Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756750AbXHVHqY (ORCPT ); Wed, 22 Aug 2007 03:46:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754666AbXHVHqO (ORCPT ); Wed, 22 Aug 2007 03:46:14 -0400 Received: from netops-testserver-4-out.sgi.com ([192.48.171.29]:55920 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751026AbXHVHqM (ORCPT ); Wed, 22 Aug 2007 03:46:12 -0400 Message-ID: <46CBE960.4090702@sgi.com> Date: Wed, 22 Aug 2007 09:44:32 +0200 From: Jes Sorensen User-Agent: Thunderbird 2.0.0.0 (X11/20070719) MIME-Version: 1.0 To: Matthew Wilcox Cc: akepner@sgi.com, linux-kernel , rdreier@cisco.com, linux-ia64 Subject: Re: [PATCH 2/3] dma: override "dma_flags_set_dmaflush" for sn-ia64 References: <20070818002746.GU1813@sgi.com> <46C94FD5.6000006@sgi.com> <20070821193522.GD5592@sgi.com> <20070821201631.GF9163@parisc-linux.org> In-Reply-To: <20070821201631.GF9163@parisc-linux.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 722 Lines: 19 Matthew Wilcox wrote: > So, let me try to understand ... your hardware allows writes from the > device to pass other writes from the device? Doesn't that violate the > PCI spec? I'm thinking about this (page 43 of PCI 2.3): Hi Matthew, Yes I believe this behavior on sn2 is 'bending' the PCI spec a bit. The problem is that the NUMA fabric is a routed network in itself so there can be multiple paths between the device and the physical memory it DMAs to/from. Cheers, Jes - 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/