From owner-freebsd-alpha Sun Jan 28 12:21:32 2001 Delivered-To: freebsd-alpha@freebsd.org Received: from netau1.alcanet.com.au (ntp.alcanet.com.au [203.62.196.27]) by hub.freebsd.org (Postfix) with ESMTP id 83E0437B400 for ; Sun, 28 Jan 2001 12:21:14 -0800 (PST) Received: from mfg1.cim.alcatel.com.au (mfg1.cim.alcatel.com.au [139.188.23.1]) by netau1.alcanet.com.au (8.9.3 (PHNE_22672)/8.9.3) with ESMTP id HAA02334 for ; Mon, 29 Jan 2001 07:20:59 +1100 (EDT) Received: from gsmx07.alcatel.com.au by cim.alcatel.com.au (PMDF V5.2-32 #37640) with ESMTP id <01JZGZ3U6QU88ZUU1E@cim.alcatel.com.au> for freebsd-alpha@freebsd.org; Mon, 29 Jan 2001 07:20:57 +1100 Received: (from jeremyp@localhost) by gsmx07.alcatel.com.au (8.11.1/8.11.1) id f0SKKuh61360 for freebsd-alpha@freebsd.org; Mon, 29 Jan 2001 07:20:56 +1100 (EST envelope-from jeremyp) Content-return: prohibited Date: Mon, 29 Jan 2001 07:20:55 +1100 From: Peter Jeremy Subject: Multia problems To: freebsd-alpha@freebsd.org Mail-followup-to: freebsd-alpha@freebsd.org Message-id: <20010129072055.X52423@gsmx07.alcatel.com.au> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-disposition: inline User-Agent: Mutt/1.2.5i Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org I have a Multia VX40 that is displaying normal `dodgy hardware' symptoms - specifically random segmentation violations whilst trying to make world. Having poked around, I've found that writing 0x0000000000000000/ 0xFFFFFFFFFFFFFFFF to alternate longs shows up the problem more reliably: Bits 27-31 (the top 5 bits of the low word) occasionally read as 0 instead of 1 (but never the opposite). Swapping the memory modules around does not affect the problem - which pretty well clears the RAM. Based on re-reading and cache-flushing, the problem seems to be the CPU reading the L2 (external) cache. The problem does not seem to occur using 0x5555555555555555/0xAAAAAAAAAAAAAAAA as a pattern. I've already replaced the (notorious) 74F623 and heat does not seem to be a problem. Does anyone have any suggestions on how to further narrow down my problem? Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message