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Commit de8dd7b2 authored by Sakari Ailus's avatar Sakari Ailus Committed by Mauro Carvalho Chehab
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media: v4l: async: Remove re-probing support 



Remove V4L2 async re-probing support. The re-probing support has been
there to support cases where the sub-devices require resources provided by
the main driver's hardware to function, such as clocks.

Reprobing has allowed unbinding and again binding the main driver without
explicitly unbinding the sub-device drivers. This is certainly not a
common need, and the responsibility will be the user's going forward.

An alternative could have been to introduce notifier specific locks.
Considering the complexity of the re-probing and that it isn't really a
solution to a problem but a workaround, remove re-probing instead.

If there is a need to support the clock provider unregister/register cycle
while keeping the clock references in the consumers in the future, this
should be implemented in the clock framework instead, not in V4L2.

Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Acked-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: default avatarSebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: default avatarNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent f283c01b

drivers/media/v4l2-core/v4l2-async.c

+1 −53
Original line number Diff line number Diff line
@@ -198,78 +198,26 @@ EXPORT_SYMBOL(v4l2_async_notifier_register); 
void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)

{

	struct v4l2_subdev *sd, *tmp;

	unsigned int notif_n_subdev = notifier->num_subdevs;

	unsigned int n_subdev = min(notif_n_subdev, V4L2_MAX_SUBDEVS);

	struct device **dev;

	int i = 0;



	if (!notifier->v4l2_dev)

		return;



	dev = kvmalloc_array(n_subdev, sizeof(*dev), GFP_KERNEL);

	if (!dev) {

		dev_err(notifier->v4l2_dev->dev,

			"Failed to allocate device cache!\n");

	}



	mutex_lock(&list_lock);



	list_del(&notifier->list);



	list_for_each_entry_safe(sd, tmp, &notifier->done, async_list) {

		struct device *d;



		d = get_device(sd->dev);



		v4l2_async_cleanup(sd);



		/* If we handled USB devices, we'd have to lock the parent too */

		device_release_driver(d);



		if (notifier->unbind)

			notifier->unbind(notifier, sd, sd->asd);



		/*

		 * Store device at the device cache, in order to call

		 * put_device() on the final step

		 */

		if (dev)

			dev[i++] = d;

		else

			put_device(d);

		list_move(&sd->async_list, &subdev_list);

	}



	mutex_unlock(&list_lock);



	/*

	 * Call device_attach() to reprobe devices

	 *

	 * NOTE: If dev allocation fails, i is 0, and the whole loop won't be

	 * executed.

	 */

	while (i--) {

		struct device *d = dev[i];



		if (d && device_attach(d) < 0) {

			const char *name = "(none)";

			int lock = device_trylock(d);



			if (lock && d->driver)

				name = d->driver->name;

			dev_err(d, "Failed to re-probe to %s\n", name);

			if (lock)

				device_unlock(d);

		}

		put_device(d);

	}

	kvfree(dev);



	notifier->v4l2_dev = NULL;



	/*

	 * Don't care about the waiting list, it is initialised and populated

	 * upon notifier registration.

	 */

}

EXPORT_SYMBOL(v4l2_async_notifier_unregister);