Dear Takashi, please can you help me getting this issue started? I would like to go in deep and help solve this issue. Would you please tell me how to be useful? (which kind of info to gather, which people-mailing list to write to, etc.) Thanks in advance, Giovanni On Wed, Mar 11, 2009 at 8:08 PM, Giovanni Maruzzelli <gmaruzz.lists@xxxxxxxxx> wrote: > 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 & > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
