Hi Yvan,
I have libraw1394 version 2.0.4-1 and kernel
2.6.31-9-rt so I guess that
this is the 'old' firewire stack ?
It sounds like your distro uses the rt kernel from Karmic:
http://packages.ubuntu.com/karmic/linux-image-2.6.31-9-rt
If so, your ffado version is probably 2.0~rc2 which is a prerelease
version, and a year old now.
You might like to try building ffado 2.0.0 final, then if the problem
persists, report it via the ffado-user list:
https://lists.sourceforge.net/lists/listinfo/ffado-user
Cheers!
Daniel