diff options
| author | Hans Verkuil <hans.verkuil@cisco.com> | 2011-08-26 07:31:13 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-09-21 09:52:21 -0300 |
| commit | 74a45790861f659058e8f8b565d98e5a1fdd8440 (patch) | |
| tree | 753280699fda90996de8006469046876124bea0e /Documentation/DocBook/media/v4l/vidioc-queryctrl.xml | |
| parent | b57ce4179b502b3f481f7632da20aae3e488e31a (diff) | |
[media] videodev2.h: add V4L2_CTRL_FLAG_VOLATILE
Add a new VOLATILE control flag that is set for volatile controls.
That way applications know whether the value of the control is volatile
(i.e. can change continuously) or not.
Until now this was an internal property, but it is useful to know in
userspace as well.
A typical use case is the gain value when autogain is on. In that case the
hardware will continuously adjust the gain based various environmental
factors.
This patch just adds and documents the flag, it's not yet used.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-queryctrl.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-queryctrl.xml | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml index 677ea646c29f..0ac0057a51c4 100644 --- a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml +++ b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml @@ -406,6 +406,15 @@ flag is typically present for relative controls or action controls where writing a value will cause the device to carry out a given action (⪚ motor control) but no meaningful value can be returned.</entry> </row> + <row> + <entry><constant>V4L2_CTRL_FLAG_VOLATILE</constant></entry> + <entry>0x0080</entry> + <entry>This control is volatile, which means that the value of the control +changes continuously. A typical example would be the current gain value if the device +is in auto-gain mode. In such a case the hardware calculates the gain value based on +the lighting conditions which can change over time. Note that setting a new value for +a volatile control will have no effect. The new value will just be ignored.</entry> + </row> </tbody> </tgroup> </table> |