Thanks for the quick reply! I'll try to answer these questions...
I assume you are using freebob and not ffado.
Yes.
Some things to check:
* are you running jackd with the realtime flag?
Yes, 'realtime' is ticked in the qjackctl settings.
* do you alleviate the priority of the ohci1394
interrupt above other
interrupt sources? (e.g. with the rtirq)
No. I tried messing with IRQ priorities a couple of days back, but I
didn't really know what I was doing and the only thing that happened was
the menu bars on my desktop would disappear randomly when I started jack,
I've reinstalled Ubuntu since then. Do you think it would help if I
installed rtirq?
* does dmesg show anything special regarding 1394?
$ dmesg|grep 1394
[ 12.564436] ohci1394: fw-host0: OHCI-1394 1.1 (PCI): IRQ=[19]
MMIO=[fe4ff000-fe4ff7ff] Max Packet=[2048] IR/IT contexts=[8/8]
[ 13.822759] ieee1394: Host added: ID:BUS[0-00:1023]
GUID[384fc00039a11470]
[ 13.829370] ieee1394: Node added: ID:BUS[0-01:1023]
GUID[000d6c0b00e0fb02]
[ 20.828189] ieee1394: raw1394: /dev/raw1394 device initialized
[ 20.835615] NOTE: The dv1394 driver is unsupported and may be removed
in a future Linux release. Use raw1394 instead.
$
* what firewire chipset do you use? (lspci | grep
1394)
$ lspci|grep 1394
03:01.4 FireWire (IEEE 1394): O2 Micro, Inc. Firewire (IEEE 1394) (rev 02)
$
* are you using -n3 (to specify the usage of 3 buffers
of one period)?
Normally I just start jackd with qjackctl. Just now I tried starting it in
the terminal with:
$ jackd -R -d freebob -n3
and it didn't make any difference to the sound.
I don't know if any of that is interesting...
Cheers,
Katie.