Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/Documentation/media/uapi/v4l/dev-meta.rst b/Documentation/media/uapi/v4l/dev-meta.rst
index f7ac8d0..c5dbe88 100644
--- a/Documentation/media/uapi/v4l/dev-meta.rst
+++ b/Documentation/media/uapi/v4l/dev-meta.rst
@@ -1,4 +1,11 @@
-.. -*- coding: utf-8; mode: rst -*-
+.. Permission is granted to copy, distribute and/or modify this
+.. document under the terms of the GNU Free Documentation License,
+.. Version 1.1 or any later version published by the Free Software
+.. Foundation, with no Invariant Sections, no Front-Cover Texts
+.. and no Back-Cover Texts. A copy of the license is included at
+.. Documentation/media/uapi/fdl-appendix.rst.
+..
+.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
.. _metadata:
@@ -7,21 +14,27 @@
******************
Metadata refers to any non-image data that supplements video frames with
-additional information. This may include statistics computed over the image
-or frame capture parameters supplied by the image source. This interface is
-intended for transfer of metadata to userspace and control of that operation.
+additional information. This may include statistics computed over the image,
+frame capture parameters supplied by the image source or device specific
+parameters for specifying how the device processes images. This interface is
+intended for transfer of metadata between the userspace and the hardware and
+control of that operation.
-The metadata interface is implemented on video capture device nodes. The device
-can be dedicated to metadata or can implement both video and metadata capture
-as specified in its reported capabilities.
+The metadata interface is implemented on video device nodes. The device can be
+dedicated to metadata or can support both video and metadata as specified in its
+reported capabilities.
Querying Capabilities
=====================
-Device nodes supporting the metadata interface set the ``V4L2_CAP_META_CAPTURE``
-flag in the ``device_caps`` field of the
+Device nodes supporting the metadata capture interface set the
+``V4L2_CAP_META_CAPTURE`` flag in the ``device_caps`` field of the
:c:type:`v4l2_capability` structure returned by the :c:func:`VIDIOC_QUERYCAP`
-ioctl. That flag means the device can capture metadata to memory.
+ioctl. That flag means the device can capture metadata to memory. Similarly,
+device nodes supporting metadata output interface set the
+``V4L2_CAP_META_OUTPUT`` flag in the ``device_caps`` field of
+:c:type:`v4l2_capability` structure. That flag means the device can read
+metadata from memory.
At least one of the read/write or streaming I/O methods must be supported.
@@ -35,12 +48,13 @@
supported as well.
To use the :ref:`format` ioctls applications set the ``type`` field of the
-:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_META_CAPTURE`` and use the
-:c:type:`v4l2_meta_format` ``meta`` member of the ``fmt`` union as needed per
-the desired operation. Both drivers and applications must set the remainder of
-the :c:type:`v4l2_format` structure to 0.
+:c:type:`v4l2_format` structure to ``V4L2_BUF_TYPE_META_CAPTURE`` or to
+``V4L2_BUF_TYPE_META_OUTPUT`` and use the :c:type:`v4l2_meta_format` ``meta``
+member of the ``fmt`` union as needed per the desired operation. Both drivers
+and applications must set the remainder of the :c:type:`v4l2_format` structure
+to 0.
-.. _v4l2-meta-format:
+.. c:type:: v4l2_meta_format
.. tabularcolumns:: |p{1.4cm}|p{2.2cm}|p{13.9cm}|