userspace driver API ?

[John-Mark Gurney]

Dieter wrote this message on Sun, Jul 22, 2007 at 12:20 +0100:
> The penguins have developed a "stable" userspace driver
> API to allow "most" of a driver to be in userland.
> 
> http://liquidat.wordpress.com/2007/07/21/linux-kernel-2623-to-have-stable-userspace-driver-api/
> 
> No DMA (yet?).  Not for drivers requiring the highest
> possible performance.
> 
> It doesn't solve the problems of binary-only drivers.
> (security, fixing bugs, CPU arch, ...)
> 
> But if they did a reasonable job (and yes that's a significant if),
> it might be useful for many drivers.  Perhaps a way to share
> drivers between Linux, the BSDs, OS-X, OpenSolaris, ...
> 
> Thoughts?

I've been thinking about similar things for a while...   Though I have
a few concerns...

a) a stable API is something that Linus has touted as something that will
not happen for Linux, so yes, it's "stable" but can we truely depend
upon that?

b) w/o direct DMA, it's not as useful, and implementing direct DMA
isn't that difficult (I do direct DMA to userland buffers for bktrau
and cxd)...

c) I'm also interested in emulating a cdev from userland so that we
could do something like let userland code "emulate" V4L...

I looked at a few of the links, but I didn't see a good man page or
document describing how to interface w/ the code posted...

It does look insteresting...

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."