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Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-create-bufs.xml')
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diff --git a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml deleted file mode 100644 index d81fa0d4016b..000000000000 --- a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml +++ /dev/null @@ -1,164 +0,0 @@ -<refentry id="vidioc-create-bufs"> - <refmeta> - <refentrytitle>ioctl VIDIOC_CREATE_BUFS</refentrytitle> - &manvol; - </refmeta> - - <refnamediv> - <refname>VIDIOC_CREATE_BUFS</refname> - <refpurpose>Create buffers for Memory Mapped or User Pointer or DMA Buffer - I/O</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_create_buffers *<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_CREATE_BUFS</para> - </listitem> - </varlistentry> - <varlistentry> - <term><parameter>argp</parameter></term> - <listitem> - <para></para> - </listitem> - </varlistentry> - </variablelist> - </refsect1> - - <refsect1> - <title>Description</title> - - <note> - <title>Experimental</title> - <para>This is an <link linkend="experimental"> experimental </link> - interface and may change in the future.</para> - </note> - - <para>This ioctl is used to create buffers for <link linkend="mmap">memory -mapped</link> or <link linkend="userp">user pointer</link> or <link -linkend="dmabuf">DMA buffer</link> I/O. It can be used as an alternative or in -addition to the &VIDIOC-REQBUFS; ioctl, when a tighter -control over buffers is required. This ioctl can be called multiple times to -create buffers of different sizes.</para> - - <para>To allocate the device buffers applications must initialize the -relevant fields of the <structname>v4l2_create_buffers</structname> structure. -The <structfield>count</structfield> field must be set to the number of -requested buffers, the <structfield>memory</structfield> field specifies the -requested I/O method and the <structfield>reserved</structfield> array must be -zeroed.</para> - - <para>The <structfield>format</structfield> field specifies the image format -that the buffers must be able to handle. The application has to fill in this -&v4l2-format;. Usually this will be done using the &VIDIOC-TRY-FMT; or &VIDIOC-G-FMT; ioctls -to ensure that the requested format is supported by the driver. -Based on the format's <structfield>type</structfield> field the requested buffer -size (for single-planar) or plane sizes (for multi-planar formats) will be -used for the allocated buffers. The driver may return an error if the size(s) -are not supported by the hardware (usually because they are too small).</para> - - <para>The buffers created by this ioctl will have as minimum size the size -defined by the <structfield>format.pix.sizeimage</structfield> field (or the -corresponding fields for other format types). Usually if the -<structfield>format.pix.sizeimage</structfield> field is less than the minimum -required for the given format, then an error will be returned since drivers will -typically not allow this. If it is larger, then the value will be used as-is. -In other words, the driver may reject the requested size, but if it is accepted -the driver will use it unchanged.</para> - - <para>When the ioctl is called with a pointer to this structure the driver -will attempt to allocate up to the requested number of buffers and store the -actual number allocated and the starting index in the -<structfield>count</structfield> and the <structfield>index</structfield> fields -respectively. On return <structfield>count</structfield> can be smaller than -the number requested.</para> - - <table pgwide="1" frame="none" id="v4l2-create-buffers"> - <title>struct <structname>v4l2_create_buffers</structname></title> - <tgroup cols="3"> - &cs-str; - <tbody valign="top"> - <row> - <entry>__u32</entry> - <entry><structfield>index</structfield></entry> - <entry>The starting buffer index, returned by the driver.</entry> - </row> - <row> - <entry>__u32</entry> - <entry><structfield>count</structfield></entry> - <entry>The number of buffers requested or granted. If count == 0, then - <constant>VIDIOC_CREATE_BUFS</constant> will set <structfield>index</structfield> - to the current number of created buffers, and it will check the validity of - <structfield>memory</structfield> and <structfield>format.type</structfield>. - If those are invalid -1 is returned and errno is set to &EINVAL;, - otherwise <constant>VIDIOC_CREATE_BUFS</constant> returns 0. It will - never set errno to &EBUSY; in this particular case.</entry> - </row> - <row> - <entry>__u32</entry> - <entry><structfield>memory</structfield></entry> - <entry>Applications set this field to -<constant>V4L2_MEMORY_MMAP</constant>, -<constant>V4L2_MEMORY_DMABUF</constant> or -<constant>V4L2_MEMORY_USERPTR</constant>. See <xref linkend="v4l2-memory" -/></entry> - </row> - <row> - <entry>&v4l2-format;</entry> - <entry><structfield>format</structfield></entry> - <entry>Filled in by the application, preserved by the driver.</entry> - </row> - <row> - <entry>__u32</entry> - <entry><structfield>reserved</structfield>[8]</entry> - <entry>A place holder for future extensions. Drivers and applications -must set the array to zero.</entry> - </row> - </tbody> - </tgroup> - </table> - </refsect1> - - <refsect1> - &return-value; - - <variablelist> - <varlistentry> - <term><errorcode>ENOMEM</errorcode></term> - <listitem> - <para>No memory to allocate buffers for <link linkend="mmap">memory -mapped</link> I/O.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><errorcode>EINVAL</errorcode></term> - <listitem> - <para>The buffer type (<structfield>format.type</structfield> field), -requested I/O method (<structfield>memory</structfield>) or format -(<structfield>format</structfield> field) is not valid.</para> - </listitem> - </varlistentry> - </variablelist> - </refsect1> -</refentry> |