Ok, perhaps the problem lies with real-time mode. ALSA has some flags
that let you open a stream in "real-time" mode, and we tell explicitly
tell PortAudio to do this if you're on Linux. (I think I made this
change between 1.6.0 and 1.6.1.) It's possible that the kernel (maybe
ALSA) has some sort of runaway process shutdown mechanism (like JACK's
watchdog) that's giving Mixxx the boot because we're using up too much
CPU time. That mechanism is probably only enabled when ALSA's in
real-time mode.

The attached patch should disable the use of ALSA's realtime mode in
Mixxx. If Owen or Jim could please test this and report back, it would
be greatly appreciated. If this fixes the problem, then I think some
of the nasty things we've done in our real-time callback code are
finally catching up with us, and we end up waiting/blocking on things
for too long. (Otherwise I don't understand why my C2D E8500 has this
problem. It's a fast CPU.) On the other hand, I don't understand why
neither Windows nor Mac OS X have this problem. I can push much lower
latencies on my 2.2 GHz Macbook with the same crappy onboard Intel HDA
chip than on my 3.0 GHz Linux box.

Thanks,
Albert

On Sat, Jun 27, 2009 at 6:33 AM, James Evans<[email protected]> wrote:
> Albert Santoni wrote:
>>
>> ... which is probably telling us that the bug isn't in Mixxx directly,
>> but that's moot since this bug will affect Mixxx (ALSA) users on
>> Ubuntu 8.10/9.04/9.10. Is there anyone who _hasn't_ seen Mixxx the
>> audio stop (ever) on Ubuntu 8.10+?
>>
>
> I was having no trouble with Intrepid (8.10) so the problem appears in
> Ububntu versions 9.04+.
>
> Jim.
>
>

Attachment: alsa-nort.patch
Description: Binary data

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