On Mon, 12 Apr 2010, Andi Kleen wrote:
Well, the sound driver itself doesn't care for any of those things, just like any other USB driver doesn't. The USB core itself of the host controller driver should do, and as far as I can see, it does that, yes.
Hmm, still things must go wrong somewhere. Perhaps need some instrumentation to see if all the transfer buffers really hit the PCI mapping functions.
Such a test has already been carried out earlier in this thread:
http://marc.info/?l=linux-usb&m=127074587029353&w=2 http://marc.info/?l=linux-usb&m=127076841801051&w=2 http://marc.info/?l=linux-usb&m=127082890510415&w=2
It might be interesting to test if the device works with enabled IOMMU. That would trigger any failures to properly map the buffers earlier.
Alan Stern