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Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-querybuf.xml')
-rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-querybuf.xml | 106 |
1 files changed, 0 insertions, 106 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-querybuf.xml b/Documentation/DocBook/media/v4l/vidioc-querybuf.xml deleted file mode 100644 index 50bfcb5e8..000000000 --- a/Documentation/DocBook/media/v4l/vidioc-querybuf.xml +++ /dev/null @@ -1,106 +0,0 @@ -<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">streaming -</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 was previously used with -&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. -The <structfield>reserved</structfield> and <structfield>reserved2 </structfield> -fields must be set to 0. -When using the <link linkend="planar-apis">multi-planar API</link>, the -<structfield>m.planes</structfield> field must contain a userspace pointer to an -array of &v4l2-plane; and the <structfield>length</structfield> field has -to be set to the number of elements in that array. -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_PREPARED</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 the current -I/O method. For the single-planar API, 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. For the multi-planar API, -fields <structfield>m.mem_offset</structfield> and -<structfield>length</structfield> in the <structfield>m.planes</structfield> -array elements will be used instead and the <structfield>length</structfield> -field of &v4l2-buffer; is set to the number of filled-in array elements. -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> |