bge & vlan stranges
Peter Edwards
pmedwards at eircom.net
Fri Aug 1 10:37:49 PDT 2003
John Polstra <jdp at polstra.com> wrote:
> Peter Edwards <pmedwards at eircom.net> wrote:
> > > CSR_WRITE_4(sc, BGE_RX_MTU, ifp->if_mtu +
> > > ETHER_HDR_LEN + ETHER_CRC_LEN + ETHER_VLAN_ENCAP_LEN);
> Good guess, but the approved way of doing it is to add this code
> near the point where IFCAP_VLAN_MTU is set:
>
> ifp->if_data.ifi_hdrlen = sizeof(struct ether_vlan_header);
>
> See "sys/dev/fxp/if_fxp.c" for an example that works.
Sorry for being obtuse, but just to clarify:
fxp just seems to have an "allow long frames" flag, rather than a "max frame size"
register in the hardware, so you never seem to have to tell the hardware the max
size of a frame it needs to accept. I assume you mean, that after setting if_hdrlen,
you still need to write to the PCI register, like this:
CSR_WRITE_4(sc, BGE_RX_MTU,
ifp->if_mtu + ifp->if_hdrlen + ETHER_CRC_LEN);
I don't have a bge device, so I can't muck about with it to try.
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