Re: [PATCH v6 6/8] [media] media: add messages when media device gets (un)registered

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Mauro,

Thank you for the patch.

On Wednesday 19 August 2015 08:01:53 Mauro Carvalho Chehab wrote:
> We can only free the media device after being sure that no
> graph object is used.

media_device_release() is currently broken as it should call back to the 
driver that has allocated the media_device() structure. I think we should fix 
that before adding more code on top of the problem.

> In order to help tracking it, let's add debug messages
> that will print when the media controller gets registered
> or unregistered.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
> 
> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
> index 065f6f08da37..0f3844470147 100644
> --- a/drivers/media/media-device.c
> +++ b/drivers/media/media-device.c
> @@ -359,6 +359,7 @@ static DEVICE_ATTR(model, S_IRUGO, show_model, NULL);
> 
>  static void media_device_release(struct media_devnode *mdev)
>  {
> +	dev_dbg(mdev->parent, "Media device released\n");

As commented on patch 7/8, ftrace is a better candidate for function tracing.

>  }
> 
>  /**
> @@ -397,6 +398,8 @@ int __must_check __media_device_register(struct
> media_device *mdev, return ret;
>  	}
> 
> +	dev_dbg(mdev->dev, "Media device registered\n");
> +
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(__media_device_register);
> @@ -416,6 +419,8 @@ void media_device_unregister(struct media_device *mdev)
> 
>  	device_remove_file(&mdev->devnode.dev, &dev_attr_model);
>  	media_devnode_unregister(&mdev->devnode);
> +
> +	dev_dbg(mdev->dev, "Media device unregistered\n");
>  }
>  EXPORT_SYMBOL_GPL(media_device_unregister);

-- 
Regards,

Laurent Pinchart