Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755593AbXJ2Tu1 (ORCPT ); Mon, 29 Oct 2007 15:50:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753213AbXJ2TuG (ORCPT ); Mon, 29 Oct 2007 15:50:06 -0400 Received: from mga03.intel.com ([143.182.124.21]:56667 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753316AbXJ2TuF (ORCPT ); Mon, 29 Oct 2007 15:50:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.21,343,1188802800"; d="scan'208";a="307935496" From: Jesse Barnes To: dri-devel@lists.sourceforge.net Subject: Re: [RFC] AGP initial support for chipset flushing.. Date: Mon, 29 Oct 2007 12:47:23 -0700 User-Agent: KMail/1.9.7 Cc: Dave Airlie , linux-kernel@vger.kernel.org, dri-devel@lists.sourceforge.net, keithp@keithp.com References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200710291247.24791.jesse.barnes@intel.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1418 Lines: 32 On Monday, October 29, 2007 1:15 am Dave Airlie wrote: > Hi, > > We've uncovered a need when using the new memory manager to flush the > chipset global write buffers on certain intel chipset due to a lack > of coherency.. > > The attached patches add a new AGP interface for this purpose and > implements this in the Intel AGP driver. This stuff is based of some > guesswork in the 915 case from comments in the documentation :). In this case, we're performing basically a dma_sync*(...DMA_TO_DEVICE) right? Can we be sure that a single flush is sufficient? Is there any window between when we flush and when we start accessing memory with the device that we could get into more caching trouble? > Unfortuantely the 965 BIOS doesn't set this stuff up properly and it > doesn't use a standard BAR address, so I have to do it by hand, I'd > appreciate any commentary particularly in the setting up of the > resource stuff. Looks reasonable, I'm not sure we can do much better. The only concern I have is that allocating some more PCI space like that may end up clobbering some *other* hidden BIOS mapping, but there's not a whole lot we can do about that. Jesse - 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/