Userspace Device Driver

[Klaus Zimmermann <klaus_zimmermann@gmx.de>]

Greetings List,

on various places on the alsa site I read about the possibility of
writing a userspace device driver.
I am interested thatin, since I have a nice Edirol FA-66 ieee1394
interface which works nicely under jack with the ffado
(http://ffado.org , former freebob) driver. 

>From what I read it seems I could either write an external plugin to the
alsa-lib, which would be truly userspace and fine except I it would
always have to be configured from .asoundrc and would probably not be
found by legacy programs like ekiga.

Or I could get really messy and have a userspace daemon relay audio data
between the ffado library, i.e. librawieee1394, and a yet to be written
alsa-driver module.
This would at least yield the advantage, that the driver was
indistinguishable from a true hardware driver.

So: Is it possible to write a userspace driver that is indistinguishable
from a hardware driver?

TIA
Klaus Zimmermann

P.S.: I am aware of the jackplug plugin. However even with very
conservative buffer settings I get underruns and x-runs quickly leading
to a failing jack :(