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
 (&eg; 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>