Date: Thu, 19 Jul 2001 22:05:18 -0500 From: Mike Meyer <mwm@mired.org> To: "Danny Yoo" <danny@vkpc.com> Cc: questions@freebsd.org Subject: Re: Illegal cable configuration?? (SCSI, new install of FreeBSD) Message-ID: <15191.40942.174740.826610@guru.mired.org> In-Reply-To: <84311862@toto.iv>
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Danny Yoo <danny@vkpc.com> types: > I'm trying to set up FreeBSD 4.3-RELEASE on an old IBM PC Server 330 > (Pentium Pro 200). It's got an on-board Adaptec 7880 SCSI controller, and > I've only got two SCSI devices inside: a Quantum HD and an IBM CD-ROM. > > My problem is that when the system boots up with mfsroot.flp (boot disk #2) > AFTER the kernel configuration, I get a message akin to: > > ahc0: Illegal cable configuration!! Only two connectors on the adapter may > be used at a time! > > And then a few lines later it hangs at: "Waiting 15 seconds for SCSI devices > to settle" > > Now, the system is currently running Corel Linux just fine; I can access the > HD and CD-ROM without a hitch. I'm _pretty_ sure that the SCSI connections > are properly terminated (this is my first time using a SCSI system)... I say > that solely based on the fact that Corel works just fine. I'd assume that an > ill-configured SCSI system would create noticeable problems right away? That assumption is in general wrong. While some problems - two devices on the same id, for instance - show up right away, some problems tend to require stressing the bus to reveal themselves. The more subtle the problem, the more you have to stress them to bring it out. I had a system that was working fine until I built and installed a world that included some performance enhancements to the SCSI drivers. After that, the SCSI bus would lock up trying to build the world. The problem was that one of the SCSI buses was just slightly to long, but it took a "make buildworld" on the system with the enhancements to put enough traffic on the bus to trigger it. Moving an external device to a shorter internal bus solved the problem. FreeBSD tends to load systems more than other OS's, so it's not uncommon for a hardware problem to show up under FreeBSD but not other OSs. This is as true for SCSI hardware as anything else in the system. The best way to avoid SCSI problems is to sacrifice one farm animal a month to the SCSI gods during the dark of the moon. > I'm not sure what the system means by: "Only two connectors on the adapter > may be used at a time!" The external connector isn't used and the external > termination jumper is set (I've tried it in both positions); only the > internal connector cable is used which connects first to the HD then to the > CD-ROM. I've tried reversing the order, I've tried disconnecting the CD-ROM > from the system to no avail. It's not unusual for a SCSI controller to have three connectors: one external, one internal for 50 pin, and one internal for 68 pin. Having all three in use at once violates the SCSI calbe spec. That's what you're being warned about. > I've looked through the BIOS for "auto-termination/hardware-termination" > options (suggested in an archive posting) but my system apparently does not > have such a feature. One possibility is that the FreeBSD drivers check to see how many of the connectors are enabled, and complains if that number is more than two, where the Linux drivers don't do that check. So I'd check for features to disable those in the board BIOS, not just terminate them. I'd also suggest you bring this up on freebsd-scsi, as you're more likely to find people who can help with the problem there. <mike -- Mike Meyer <mwm@mired.org> http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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