diff options
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml | 28 |
1 files changed, 25 insertions, 3 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml index 842536aae8b4..eb82f7e7d06b 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml @@ -61,7 +61,7 @@ must belong to the same control class.</para> <para>Applications must always fill in the <structfield>count</structfield>, -<structfield>ctrl_class</structfield>, +<structfield>which</structfield>, <structfield>controls</structfield> and <structfield>reserved</structfield> fields of &v4l2-ext-controls;, and initialize the &v4l2-ext-control; array pointed to by the @@ -109,7 +109,7 @@ the driver whether wrong values are automatically adjusted to a valid value or if an error is returned.</para> <para>When the <structfield>id</structfield> or -<structfield>ctrl_class</structfield> is invalid drivers return an +<structfield>which</structfield> is invalid drivers return an &EINVAL;. When the value is out of bounds drivers can choose to take the closest valid value or return an &ERANGE;, whatever seems more appropriate. In the first case the new value is set in @@ -223,7 +223,12 @@ Valid if <constant>V4L2_CTRL_FLAG_HAS_PAYLOAD</constant> is set for this control <tgroup cols="3"> &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 @@ -235,6 +240,23 @@ 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> <entry><structfield>count</structfield></entry> <entry>The number of controls in the controls array. May @@ -390,7 +412,7 @@ These controls are described in <xref linkend="rf-tuner-controls" />.</entry> <listitem> <para>The &v4l2-ext-control; <structfield>id</structfield> is invalid, the &v4l2-ext-controls; -<structfield>ctrl_class</structfield> is invalid, or the &v4l2-ext-control; +<structfield>which</structfield> is invalid, or the &v4l2-ext-control; <structfield>value</structfield> was inappropriate (e.g. the given menu index is not supported by the driver). This error code is also returned by the <constant>VIDIOC_S_EXT_CTRLS</constant> and |