Luis Garrido wrote: > So now I am throwing a powered USB hub in. As long as I keep it to > ALSA usage there is no problem: I can record and playback with, for > instance, Audacity using the ALSA backend. But anytime I try to launch > jackd the daemon fails and I get this in /var/log/messages: > > kernel: ALSA sound/usb/usbaudio.c:882: cannot submit datapipe for urb 0, > error -28: not enough bandwidth
The code in the EHCI driver that schedules full-speed audio packets is buggy, so using two audio streams at the same time often does not work. EHCI is used for all high-speed (USB 2.0) controllers, so to work around this, you could connect the device directly to the computer (without a hub) so that the full-speed (USB 1.x) UHCI/OHCI controller driver is used, or unload the ehci_hcd module so that the hub is forced to run at USB 1.x speed. (The rate-matching hub in the Intel P/Q/H 55/57 chipsets makes both workarounds impossible.) Regards, Clemens _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
