On Mon, 12 Apr 2010, Andi Kleen wrote: > On Mon, Apr 12, 2010 at 12:17:22PM -0400, Alan Stern wrote: > > 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 > > Hmm, thanks. But things must still go wrong somewhere, otherwise > the GFP_DMA32 wouldn't be needed? Indeed, something must go wrong somewhere. Since Daniel's patch fixed the problem by changing the buffer from a streaming mapping to a coherent mapping, it's logical to assume that bad DMA addresses have something to do with it. But we don't really know for certain. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
