Then try to pass implicit_fb=1 option to snd-usb-audio module. It's a new option that was added recently.
Takashi
Nice, that did the trick. there was a small glitch on first playback but I can not reproduce it now. Playback seems glitch-free now. I will test it with pulseaudio in the gui if I can. It's not quite easy to test, because the system locks up after a while with the new kernel and gnome 3. I will also test concurrent playback and recording, too. Thank you very much, that was a huge help!
Good to hear. If the implicit_fb option works, we can add a static quirk table entry easily. Just add IMPLICIT_FB_GENERIC_DEV() with the device ID to playback_implicit_fb_quirks[] table in sound/usb/implicit.c.
Takashi
Still having problems with the nouveau driver, so i couldn't thest this with pulseaudio. Recording with arecord works parallel to playing back with aplay. so here is my patch for implicit.c
diff --git a/sound/usb/implicit.c b/sound/usb/implicit.c index 386198b36b87..c729ff634b9d 100644 --- a/sound/usb/implicit.c +++ b/sound/usb/implicit.c @@ -46,6 +46,7 @@ static const struct snd_usb_implicit_fb_match playback_implicit_fb_quirks[] = { IMPLICIT_FB_GENERIC_DEV(0x0763, 0x2081), /* M-Audio FastTrack Ultra */ IMPLICIT_FB_GENERIC_DEV(0x0763, 0x2030), /* M-Audio Fast Track C400 */ IMPLICIT_FB_GENERIC_DEV(0x0763, 0x2031), /* M-Audio Fast Track C600 */ + IMPLICIT_FB_GENERIC_DEV(0x0499, 0x1509), /* Steinberg UR22 */
/* Fixed EP */ /* FIXME: check the availability of generic matching */