On Sat, Jul 6, 2013 at 10:36 AM, James Stone <jamesmstone@xxxxxxxxx> wrote: > On Sat, Jul 6, 2013 at 9:57 AM, Clemens Ladisch <clemens@xxxxxxxxxx> wrote: >> Alan Stern wrote: >>> The first half is audio-out only. About 2 seconds after the start, the >>> audio-in stream starts up. After 2 URBs (2 ms) of data, everything >>> is shut down for no apparent reason -- there were no I/O errors. >>> [...] >>> I can't tell whether all these starts and stops are caused by JACK or >>> by the ALSA layer, let alone figure out the reason for them. >> >> Two URBs is the Jack buffer size, isn't it? Does Jack complain? >> >> James, pleasy try running aplay and arecord at the same time; something >> like this: >> >> aplay -D hw:x -t raw -c 4 -f S32_LE -r 44100 --period-size=128 --buffer-size=256 /dev/zero & >> arecord -D hw:x -c 2 -f S32_LE -r 44100 --period-size=128 --buffer-size=256 test.wav >> > > Yes - this works fine, without issue. (I assumed you wanted me to run these without jack running?) The output when I try to start jack with 128 frames/period is: /usr/bin/jackd -dalsa -r44100 -p128 -n2 -D -Chw:USB,0 -Phw:USB,0 -I512 -O512 -S jackdmp 1.9.9.5 Copyright 2001-2005 Paul Davis and others. Copyright 2004-2012 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 no message buffer overruns no message buffer overruns no message buffer overruns JACK server starting in realtime mode with priority 10 audio_reservation_init Acquire audio card Audio0 creating alsa driver ... hw:USB,0|hw:USB,0|128|2|44100|0|0|nomon|swmeter|-|16bit Using ALSA driver USB-Audio running on card 0 - Focusrite Scarlett 2i4 USB at usb-0000:00:12.2-3, high speed configuring for 44100Hz, period = 128 frames (2.9 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 ^CJack main caught signal 2 ..the device is unusable with the lights flashing on and off. Jack then shuts down as seen above. At 256 frames/period it starts OK. James -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
