From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764131AbXLNWBg (ORCPT ); Fri, 14 Dec 2007 17:01:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756467AbXLNWBV (ORCPT ); Fri, 14 Dec 2007 17:01:21 -0500 Received: from mga11.intel.com ([192.55.52.93]:50127 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752862AbXLNWBU (ORCPT ); Fri, 14 Dec 2007 17:01:20 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.24,169,1196668800"; d="scan'208";a="238801929" Date: Fri, 14 Dec 2007 14:00:15 -0800 From: "Siddha, Suresh B" To: Dave Airlie Cc: venkatesh.pallipadi@intel.com, ak@muc.de, ebiederm@xmission.com, rdreier@cisco.com, torvalds@linux-foundation.org, gregkh@suse.de, davej@redhat.com, mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com, akpm@linux-foundation.org, arjan@infradead.org, jesse.barnes@intel.com, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 00/12] PAT 64b: PAT support for X86_64 Message-ID: <20071214220015.GD717@linux-os.sc.intel.com> References: <20071213235543.568682000@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 14, 2007 at 12:28:25AM +0000, Dave Airlie wrote: > Yes, the main use for GPUs is to have RAM pages mapped WC, and placed into > a GART on the GPU side, currently for Intel IGD we are okay as the CPU can > access the GPU GART aperture, but other chips exist where this isn't > possible, I think poulsbo and possible some of the AMD IGPs.. Ok. So how is it working today on these platforms with no PAT support. Open source drivers use UC or WB on these platforms? As this RAM is not contiguous, one can't use MTRRs to set WC. Right? Well, if WC is needed for RAM, then we have to address it too. thanks, suresh