Dear ALSA developers,
my application needs to use multiple USB soundcards (based on standard cm-108 chipset) for I/O.
Seems to me that with recent kernels (after 2.6.21) this is almost impossible:
-if you use uhci_hcd it crashes with 4 running soundcards (cannot submit datapipe: not enough bandwidth) -if you use ehci_hcd it crashes way before (device resets)
With older kernels, at least uhci_hcd seems to work. This maybe is related to the reworking of the bandwidth management into the uhci_hcd introduced in 2.6.21.
I'm available to and I would be glad to help you ALSA developers with all the information possible: just tell me wich infos you need and I'll gather all the infos for you.
You can test the problem with: arecord -Dplughw:0 | aplay plughw:0 & arecord -Dplughw:1 | aplay plughw:1 & arecord -Dplughw:2 | aplay plughw:2 & arecord -Dplughw:3 | aplay plughw:3 &