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-rw-r--r--Documentation/media/uapi/v4l/vidioc-cropcap.rst23
1 files changed, 13 insertions, 10 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-cropcap.rst b/Documentation/media/uapi/v4l/vidioc-cropcap.rst
index f21a69b554e1..0f80d5ca2643 100644
--- a/Documentation/media/uapi/v4l/vidioc-cropcap.rst
+++ b/Documentation/media/uapi/v4l/vidioc-cropcap.rst
@@ -39,17 +39,10 @@ structure. Drivers fill the rest of the structure. The results are
constant except when switching the video standard. Remember this switch
can occur implicit when switching the video input or output.
-Do not use the multiplanar buffer types. Use
-``V4L2_BUF_TYPE_VIDEO_CAPTURE`` instead of
-``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE`` and use
-``V4L2_BUF_TYPE_VIDEO_OUTPUT`` instead of
-``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``.
-
This ioctl must be implemented for video capture or output devices that
support cropping and/or scaling and/or have non-square pixels, and for
overlay devices.
-
.. c:type:: v4l2_cropcap
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
@@ -62,9 +55,9 @@ overlay devices.
* - __u32
- ``type``
- Type of the data stream, set by the application. Only these types
- are valid here: ``V4L2_BUF_TYPE_VIDEO_CAPTURE``,
- ``V4L2_BUF_TYPE_VIDEO_OUTPUT`` and
- ``V4L2_BUF_TYPE_VIDEO_OVERLAY``. See :c:type:`v4l2_buf_type`.
+ are valid here: ``V4L2_BUF_TYPE_VIDEO_CAPTURE``, ``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE``,
+ ``V4L2_BUF_TYPE_VIDEO_OUTPUT``, ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE`` and
+ ``V4L2_BUF_TYPE_VIDEO_OVERLAY``. See :c:type:`v4l2_buf_type` and the note above.
* - struct :ref:`v4l2_rect <v4l2-rect-crop>`
- ``bounds``
- Defines the window within capturing or output is possible, this
@@ -90,6 +83,16 @@ overlay devices.
``pixelaspect`` to 1/1. Other common values are 54/59 for PAL and
SECAM, 11/10 for NTSC sampled according to [:ref:`itu601`].
+.. note::
+ Unfortunately in the case of multiplanar buffer types
+ (``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE`` and ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``)
+ this API was messed up with regards to how the :c:type:`v4l2_cropcap` ``type`` field
+ should be filled in. Some drivers only accepted the ``_MPLANE`` buffer type while
+ other drivers only accepted a non-multiplanar buffer type (i.e. without the
+ ``_MPLANE`` at the end).
+
+ Starting with kernel 4.13 both variations are allowed.
+
.. _v4l2-rect-crop: