From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:40300 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751366AbdJDVu6 (ORCPT ); Wed, 4 Oct 2017 17:50:58 -0400 From: Sakari Ailus To: linux-media@vger.kernel.org Cc: niklas.soderlund@ragnatech.se, maxime.ripard@free-electrons.com, hverkuil@xs4all.nl, laurent.pinchart@ideasonboard.com, pavel@ucw.cz, sre@kernel.org Subject: [PATCH v15 16/32] v4l: async: Allow async notifier register call succeed with no subdevs Date: Thu, 5 Oct 2017 00:50:35 +0300 Message-Id: <20171004215051.13385-17-sakari.ailus@linux.intel.com> In-Reply-To: <20171004215051.13385-1-sakari.ailus@linux.intel.com> References: <20171004215051.13385-1-sakari.ailus@linux.intel.com> Sender: linux-media-owner@vger.kernel.org List-ID: 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 Acked-by: Hans Verkuil --- drivers/media/v4l2-core/v4l2-async.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c index 46db85685894..1b536d68cedf 100644 --- a/drivers/media/v4l2-core/v4l2-async.c +++ b/drivers/media/v4l2-core/v4l2-async.c @@ -180,14 +180,22 @@ int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, int ret; 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) { + int ret; + + ret = v4l2_async_notifier_call_complete(notifier); + notifier->v4l2_dev = NULL; + + return ret; + } + for (i = 0; i < notifier->num_subdevs; i++) { asd = notifier->subdevs[i]; -- 2.11.0