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[media] V4L2 Spec: fix extended control documentation

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Update the spec to the behavior implemented by the control framework.
This should have been documented long ago but for some reason it was
never done.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil
2012-01-11 07:30:55 -03:00
committed by Mauro Carvalho Chehab
parent 047a01fdc8
commit 6055b12ae0
2 changed files with 13 additions and 26 deletions
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18
Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml
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@@ -183,7 +183,12 @@ applications must set the array to zero.</entry>
<entry>__u32</entry>
<entry><structfield>ctrl_class</structfield></entry>
<entry>The control class to which all controls belong, see
<xref linkend="ctrl-class" />.</entry>
<xref linkend="ctrl-class" />. Drivers that use a kernel framework for handling
controls will also accept a value of 0 here, meaning that the controls can
belong to any control class. Whether drivers support this can be tested by setting
<structfield>ctrl_class</structfield> to 0 and calling <constant>VIDIOC_TRY_EXT_CTRLS</constant>
with a <structfield>count</structfield> of 0. If that succeeds, then the driver
supports this feature.</entry>
</row>
<row>
<entry>__u32</entry>
@@ -194,10 +199,13 @@ also be zero.</entry>
<row>
<entry>__u32</entry>
<entry><structfield>error_idx</structfield></entry>
<entry>Set by the driver in case of an error. It is the
index of the control causing the error or equal to 'count' when the
error is not associated with a particular control. Undefined when the
ioctl returns 0 (success).</entry>
<entry>Set by the driver in case of an error. If it is equal
to <structfield>count</structfield>, then no actual changes were made to
controls. In other words, the error was not associated with setting a particular
control. If it is another value, then only the controls up to <structfield>error_idx-1</structfield>
were modified and control <structfield>error_idx</structfield> is the one that
caused the error. The <structfield>error_idx</structfield> value is undefined
if the ioctl returned 0 (success).</entry>
</row>
<row>
<entry>__u32</entry>