Re: [Jack-Devel] Jack 1.9.7 on ARM crashes when killing a client
On 02/14/2011 03:14 PM, Stéphane Letz wrote:
>>>>
>>>
>>> Since I cannot reproduce the original issue here on my Linux machine, I cannot go much further. To summarize:
>>>
>>> - when JACK2 in synchronous mode, the server does : blocking ALSA read (actually, wait + read), graph activation, wait for graph to complete, write ALSA.
>>>
>>> - when a client is killed, it may fail to correctly complete a cycle, before the server detect the client has been removed, and cleanup the graph. The server has a timeout to decide when the graph has really failed before trying to write back in ALSA. Since the server is late, ALSA backend issue a "ALSA: could not complete playback" error in alsa_driver_write. This is considered as a "non recoverable error" and the backend wrapping thread is just stopped.
>>>
>>> - how does JACK1 behave is a similar situation? I guess there is a "graph late" problem also? Is there a timeout to decide when the graph has really failed? why is the "ALSA: could not complete playback" error not triggered in this precise case?
>>
>> jack1 will be late too.
>> but jack1 does not try to write to the driver when the graph is late.
>> the next alsa wait will detect the xrun and recover.
>> so the next cycle, things should be fine again.
>>
>
>
> OK this makes sense, Valerio here a patch to test that does not write back in the backend if the "graph process" fails:
>
>
while you're at it: Would it be unreasonable to ask looking into
ignoring device disconnect? f.i. have jackd survive and not crash when
an interface (eg ALSA-USB) goes away.
No further action should be taken by JACK (well, maybe some hook-script
could be invoked or a d-bus command send); some 3rd party software could
issue d-bus commands to switch backends.
>
> Can you try is and report?
>
> Thanks
>
> Stéphane
>
>
>
>
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