Hi Yvan,
I'm using pure-dyne 9.11 (with kernel 2.6.31-9-rt)
and a Presonus Firebox.
For some reasons, I cannot use this FW soundcard with jack as I have *a
lot* of xruns (1 every 2 or 3 seconds).
Which firewire stack are you using?
http://www.ffado.org/?q=node/1316
Cheers!
Daniel