From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Clarify the behavior of v4l2_buffer in the multiplanar case,
including fixing a false statement: you can't set m.planes to NULL
when calling DQBUF.
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
Documentation/DocBook/media/v4l/io.xml | 6 ++++--
Documentation/DocBook/media/v4l/vidioc-qbuf.xml | 3 +--
Documentation/DocBook/media/v4l/vidioc-querybuf.xml | 11 +++++++----
3 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml
index 1885cc0..c6d39fe 100644
--- a/Documentation/DocBook/media/v4l/io.xml
+++ b/Documentation/DocBook/media/v4l/io.xml
@@ -677,8 +677,10 @@ memory, set by the application. See <xref linkend="userp" /> for details.
<entry><structfield>length</structfield></entry>
<entry></entry>
<entry>Size of the buffer (not the payload) in bytes for the
- single-planar API. For the multi-planar API should contain the
- number of elements in the <structfield>planes</structfield> array.
+ single-planar API. For the multi-planar API the application sets
+ this to the number of elements in the <structfield>planes</structfield>
+ array. The driver will fill in the actual number of valid elements in
+ that array.
</entry>
</row>
<row>
diff --git a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml
index 6a821a6..2d37abe 100644
--- a/Documentation/DocBook/media/v4l/vidioc-qbuf.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-qbuf.xml
@@ -121,8 +121,7 @@ remaining fields or returns an error code. The driver may also set
field. It indicates a non-critical (recoverable) streaming error. In such case
the application may continue as normal, but should be aware that data in the
dequeued buffer might be corrupted. When using the multi-planar API, the
-planes array does not have to be passed; the <structfield>m.planes</structfield>
-member must be set to NULL in that case.</para>
+planes array must be passed in as well.</para>
<para>By default <constant>VIDIOC_DQBUF</constant> blocks when no
buffer is in the outgoing queue. When the
diff --git a/Documentation/DocBook/media/v4l/vidioc-querybuf.xml b/Documentation/DocBook/media/v4l/vidioc-querybuf.xml
index 6e414d7..a597155 100644
--- a/Documentation/DocBook/media/v4l/vidioc-querybuf.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-querybuf.xml
@@ -48,8 +48,8 @@
<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
+ <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>
@@ -71,6 +71,7 @@ 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
@@ -79,8 +80,10 @@ 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. The driver may or may not set the remaining
-fields and flags, they are meaningless in this context.</para>
+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>
--
1.7.10.4
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