On Tuesday, July 26, 2011 15:51:26 Sakari Ailus wrote: > On Tue, Jul 26, 2011 at 01:52:44PM +0200, Hans Verkuil wrote: > > On Tuesday, July 19, 2011 15:38:07 Sakari Ailus wrote: > > > Define a frame start event to tell user space when the reception of a frame > > > starts. > > > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxx> > > > --- > > > Documentation/DocBook/media/v4l/vidioc-dqevent.xml | 26 ++++++++++++++++++++ > > > .../DocBook/media/v4l/vidioc-subscribe-event.xml | 18 +++++++++++++ > > > include/linux/videodev2.h | 12 +++++++-- > > > 3 files changed, 53 insertions(+), 3 deletions(-) > > > > > > diff --git a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml > > > index 5200b68..d2cb8db 100644 > > > --- a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml > > > +++ b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml > > > @@ -88,6 +88,12 @@ > > > </row> > > > <row> > > > <entry></entry> > > > + <entry>&v4l2-event-frame-sync;</entry> > > > + <entry><structfield>frame</structfield></entry> > > > + <entry>Event data for event V4L2_EVENT_FRAME_START.</entry> > > > > The name of the struct and the event are not in sync (pardon the expression :-) ). > > > > Both should either be named FRAME_SYNC or FRAME_START. > > Should they be in sync? FRAME_START event is for frame start, not for other > purposes. Ah, you expect other events to reuse the same payload struct. I missed that part. > The buffer sequence number, however, could be used by other events, too. > This is directly related to the question of how to subscribe line-based > events. Albeit whether they are really ever needed is another question. > > Getting _one_ event giving frame synchronisation timestamps is important, > however; that's also why I sent the RFC. > > What I might do now is that we define a FRAME_SYNC (or FRAME_START) event > and specify the id == 0 always, and worry about the rest later on. It is > quite possible that line based events will never be needed. I would go for that. > If they are, then we must also specify how to subscribe them. Using 'id' as the line number seems sensible to me, but I would definitely leave that part out for now. I am not convinced it is possible to use that reliably in any case due to the difficult timing requirements. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
