linux-kernel - Re: [PATCH v3 06/22] media: Media Controller enable/disable source handler API

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20160310073500.GK11084@valkosipuli.retiisi.org.uk>
Date:	Thu, 10 Mar 2016 09:35:00 +0200
From:	Sakari Ailus <sakari.ailus@....fi>
To:	Shuah Khan <shuahkh@....samsung.com>
Cc:	mchehab@....samsung.com, tiwai@...e.com, clemens@...isch.de,
	hans.verkuil@...co.com, laurent.pinchart@...asonboard.com,
	sakari.ailus@...ux.intel.com, javier@....samsung.com,
	pawel@...iak.com, m.szyprowski@...sung.com,
	kyungmin.park@...sung.com, perex@...ex.cz, arnd@...db.de,
	dan.carpenter@...cle.com, tvboxspy@...il.com, crope@....fi,
	ruchandani.tina@...il.com, corbet@....net, chehabrafael@...il.com,
	k.kozlowski@...sung.com, stefanr@...6.in-berlin.de,
	inki.dae@...sung.com, jh1009.sung@...sung.com,
	elfring@...rs.sourceforge.net, prabhakar.csengg@...il.com,
	sw0312.kim@...sung.com, p.zabel@...gutronix.de,
	ricardo.ribalda@...il.com, labbott@...oraproject.org,
	pierre-louis.bossart@...ux.intel.com, ricard.wanderlof@...s.com,
	julian@...st.de, takamichiho@...il.com, dominic.sacre@....de,
	misterpib@...il.com, daniel@...que.org, gtmkramer@...all.nl,
	normalperson@...t.net, joe@...po.co.uk, linuxbugs@...tgam.net,
	johan@...ud.se, klock.android@...il.com, nenggun.kim@...sung.com,
	j.anaszewski@...sung.com, geliangtang@....com, albert@...tsing.nl,
	linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
	alsa-devel@...a-project.org
Subject: Re: [PATCH v3 06/22] media: Media Controller enable/disable source
 handler API

Hi Shuah,

On Thu, Feb 11, 2016 at 04:41:22PM -0700, Shuah Khan wrote:
> Add new fields to struct media_device to add enable_source, and
> disable_source handlers, and source_priv to stash driver private
> data that is used to run these handlers. The enable_source handler
> finds source entity for the passed in entity and checks if it is
> available. When link is found, it activates it. Disable source
> handler deactivates the link.
> 
> Bridge driver is expected to implement and set these handlers.
> 
> Signed-off-by: Shuah Khan <shuahkh@....samsung.com>
> ---
>  include/media/media-device.h | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/include/media/media-device.h b/include/media/media-device.h
> index 075a482..1a04644 100644
> --- a/include/media/media-device.h
> +++ b/include/media/media-device.h
> @@ -302,6 +302,11 @@ struct media_entity_notify {
>   * @entity_notify: List of registered entity_notify callbacks
>   * @lock:	Entities list lock
>   * @graph_mutex: Entities graph operation lock
> + *
> + * @source_priv: Driver Private data for enable/disable source handlers
> + * @enable_source: Enable Source Handler function pointer
> + * @disable_source: Disable Source Handler function pointer
> + *
>   * @link_notify: Link state change notification callback
>   *
>   * This structure represents an abstract high-level media device. It allows easy
> @@ -313,6 +318,26 @@ struct media_entity_notify {
>   *
>   * @model is a descriptive model name exported through sysfs. It doesn't have to
>   * be unique.
> + *
> + * @enable_source is a handler to find source entity for the
> + * sink entity  and activate the link between them if source
> + * entity is free. Drivers should call this handler before
> + * accessing the source.
> + *
> + * @disable_source is a handler to find source entity for the
> + * sink entity  and deactivate the link between them. Drivers
> + * should call this handler to release the source.
> + *

Is there a particular reason you're not simply (de)activating the link, but
instead add a new callback?

> + * Note: Bridge driver is expected to implement and set the
> + * handler when media_device is registered or when
> + * bridge driver finds the media_device during probe.
> + * Bridge driver sets source_priv with information
> + * necessary to run enable/disable source handlers.
> + *
> + * Use-case: find tuner entity connected to the decoder
> + * entity and check if it is available, and activate the
> + * the link between them from enable_source and deactivate
> + * from disable_source.
>   */
>  struct media_device {
>  	/* dev->driver_data points to this struct. */
> @@ -344,6 +369,11 @@ struct media_device {
>  	/* Serializes graph operations. */
>  	struct mutex graph_mutex;
>  
> +	void *source_priv;
> +	int (*enable_source)(struct media_entity *entity,
> +			     struct media_pipeline *pipe);
> +	void (*disable_source)(struct media_entity *entity);
> +
>  	int (*link_notify)(struct media_link *link, u32 flags,
>  			   unsigned int notification);
>  };

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus@....fi	XMPP: sailus@...iisi.org.uk