Adding upstream version 4.19.249.upstream/4.19.249upstream

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

1 files changed, 130 insertions, 0 deletions

diff --git a/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst b/Documentation/media/uapi/v4l/vidioc-enum-fmt.rst
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _VIDIOC_ENUM_FMT:
+
+*********************
+ioctl VIDIOC_ENUM_FMT
+*********************
+
+Name
+====
+
+VIDIOC_ENUM_FMT - Enumerate image formats
+
+
+Synopsis
+========
+
+.. c:function:: int ioctl( int fd, VIDIOC_ENUM_FMT, struct v4l2_fmtdesc *argp )
+    :name: VIDIOC_ENUM_FMT
+
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :ref:`open() <func-open>`.
+
+``argp``
+    Pointer to struct :c:type:`v4l2_fmtdesc`.
+
+
+Description
+===========
+
+To enumerate image formats applications initialize the ``type`` and
+``index`` field of struct :c:type:`v4l2_fmtdesc` and call
+the :ref:`VIDIOC_ENUM_FMT` ioctl with a pointer to this structure. Drivers
+fill the rest of the structure or return an ``EINVAL`` error code. All
+formats are enumerable by beginning at index zero and incrementing by
+one until ``EINVAL`` is returned.
+
+.. note::
+
+   After switching input or output the list of enumerated image
+   formats may be different.
+
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. c:type:: v4l2_fmtdesc
+
+.. flat-table:: struct v4l2_fmtdesc
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - __u32
+      - ``index``
+      - Number of the format in the enumeration, set by the application.
+	This is in no way related to the ``pixelformat`` field.
+    * - __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`.
+    * - __u32
+      - ``flags``
+      - See :ref:`fmtdesc-flags`
+    * - __u8
+      - ``description``\ [32]
+      - Description of the format, a NUL-terminated ASCII string. This
+	information is intended for the user, for example: "YUV 4:2:2".
+    * - __u32
+      - ``pixelformat``
+      - The image format identifier. This is a four character code as
+	computed by the v4l2_fourcc() macro:
+    * - :cspan:`2`
+
+	.. _v4l2-fourcc:
+
+	``#define v4l2_fourcc(a,b,c,d)``
+
+	``(((__u32)(a)<<0)|((__u32)(b)<<8)|((__u32)(c)<<16)|((__u32)(d)<<24))``
+
+	Several image formats are already defined by this specification in
+	:ref:`pixfmt`.
+
+	.. attention::
+
+	   These codes are not the same as those used
+	   in the Windows world.
+    * - __u32
+      - ``reserved``\ [4]
+      - Reserved for future extensions. Drivers must set the array to
+	zero.
+
+
+
+.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
+
+.. _fmtdesc-flags:
+
+.. flat-table:: Image Format Description Flags
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       3 1 4
+
+    * - ``V4L2_FMT_FLAG_COMPRESSED``
+      - 0x0001
+      - This is a compressed format.
+    * - ``V4L2_FMT_FLAG_EMULATED``
+      - 0x0002
+      - This format is not native to the device but emulated through
+	software (usually libv4l2), where possible try to use a native
+	format instead for better performance.
+
+
+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.
+
+EINVAL
+    The struct :c:type:`v4l2_fmtdesc` ``type`` is not
+    supported or the ``index`` is out of bounds.