For information, I found some good news on Slashdot :
Preemptible Kernel Patch Accepted : http://slashdot.org/article.pl?sid=02/02/10/2216207&mode=thread
Linus Merges ALSA Into 2.5.4 : http://slashdot.org/articles/02/02/13/2227233.shtml?tid=106
nicolas