On 07/08/2024 10:39, Hans Verkuil wrote: > On 31/07/2024 11:34, Benjamin Gaignard wrote: >> When the index is ORed with V4L2_FMTDESC_FLAG_ENUM_ALL the >> driver clears the flag and enumerate all the possible formats, >> ignoring any limitations from the current configuration. >> Drivers which do not support this flag yet always return an EINVAL. >> >> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx> >> --- >> change in version 6: >> - Change flag name. >> - Improve documentation. >> >> .../userspace-api/media/v4l/vidioc-enum-fmt.rst | 16 +++++++++++++++- >> .../media/videodev2.h.rst.exceptions | 1 + >> include/uapi/linux/videodev2.h | 3 +++ >> 3 files changed, 19 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..1112dc9044b2 100644 >> --- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst >> +++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst >> @@ -85,7 +85,15 @@ 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 index is ORed with ``V4L2_FMTDESC_FLAG_ENUM_ALL`` the >> + driver clears the flag and enumerate all the possible formats, > > enumerate -> enumerates > >> + ignoring any limitations from the current configuration. Drivers >> + which do not support this flag yet always return an ``EINVAL`` > > Drop the 'yet'. > > But this raises a question: should this flag only be supported by drivers > that can actually return different format lists depending on this flag? > > Or can it be supported as well by a driver where this makes no difference? > > I'm inclined to limit it to drivers that actually can return different > results. If nothing else, that will indicate to the application that this > is actually possible. > > If we agree on that, then that should be documented as well. I also think that this flag makes no sense for drivers that have V4L2_CAP_IO_MC set, since in that case the list of returned formats shall not depend on the active configuration (see https://hverkuil.home.xs4all.nl/spec/userspace-api/v4l/vidioc-enum-fmt.html ). I think this should be mentioned in the documentation and tested for in the compliance test. Regards, Hans > >> + error code. >> + Formats enumerated when using ``V4L2_FMTDESC_FLAG_ENUM_ALL`` flag >> + shouldn't be used when calling :c:func:`VIDIOC_ENUM_FRAMESIZES` >> + or :c:func:`VIDIOC_ENUM_FRAMEINTERVALS`. >> * - __u32 >> - ``type`` >> - Type of the data stream, set by the application. Only these types >> @@ -234,6 +242,12 @@ 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_FMTDESC_FLAG_ENUM_ALL`` >> + - 0x80000000 >> + - When the applications ORs ``index`` with ``V4L2_FMTDESC_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``. > > Drop 'yet' > >> >> Return Value >> ============ >> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions >> index bdc628e8c1d6..0a9ea9686c24 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_FMTDESC_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..421a30cb0c51 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_FMTDESC_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 >
