[media] DocBook: Mark CROPCAP as optional instead of as compulsory
While the documentation says that VIDIOC_CROPCAP is compulsory for all video capture and output devices, in practice VIDIOC_CROPCAP is only implemented for devices that can do cropping and/or scaling. Update the documentation to no longer require VIDIOC_CROPCAP if the driver does not support cropping or scaling or non-square pixels. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Sakari Ailus <sakari.ailus@iki.fi> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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@ -59,6 +59,9 @@ constant except when switching the video standard. Remember this
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switch can occur implicit when switching the video input or
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output.</para>
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<para>This ioctl must be implemented for video capture or output devices that
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support cropping and/or scaling and/or have non-square pixels, and for overlay devices.</para>
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<table pgwide="1" frame="none" id="v4l2-cropcap">
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<title>struct <structname>v4l2_cropcap</structname></title>
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<tgroup cols="3">
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@ -70,7 +73,9 @@ output.</para>
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<entry>Type of the data stream, set by the application.
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Only these types are valid here:
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<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>,
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<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> and
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<constant>V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE</constant>,
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<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>,
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<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant> and
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<constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>. See <xref linkend="v4l2-buf-type" />.</entry>
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</row>
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<row>
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@ -154,8 +159,7 @@ on 22 Oct 2002 subject "Re:[V4L][patches!] Re:v4l2/kernel-2.5" -->
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<term><errorcode>EINVAL</errorcode></term>
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<listitem>
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<para>The &v4l2-cropcap; <structfield>type</structfield> is
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invalid. This is not permitted for video capture, output and overlay devices,
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which must support <constant>VIDIOC_CROPCAP</constant>.</para>
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invalid.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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