405GP network receive problem

John Cagle jcagle at kernel.org
Sat Jun 30 03:46:18 EST 2001

I am debugging a custom board design based on the 405GP and have a problem
receiving lots of TCP/IP traffic (like FTP).  We're using a 2.4 kernel based
on Monta Vista's CDK 1.2.  UDP traffic (like TFTP) works very well, but it
doesn't ever have back-to-back receives, typically.  The problem occurs
at both 10mbit and 100Mbit.

I have narrowed the problem down (using ttcp) to the following:

During back-to-back receives (within microseconds) of two large (1500 bytes)
TCP packets, the second packet is usually dropped by the 405GP.  When I
check ifconfig statistics, it shows the 1 lost packet, but also shows 2
framing errors.

Has anyone else seen this type of problem with the 405GP or does anyone
know what the problem might be?

John Cagle <jcagle at kernel.org>

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