Re: [Workshop-2011] Media Subsystem Workshop 2011

[Jean-Francois Moine <moinejf@free.fr>]

On Thu, 04 Aug 2011 09:40:18 -0300
Mauro Carvalho Chehab <mchehab@redhat.com> wrote:

> > What we need for this is a simple API (new v4l ioctl's I guess) for the
> > stillcam mode of these dual mode cameras (stillcam + webcam). So that the
> > webcam drivers can grow code to also allow access to the stored pictures,
> > which were taken in standalone (iow not connected to usb) stillcam mode.
> > 
> > This API does not need to be terribly complex. AFAIK all of the currently
> > supported dual cam cameras don't have filenames only picture numbers,
> > so the API could consist of a simple, get highest picture nr, is picture
> > X present (some slots may contain deleted pictures), get picture X,
> > delete picture X, delete all API.  
> 
> That sounds to work. I would map it on a way close to the controls API
> (or like the DVB FE_[GET|SET]_PROPERTY API), as this would make easier to expand
> it in the future, if we start to see webcams with file names or other things
> like that.

I did not follow all the thread, but I was wondering about an other
solution: what about offering both USB mass storage and webcam accesses?

When a dual-mode webcam is plugged in, the driver creates two devices,
the video device /dev/videox and the volume /dev/sdx. When the webcam is
opened, the volume cannot be mounted. When the volume is mounted, the
webcam cannot be opened. There is no need for a specific API. As Mauro
said:

> For those, we may eventually need some sort of locking between
> the USB storage and V4L.

That's all. By where am I wrong?

-- 
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