From owner-freebsd-alpha Thu Mar 30 10:48:22 2000 Delivered-To: freebsd-alpha@freebsd.org Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by hub.freebsd.org (Postfix) with ESMTP id 632D537BF8D; Thu, 30 Mar 2000 10:48:16 -0800 (PST) (envelope-from gallatin@cs.duke.edu) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.9.3/8.9.3) with ESMTP id NAA04941; Thu, 30 Mar 2000 13:48:11 -0500 (EST) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.9.3/8.9.1) id NAA02113; Thu, 30 Mar 2000 13:47:41 -0500 (EST) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Thu, 30 Mar 2000 13:47:41 -0500 (EST) To: wilko@FreeBSD.ORG Cc: Dave Haney , freebsd-alpha@FreeBSD.ORG Subject: Re: Unexpected machine check In-Reply-To: <20000330201513.A1750@yedi.iaf.nl> References: <20000330201513.A1750@yedi.iaf.nl> X-Mailer: VM 6.43 under 20.4 "Emerald" XEmacs Lucid Message-ID: <14563.40742.553401.107502@grasshopper.cs.duke.edu> Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Wilko Bulte writes: > > There is definitely a bogon somewhere as far as X on Alpha goes. The problem > seems to be core logic chipset related, people fortunate enough to own > Tsunami based systems do not seem to have these problems. Also the type of > VGA chip seems to matter. I suspect the real problem is bugs in the X server & that's why some cards (Matrox, 3DLabs Permedia) work and others don't. The Tsunami chipset itself just masks bugs. Like a PC, writes to invalid I/O ports, etc are ignored & reads return -1. Such accesses will cause machine checks on all other alphas. If somebody was to go through the effort of building one of these failing X servers with symbols, the PC mentioned in the machine check would likely be the PC of the offending instruction. Or close to it. In fact, I wonder if we couldn't hack up a kernel to send a sigbus to the offending X server & get a core dump rather than panicing. Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message