Date: Mon, 26 Aug 2002 08:20:30 -0600 From: "Justin T. Gibbs" <gibbs@scsiguy.com> To: "Fedor G. Pikus" <pikus@pikus.net>, aic7xxx@FreeBSD.ORG Subject: Re: Strange log messages from AHA2940UW Message-ID: <3763950000.1030371630@aslan.scsiguy.com> In-Reply-To: <Pine.LNX.4.33.0208252337230.2280-100000@valinor.pikus.net> References: <Pine.LNX.4.33.0208252337230.2280-100000@valinor.pikus.net>
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> First, the problem, in a nutshell: > I'm getting alot of the following in my log: > kernel: (scsi0:A:3:0): Sending SDTR period 19, offset f > kernel: (scsi0:A:3:0): Received SDTR period 19, offset f > kernel: ^IFiltered to period 19, offset f > > Usually when I start getting these, my SCSI devices become slow, and > quite often the whole system starts freezing for a second or two > (total freeze, mouse is frozen in X) then wakes up, then freezes again. > System load goes way up, to 4 or 5, but top does not show anything > actually using the CPU. > The freezing happens less often if I give Adaptec its own IRQ. > What does the message mean, what's wrong, and how do I fix it? My guess is that you have a daemon probing your CDROM drives to see if they have any media. This is usually done via a "Test Unit Ready" command. If the device does not have any media in its drive, it will respond to the TUR with check condition status. The aic7xxx driver will always renegotiate with a device when a check condition occurs since it may indicate that the device lost power and thus the negotiated transfer agreement. I don't know why this would cause your system to slow down noticibly. You don't want to be negotiating all of the time since it does hog some SCSI bus cycles, but it is not computationally intensive. To test my theory, stick media in your drives the next time you see the messages on your console. They should go away. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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