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Commit 45339d5b authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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[media] DocBook/media: Improve G_EDID specification 



When using VIDIOC_G_EDID there is a special case where start_blocks and
blocks are both set to 0. In that case the driver just has to set blocks to
the total number of available blocks and return 0.

Even though the drivers do this right and v4l2-compliance tests for it, it
turned out not to be documented in the spec. Fix this.

Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Reported-by: default avatarMats Randgaard <matrandg@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent e56f8ef0

Documentation/DocBook/media/v4l/vidioc-g-edid.xml

+7 −0
Original line number Diff line number Diff line
@@ -82,6 +82,13 @@ 
    <para>If blocks have to be retrieved from the sink, then this call will block until they

    have been read.</para>



    <para>If <structfield>start_block</structfield> and <structfield>blocks</structfield> are

    both set to 0 when <constant>VIDIOC_G_EDID</constant> is called, then the driver will

    set <structfield>blocks</structfield> to the total number of available EDID blocks

    and it will return 0 without copying any data. This is an easy way to discover how many

    EDID blocks there are. Note that if there are no EDID blocks available at all, then

    the driver will set <structfield>blocks</structfield> to 0 and it returns 0.</para>



    <para>To set the EDID blocks of a receiver the application has to fill in the <structfield>pad</structfield>,

    <structfield>blocks</structfield> and <structfield>edid</structfield> fields and set

    <structfield>start_block</structfield> to 0. It is not possible to set part of an EDID,