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| author |   Ricardo Ribalda <ricardo.ribalda@gmail.com> | 2015-10-29 08:10:32 -0200 |
|---|---|---|
| committer |   Mauro Carvalho Chehab <mchehab@osg.samsung.com> | 2015-11-17 14:48:14 -0200 |
| commit | 5d273c7513ed1cd39611b037378a73295bd11a7a (patch) | |
| tree | e679f005180a05a34bec755cd7f93a64795fa41a /Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml | |
| parent | [media] media/usb/pvrusb2: Support for V4L2_CTRL_WHICH_DEF_VAL (diff) | |
| download | linux-dev-5d273c7513ed1cd39611b037378a73295bd11a7a.tar.xz linux-dev-5d273c7513ed1cd39611b037378a73295bd11a7a.zip | |
[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: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml index 47f9fee91442..eb82f7e7d06b 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-ext-ctrls.xml @@ -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 |