAG_META_LINE_BASED 0x0200
>
> +/* Format description flag, to be ORed with the index */
> +#define V4L2_FMT_FLAG_ENUM_ALL 0x80000000
> +
> /* Frame Size and frame rate enumeration */
> /*
> * F R A M E S I Z E E N U M E R A T I O N
Regards,
Hans
