Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 112 insertions, 0 deletions

diff --git a/Documentation/media/uapi/v4l/vidioc-g-crop.rst b/Documentation/media/uapi/v4l/vidioc-g-crop.rst
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index 000000000..a6ed43ba9
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+++ b/Documentation/media/uapi/v4l/vidioc-g-crop.rst
@@ -0,0 +1,112 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _VIDIOC_G_CROP:
+
+**********************************
+ioctl VIDIOC_G_CROP, VIDIOC_S_CROP
+**********************************
+
+Name
+====
+
+VIDIOC_G_CROP - VIDIOC_S_CROP - Get or set the current cropping rectangle
+
+
+Synopsis
+========
+
+.. c:function:: int ioctl( int fd, VIDIOC_G_CROP, struct v4l2_crop *argp )
+    :name: VIDIOC_G_CROP
+
+.. c:function:: int ioctl( int fd, VIDIOC_S_CROP, const struct v4l2_crop *argp )
+    :name: VIDIOC_S_CROP
+
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :ref:`open() <func-open>`.
+
+``argp``
+    Pointer to struct :c:type:`v4l2_crop`.
+
+
+Description
+===========
+
+To query the cropping rectangle size and position applications set the
+``type`` field of a struct :c:type:`v4l2_crop` structure to the
+respective buffer (stream) type and call the :ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` ioctl
+with a pointer to this structure. The driver fills the rest of the
+structure or returns the ``EINVAL`` error code if cropping is not supported.
+
+To change the cropping rectangle applications initialize the ``type``
+and struct :c:type:`v4l2_rect` substructure named ``c`` of a
+v4l2_crop structure and call the :ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` ioctl with a pointer
+to this structure.
+
+The driver first adjusts the requested dimensions against hardware
+limits, i. e. the bounds given by the capture/output window, and it
+rounds to the closest possible values of horizontal and vertical offset,
+width and height. In particular the driver must round the vertical
+offset of the cropping rectangle to frame lines modulo two, such that
+the field order cannot be confused.
+
+Second the driver adjusts the image size (the opposite rectangle of the
+scaling process, source or target depending on the data direction) to
+the closest size possible while maintaining the current horizontal and
+vertical scaling factor.
+
+Finally the driver programs the hardware with the actual cropping and
+image parameters. :ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` is a write-only ioctl, it does not
+return the actual parameters. To query them applications must call
+:ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` and :ref:`VIDIOC_G_FMT`. When the
+parameters are unsuitable the application may modify the cropping or
+image parameters and repeat the cycle until satisfactory parameters have
+been negotiated.
+
+When cropping is not supported then no parameters are changed and
+:ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` returns the ``EINVAL`` error code.
+
+
+.. c:type:: v4l2_crop
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. flat-table:: struct v4l2_crop
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - __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_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 :c:type:`v4l2_rect`
+      - ``c``
+      - Cropping rectangle. The same co-ordinate system as for struct
+	:c:type:`v4l2_cropcap` ``bounds`` is used.
+
+.. 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_crop` ``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.
+
+
+Return Value
+============
+
+On success 0 is returned, on error -1 and the ``errno`` variable is set
+appropriately. The generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.
+
+ENODATA
+    Cropping is not supported for this input or output.