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Date: Mon, 28 Jul 2014 00:22:59 +0200
From: Hans Verkuil <hverkuil@xs4all.nl>
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To: Nicolas Dufresne <nicolas.dufresne@collabora.com>
CC: Nicolas Dufresne <nicolas.dufresne@collabora.co.uk>,
	Philipp Zabel <philipp.zabel@gmail.com>,
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	Kamil Debski <k.debski@samsung.com>,
	Sascha Hauer <kernel@pengutronix.de>
Subject: Re: [PATCH 2/3] [media] coda: fix coda_g_selection
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On 07/27/2014 11:32 PM, Nicolas Dufresne wrote:
> Le dimanche 27 juillet 2014 à 20:21 +0200, Hans Verkuil a écrit :
>> If cropcap returns -EINVAL then that means that the current input or
>> output does
>> not support cropping (for input) or composing (for output). In that case the
>> pixel aspect ratio is undefined and you have no way to get hold of that information,
>> which is a bug in the V4L2 API.
>>
>> In the case of an m2m device you can safely assume that whatever the pixel aspect
>> is of the image you give to the m2m device, it will still be the same pixel
>> aspect when you get it back. In fact, I would say that if an m2m device returns
>> cropcap information, then the pixel aspect ratio information is most likely not
>> applicable to the device and will typically be 1:1.
>>
>> Pixel aspect ratio is only relevant if the video comes in or goes out to a physical
>> interface (sensor, video receiver/transmitter).
> 
> So far "not applicable" has been interpreted as not implemented /
> ENOTTY. Can't CODA just do that and we can close this subject ?

Yes, that might be the best solution. Just call v4l2_disable_ioctl for CROPCAP and
G/S_CROP, since none of them apply to the coda driver.

Regards,

	Hans