Date: Fri, 8 Aug 1997 17:24:08 -0700 (PDT) From: Alex <garbanzo@hooked.net> To: Tom <tom@uniserve.com> Cc: "John W. DeBoskey" <jwd@unx.sas.com>, freebsd-current@FreeBSD.ORG Subject: Re: scsi time-out & lockup under smp Message-ID: <Pine.BSF.3.96.970808172156.4871B-100000@zippy.dyn.ml.org> In-Reply-To: <Pine.BSF.3.96.970808171158.28159A-100000@shell.uniserve.com>
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On Fri, 8 Aug 1997, Tom wrote: > > This is a fairly well known problem with the 2940U/UW, and probably > > anything else based on the 7880. All I can say is that for heavy disk io, > > don't use that controller, two controllers might be causing some of those > > problems too. However I'd also suggest that you take the number of busses > > down a notch, unless you have devices on bus 255, and that you cvsup the > > most recent FreeBSD sources,as I think some improvments have been made to > > this driver, and many improvments have been made to the smp code. > > > > - alex > > Well known problem? I've never seen it, even with heavy io on a 3940UW. > I use AHC_TAGENABLE, but NOT AHC_SCBPAGING. I use both with no problems on an aic-7880 (2940UW). However I've seen many reports of people having problems with the 2940U/UW doing this sort of thing under _continuous heavy_ io. However there's a really great explaination of what scb paging is in the aic7xxx driver. Stuff like that deserves a place in either a.) the man pages or b.) the texinfo database (or whatever it's called). > I don't believe that any changes have been made to the ahc driver > lately. True. > I think this problem is device dependant. Certain devices will seize > the bus, and driver is unable to get it back. - alex
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