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Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-streamon.xml')
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1 files changed, 0 insertions, 136 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-streamon.xml b/Documentation/DocBook/media/v4l/vidioc-streamon.xml deleted file mode 100644 index 89fd7ce964f9..000000000000 --- a/Documentation/DocBook/media/v4l/vidioc-streamon.xml +++ /dev/null @@ -1,136 +0,0 @@ -<refentry id="vidioc-streamon"> - <refmeta> - <refentrytitle>ioctl VIDIOC_STREAMON, VIDIOC_STREAMOFF</refentrytitle> - &manvol; - </refmeta> - - <refnamediv> - <refname>VIDIOC_STREAMON</refname> - <refname>VIDIOC_STREAMOFF</refname> - <refpurpose>Start or stop streaming 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>const int *<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_STREAMON, VIDIOC_STREAMOFF</para> - </listitem> - </varlistentry> - <varlistentry> - <term><parameter>argp</parameter></term> - <listitem> - <para></para> - </listitem> - </varlistentry> - </variablelist> - </refsect1> - - <refsect1> - <title>Description</title> - - <para>The <constant>VIDIOC_STREAMON</constant> and -<constant>VIDIOC_STREAMOFF</constant> ioctl start and stop the capture -or output process during streaming (<link linkend="mmap">memory -mapping</link>, <link linkend="userp">user pointer</link> or -<link linkend="dmabuf">DMABUF</link>) I/O.</para> - - <para>Capture hardware is disabled and no input -buffers are filled (if there are any empty buffers in the incoming -queue) until <constant>VIDIOC_STREAMON</constant> has been called. -Output hardware is disabled and no video signal is -produced until <constant>VIDIOC_STREAMON</constant> has been called. -The ioctl will succeed when at least one output buffer is in the -incoming queue.</para> - - <para>Memory-to-memory devices will not start until -<constant>VIDIOC_STREAMON</constant> has been called for both the capture -and output stream types.</para> - - <para>If <constant>VIDIOC_STREAMON</constant> fails then any already -queued buffers will remain queued.</para> - - <para>The <constant>VIDIOC_STREAMOFF</constant> ioctl, apart of -aborting or finishing any DMA in progress, unlocks any user pointer -buffers locked in physical memory, and it removes all buffers from the -incoming and outgoing queues. That means all images captured but not -dequeued yet will be lost, likewise all images enqueued for output but -not transmitted yet. I/O returns to the same state as after calling -&VIDIOC-REQBUFS; and can be restarted accordingly.</para> - - <para>If buffers have been queued with &VIDIOC-QBUF; and -<constant>VIDIOC_STREAMOFF</constant> is called without ever having -called <constant>VIDIOC_STREAMON</constant>, then those queued buffers -will also be removed from the incoming queue and all are returned to the -same state as after calling &VIDIOC-REQBUFS; and can be restarted -accordingly.</para> - - <para>Both ioctls take a pointer to an integer, the desired buffer or -stream type. This is the same as &v4l2-requestbuffers; -<structfield>type</structfield>.</para> - - <para>If <constant>VIDIOC_STREAMON</constant> is called when streaming -is already in progress, or if <constant>VIDIOC_STREAMOFF</constant> is called -when streaming is already stopped, then 0 is returned. Nothing happens in the -case of <constant>VIDIOC_STREAMON</constant>, but <constant>VIDIOC_STREAMOFF</constant> -will return queued buffers to their starting state as mentioned above.</para> - - <para>Note that applications can be preempted for unknown periods right -before or after the <constant>VIDIOC_STREAMON</constant> or -<constant>VIDIOC_STREAMOFF</constant> calls, there is no notion of -starting or stopping "now". Buffer timestamps can be used to -synchronize with other events.</para> - </refsect1> - - <refsect1> - &return-value; - - <variablelist> - <varlistentry> - <term><errorcode>EINVAL</errorcode></term> - <listitem> - <para>The buffer <structfield>type</structfield> is not supported, - or no buffers have been allocated (memory mapping) or enqueued - (output) yet.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><errorcode>EPIPE</errorcode></term> - <listitem> - <para>The driver implements <link - linkend="pad-level-formats">pad-level format configuration</link> and - the pipeline configuration is invalid. - </para> - </listitem> - </varlistentry> - <varlistentry> - <term><errorcode>ENOLINK</errorcode></term> - <listitem> - <para>The driver implements Media Controller interface and - the pipeline link configuration is invalid. - </para> - </listitem> - </varlistentry> - </variablelist> - </refsect1> -</refentry> |