hi! sorry for warming up an older thread here...
On 12/16/2010 04:21 AM, Lee Azzarello wrote: > Hello, I'm looking for some advice for an interesting symptom of > putting my M-Audio Fast Track Pro USB sound card into ALSA multi mode. > This sound card has four physical outputs which are mapped to two 2 > channel ALSA streams rather than one four channel stream. I used the > ALSA multi plugin to combine these two streams into a single pcm > device so JACK can interface with all four outputs. It is working > nicely. > > Despite no perceptible problems in sound quality or latency, jackd is > printing hundreds of XRUN callback warnings to the message console > each second! I can operate the system perfectly fine, run multiple > applications, connect them to the four virtual outputs with no audible > timing issues. > > What is the meaning of this many XRUN callbacks per second? What kind > of performance will this impact if not sound playback? i've just tried to link a hdspm (using faberman's driver) and an ancient digi9652 into a monster 90 channel device. my .asoundrc looks like this: pcm.multi { type multi; # the hdspm: first 64 channels slaves.a.pcm "hw:2,0"; slaves.a.channels 64; # the digi9652: last 26 channels slaves.b.pcm "hw:1,0"; slaves.b.channels 26; bindings.0.slave a; bindings.0.channel 0; ... bindings.63.slave a; bindings.63.channel 63; bindings.65.slave b; bindings.65.channel 0; ... bindings.90.slave b; bindings.90.channel 1; } ctl.multi { type hw; card 2; } the two cards are synced via wordclock at 48k, the hdspm is the master. miraculously enough, i can actually start jack with this device: 22:06:48.259 ALSA connection graph change. 22:06:48.393 ALSA connection change. 22:11:42.707 JACK is starting... 22:11:42.708 /usr/local/bin/jackd -P80 -p2048 -t9999 -u -dalsa -dmulti -r48000 -p1024 -n2 -zs Cannot connect to server socket err = Connection refused Cannot connect to server socket jack server is not running or cannot be started no message buffer overruns no message buffer overruns jackdmp 1.9.7 Copyright 2001-2005 Paul Davis and others. Copyright 2004-2010 Grame. jackdmp comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details JACK server starting in realtime mode with priority 80 22:11:42.844 JACK was started with PID=28260. creating alsa driver ... multi|multi|1024|2|48000|0|0|nomon|swmeter|-|32bit Using ALSA driver HDSPM running on card 2 - RME MADI S/N 0xc62105 at 0xf9ff0000, irq 19 configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 2 periods ALSA: final selected sample format for capture: 32bit integer little-endian ALSA: use 2 periods for capture ALSA: final selected sample format for playback: 32bit integer little-endian ALSA: use 2 periods for playback 22:11:45.082 JACK connection change. 22:11:45.220 Server configuration saved to "/home/nettings/.jackdrc". 22:11:45.222 Statistics reset. 22:11:45.238 Client activated. 22:11:45.341 XRUN callback (1). 22:11:45.341 JACK connection graph change. and like lee, i immediately get hundreds of "little xruns", i.e. the type that qjackctl displays in parentheses. the "big" xrun count stays at zero. meanwhile, i'm getting these errors in the log: JackPosixMutex::Unlock res = 1 JackPosixMutex::Unlock res = 1 JackPosixMutex::Unlock res = 1 i had it crash once when loading a really demanding session, but with another average ardour project, it has now played fine and without glitches for 10 minutes or so, while the xrun count goes through the roof. i wonder what's really going on here, but i'm also happy i can combine those two cards which means i finally get a Grand Unified interface without the need to restart jack, ever again :) best, jörn _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev