Re: [GIT PATCH FOR 2.6.40] uvcvideo patches

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em 25-05-2011 20:43, Laurent Pinchart escreveu:

> Issues arise when devices have floating point registers. And yes, that 
> happens, I've learnt today about an I2C sensor with floating point registers 
> (in this specific case it should probably be put in the broken design 
> category, but it exists :-)).

Huh! Yeah, an I2C sensor with FP registers sound weird. We need more details
in order to address those.

>>> There's an industry trend there, and we need to think about solutions now
>>> otherwise we will be left without any way forward when too many devices
>>> will be impossible to support from kernelspace (OMAP4 is a good example
>>> there, some device drivers require communication with other cores, and
>>> the communication API is implemented in userspace).
>>
>> Needing to go to userspace to allow inter-core communication seems very
>> bad. I seriously doubt that this is a trend. It seems more like a
>> broken-by-design type of architecture.
> 
> I'm inclined to agree with you, but we should address these issues now, while 
> we have relatively few devices impacted by them. I fear that ignoring the 
> problem and hoping it will go away by itself will bring us to a difficult 
> position in the future. We should show the industry in which direction we 
> would like it to go.

I'm all about showing the industry in with direction we would like it to go.
We want that all Linux-supported architectures/sub-architectures support 
inter-core communications in kernelspace, in a more efficient way
that it would happen if such communication would happen in userspace.

Thanks,
Mauro.