[LAU] Using multiple audio interface on a UDOO board

Hi Everyone, I'm trying to use two audio interfaces (Guitar Link UC6102) in parallel in Alsa on a UDOO board that runs Ubuntu. The two interfaces are connected on the two USB 2.0 port available on the board: I'm not using any hub. In 20% of the cases, this works fine and I'm able to use the two interface as one single "virtual" interface with 4 inputs and 4 outputs (see my .asoundrc file bellow). However, in 80% of the cases, this doesn't work and dmesg says: "cannot submit datapipe for urb 0, error -28: not enough bandwidth". Any idea of where this problem comes from? I can use 4 of these interfaces on the same USB port with a hub on my laptop without any problem... Thanks for your help :) Cheers, Romain .asoundrc: pcm.myMAIN { type route; slave.pcm { type multi; slaves.a.pcm "myOUT0"; slaves.b.pcm "myOUT1"; slaves.a.channels 2; slaves.b.channels 2; bindings.0.slave a; bindings.0.channel 0; bindings.1.slave a; bindings.1.channel 1; bindings.2.slave b; bindings.2.channel 0; bindings.3.slave b; bindings.3.channel 1; } ttable.0.0 1; ttable.1.1 1; ttable.2.2 1; ttable.3.3 1; #ttable.0.2 1; # front left #ttable.1.3 1; # front right #ttable.0.4 1; # copy front left to rear left #ttable.1.5 1; # copy front right to rear right } ctl.myMAIN { type hw; card CODEC; } pcm.builtIn { type hw card vt1613audio } ctl.builtIn { type hw card vt1613audio } pcm.myOUT0 { type hw card CODEC } ctl.myOUT0 { type hw card CODEC } pcm.myOUT1 { type hw card CODEC_1 } ctl.myOUT1 { type hw card CODEC_1 } -- Romain Michon PhD Candidate Center for Computer Research in Music and Acoustics Stanford Universityhttp://ccrma.stanford.edu/~rmichon