kern/64556: [sis] if_sis short cable fix problems with NetGear FA311's

[Bruce Cran]

The following reply was made to PR kern/64556; it has been noted by GNATS.

From: Bruce Cran <bruce at cran.org.uk>
To: bug-followup at FreeBSD.org, tom at hur.st
Cc:  
Subject: Re: kern/64556: [sis] if_sis short cable fix problems with NetGear
 FA311's
Date: Thu, 10 Sep 2009 02:24:17 +0100

 I'm still seeing this problem on 8.0-BETA4. Running two ttcp's (one rx,
 one tx) causes the system to print lots of "Applying short cable fix"
 messages.  I've had a look through the NetBSD driver, the original
 Linux driver from http://www.soekris.com/downloads.htm and also the
 latest Linux sources.  
 
 When the issue occurs, I see throughput drop to around 5Mb.  The first
 issues seems to be the 100ms delay. From the other code I've looked at,
 it looks like it should be 100us which would speed up the reset
 process. Secondly, it seems that only FreeBSD resets the chip when an
 RX overrun occurs; on NetBSD it does a printf and continues, and Linux
 increments the error statistics.  Both only apply the short cable fix
 when a media change occurs.
 
 -- 
 Bruce Cran