Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934573AbZKYH50 (ORCPT ); Wed, 25 Nov 2009 02:57:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934084AbZKYH5Z (ORCPT ); Wed, 25 Nov 2009 02:57:25 -0500 Received: from sh.osrg.net ([192.16.179.4]:57351 "EHLO sh.osrg.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933842AbZKYH5Z (ORCPT ); Wed, 25 Nov 2009 02:57:25 -0500 Date: Wed, 25 Nov 2009 16:56:32 +0900 To: mingo@elte.hu Cc: fujita.tomonori@lab.ntt.co.jp, yinghai@kernel.org, hpa@zytor.com, tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: fix gart iommu using for amd 64 bit system From: FUJITA Tomonori In-Reply-To: <20091125072504.GA6568@elte.hu> References: <20091124152645.GD21821@elte.hu> <20091125085730S.fujita.tomonori@lab.ntt.co.jp> <20091125072504.GA6568@elte.hu> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20091125165601R.fujita.tomonori@lab.ntt.co.jp> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (sh.osrg.net [192.16.179.4]); Wed, 25 Nov 2009 16:56:32 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1734 Lines: 43 On Wed, 25 Nov 2009 08:25:04 +0100 Ingo Molnar wrote: > > * FUJITA Tomonori wrote: > > > On Tue, 24 Nov 2009 16:26:45 +0100 > > Ingo Molnar wrote: > > > > > > > > * FUJITA Tomonori wrote: > > > > > > > > don't think user will like to use SWIOTLB instead of swiotlb. > > > > > > > > I doubt that users care about a way to fix their problems. > > > > > > As far as swiotlb vs. GART goes, arguably a non-bouncing hw based > > > solution (GART) is superior to a bouncing one (swiotlb), right? > > > > Yeah, but GART is not a real IOMMU that always does address > > translation. If users want performance, they need 64bit DMA capable > > devices to skip GART. With such devices, GART and SWIOTLB are same. > > > > So this hacky GART workaround is useful for only people who use non > > 64bit DMA devices and broken BIOS with GART. IMO, it's not worth > > having the workaround. > > Well, what Yinghai is saying that for that (nonzero) subset of people > this change is a regression, and his patch fixes that. We dont do > regressions so this needs to be addressed. OK, I guess that I have to wait until nobody cares about GART. Anyway, my patch fixes his issue without any regression: http://marc.info/?l=linux-kernel&m=125907069703595&w=2 I'll post the second version of it after you merge the following fix: http://marc.info/?l=linux-kernel&m=125910650500523&w=2 Thanks, -- 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/