Re: [PATCH v13 13/25] v4l: async: Allow async notifier register call succeed with no subdevs
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: 2017-09-19 12:04:43
Also in:
linux-media
Hi Sakari, Thank you for the patch. On Friday, 15 September 2017 17:17:12 EEST 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@linux.intel.com> Acked-by: Hans Verkuil <redacted>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
quoted hunk ↗ jump to hunk
--- drivers/media/v4l2-core/v4l2-async.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)diff --git a/drivers/media/v4l2-core/v4l2-async.cb/drivers/media/v4l2-core/v4l2-async.c index 9895b610e2a0..4be2f16af051 100644--- a/drivers/media/v4l2-core/v4l2-async.c +++ b/drivers/media/v4l2-core/v4l2-async.c@@ -170,14 +170,16 @@ 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; notifier->v4l2_dev = v4l2_dev; INIT_LIST_HEAD(¬ifier->waiting); INIT_LIST_HEAD(¬ifier->done); + if (!notifier->num_subdevs) + return v4l2_async_notifier_call_complete(notifier); + for (i = 0; i < notifier->num_subdevs; i++) { asd = notifier->subdevs[i];
-- Regards, Laurent Pinchart