From owner-freebsd-stable@FreeBSD.ORG Sat Sep 23 22:40:34 2006 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 32B8716A417 for ; Sat, 23 Sep 2006 22:40:34 +0000 (UTC) (envelope-from janm@transactionware.com) Received: from mail.transactionware.com (mail.transactionware.com [203.14.245.7]) by mx1.FreeBSD.org (Postfix) with SMTP id 60E2643D5F for ; Sat, 23 Sep 2006 22:40:26 +0000 (GMT) (envelope-from janm@transactionware.com) Received: (qmail 77695 invoked from network); 23 Sep 2006 22:40:45 -0000 Received: from new.transactionware.com (192.168.1.55) by dm.transactionware.com with SMTP; 23 Sep 2006 22:40:45 -0000 Received: (qmail 44254 invoked by uid 1026); 23 Sep 2006 22:40:45 -0000 Received: from 192.168.2.2 by new.transactionware.com (envelope-from , uid 1003) with qmail-scanner-1.25 (spamassassin: 3.0.2. Clear:RC:1(192.168.2.2):. Processed in 3.250679 secs); 23 Sep 2006 22:40:45 -0000 Received: from unknown (HELO transactzbkv04) (192.168.2.2) by new.transactionware.com with SMTP; 23 Sep 2006 22:40:41 -0000 From: "Jan Mikkelsen" To: "'Stefan Esser'" , "'Scott Long'" Date: Sun, 24 Sep 2006 08:40:34 +1000 Message-ID: <001701c6df61$48504640$0202a8c0@transactzbkv04> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2962 In-Reply-To: <4514206A.8030601@FreeBSD.org> Importance: Normal Cc: freebsd-stable@freebsd.org Subject: RE: Patch: sym(4) "VTOBUS FAILED" panics on amd64, amd64/89550 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 23 Sep 2006 22:40:34 -0000 Stefan Esser wrote: > I've been the co-author of the ncr SCSI driver, on which sym is based > (though not that particular code fragment). Since I know the structure > and principals of the driver (and since I have and know the docs up to > the 53c875, possibly also the 53c895), I'd probably be in a position > to work on this with the least effort to get started. Only problem is > that I do not have an amd64 system for testing ... >=20 > I changed the private allocator in the sym driver to use contigmalloc, > some time ago, but now I understand that there are stricter alignment > requirements. For a start, a work-around could be committed,=20 > IMHO (even > if it is ugly). The better approach is of course an extension=20 > of busdma > to support aligned physical chunks as required by the driver. >=20 > But I could also try to find a clean fix for the affected driver code. What are the "stricter alignment requirements" you have seen? The only = ones I have seen are those on virtual addresses caused by the buddy = allocator. Replacing that would remove the virtual address alignment requirements, unless I've missed something else. Are there special physical alignment requirements that the driver is not currently meeting? > Is the Symbios SCSI controller still used that much that the effort > required for a "clean" fix is well spent? This is a broader question. For my immediate purposes, my patch and = wasting a few pages gets a functional tape drive, which is a reasonable tradeoff = to me. I don't know how anyone else feels. This does seem to have been = broken on amd64 for a while and I haven't seen a large number of messages complaining. However: I needed an inexpensive SCSI controller for a machine, looked = at the supported hardware list, and bought a sym(4) controller. It didn't work. I think either the driver or the supported hardware list should = be fixed; my preference is the driver. Regards, Jan.