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Commit 5d273c75 authored by Ricardo Ribalda Delgado's avatar Ricardo Ribalda Delgado Committed by Mauro Carvalho Chehab
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[media] Docbook: media: Document changes on struct v4l2_ext_controls 



Vidioc-g-ext-ctrls can now be used to get the default value of the
controls.

Signed-off-by: default avatarRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent 082afb7c

Documentation/DocBook/media/v4l/v4l2.xml

+10 −0
Original line number Diff line number Diff line
@@ -151,6 +151,16 @@ Rubli, Andy Walls, Muralidharan Karicheri, Mauro Carvalho Chehab, 
structs, ioctls) must be noted in more detail in the history chapter

(compat.xml), along with the possible impact on existing drivers and

applications. -->

      <revision>

	<revnumber>4.5</revnumber>

	<date>2015-10-29</date>

	<authorinitials>rr</authorinitials>

	<revremark>Extend vidioc-g-ext-ctrls;. Replace ctrl_class with a new

union with ctrl_class and which. Which is used to select the current value of

the control or the default value.

	</revremark>

      </revision>



      <revision>

	<revnumber>4.4</revnumber>

	<date>2015-05-26</date>

Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml

+22 −0
Original line number Diff line number Diff line
@@ -224,6 +224,11 @@ Valid if <constant>V4L2_CTRL_FLAG_HAS_PAYLOAD</constant> is set for this control 
	&cs-str;

	<tbody valign="top">

	 <row>

	    <entry>union</entry>

	    <entry>(anonymous)</entry>

	  </row>

	  <row>

	    <entry></entry>

	    <entry>__u32</entry>

	    <entry><structfield>ctrl_class</structfield></entry>

	    <entry>The control class to which all controls belong, see
@@ -233,6 +238,23 @@ belong to any control class. Whether drivers support this can be tested by setti 
<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></entry>

	    <entry>__u32</entry>

	    <entry><structfield>which</structfield></entry>

	    <entry><para>Which value of the control to get/set/try. <constant>V4L2_CTRL_WHICH_CUR_VAL</constant>

will return the current value of the control and <constant>V4L2_CTRL_WHICH_DEF_VAL</constant> will

return the default value of the control. Please note that you can only get the default value of the

control, you cannot set or try it.</para>

<para>For backwards compatibility you can also use a control class here (see

<xref linkend="ctrl-class" />). In that case all controls have to belong to that

control class. This usage is deprecated, instead just use <constant>V4L2_CTRL_WHICH_CUR_VAL</constant>.

There are some very old drivers that do not yet support <constant>V4L2_CTRL_WHICH_CUR_VAL</constant>

and that require a control class here. You can test for such drivers by setting ctrl_class to

<constant>V4L2_CTRL_WHICH_CUR_VAL</constant> and calling VIDIOC_TRY_EXT_CTRLS with a count of 0.

If that fails, then the driver does not support <constant>V4L2_CTRL_WHICH_CUR_VAL</constant>.</para>

</entry>

	  </row>

	  <row>

	    <entry>__u32</entry>