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author | 2015-08-04 12:17:53 -0700 | |
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committer | 2015-08-04 15:44:42 -0700 | |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/DocBook/media/v4l/vidioc-querybuf.xml | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/Documentation/DocBook/media/v4l/vidioc-querybuf.xml')
-rw-r--r-- | kernel/Documentation/DocBook/media/v4l/vidioc-querybuf.xml | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/kernel/Documentation/DocBook/media/v4l/vidioc-querybuf.xml b/kernel/Documentation/DocBook/media/v4l/vidioc-querybuf.xml new file mode 100644 index 000000000..a597155c0 --- /dev/null +++ b/kernel/Documentation/DocBook/media/v4l/vidioc-querybuf.xml @@ -0,0 +1,105 @@ +<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> field should to 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> |