From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C585C54E4B for ; Mon, 11 May 2020 20:56:54 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1DAC5206D9 for ; Mon, 11 May 2020 20:56:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1DAC5206D9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sympatico.ca Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 64D006E58B; Mon, 11 May 2020 20:56:53 +0000 (UTC) Received: from mtlfep02.bell.net (belmont80srvr.owm.bell.net [184.150.200.80]) by gabe.freedesktop.org (Postfix) with ESMTPS id C951589DBA; Mon, 11 May 2020 20:56:51 +0000 (UTC) Received: from bell.net mtlfep02 184.150.200.30 by mtlfep02.bell.net with ESMTP id <20200511205650.TLGP3628.mtlfep02.bell.net@mtlspm01.bell.net>; Mon, 11 May 2020 16:56:50 -0400 Received: from [192.168.1.208] (really [70.49.140.223]) by mtlspm01.bell.net with ESMTP id <20200511205650.JAUU130487.mtlspm01.bell.net@[192.168.1.208]>; Mon, 11 May 2020 16:56:50 -0400 Date: Mon, 11 May 2020 16:56:48 -0400 From: Al Dunsmuir Message-ID: <1266714942.20200511165648@sympatico.ca> To: Dave Airlie , Alex Deucher Subject: Re: [RFC] Remove AGP support from Radeon/Nouveau/TTM In-Reply-To: References: <20200511171722.96576-1-christian.koenig@amd.com> <1815605280.20200511161440@sympatico.ca> MIME-Version: 1.0 X-CM-Analysis: v=2.3 cv=I5Mbu+og c=1 sm=1 tr=0 a=nyNe8J8XL+yB5u22Hc0alw==:117 a=nyNe8J8XL+yB5u22Hc0alw==:17 a=IkcTkHD0fZMA:10 a=sTwFKg_x9MkA:10 a=pGLkceISAAAA:8 a=k_m-kdumAAAA:8 a=MKYSiYnM_ShKeF4uUZ4A:9 a=QEXdDO2ut3YA:10 a=2aFmp3DG3lfw9CblUY6y:22 X-CM-Envelope: MS4wfIx70+UzrDIciCO0zrkfyt17Douf6fJwd69A/rgJ6esorF4fGqIvCGHQ7lKO4EppqyAUqESAU0JrhzQkfEaoFNXBJbn6aHQ+q3EsRzWGoBosFMY7v9gA UEAE/d0KHpQ5x+bxf5cuuFcBs8sWBH+nJDG34jHF52xVwwXHFMDt0SVuzk+yirLlwNeet9xFomoR3UM5Raf6Havft3P2YUekwWG8ucHMhnv5/nE2W8M/LLsy h+4rmFRXszaR/A5CnoukTR2o8ctzLgV9uH9EhAqDexdfc61dQvwUM4BptH9FjWlL X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?utf-8?Q?Christian_K=C3=B6nig?= , Maling list - DRI developers , amd-gfx list , nouveau Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hello Dave, On Monday, May 11, 2020, 4:43:01 PM, Dave Airlie wrote: > On Tue, 12 May 2020 at 06:28, Alex Deucher wrote: >> >> On Mon, May 11, 2020 at 4:22 PM Al Dunsmuir wrote: >> Note there is no loss of functionality here, at least on radeon >> hardware. It just comes down to which MMU gets used for access to >> system memory, the AGP MMU on the chipset or the MMU built into the >> GPU. On powerpc hardware, AGP has been particularly unstable, and AGP >> has been disabled by default on radeon on powerpc for years now. In >> fact, this will probably make older hardware more reliable as it takes >> AGP out of the equation. >> > From memory there is quite a loss in speed though, like pretty severe. > The radeon PCI GART has a single slot TLB, if memory serves. > I think this is going to be a hard sell at this stage, I'm guessing > users will crawl out of the woodwork, I'm sure with 2 hours after I'm > able to access the office, I can boot the 865 AGP box with an rv350 in > it on a modern distro. > Maybe we can find some way to compartmentalise AGP further? > Dave. Significantly reduced caching on memory accesses definitely sounds like something that would be noticeable and objectionable. I would speculate that this would also vary a lot across chipsets, depending on the capabilities of the PCI MMU vs the AGP MMU. In the end, it may be best to leave things as is, or as Dave suggested try to keep AGP in the picture. Nothing is ever simple, is it? Al _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel