V4L/DVB (12761): DocBook: add media API specs
The V4L and DVB API's are there for a long time. however, up to now,
no efforts were done to merge them to kernel DocBook.
This patch adds the current versions of the specs as an unique compendium.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/Documentation/DocBook/v4l/vidioc-querybuf.xml b/Documentation/DocBook/v4l/vidioc-querybuf.xml
new file mode 100644
index 0000000..d834993
--- /dev/null
+++ b/Documentation/DocBook/v4l/vidioc-querybuf.xml
@@ -0,0 +1,103 @@
+<refentry id="vidioc-querybuf">
+ <refmeta>
+ <refentrytitle>ioctl VIDIOC_QUERYBUF</refentrytitle>
+ &manvol;
+ </refmeta>
+
+ <refnamediv>
+ <refname>VIDIOC_QUERYBUF</refname>
+ <refpurpose>Query the status of a buffer</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcprototype>
+ <funcdef>int <function>ioctl</function></funcdef>
+ <paramdef>int <parameter>fd</parameter></paramdef>
+ <paramdef>int <parameter>request</parameter></paramdef>
+ <paramdef>struct v4l2_buffer *<parameter>argp</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Arguments</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><parameter>fd</parameter></term>
+ <listitem>
+ <para>&fd;</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>request</parameter></term>
+ <listitem>
+ <para>VIDIOC_QUERYBUF</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>argp</parameter></term>
+ <listitem>
+ <para></para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>This ioctl is part of the <link linkend="mmap">memory
+mapping</link> I/O method. It can be used to query the status of a
+buffer at any time after buffers have been allocated with the
+&VIDIOC-REQBUFS; ioctl.</para>
+
+ <para>Applications set the <structfield>type</structfield> field
+ of a &v4l2-buffer; to the same buffer type as previously
+&v4l2-format; <structfield>type</structfield> and &v4l2-requestbuffers;
+<structfield>type</structfield>, and the <structfield>index</structfield>
+ field. Valid index numbers range from zero
+to the number of buffers allocated with &VIDIOC-REQBUFS;
+ (&v4l2-requestbuffers; <structfield>count</structfield>) minus one.
+After calling <constant>VIDIOC_QUERYBUF</constant> with a pointer to
+ this structure drivers return an error code or fill the rest of
+the structure.</para>
+
+ <para>In the <structfield>flags</structfield> field the
+<constant>V4L2_BUF_FLAG_MAPPED</constant>,
+<constant>V4L2_BUF_FLAG_QUEUED</constant> and
+<constant>V4L2_BUF_FLAG_DONE</constant> flags will be valid. The
+<structfield>memory</structfield> field will be set to
+<constant>V4L2_MEMORY_MMAP</constant>, the <structfield>m.offset</structfield>
+contains the offset of the buffer from the start of the device memory,
+the <structfield>length</structfield> field its size. The driver may
+or may not set the remaining fields and flags, they are meaningless in
+this context.</para>
+
+ <para>The <structname>v4l2_buffer</structname> structure is
+ specified in <xref linkend="buffer" />.</para>
+ </refsect1>
+
+ <refsect1>
+ &return-value;
+
+ <variablelist>
+ <varlistentry>
+ <term><errorcode>EINVAL</errorcode></term>
+ <listitem>
+ <para>The buffer <structfield>type</structfield> is not
+supported, or the <structfield>index</structfield> is out of bounds.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+</refentry>
+
+<!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+-->