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Commit e3b1b4e7 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
Browse files

[media] DocBook: various updates w.r.t. v4l2_buffer and multiplanar 



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: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 96b1a702

Documentation/DocBook/media/v4l/io.xml

+4 −2
Original line number Diff line number Diff line
@@ -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>

Documentation/DocBook/media/v4l/vidioc-qbuf.xml

+1 −2
Original line number Diff line number Diff line
@@ -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

Documentation/DocBook/media/v4l/vidioc-querybuf.xml

+7 −4
Original line number Diff line number Diff line
@@ -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>