From owner-freebsd-current@FreeBSD.ORG Mon Jun 7 20:12:37 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id AFB8A16A4CE for ; Mon, 7 Jun 2004 20:12:37 +0000 (GMT) Received: from outbound0.sv.meer.net (outbound0.sv.meer.net [205.217.152.13]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5813943D53 for ; Mon, 7 Jun 2004 20:12:37 +0000 (GMT) (envelope-from jrhett@mail.meer.net) Received: from mail.meer.net (mail.meer.net [209.157.152.14]) i57KB5GO040787; Mon, 7 Jun 2004 13:11:06 -0700 (PDT) (envelope-from jrhett@mail.meer.net) Received: from mail.meer.net (localhost [127.0.0.1]) by mail.meer.net (8.12.1/8.12.2/meer) with ESMTP id i57KB4CT096533; Mon, 7 Jun 2004 13:11:04 -0700 (PDT) (envelope-from jrhett@mail.meer.net) Received: (from jrhett@localhost) by mail.meer.net (8.12.1/8.12.10) id i57KB4tw096526; Mon, 7 Jun 2004 13:11:04 -0700 (PDT) (envelope-from jrhett) Date: Mon, 7 Jun 2004 13:11:04 -0700 From: Joe Rhett To: Soren Schmidt Message-ID: <20040607201103.GA95679@meer.net> Mail-Followup-To: Soren Schmidt , freebsd-current@freebsd.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4i X-Mailman-Approved-At: Tue, 08 Jun 2004 12:16:11 +0000 cc: freebsd-current@freebsd.org Subject: major problem -- Bad CDs require system reboot? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Jun 2004 20:12:37 -0000 I just spent most of the last few days trying to diagnose and resolve a fairly major problem with FreeBSD that forced reboots. Here is the long and short of the deal. 1. FreeBSD assumes DMA access for hard drives, but assumes PIO access for ATAPI devices like CD-ROMs. Your notes say that this is because DMA access for CD-ROMs is broken too often. However, some CD-ROMs are actually broken in PIO mode but work great in DMA mode (like my Acer 50x unit) -- learned this through many reports regarding the unit under Windows To fix, I edited /boot/loader.conf and added hw.ata.atapi="1" 2. If you have a bad CD-ROM (or you are using broken PIO mode) you'll see failed BIG_READ errors. When this happens, the process accessing the drive will Zombie. You can't kill it, as it will show "D" locked status. You can't unmount the CD either. You'll be forced to reboot at this point. notes: this was nasty to diagnose because of the dual problems. I switched CDs several times and still had the problem so I ruled out it being the CD. Learned to switch DMA mode and still had the problem, but had had stopped swapping CDs at this point. Reburning the freebsd-10 install CD solved the problem after DMA mode was enabled. And yes, I went back and undid everything I did to confirm these issues before I brought it back to working mode. So in the end run, there are two issues: 1. Having a CD-ROM in PIO mode instead of DMA mode should not force a reboot. 2. Having a CD which burned incorrectly or has a scratch should not force a reboot. There must be some way to recover from this. And in particular, shouldn't the driver be able to deal with case #2 better? -- Joe Rhett Senior Systems Engineer Meer.net