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Date: Fri, 12 Aug 2011 11:11:12 +0100
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Mauro Carvalho Chehab <mchehab@infradead.org>
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Subject: Re: USB mini-summit at LinuxCon Vancouver
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> instead of using the V4L2 device node to access the stored images, it probably makes 
> more sense to use a separate device for that, that will handle a separate set of 
> ioctl's, and just use read() to retrieve the image data, after selecting the desired
> image number, via ioctl().

How will you handle the permission model, what about devices where you
need the V4L2 controls to take the picture in the first place ?

It seems it should really be the same device and just a minor tweak to
the API. V4L2 already provides frame reading and mapping functionality
and the media layer provides post processing services which I could
conceive some setups needing to use.

gphoto would just open the v4l device ask for still image stuff and
discover it wasn't available.