On Mon, Sep 11, 2017 at 10:05:40AM +0200, Hans Verkuil wrote: > On 09/08/2017 03:18 PM, Sakari Ailus wrote: > > The information on how many async sub-devices would be bindable to a > > notifier is typically dependent on information from platform firmware and > > it's not driver's business to be aware of that. > > > > Many V4L2 main drivers are perfectly usable (and useful) without async > > sub-devices and so if there aren't any around, just proceed call the > > notifier's complete callback immediately without registering the notifier > > itself. > > > > If a driver needs to check whether there are async sub-devices available, > > it can be done by inspecting the notifier's num_subdevs field which tells > > the number of async sub-devices. > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > --- > > drivers/media/v4l2-core/v4l2-async.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c > > index 7b396ff4302b..9ebc2e079d03 100644 > > --- a/drivers/media/v4l2-core/v4l2-async.c > > +++ b/drivers/media/v4l2-core/v4l2-async.c > > @@ -170,10 +170,12 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, > > struct v4l2_async_subdev *asd; > > int i; > > > > - if (!v4l2_dev || !notifier->num_subdevs || > > - notifier->num_subdevs > V4L2_MAX_SUBDEVS) > > + if (!v4l2_dev || notifier->num_subdevs > V4L2_MAX_SUBDEVS) > > return -EINVAL; > > > > + if (!notifier->num_subdevs) > > + return v4l2_async_notifier_call_complete(notifier); > > + > > I would move this 'if' down to after the next three lines... > > > notifier->v4l2_dev = v4l2_dev; > > INIT_LIST_HEAD(¬ifier->waiting); > > INIT_LIST_HEAD(¬ifier->done); > > > > ...that way the notifier struct is properly initialized. Just in case anyone > ever looks at these three fields. Makes sense. Fixed. -- Sakari Ailus e-mail: sakari.ailus@xxxxxx
