From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>,
Hans Verkuil <hverkuil@xs4all.nl>
Subject: Re: [PATCH v3 4/4] uvcvideo: add a metadata device node
Date: Fri, 30 Dec 2016 14:32:30 +0200 [thread overview]
Message-ID: <3119423.ZqlLJHYUgu@avalon> (raw)
In-Reply-To: <Pine.LNX.4.64.1612300938110.9905@axis700.grange>
Hi Guennadi,
On Friday 30 Dec 2016 11:43:02 Guennadi Liakhovetski wrote:
> Hi Laurent,
>
> I'd like to discuss extending this patch a bit, preferably as an
> incremental patch.
>
> First let me confirm my current understanding of the way the UVC driver
> creates its media device topology. Do I understand it correctly, that the
> driver allocates UVC entities (not media controller entities) for all UVC
> units and terminals, but then uses subdevices for all such UVC entities,
> except terminals, i.e. only for UVC units? struct uvc_entity has an
> embedded struct v4l2_subdev object, but it's unused for UVC terminals.
> Instead terminals are associated to video devices, which are then linked
> into the MC topology? Is this my understanding correct?
That's correct, but looking at the code now, I think the driver should use a
struct media_entity directly instead of a struct v4l2_subdev as it doesn't
need any of the infrastructure provided by subdevs.
> I have a problem with the current version of this patch, that there is no
> way to associate video device nodes with respepctive metadata nodes. Would
> it be acceptable to use an MC link for this association?
No, links describe data connections.
> Is it allowed for video device MC entities to have source pads additionally
> to their (usually single) sink pad(s) (in case of input video devices)? If
> that would be acceptable, I could create an additional patch to add a source
> pad to output terminal video nodes to link it to metadata nodes.
That's a hack, I don't think it's a good idea.
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2016-12-30 12:32 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-12 11:16 [PATCH v3 0/4] uvcvideo: metadata device node Guennadi Liakhovetski
2016-12-12 11:16 ` [PATCH v3 1/4] uvcvideo: (cosmetic) add and use an inline function Guennadi Liakhovetski
2016-12-30 13:28 ` Laurent Pinchart
2016-12-30 13:50 ` Guennadi Liakhovetski
2016-12-12 11:16 ` [PATCH v3 2/4] uvcvideo: (cosmetic) remove a superfluous assignment Guennadi Liakhovetski
2016-12-30 13:30 ` Laurent Pinchart
2016-12-12 11:16 ` [PATCH v3 3/4] uvcvideo: fix a wrong macro Guennadi Liakhovetski
2016-12-30 13:33 ` Laurent Pinchart
2016-12-12 11:16 ` [PATCH v3 4/4] uvcvideo: add a metadata device node Guennadi Liakhovetski
2016-12-12 17:31 ` kbuild test robot
2016-12-12 18:56 ` kbuild test robot
2016-12-12 19:32 ` kbuild test robot
2016-12-30 10:43 ` Guennadi Liakhovetski
2016-12-30 12:32 ` Laurent Pinchart [this message]
2016-12-30 13:04 ` Guennadi Liakhovetski
2016-12-30 13:20 ` Laurent Pinchart
2017-01-03 14:55 ` Guennadi Liakhovetski
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