Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754406Ab0BBEY1 (ORCPT ); Mon, 1 Feb 2010 23:24:27 -0500 Received: from 124x34x33x190.ap124.ftth.ucom.ne.jp ([124.34.33.190]:39555 "EHLO master.linux-sh.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752927Ab0BBEYZ (ORCPT ); Mon, 1 Feb 2010 23:24:25 -0500 Date: Tue, 2 Feb 2010 13:24:02 +0900 From: Paul Mundt To: Alan Stern Cc: Catalin Marinas , Matthew Dharm , Sergei Shtylyov , Ming Lei , linux-usb@vger.kernel.org, linux-kernel , Sebastian Siewior , Greg KH Subject: Re: USB mass storage and ARM cache coherency Message-ID: <20100202042402.GJ13428@linux-sh.org> References: <1265045354.25750.52.camel@pc1117.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1518 Lines: 31 On Mon, Feb 01, 2010 at 03:14:04PM -0500, Alan Stern wrote: > On Mon, 1 Feb 2010, Catalin Marinas wrote: > > > On Fri, 2010-01-29 at 18:54 +0000, Matthew Dharm wrote: > > > HOWEVER, I firmly believe that the cache-management functions belong with > > > the driver that actually talks to the low-level hardware, as that's the > > > only place where you can be 100% certain of what cache operations are > > > needed. After all, I think someone is working on a USB-over-IP transport, > > > and trying to manage cache at the usb-storage level in that scenario is > > > just silly. > > > > > > So, let's put this in the HCD drivers and be done with it. > > > > The patch below is what fixes the I-D cache incoherency issues on ARM. I > > don't particularly like the solution but it seems to be the only one > > available. > > > > IMHO, Linux should have functions similar to the DMA API but for PIO > > drivers (e.g. pio_map_single/pio_unmap_single) that non-coherent > > architectures can define, otherwise being no-ops. Any thoughts? > > You should bring this up on the linux-arm-kernel mailing list and CC: > the ARM maintainer. They are the ones most directly affected. > No, this belongs on linux-arch, as it's something that impacts a lot of people besides ARM. -- 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/