[LAU] Jack conking out, How to debug?

[Jeremy Jongepier]

On 02/16/2011 08:27 PM, S. Massy wrote:
> Hello, all,
>
> So, thanks to the excellent advice received on this list, I recently
> purchased a Roland UA25EX and it works just great, and out of the box at
> that.
>
> Also thanks to this list, I now have my RT kernel sorted out, lean and
> mean as ever. All great!
>
> With my (crappy) internal sound interface, I used to be able to leave
> jack running for days at "-p128" without any problem, at least with my
> new kernel. With my new USB soundcard, however, jack works flawlessly
> for a few hours and then abruptly exits saying something to the effect
> that jack timed out and the watchdog is doing its painful duty.
>
> Here is my jack command-line:
> $ jackd -P61 -t100 -d alsa -d hw:2,0 -p128 -r 44100
>
> I tried adding "-v" for good measure and redirecting to a file, here's
> what it looks like before the downfall:
> -Couple 100K of boredom- [...]
> load = 0.2478 max usecs: 4.000, spare = 1447.000
> load = 0.2273 max usecs: 3.000, spare = 1448.000
> load = 0.2859 max usecs: 5.000, spare = 1446.000
> (and then tonnes of)
> **** alsa_pcm: xrun of at least 0.029 msecs
> **** alsa_pcm: xrun of at least 0.025 msecs
> **** alsa_pcm: xrun of at least 0.026 msecs
> **** alsa_pcm: xrun of at least 0.024 msecs
> ---and so forth until jackd gets killed.
>
> Does anyone know what the problem could be? Is something wrong with my
> jackd command-line? Is there anything further I can do to debug?
>
> Cheers,
> S.M.
>

Hello, what distro are you using? And did you also check your system 
logs to see if anything happened around that time? And try using -n 3, I 
think JACK uses 2 by default for the ALSA backend and the man page 
recommends a setting of 3 for USB cards.

Best,

Jeremy