receive errors and FIFO overflow with vr nic

[Matthew Dillon]

   Try bumping VR_RX_LIST_CNT in if_vrreg.h in our driver from 64
   to 128.  The FBsd driver has some flow control stuff in it too but
   that's only for 6105+ chips, and yours is a 6102 or 6103.  There
   is a RX pause feature commented out in the FBsd driver for 6102+
   chips (but its commented out so...).

   DragonFly's NFS implementation runs RPCs fully asynchronously so it
   can seriously load down the network.  Both FBsd and DragonFly have
   variable-sized TCP buffers so scp-style transfers should work about
   the same, but you can check by looking at the backlog in the sockbuf
   on the sender for the connection ('netstat -p tcp' on the sending side)
   while it is going full-bore.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>