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

Em 27-09-2011 19:41, Laurent Pinchart escreveu:

Hi Mauro,

On Wednesday 28 September 2011 00:31:32 Mauro Carvalho Chehab wrote:

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Em 19-09-2011 12:31, Hiremath, Vaibhav escreveu:

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On Friday, September 16, 2011 6:36 PM Laurent Pinchart wrote: > >> On 

Friday 16 September 2011 15:00:53 Ravi, Deepthy wrote:

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On Thursday, September 08, 2011 10:51 PM Laurent Pinchart wrote:

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On Thursday 08 September 2011 15:35:22 Deepthy Ravi wrote:

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From: Vaibhav Hiremath <redacted>

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.

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.

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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.

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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.

No. Please see my reply to Vaibhav's e-mail. Standard selection should be done 
on the subdev pads, for the exact same reason why formats and selection 
rectangles are configured on subdev pads.

NACK. Let's not reinvent the wheel. the MC should not replace the V4L2 API.

Mauro.