Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 22 Oct 2002 05:38:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 22 Oct 2002 05:38:44 -0400 Received: from pc1-cwma1-5-cust42.swa.cable.ntl.com ([80.5.120.42]:49079 "EHLO irongate.swansea.linux.org.uk") by vger.kernel.org with ESMTP id ; Tue, 22 Oct 2002 05:38:43 -0400 Subject: Re: NatSemi Geode improvement From: Alan Cox To: Hiroshi Miura Cc: davej@suse.de, hpa@zytor.com, Linux Kernel Mailing List In-Reply-To: <20021022001248.3F70A117B00@triton2> References: <20021017171217.4749211782A@triton2> <1035209178.27318.118.camel@irongate.swansea.linux.org.uk> <20021022001248.3F70A117B00@triton2> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8 (1.0.8-10) Date: 22 Oct 2002 11:00:51 +0100 Message-Id: <1035280851.31917.29.camel@irongate.swansea.linux.org.uk> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 950 Lines: 27 On Tue, 2002-10-22 at 01:12, Hiroshi Miura wrote: > It means that mmio must map to over 1GB area or disable this feature. You need to think about bus mastering devices as well. With re-ordering enabled you may confuse bus master hardware by writing fields in the wrong order (as the PCI device sees it). This is not a big problem. On the winchip we avoid this by using locked operations at the end of each of the PCI DMA mapping functions. I think all that is needed is to also define CONFIG_X86_OOSTORE for a Geode target. The kernel will then generate lock; addl $0, 0(%%esp) to force write ordering where it might be essential, and if OOSTORE is defined we can safely turn on the speed up. - 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/