[alsa-devel] USB transfer_buffer allocations on 64bit systems

Alan Stern stern at rowland.harvard.edu
Mon Apr 12 18:17:22 CEST 2010

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:


> 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

More information about the Alsa-devel mailing list