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Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!msuinfo!agate!ames!decwrl!pa.dec.com!nntpd.lkg.dec.com!lkg.dec.com!thomas From: thomas@lkg.dec.com (Matt Thomas) Newsgroups: comp.os.386bsd.bugs Subject: Re: FreeBSD: ASUS SP3G and writeback caches Date: 4 Sep 1994 15:44:17 GMT Organization: Digital Equipment Corporation Lines: 27 Sender: thomas@netrix.lkg.dec.com (Matt Thomas) Distribution: world Message-ID: <34cq0h$ei3@nntpd.lkg.dec.com> References: <344vevINN2t7j@rs1.rrz.Uni-Koeln.DE> Reply-To: thomas@lkg.dec.com NNTP-Posting-Host: netrix.lkg.dec.com Keywords: FreeBSD X-Newsreader: mxrn 6.18-16 In article <344vevINN2t7j@rs1.rrz.Uni-Koeln.DE>, se@fileserv1.MI.Uni-Koeln.DE (Stefan Esser) writes: |>Maybe something got broken in going from FreeBSD-1.1 to 1.1.5 ? |> |>There have been some reports on problems with the ASUS SP3G |>and the PCI SCSI driver, if the secondary cache has been |>configured for writeback operation. The PCI driver makes |>the NCR do lots of bus master operations to a data area that |>is written to by the CPU as well (command queues), and is the |>only FreeBSD driver so far, that depends on cache coherency |>for PCI to memory operations. Not quite the only one. I also have a driver for the DEC DE435 Ethernet PCI NIC. It also uses in-memory structures that are R/W for both the CPU and DC21040 chip. How ever, since my only disk controller is the NCR 53C810 I've never been able to tell if my driver has the same problems with writeback as the NCR 53C810. My 486 66dx2 PC always panics on startup when the writeback cache is enabled. -- Matt Thomas Internet: thomas@lkg.dec.com U*X Networking WWW URL: http://ftp.dec.com/%7Ethomas/ Digital Equipment Corporation Disclaimer: This message reflects my Littleton, MA own warped views, etc.