Date: Thu, 17 Feb 2000 17:22:43 -0500 (EST) From: Andy Smith <asmith@umdgrb.umd.edu> To: aic7xxx@FreeBSD.ORG Subject: Unknown Source of SCSI Bus Errors (fwd) Message-ID: <Pine.LNX.4.10.10002171656001.11535-100000@umdgrb.umd.edu>
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Hi, I sent the message below to the aic7xxx mailing list last week with no reply. Since then I have made more progress on understanding the problem, however I have no solution. The more I look, the more I am convinced that the problem is in software. For starters, I have updated my aic7xxx module to the latest version (5.1.26). This changed in no way the behavior of the computer. Then I went through each of the switches in the SCSI Select BIOS utility. I switched things that are by default disabled to enabled and vice versa. I found that if I turn off "Initiate Sync Negotiation", the SCSI bus and the disks work: No SCSI errors! The problems is that the disks are accessed in asynchronous mode at 20MB/s. As the mode is asynchronous, the actual speed of the disks is more like 10MB/s. (dd if=bigfile of=/dev/null bs=10000). Pretty pitiful for an ultra-wide bus connected to an array of ultra2 disks. The problem seems to be with synchronous data transfers, not termination as I suspected before. Any help? -Andy ---------- Forwarded message ---------- Date: Mon, 14 Feb 2000 09:25:37 -0500 (EST) From: Andy Smith <asmith@umdgrb.umd.edu> To: aic7xxx@FreeBSD.ORG Subject: Unknown Source of SCSI Bus Errors Hi, I have a problem which seems to be closely linked to the aic7xxx driver. I have a Dell Precision 410 with 2 500 MHz cpus running the smp version of the redhat 6.1 kernel (2.2.12-20smp). The motherboard has 2 imbeded scsi hosts, an AIC-7890/1 Ultra2 Controller and a AIC-7880 Ultra SCSI Controller. In Addition I have added an AHA-2940UW. Attached to the system I have an array of 8 SCSI disks the disks themselves are Ultra2 (SEAGATE Model: ST150176LC), but the enclosure only supports ultra-wide access. When I plug the array into the motherboard's AIC-7890 adaptor the disks are detected as "SE" devices and I can access them to my hearts delight at 40Mb/s. When the same disk array is attached to the card based AHA-2940UW controller or to a AHA-2940U2W controller that I have arround the office, continuous SCSI bus errors make the drives unusable. For a long time to assumed that the problem was due to hardware, but the problem is idendentical with the UW and U2W controllers. Then I thought that the prbolem might be due to a poor connection or cable, but I can use the SCSI Select BIOS configuration utility to "verify" the contents of the disk without errors. Finally I noticed the following in my /var/log/messages file: (scsi0) <Adaptec AHA-294X Ultra SCSI host found at PCI 14/0 (scsi0) Wide Channel, SCSI ID=7, 16/255 SCBs (scsi0) Warning - detected auto-termination (scsi0) Please verify driver detected settings are correct. (scsi0) If not, then please properly set the device termination (scsi0) in the Adaptec SCSI BIOS by hitting CTRL-A when prompted (scsi0) during machine bootup. (scsi0) Cables present (Int-50 NO, Int-68 NO, Ext-68 NO) (scsi0) Downloading sequencer code... 413 instructions downloaded (scsi1) <Adaptec AIC-7890/1 Ultra2 SCSI host adapter> found at PCI 10/0 (scsi1) Wide Channel, SCSI ID=7, 32/255 SCBs (scsi1) Downloading sequencer code... 374 instructions downloaded (scsi2) <Adaptec AIC-7880 Ultra SCSI host adapter> found at PCI 14/0 (scsi2) Wide Channel, SCSI ID=7, 16/255 SCBs (scsi2) Downloading sequencer code... 413 instructions downloaded The aic7xxx driver has detected that my AHA-2940UW has termination set to automatic. It doesn't like that. It is not clear to me why the driver cares about the termination, but it clearly does. I set the termination manually using SCSI Select to LOW:on and HIGH on and the warning goes away: (scsi0) <Adaptec AHA-294X Ultra SCSI host adapter> found at PCI 14/0 (scsi0) Wide Channel, SCSI ID=7, 16/255 SCBs (scsi0) Downloading sequencer code... 413 instructions downloaded Unfortunately, the SCSI bus works no better than before. I am out of ideas. I have a feeling that I am one switch away from the thing working, but I have no idea where to look for the solution. -Andy Smith (asmith@umdgrb.umd.edu) A few more details: the case is a Pacific Micro Data MAST 9500 configured with 8 disks on a single back plane and automatic termination. The disks are SEAGATE model ST150176LC 50Gb Ultra2 disks detected in the following manner (when connected to the AIC-7890 controller): (scsi1:0:0:0) Synchronous at 40.0 Mbyte/sec, offset 15. Vendor: SEAGATE Model: ST150176LC Rev: 0002 Type: Direct-Access ANSI SCSI revision: 02 Detected scsi disk sda at scsi1, channel 0, id 0, lun 0 (scsi1:0:1:0) Synchronous at 40.0 Mbyte/sec, offset 15. Vendor: SEAGATE Model: ST150176LC Rev: 0002 Type: Direct-Access ANSI SCSI revision: 02 Detected scsi disk sdb at scsi1, channel 0, id 1, lun 0 (scsi1:0:2:0) Synchronous at 40.0 Mbyte/sec, offset 15. Vendor: SEAGATE Model: ST150176LC Rev: 0002 Type: Direct-Access ANSI SCSI revision: 02 Detected scsi disk sdc at scsi1, channel 0, id 2, lun 0 (scsi1:0:3:0) Synchronous at 40.0 Mbyte/sec, offset 15. Vendor: SEAGATE Model: ST150176LC Rev: 0002 Type: Direct-Access ANSI SCSI revision: 02 Detected scsi disk sdd at scsi1, channel 0, id 3, lun 0 (scsi1:0:8:0) Synchronous at 40.0 Mbyte/sec, offset 15. Vendor: SEAGATE Model: ST150176LC Rev: 0002 Type: Direct-Access ANSI SCSI revision: 02 Detected scsi disk sde at scsi1, channel 0, id 8, lun 0 (scsi1:0:9:0) Synchronous at 40.0 Mbyte/sec, offset 15. Vendor: SEAGATE Model: ST150176LC Rev: 0002 Type: Direct-Access ANSI SCSI revision: 02 Detected scsi disk sdf at scsi1, channel 0, id 9, lun 0 (scsi1:0:10:0) Synchronous at 40.0 Mbyte/sec, offset 15. Vendor: SEAGATE Model: ST150176LC Rev: 0002 Type: Direct-Access ANSI SCSI revision: 02 Detected scsi disk sdg at scsi1, channel 0, id 10, lun 0 (scsi1:0:11:0) Synchronous at 40.0 Mbyte/sec, offset 15. Vendor: SEAGATE Model: ST150176LC Rev: 0002 Type: Direct-Access ANSI SCSI revision: 02 If it matters, the disks are configured as a raid-5 (7+1) software RAID array, and are not used for system files. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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