Hello,
I have a weird issue using a BCM95721 in bridged mode. In a production
server I have eth0: Tigon3 [partno(BCM95721) rev 4201] (PCI Express),
which is part of a bridge, with some tap interfaces on which some
virtual machines reside. Everything works like a charm. This server runs
Debian squeeze, 2.6.32-5-amd64 kernel.
On a testing server I have eth0: Tigon3 [partno(BCM95721) rev 4101] (PCI
Express) (older revision, same hardware?). Here, the card will not work
properly in briding mode: it does not 'see' packets not destined for its
own MAC address. Even running a tcpdump in promiscous mode does not show
these packets. Running it non-bridged works fine.
The result is that, if the bridge MAC is different from the eth0 MAC,
the host is not reachable. If the bridge MAC happens to be the same as
the eth0 MAC, the host itself is reachable, but bridging obviously still
doesn't work.
I tested the testing server using the same 2.6.32-5-amd64 kernel as the
production machine uses (including firmware), and to my surprise that
kernel also doesn't work. So apparently rev 4101 contains some kind of
bug wrt bridging mode. It almost seems like promiscous mode is reset
somehow, kind of like the (very old) problem described here:
http://www.spinics.net/lists/linux-ethernet-bridging/msg00756.html
This is on a very old version however, I could not reuse those steps in
debugging this issue on my kernel version.
To rule out hardware issues, I have another identical machine (hw and
sw) with the same issue. Also, plugging in an intel card which I
happened to have lying around works just fine...
Does anyone have any ideas on how to test/debug/fix this issue?
Michel.
