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Date:      Sat, 31 Oct 2009 17:06:36 +0000 (UTC)
From:      Stefan Esser <se@FreeBSD.org>
To:        cvs-src-old@freebsd.org
Subject:   cvs commit: src/sys/dev/sym sym_hipd.c
Message-ID:  <200910311706.n9VH6qf0000298@repoman.freebsd.org>

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se          2009-10-31 17:06:36 UTC

  FreeBSD src repository

  Modified files:
    sys/dev/sym          sym_hipd.c 
  Log:
  SVN rev 198719 on 2009-10-31 17:06:36Z by se
  
  While certain supported Symbios/LSI SCSI chips (532c896, 53c1000, 53c1010)
  do support 64bit addresses, the current SCRIPTS code supports only 32bit
  addresses causing data corruption for buffer addresses >4GB. This problem
  affects 64bit machines with more than 4GB RAM or amd64 with 4GB and
  memory hole remapping.
  Work-around this problem with a bus_dma tag that requests bounce-buffers
  for addresses >4GB. This causes some overhead, but given the maximum SCSI
  bus speed of 160MB/s compared, the effect should hardly be noticeable.
  The problem was reported by Mike Watters (mike at mwatters net) who also
  verified that this fix cures the problem.
  
  Since this change is a NOOP on systems with less than 4GB RAM and fixes
  data corruption (in RAM and on disk) on systems with more than 4GB, I hope
  that this change is accepted for 8.0.
  
  MFC after:      3 days (pending approval)
  
  Revision  Changes    Path
  1.73      +1 -1      src/sys/dev/sym/sym_hipd.c



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