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

Mauro Carvalho Chehab
2011-09-27T22:31:47Z

Em 19-09-2011 12:31, Hiremath, Vaibhav escreveu:
>
>> -----Original Message-----
>> From: Laurent Pinchart [mailto:laurent.pinchart@ideasonboard.com]
>> Sent: Friday, September 16, 2011 6:36 PM
>> To: Ravi, Deepthy
>> Cc: linux-media@vger.kernel.org; tony@atomide.com; linux@arm.linux.org.uk;
>> linux-omap@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-
>> kernel@vger.kernel.org; mchehab@infradead.org; g.liakhovetski@gmx.de;
>> 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@ti.com>
>>>>>
>>>>> 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.

Regards,
Mauro