This is actually a jack problem I think, but I haven’t had any responses on the jackit-devel list so I am trying here:
I have successfully used a Tascam US-122 for some years, but today it started producing crackly output when using JACK. I don’t think I have changed any settings since yesterday when it was working fine but obviously I must have missed something. No xruns or other snags are reported by jack, however it does seem to segfault when stopping:
My kernel is linux-2.6.21-gentoo on AMD64 so I don't have full realtime, just desktop preemption. This lack has never affected me before, but I am unable to get rt-sources to boot to test further.
jackd: segfault at 00000000000003dc rip 0002b35aa410071 rsp 00007fff006a8e90 error 4
Diagnostics thus far:
- Tascam output is perfectly fine under plain ALSA, so the card isn’t broken.
- My other sound card in this machine (SB Live) is fine under JACK.
- I have tried various settings from massively low latency (128 frames) to very high. Under 4 periods at 2048 frames the crackle became a major stutter but otherwise the usual crackle persists.
- The problem occurs running as root as well as a normal user. The same issue strikes using ardour and audacious with jack output.
/usr/bin/jackd -R -P80 -p128 -dalsa -dhw:1 -r44100 -p512 -n3 -i2 -o2 -HCan anyone suggest where I might look to resolve this one?
Copyright 2001-2005 Paul Davis and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK compiled with System V SHM support.
loading driver …
apparent rate = 44100
creating alsa driver … hw:1|hw:1|512|3|44100|2|2|hwmon|swmeter|-|32bit
control device hw:1
configuring for 44100Hz, period = 512 frames, buffer = 3 periods
ALSA: final selected sample format for capture: 24bit little-endian
ALSA: use 3 periods for capture
ALSA: final selected sample format for playback: 24bit little-endian
ALSA: use 3 periods for playback