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[media] media-device: split media initialization and registration

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The media device node is registered and so made visible to user-space
before entities are registered and links created which means that the
media graph obtained by user-space could be only partially enumerated
if that happens too early before all the graph has been created.

To avoid this race condition, split the media init and registration
in separate functions and only register the media device node when
all the pending subdevices have been registered, either explicitly
by the driver or asynchronously using v4l2_async_register_subdev().

The media_device_register() had a check for drivers not filling dev
and model fields but all drivers in mainline set them and not doing
it will be a driver bug so change the function return to void and
add a BUG_ON() for dev being NULL instead.

Also, add a media_device_cleanup() function that will destroy the
graph_mutex that is initialized in media_device_init().

[mchehab@osg.samsung.com: Fix compilation if !CONFIG_MEDIA_CONTROLLER
 and remove two warnings added by this changeset]
Suggested-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Javier Martinez Canillas
2015-12-11 20:57:08 -02:00
committed by Mauro Carvalho Chehab
parent 821ed36629
commit 9832e155f1
14 changed files with 158 additions and 99 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/media/platform/xilinx/xilinx-vipp.c
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@@ -311,7 +311,7 @@ static int xvip_graph_notify_complete(struct v4l2_async_notifier *notifier)
if (ret < 0)
dev_err(xdev->dev, "failed to register subdev nodes\n");
return ret;
return media_device_register(&xdev->media_dev);
}
static int xvip_graph_notify_bound(struct v4l2_async_notifier *notifier,
@@ -573,6 +573,7 @@ static void xvip_composite_v4l2_cleanup(struct xvip_composite_device *xdev)
{
v4l2_device_unregister(&xdev->v4l2_dev);
media_device_unregister(&xdev->media_dev);
media_device_cleanup(&xdev->media_dev);
}
static int xvip_composite_v4l2_init(struct xvip_composite_device *xdev)
@@ -584,19 +585,14 @@ static int xvip_composite_v4l2_init(struct xvip_composite_device *xdev)
sizeof(xdev->media_dev.model));
xdev->media_dev.hw_revision = 0;
ret = media_device_register(&xdev->media_dev);
if (ret < 0) {
dev_err(xdev->dev, "media device registration failed (%d)\n",
ret);
return ret;
}
media_device_init(&xdev->media_dev);
xdev->v4l2_dev.mdev = &xdev->media_dev;
ret = v4l2_device_register(xdev->dev, &xdev->v4l2_dev);
if (ret < 0) {
dev_err(xdev->dev, "V4L2 device registration failed (%d)\n",
ret);
media_device_unregister(&xdev->media_dev);
media_device_cleanup(&xdev->media_dev);
return ret;
}