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Date:      Mon, 24 Jun 2002 15:06:21 -0400 (EDT)
From:      Andrew Gallatin <gallatin@cs.duke.edu>
To:        John Polstra <jdp@polstra.com>
Cc:        hackers@freebsd.org
Subject:   Re: Re: bge driver issue
Message-ID:  <15639.28077.881363.884693@grasshopper.cs.duke.edu>
In-Reply-To: <200206241645.g5OGjZH31049@vashon.polstra.com>
References:  <200206231552.g5NFqS002122@pacbell.net> <200206241645.g5OGjZH31049@vashon.polstra.com>

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John Polstra writes:
 > On the i386, living with the misalignment is probably the best
 > solution, unfortunately.  The only alternatives I can think of are:
 > 
 >     - bcopy the packet up by 2 bytes after reception to align the
 >       payload, or
 > 
 >     - disable PCI-X mode on the bus
 > 

If the bge's API allows it, you could setup a receive descriptor with
a length of 14 bytes (size of ethernet header), and start the next
descripter 2 bytes after it (at a 16 byte offset from the front of the
mbuf).  When the receive is done, just copy the 14 bytes.

Drew



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