8260 FCC buffer underrun

Jeff Angielski jangiels at speakeasy.net
Tue Aug 17 22:24:26 EST 2004

Does anybody know what conditions would cause the FCC to report a buffer
underrun transmit error when we are transmitting small ethernet
packets?  Especially since the packets are so small they only use 1
buffer descriptor.

The wierd thing is that ARP packets gets transmitted fine.  Anything
larger than that, however, generate the underrun errors.

The receive side appears to work fine.  Pings come in, get processed,
and then we attempt to transmit the reply.

This is on an EP8260 H2, a couple weeks old u-boot cvs, and bk pull of

The hardware works because PlanetCore with bk pull of linuxppc-2.4.27
works fine [although PlanetCore has it's own configuration issues...].

Jeff Angielski

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