Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 7 Dec 2001 14:04:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 7 Dec 2001 14:03:47 -0500 Received: from zmamail05.zma.compaq.com ([161.114.64.105]:59145 "EHLO zmamail05.zma.compaq.com") by vger.kernel.org with ESMTP id ; Fri, 7 Dec 2001 14:03:36 -0500 Date: Fri, 7 Dec 2001 13:50:31 -0500 From: Jay Estabrook To: Kurt Garloff , rth@twiddle.net, Ivan Kokshaysky , Linux kernel list , linux-alpha@vger.kernel.org Subject: Re: IDE DMA on AXP & barriers Message-ID: <20011207135031.A9962@linux04.mro.cpqcorp.net> In-Reply-To: <20011206061315.J13427@garloff.etpnet.phys.tue.nl> <20011206125935.A3930@jurassic.park.msu.ru> <20011207132505.B4229@garloff.etpnet.phys.tue.nl> <20011207170341.A9959@jurassic.park.msu.ru> <20011207154815.A14011@garloff.etpnet.phys.tue.nl> <20011207194347.A2718@jurassic.park.msu.ru> <20011207180214.D14011@garloff.etpnet.phys.tue.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20011207180214.D14011@garloff.etpnet.phys.tue.nl>; from garloff@suse.de on Fri, Dec 07, 2001 at 06:02:14PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 07, 2001 at 06:02:14PM +0100, Kurt Garloff wrote: > > > > How do I recognize the broken PYXIS in software? (Except for waiting for > > > your hard disk to be corrupted?) > > > > Put the chip into PCI loopback mode, read some memory (crossing the > > page boundary) via direct PCI window and check for corruption - > > perhaps this will work. > > I guess the manual will tell me how to do that ... You might be able to adapt/add to Richard's code that probes CIA/PYXIS to determine if workarounds (for other things :-) are needed. > That's why I'm looking for something better ... > But on a generic kernel, we have to do a number of things, then: > * Detect PYXIS > * Set into PCI loopback > * Do the cross 8k DMA read > * Set flag if corruption > > (And even this test is not completely perfect, as only devices on the > primary PCI bus seem to be affected.) Correct; if you put the problematic card/driver behind the bridge on MIATA (ie one of the 32-bit slots), the problems go away. No such luck on LX/SX, but they may have HW workarounds already implemented. > > Jay, your opinion? Perhaps you have the info which systems are affected? > > ... and how they can be identified. "Identification" may need to be done via "probe and see"... :-\ IIRC, there was only ever one rev of PYXIS, which has a number of problems. The first MIATAs went out with (nearly) no fixes, except for the console cruft to prevent "unknown" cards from being placed in the 64-bit slots (unkown cards == unknown drivers == possibly susceptible to the 8K boundary DMA error). LX and SX introduced off-chip PYXIS fixes, which fixed at least the 8K boundary DMA problem, and some others, but NOT all, most notably the PCI READ prefetch. Late MIATAs, aka MIATA-GL, have off-chip logic that fix ALL the PYXIS problems, AFAIK. These are distinguished from the earlier model by the presence of a QLogic ISP-1040C(?) SCSI chip built into the motherboard. --Jay++ ----------------------------------------------------------------------------- Jay A Estabrook Alpha Engineering - LINUX Project Compaq Computer Corp. - MRO1-2/K15 (508) 467-2080 200 Forest Street, Marlboro MA 01752 Jay.Estabrook@compaq.com ----------------------------------------------------------------------------- - 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/