Re: [Jack-Devel] ARM JACK2 probs

>
> The issues you describe are likely not related to jack at all.
>
> Please try to play a long song with alsa's "aplay". ie confirm it's not
> a general USB or audio problem.
>

I shall try that on the Focusrite and Startech soon.

>
> My first guess would be power: The 2i4 is USB bus powered. Can your
> panda-board provide 500mA to the USB bus? Is the Phillips device also
> bus-powered? In either case it could explain the behavior (slight
> background noise, pops, unstable USB connection) that you're experiencing.
>

The Philips device is mains powered and I do not hear the popping sound
when I run JACK on it on a x86 machine (and there are no xruns) so this is
certainly not a power issue in the case of this device. Cadence reports 0
xruns yet the constant pop persists.


> Also try running with 3 periods of playback latency (-n option). e.g.
>   jackd -d alsa -p 1024 -n 3
> that helps with many USB devices. Try different period-sizes as well.
>

I've tried the optimal (made period 3) sizes and they all have the same
result. I know what values work well through having experimented with my
devices on x86.

>
> Check the output of 'dmesg' when jack disconnects. And also watch
> /proc/interrupts (does the audio-device share IRQ with other hardware?)
>
>
> Some other hints which -- are likely unrelated at this stage but -- can
> improve general jack performance (less x-runs at lower latencies) are
> apt-get install rtirq (setup IRQ priorities prefer audio-devices)
> and also try the Debian's rt-preemt realtime kernel...
>

Hmm, I wonder if they do such a kernel for ARM devices too? Prob not.

Thanks for the suggestions Robin!

>
> so long,
> robin
>
>
>

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