Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753161Ab0DLQ5T (ORCPT ); Mon, 12 Apr 2010 12:57:19 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:56763 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752886Ab0DLQ5R (ORCPT ); Mon, 12 Apr 2010 12:57:17 -0400 Date: Mon, 12 Apr 2010 12:57:16 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Andi Kleen cc: Daniel Mack , Pedro Ribeiro , , , Greg KH , , Subject: Re: USB transfer_buffer allocations on 64bit systems In-Reply-To: <20100412162947.GQ18855@one.firstfloor.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1440 Lines: 33 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-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/