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[media] DocBook: mention the memory type to be set for all streaming I/O 

The DMA buffer importing streaming I/O section mentions the memory type
value that has to be set when calling the VIDIOC_REQBUFS ioctl but this
isn't mentioned in neither the Memory Mapping nor User Pointer sections.

A user can know the values by looking at the examples but it's better
to explicitly mention in the documentation, and also makes all sections
about streaming I/O methods more consistent.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Javier Martinez Canillas 2016-05-31 13:56:08 -03:00 committed by Mauro Carvalho Chehab
parent e1f1cb8598
commit bcdb9040df
1 changed files with 2 additions and 2 deletions
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4
Documentation/DocBook/media/v4l/io.xml
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@ -88,7 +88,7 @@ function.<footnote>
<structfield>capabilities</structfield> field of &v4l2-capability;
returned by the &VIDIOC-QUERYCAP; ioctl is set. There are two
streaming methods, to determine if the memory mapping flavor is
supported applications must call the &VIDIOC-REQBUFS; ioctl.</para>
supported applications must call the &VIDIOC-REQBUFS; ioctl with the memory type set to <constant>V4L2_MEMORY_MMAP</constant>.</para>
<para>Streaming is an I/O method where only pointers to buffers
are exchanged between application and driver, the data itself is not
@ -369,7 +369,7 @@ rest should be evident.</para>
<structfield>capabilities</structfield> field of &v4l2-capability;
returned by the &VIDIOC-QUERYCAP; ioctl is set. If the particular user
pointer method (not only memory mapping) is supported must be
determined by calling the &VIDIOC-REQBUFS; ioctl.</para>
determined by calling the &VIDIOC-REQBUFS; ioctl with the memory type set to <constant>V4L2_MEMORY_USERPTR</constant>.</para>
<para>This I/O method combines advantages of the read/write and
memory mapping methods. Buffers (planes) are allocated by the application