Re: [PATCH 4/8] ispvideo: Add support for G/S/ENUM_STD ioctl

[Gary Thomas]

On 2011-09-27 16:31, Mauro Carvalho Chehab wrote:
> Em 19-09-2011 12:31, Hiremath, Vaibhav escreveu:
> > > -----Original Message-----
> > > From: Laurent Pinchart [mailto:laurent.pinchart@xxxxxxxxxxxxxxxx]
> > > Sent: Friday, September 16, 2011 6:36 PM
> > > To: Ravi, Deepthy
> > > Cc: linux-media@xxxxxxxxxxxxxxx; tony@xxxxxxxxxxx; linux@xxxxxxxxxxxxxxxx;
> > > linux-omap@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-
> > > kernel@xxxxxxxxxxxxxxx; mchehab@xxxxxxxxxxxxx; g.liakhovetski@xxxxxx;
> > > Hiremath, Vaibhav
> > > Subject: Re: [PATCH 4/8] ispvideo: Add support for G/S/ENUM_STD ioctl
> > >
> > > Hi Deepthy,
> > >
> > > On Friday 16 September 2011 15:00:53 Ravi, Deepthy wrote:
> > > > On Thursday, September 08, 2011 10:51 PM Laurent Pinchart wrote:
> > > > > On Thursday 08 September 2011 15:35:22 Deepthy Ravi wrote:
> > > > > > From: Vaibhav Hiremath<hvaibhav@xxxxxx>
> > > > > >
> > > > > > In order to support TVP5146 (for that matter any video decoder),
> > > > > > it is important to support G/S/ENUM_STD ioctl on /dev/videoX
> > > > > > device node.
> > > > >
> > > > > Why so ? Shouldn't it be queried on the subdev output pad directly ?
> > > >
> > > > Because standard v4l2 application for analog devices will call these std
> > > > ioctls on the streaming device node. So it's done on /dev/video to make
> > > the
> > > > existing apllication work.
> > >
> > > Existing applications can't work with the OMAP3 ISP (and similar complex
> > > embedded devices) without userspace support anyway, either in the form of
> > > a
> > > GStreamer element or a libv4l plugin. I still believe that analog video
> > > standard operations should be added to the subdev pad operations and
> > > exposed
> > > through subdev device nodes, exactly as done with formats.
> > [Hiremath, Vaibhav] Laurent,
> >
> > I completely agree with your point that, existing application will not work without setting links properly.
> > But I believe the assumption here is, media-controller should set the links (along with pad formants) and
> > all existing application should work as is. Isn't it?
>
> Yes.
>
> > The way it is being done currently is, set the format at the pad level which is same as analog standard resolution and use existing application for streaming...
>
> Yes.
>
> > I am ok, if we add s/g/enum_std api support at sub-dev level but this should also be supported on streaming device node.
>
> Agreed. Standards selection should be done at device node, just like any other
> device.

So how do you handle a part like the TVP5150 that is standard agnostic?
That device can sense the standard from the input signal and sets the
result appropriately.

--
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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