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Subject: docs/31935: FAQ: AIC7xxx termination
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>Number:         31935
>Category:       docs
>Synopsis:       FAQ: AIC7xxx termination
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-doc
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Mon Nov 12 12:10:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Michael Lucas
>Release:        FreeBSD 3.5-STABLE i386
>Organization:
None
>Environment:

today's -doc tree

>Description:

Here's an error generated by the AIC7xxx controller in certain
circumstances.

This answer was actually written by Justin Gibbs, just marked up &
send-pr'd by yours truly.

>How-To-Repeat:

Get a motherboard with a built-in AIC7xxx controller.  Play with the
BIOS until it breaks.

>Fix:


*** en_US.ISO8859-1/books/faq/book.sgml-dist	Mon Nov 12 14:26:43 2001
--- en_US.ISO8859-1/books/faq/book.sgml	Mon Nov 12 15:02:07 2001
***************
*** 3913,3918 ****
--- 3913,3941 ----
        </qandaentry>
  
        <qandaentry>
+         <question id="aci0-illegal-cable">
+           <para>When I boot my system, I get the error
+             <errorname>ahc0: illegal cable configuration</errorname>.
+             My cabling is correct.  What's going on?</para>
+         </question>
+ 
+         <answer>
+            <para>Your motherboard lacks the external logic to support
+              automatic termination.  Switch your SCSI BIOS to specify
+              the correct termination for your configuration rather
+              than automatic termination.  The AIC7XXX driver cannot
+              determine if the external logic for cable detection (and
+              thus auto-termination) is available.  The driver simply
+              assumes that this support must exist if the configuration
+              contained in the serial EEPROM is set to "automatic
+              termination".  Without the external cable detection logic
+              the driver will often configure termination incorrectly,
+              which can compromise the reliability of the SCSI
+              bus.</para>
+         </answer>
+       </qandaentry>
+ 
+       <qandaentry>
          <question id="mail-loopback">
            <para>Why does Sendmail give me an error reading
              <quote><errorname>mail loops back to
>Release-Note:
>Audit-Trail:
>Unformatted:

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