Re: [Jack-Devel] Jack 1.9.7 on ARM crashes when killing a client

On Thu, Feb 17, 2011 at 02:01:06PM +0100, Robin Gareus wrote:
> 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.

i basically did this with tschack. using pyjackd this should be working.
not well tested, as i dont have an usb soundcard with me very often.

> 
> > 
> > Can you try is and report?
> > 
> > Thanks
> > 
> > Stéphane 
> > 
> > 
> > 
> > 
> > Jack-Devel mailing list
> > [hidden]
> > http://lists.jackaudio.org/listinfo.cgi/jack-devel-jackaudio.org

-- 
torben Hohn

1298028255.22873_0.ltw:2,a <20110218112357.GC3124 at siel dot b>