Have you tried a -current snapshot at all?
sys/dev/pci/if_bnx.c 1.49 may be relevant.

description:
----------------------------
revision 1.49
date: 2007/05/21 10:05:03;  author: reyk;  state: Exp;  lines: +4 -3
fix bnx vlan tagging in the rx path; do not attach the vlan tag twice
if the firmware has been told to keep it and copy the tag in network
byte order in the other case.

ok mcbride@ dlg@
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