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| author | Hans Verkuil <hans.verkuil@cisco.com> | 2011-06-18 06:58:29 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-07-27 17:53:34 -0300 |
| commit | e969084030b03f4997d63b3f718ba814290e0705 (patch) | |
| tree | 3f8e7f22c2318f9bd092d6b8d6f40f5d0d6c46fd /Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml | |
| parent | 1de7310ac9854101ecb9cdeed0f8bd5ac66cf55e (diff) | |
| download | op-kernel-dev-e969084030b03f4997d63b3f718ba814290e0705.zip op-kernel-dev-e969084030b03f4997d63b3f718ba814290e0705.tar.gz | |
[media] DocBook: update V4L Event Interface section
Starting with v3.1 the V4L2 API provides certain guarantees with respect to
events. Document these.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml index 975f603..039a969 100644 --- a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml +++ b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml @@ -100,7 +100,7 @@ <entry><constant>V4L2_EVENT_VSYNC</constant></entry> <entry>1</entry> <entry>This event is triggered on the vertical sync. - This event has &v4l2-event-vsync; associated with it. + This event has a &v4l2-event-vsync; associated with it. </entry> </row> <row> @@ -118,7 +118,7 @@ matches the control ID from which you want to receive events. This event is triggered if the control's value changes, if a button control is pressed or if the control's flags change. - This event has &v4l2-event-ctrl; associated with it. This struct + This event has a &v4l2-event-ctrl; associated with it. This struct contains much of the same information as &v4l2-queryctrl; and &v4l2-control;. @@ -126,6 +126,13 @@ &VIDIOC-S-EXT-CTRLS;, then the event will not be sent to the file handle that called the ioctl function. This prevents nasty feedback loops. + + This event type will ensure that no information is lost when + more events are raised than there is room internally. In that + case the &v4l2-event-ctrl; of the second-oldest event is kept, + but the <structfield>changes</structfield> field of the + second-oldest event is ORed with the <structfield>changes</structfield> + field of the oldest event. </entry> </row> <row> @@ -147,8 +154,8 @@ <entry>0x0001</entry> <entry>When this event is subscribed an initial event will be sent containing the current status. This only makes sense for events - that are triggered by a status change. Other events will ignore - this flag.</entry> + that are triggered by a status change such as <constant>V4L2_EVENT_CTRL</constant>. + Other events will ignore this flag.</entry> </row> </tbody> </tgroup> |
