Re: [PATCH] V4L: add convenience macros to the subdevice / Media Controller API

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Hi Guennadi,

On Thursday 29 September 2011 10:44:14 Guennadi Liakhovetski wrote:
> On Thu, 29 Sep 2011, Laurent Pinchart wrote:
> > On Thursday 29 September 2011 10:18:31 Guennadi Liakhovetski wrote:
> > > Drivers, that can be built and work with and without
> > > CONFIG_VIDEO_V4L2_SUBDEV_API, need the v4l2_subdev_get_try_format() and
> > > v4l2_subdev_get_try_crop() functions, even though their return value
> > > should never be dereferenced. Also add convenience macros to init and
> > > clean up subdevice internal media entities.
> > 
> > Why don't you just make the drivers depend on
> > CONFIG_VIDEO_V4L2_SUBDEV_API ? They don't need to actually export a
> > device node to userspace, but they require the in-kernel API.
> 
> Why? Why should the user build and load all the media controller stuff,
> buy all the in-kernel objects and code to never actually use it? Where
> OTOH all is needed to avoid that is a couple of NOP macros?

Because the automatic compatibility layer that will translate video operations 
to pad operations will need to access pads, so subdevs that implement a pad-
level API need to export it to the bridge, even if the bridge is not MC-aware.

-- 
Regards,

Laurent Pinchart
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