From owner-freebsd-stable Sat Jun 17 8: 7:27 2000 Delivered-To: freebsd-stable@freebsd.org Received: from point.osg.gov.bc.ca (point.osg.gov.bc.ca [142.32.102.44]) by hub.freebsd.org (Postfix) with ESMTP id 8F4BA37B646 for ; Sat, 17 Jun 2000 08:07:23 -0700 (PDT) (envelope-from Cy.Schubert@uumail.gov.bc.ca) Received: (from daemon@localhost) by point.osg.gov.bc.ca (8.8.7/8.8.8) id IAA00670 for ; Sat, 17 Jun 2000 08:07:23 -0700 Received: from passer.osg.gov.bc.ca(142.32.110.29) via SMTP by point.osg.gov.bc.ca, id smtpda00668; Sat Jun 17 08:07:15 2000 Received: (from uucp@localhost) by passer.osg.gov.bc.ca (8.9.3/8.9.1) id IAA78883 for ; Sat, 17 Jun 2000 08:07:15 -0700 (PDT) Received: from cwsys9.cwsent.com(10.2.2.1), claiming to be "cwsys.cwsent.com" via SMTP by passer9.cwsent.com, id smtpdB78881; Sat Jun 17 08:06:55 2000 Received: (from uucp@localhost) by cwsys.cwsent.com (8.10.2/8.9.1) id e5HF6sg00904 for ; Sat, 17 Jun 2000 08:06:54 -0700 (PDT) Message-Id: <200006171506.e5HF6sg00904@cwsys.cwsent.com> Received: from localhost.cwsent.com(127.0.0.1), claiming to be "cwsys" via SMTP by localhost.cwsent.com, id smtpdprJ897; Sat Jun 17 08:06:22 2000 X-Mailer: exmh version 2.1.1 10/15/1999 Reply-To: Cy Schubert - ITSD Open Systems Group From: Cy Schubert - ITSD Open Systems Group X-OS: FreeBSD 4.0-STABLE X-Sender: cy To: freebsd-stable@freebsd.org Subject: ATA DMA Problem Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sat, 17 Jun 2000 08:06:22 -0700 Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG I've discovered an interesting problem as follows: Jun 17 05:16:59 cwsys /kernel: ad2: HARD READ ERROR blk# 4999424ata1-master: WAR NING: WAIT_READY active=ATA_ACTIVE_ATA Jun 17 05:16:59 cwsys /kernel: ad2: DMA problem fallback to PIO mode Jun 17 05:16:59 cwsys last message repeated 15 times The IDE devices attached to the system are: Jun 17 07:06:31 cwsys /kernel: ata0: at 0x1f0 irq 14 on atapci0 Jun 17 07:06:31 cwsys /kernel: ata1: at 0x170 irq 15 on atapci0 Jun 17 07:06:32 cwsys /kernel: ad0: 2014MB [4092/16/63] at ata0-m aster using WDMA2 Jun 17 07:06:32 cwsys /kernel: ad2: 2441MB [4960/16/63] at ata1-m aster using WDMA2 At first glance it looks like a bad block on disk. However, the errors only occur when running: dd if=/dev/ad0 of=/dev/null bs=1024k After running the Western Digital wddiag scan three times, without indication of error, and running: dd if=/dev/ad0 of=/dev/null (notice no bs=1024k) ... also without error. ... and running the dd with bs=1024k a number of times subsequent to this, the above error can be repeated 100% of the time when dd is run with bs=1024k specified. (Just a hunch but bs=64k would probably not cause the error -- will have to test that theory out). Otherwise the system and disk have been running nicely, so this is not a major issue. It is an interesting problem of which I don't have too much data collected and therefore feel awkward submitting a PR regarding this. I suspect one of the following: 1. Possible heat problem, bs=1024k probably drives the disk harder than the default bs=512. Interestingly, 3.4 didn't experience this problem. Maybe 4.0's new ATA driver is more efficient, driving the disk harder and causing the disk's controller board to run a little hotter than it did under 3.4. (most) 2. Possible disk/controller/DMA timing issue, e.g. hardware problem excluding HDA failure. 3. Possible FreeBSD ATA/DMA driver bug. (least) I'm running 4.0S as of May 27. Any comments would be welcome. Regards, Phone: (250)387-8437 Cy Schubert Fax: (250)387-5766 Team Leader, Sun/DEC Team Internet: Cy.Schubert@osg.gov.bc.ca Open Systems Group, ITSD, ISTA Province of BC To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message