diff options
Diffstat (limited to 'Documentation/userspace-api')
| -rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst index 7e3142e11d77..9694111772a2 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst @@ -48,10 +48,21 @@ one until ``EINVAL`` is returned. If applicable, drivers shall return formats in preference order, where preferred formats are returned before (that is, with lower ``index`` value) less-preferred formats. -.. note:: - - After switching input or output the list of enumerated image - formats may be different. +If the driver doesn't advertise the ``V4L2_CAP_IO_MC`` :ref:`capability +<device-capabilities>`, applications shall initialize the ``mbus_code`` field +to zero and drivers shall ignore the value of the field. Drivers shall +enumerate all image formats. The enumerated formats may depend on the active +input or output of the device. + +If the driver advertises the ``V4L2_CAP_IO_MC`` :ref:`capability +<device-capabilities>`, applications may initialize the ``mbus_code`` field to +a valid :ref:`media bus format code <v4l2-mbus-pixelcode>`. If the +``mbus_code`` field is not zero, drivers shall restrict enumeration to only the +image formats that can produce (for video output devices) or be produced from +(for video capture devices) that media bus code. Regardless of the value of +the ``mbus_code`` field, the enumerated image formats shall not depend on the +active configuration of the video device or device pipeline. Enumeration shall +otherwise operate as previously described. .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| @@ -106,7 +117,13 @@ formats in preference order, where preferred formats are returned before These codes are not the same as those used in the Windows world. * - __u32 - - ``reserved``\ [4] + - ``mbus_code`` + - Media bus code restricting the enumerated formats, set by the + application. Only applicable to drivers that advertise the + ``V4L2_CAP_IO_MC`` :ref:`capability <device-capabilities>`, shall be 0 + otherwise. + * - __u32 + - ``reserved``\ [3] - Reserved for future extensions. Drivers must set the array to zero. |