On 30/07/2024 09:08, Hans Verkuil wrote:
> 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.
Should the flag be kept on return of VIDIOC_ENUM_FMT or should it be cleared?
For reference: VIDIOC_QUERYCTRL will clear the V4L2_CTRL_FLAG_NEXT_CTRL flag.
Regardless of what we pick, it should be documented.
Regards,
Hans
>
>> + 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
>
