On Saturday, May 28, 2011 12:34:21 Sakari Ailus wrote:
> Hi Hans,
>
> On Wed, May 25, 2011 at 03:33:51PM +0200, Hans Verkuil wrote:
> > From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> >
> > Whenever a control changes value or state an event is sent to anyone
> > that subscribed to it.
> >
> > This functionality is useful for control panels but also for applications
> > that need to wait for (usually status) controls to change value.
>
> Thanks for the patch!
>
> I agree that it's good to pass more information of the control (min, max
> etc.) to the user space with the event. However, to support events arriving
> from interrupt context which we've discussed in the past, such information
> must be also accessible in those situations.
>
> What do you think about more fine-grained locking of controls, say, spinlock
> for each control (cluster) as an idea?
It's on my TODO list, but I need to think carefully on how to do it.
One thing at a time :-)
>
> > Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> > ---
> > drivers/media/video/v4l2-ctrls.c | 101 ++++++++++++++++++++++++++++++
> > drivers/media/video/v4l2-event.c | 126 +++++++++++++++++++++++++++-----------
> > drivers/media/video/v4l2-fh.c | 4 +-
> > include/linux/videodev2.h | 29 ++++++++-
> > include/media/v4l2-ctrls.h | 16 +++++-
> > include/media/v4l2-event.h | 2 +
> > 6 files changed, 237 insertions(+), 41 deletions(-)
> >
> > diff --git a/drivers/media/video/v4l2-ctrls.c b/drivers/media/video/v4l2-ctrls.c
> > index 3e0d8ab..e2a7ac7 100644
> > --- a/drivers/media/video/v4l2-ctrls.c
> > +++ b/drivers/media/video/v4l2-ctrls.c
> > @@ -23,6 +23,7 @@
> > #include <media/v4l2-ioctl.h>
> > #include <media/v4l2-device.h>
> > #include <media/v4l2-ctrls.h>
> > +#include <media/v4l2-event.h>
> > #include <media/v4l2-dev.h>
> >
> > #define call_op(master, op) \
> > @@ -540,6 +541,44 @@ static bool type_is_int(const struct v4l2_ctrl *ctrl)
> > }
> > }
> >
> > +static void fill_event(struct v4l2_event *ev, struct v4l2_ctrl *ctrl, u32 changes)
> > +{
> > + memset(ev->reserved, 0, sizeof(ev->reserved));
> > + ev->type = V4L2_EVENT_CTRL;
> > + ev->id = ctrl->id;
> > + ev->u.ctrl.changes = changes;
> > + ev->u.ctrl.type = ctrl->type;
> > + ev->u.ctrl.flags = ctrl->flags;
> > + if (ctrl->type == V4L2_CTRL_TYPE_STRING)
> > + ev->u.ctrl.value64 = 0;
> > + else
> > + ev->u.ctrl.value64 = ctrl->cur.val64;
> > + ev->u.ctrl.minimum = ctrl->minimum;
> > + ev->u.ctrl.maximum = ctrl->maximum;
> > + if (ctrl->type == V4L2_CTRL_TYPE_MENU)
> > + ev->u.ctrl.step = 1;
> > + else
> > + ev->u.ctrl.step = ctrl->step;
> > + ev->u.ctrl.default_value = ctrl->default_value;
> > +}
> > +
> > +static void send_event(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl, u32 changes)
> > +{
> > + struct v4l2_event ev;
> > + struct v4l2_ctrl_fh *pos;
> > +
> > + if (list_empty(&ctrl->fhs))
> > + return;
> > + fill_event(&ev, ctrl, changes);
> > +
> > + list_for_each_entry(pos, &ctrl->fhs, node) {
> > + if (pos->fh == fh)
> > + continue;
> > + ev.u.ctrl.flags = ctrl->flags;
>
> What's the purpose of setting flags here as well? fill_event() above already
> does it.
Oops, that's a left-over from a previous version. I'll remove it.
Regards,
Hans
>
> > + v4l2_event_queue_fh(pos->fh, &ev);
> > + }
> > +}
> > +
> > /* Helper function: copy the current control value back to the caller */
> > static int cur_to_user(struct v4l2_ext_control *c,
> > struct v4l2_ctrl *ctrl)
>
> Regards,
>
>
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