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Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!saimiri.primate.wisc.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!haven.umd.edu!uunet!caen!umcc.umcc.umich.edu!jon From: jon@umcc.umcc.umich.edu (Jon Zeeff) Newsgroups: comp.os.386bsd.bugs Subject: Re: PROBLEMS WITH PATCHKIT 0.2.2 - Advice/help needed :-( Date: 27 Mar 1993 01:29:44 GMT Organization: UMCC, Ann Arbor, MI Lines: 16 Distribution: world Message-ID: <1p0am8INNpls@srvr1.engin.umich.edu> References: <C4BLJ8.GA5@ns1.nodak.edu> <1993Mar26.201921.28420@cs.wisc.edu> NNTP-Posting-Host: umcc.umcc.umich.edu >This problem goes something like this. A bus-mastering SCSI >controller, such as your 1542B writes a page in memory (suppose it's a >disk buffer) via DMA. The memory which was DMA'ed to is in the SRAM >cache, but the motherboard does not invalidate the cache. Then some >program reads from that disk buffer. However, instead of reading the >fresh-off-disk data, the program is given the garbage in the cache. Two questions: Does someone have a little test program to test for this motherboard problem. Is there an efficient way to "dump" the cache in the disk driver so that people with this problem could run? Does it tend to be cpu internal cache or external SRAM cache that causes the problem?