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Date:      Mon, 11 Mar 1996 12:46:35 +0100
From:      se@zpr.uni-koeln.de (Stefan Esser)
To:        Terry Lambert <terry@lambert.org>
Cc:        current@freebsd.org
Subject:   Re: AMD doesn't like SNAP! (panic: unwire: page not in pmap)
Message-ID:  <199603111146.AA20705@Sisyphos>
In-Reply-To: Terry Lambert <terry@lambert.org> "Re: AMD doesn't like SNAP! (panic: unwire: page not in pmap)" (Mar 10, 12:21)

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On Mar 10, 12:21, Terry Lambert wrote:
} Before, when I suggested that a DMA be triggered as part of a probe
} process on a per controller basis to determine if bounce buffers
} were necessary, I neglected the non-working cache case.  The cache
} cases need to be considered at the same time because they need to
} trigger similar controller/memory events in order to be detectable.
} 
} When a bus master DMA occurs, there is supposed to be a cache
} notification, and the L1 and L2 cache lines are supposed to be
} invalidated or written back for the memory range in which the DMA
} took place.

Just for the record:

The NCR driver does such a test,
and it has detected hardware 
problems on a few occasions ...

Regards, STefan
-- 
 Stefan Esser, Zentrum fuer Paralleles Rechnen		Tel:	+49 221 4706021
 Universitaet zu Koeln, Weyertal 80, 50931 Koeln	FAX:	+49 221 4705160
 ==============================================================================
 http://www.zpr.uni-koeln.de/~se			  <se@ZPR.Uni-Koeln.DE>



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