From e969084030b03f4997d63b3f718ba814290e0705 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Sat, 18 Jun 2011 06:58:29 -0300 Subject: [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 Signed-off-by: Mauro Carvalho Chehab --- .../DocBook/media/v4l/vidioc-subscribe-event.xml | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml') 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 @@ V4L2_EVENT_VSYNC 1 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. @@ -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 changes field of the + second-oldest event is ORed with the changes + field of the oldest event. @@ -147,8 +154,8 @@ 0x0001 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. + that are triggered by a status change such as V4L2_EVENT_CTRL. + Other events will ignore this flag. -- cgit v1.1