On Friday, June 03, 2011 21:55:10 Laurent Pinchart wrote:
> Hi Hans,
>
> Thanks for the patch.
>
> On Wednesday 25 May 2011 15:33:52 Hans Verkuil wrote:
> > From: Hans Verkuil <[email protected]>
> >
> > Signed-off-by: Hans Verkuil <[email protected]>
> > ---
> > drivers/media/video/v4l2-ctrls.c | 31 +++++++++++++++++++++++++++++++
> > include/media/v4l2-ctrls.h | 25 +++++++++++++++++++++++++
> > 2 files changed, 56 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/media/video/v4l2-ctrls.c
> > b/drivers/media/video/v4l2-ctrls.c index e2a7ac7..9807a20 100644
> > --- a/drivers/media/video/v4l2-ctrls.c
> > +++ b/drivers/media/video/v4l2-ctrls.c
> > @@ -831,6 +831,22 @@ int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler
> > *hdl, }
> > EXPORT_SYMBOL(v4l2_ctrl_handler_init);
> >
> > +/* Count the number of controls */
> > +unsigned v4l2_ctrl_handler_cnt(struct v4l2_ctrl_handler *hdl)
> > +{
> > + struct v4l2_ctrl_ref *ref;
> > + unsigned cnt = 0;
> > +
> > + if (hdl == NULL)
> > + return 0;
> > + mutex_lock(&hdl->lock);
> > + list_for_each_entry(ref, &hdl->ctrl_refs, node)
> > + cnt++;
>
> As you don't use the entry, you can replace list_for_each_entry with
> list_for_each.
True.
> Should the handler keep a controls count ? In that case you wouldn't need
> this
> function.
I'll look into this.
>
> > + mutex_unlock(&hdl->lock);
> > + return cnt;
> > +}
> > +EXPORT_SYMBOL(v4l2_ctrl_handler_cnt);
> > +
> > /* Free all controls and control refs */
> > void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
> > {
> > @@ -1999,3 +2015,18 @@ void v4l2_ctrl_del_fh(struct v4l2_ctrl *ctrl, struct
> > v4l2_fh *fh) v4l2_ctrl_unlock(ctrl);
> > }
> > EXPORT_SYMBOL(v4l2_ctrl_del_fh);
> > +
> > +int v4l2_ctrl_sub_fh(struct v4l2_fh *fh, struct v4l2_event_subscription
> > *sub, + unsigned n)
>
> I would rename this to v4l2_ctrl_subscribe_fh(). I had trouble understanding
> what v4l2_ctrl_sub_fh() before reading the documentation. sub makes me think
> about sub-devices and subtract, not subscription.
Good point.
> > +{
> > + int ret = 0;
> > +
> > + if (!fh->events)
> > + ret = v4l2_event_init(fh);
> > + if (!ret)
> > + ret = v4l2_event_alloc(fh, n);
> > + if (!ret)
> > + ret = v4l2_event_subscribe(fh, sub);
>
> I tend to return errors when they occur instead of continuing to the end of
> the function. Handling errors on the spot makes code easier to read in my
> opinion, as I expect the main code flow to be the error-free path.
Hmmm, I rather like the way the code looks in this particular case. But it;s
no big deal and I can change it.
Regards,
Hans
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