> I get this in syslog when I try to subject the card to any kind of heavy
> network traffic (i.e. FTPing a 95 megabyte tar file to a machine directly
> connected).
> 
> Feb  9 21:00:03 testsparc /netbsd: hme0: buffer overflow, ri=0;

The ring buffers are currently completely static and probably not
adequately sized (I must implement dma_load_mbuf() some day).

You may want to experiment a bit with the number of descriptors
allocated for packet reception: bump _HME_NDESC to a higher multiple
of 16.