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From: Heikki Suonsivu <hsu@cs.hut.fi>
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Date: Mon, 20 Mar 1995 06:54:53 +0200
Message-Id: <199503200454.GAA03389@shadows.cs.hut.fi>
To: freebsd-bugs@FreeBSD.org
In-Reply-To: Heikki Suonsivu's message of 13 Mar 1995 15:49:51 +0200
Subject: NCR SCSI fails
Organization: Helsinki University of Technology, Otaniemi, Finland
Sender: bugs-owner@FreeBSD.org
Precedence: bulk


Is there any hope a solution would appear for this soon?  Or should I
forget the NCR controller and shell out the $400 for a Buslogic?  Anyone
working on this?

The exact error generated was

ncr0 <ncr 53c810 scsi> int a irq 11 on pci0:3
        reg20 : virtual = 0xf665d000 physical = 0xffbeff00
CACHE TEST FAILED: reg dstat - sstat2 readback ffffffff

CACHE INCORRECTLY CONFIGURED

      This failed on our P60 motherboard with NCR SCSI, is this a broken
      motherboard, configuration problem or something else?

   More workout; This "cache test" fails even if both internal and external
   caches are disabled.  I also went through all BIOS settings and disabled
   everything which even distantly hinted into any caching or buffering, to no
   avail.  So, it seems that this cache test can't be quite correct?  The only
   oddity I can see is that the code doesn't first check what is sees in the
   "read-only" address before it tries to write 0xffffffff into it?

      /*==========================================================
      **
      **
      **	Test the pci bus snoop logic :-(
      **
      **	Has to be called with interrupts disabled.
      **
      **
      **==========================================================
      */

      #ifndef NCR_IOMAPPED
      static int ncr_regtest (struct ncb* np)
      {
	      register volatile u_long data, *addr;
	      /*
	      **	ncr registers may NOT be cached.
	      **	write 0xffffffff to a read only register area,
	      **	and try to read it back.
	      */
	      addr = (u_long*) &np->reg->nc_dstat;
	      data = 0xffffffff;
	      *addr= data;
	      data = *addr;
      #if 1
	      if (data == 0xffffffff) {
      #else
	      if ((data & 0xe2f0fffd) != 0x02000080) {
      #endif
		      printf ("CACHE TEST FAILED: reg dstat-sstat2 readback %x.\n",
			      (unsigned) data);
		      return (0x10);
	      };
	      return (0);
      }
      #endif


      -- 
      Heikki Suonsivu, T{ysikuu 10 C 83/02210 Espoo/FINLAND,
      hsu@cs.hut.fi  home +358-0-8031121 work -4513377 fax -4555276  riippu SN