On Monday 22 February 2010 23:47:49 Sakari Ailus wrote:
> >> +Drivers do not initialise events directly. The events are initialised
> >> +through v4l2_fh_init() if video_device->ioctl_ops->vidioc_subscribe_event
> >> is
> >> +non-NULL. This *MUST* be performed in the driver's
> >> +v4l2_file_operations->open() handler.
> >> +
> >> +Events are delivered to user space through the poll system call. The
> >> driver
> >> +can use v4l2_fh->events->wait wait_queue_head_t as the argument for
> >> +poll_wait().
> >> +
> >> +There are standard and private events. New standard events must use the
> >> +smallest available event type. The drivers must allocate their events
> >> +starting from base (V4L2_EVENT_PRIVATE_START + n * 1024) while individual
> >> +events start from base + 1.
> >
> > What do you mean with 'while individual events start from base + 1'? I still
> > don't understand that phrase.
>
> Will be "There are standard and private events. New standard events must
> use the smallest available event type. The drivers must allocate their
> events starting from base (V4L2_EVENT_PRIVATE_START + n * 1024) + 1." in
> the next one.
Ah, OK. But why '+ 1'? I don't really see a reason for that to be honest.
Am I missing something?
Regards,
Hans
--
Hans Verkuil - video4linux developer - sponsored by TANDBERG
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