netdev - Re: [PATCH v2 rfc 0/8] IGMP snooping for local traffic

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Date:   Wed, 6 Sep 2017 16:16:24 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Vivien Didelot <vivien.didelot@...oirfairelinux.com>
Cc:     netdev <netdev@...r.kernel.org>,
        Florian Fainelli <f.fainelli@...il.com>,
        Woojung.Huh@...rochip.com, jbe@...gutronix.de,
        sean.wang@...iatek.com, john@...ozen.org
Subject: Re: [PATCH v2 rfc 0/8] IGMP snooping for local traffic

> > What i found is that the Marvell chips don't flood broadcast frames
> > between bridged ports. What appears to happen is there is a fdb miss,
> > so it gets forwarded to the CPU port for the host to deal with. The
> > software bridge when floods it out all ports of the bridge.
> 
> Do you have this issue on a single switch?

Yes. I have two boards with a single switch in my test setup. They
fail the broadcast tests in the same way as boards with multiple
switches.

> It should be done at the DSA level. DSA core must be the single entry
> point to handle all the switch logic, calling into (dumb) DSA drivers.
> If it is buried into a specific driver, we'll likely lose track of the
> problem and make it harder to maintain.

I think we need to wait and see what driver writers report their chips
are doing. If this is just a Marvell issue, we probably should fix it
in the Marvell driver only.

If i remember correctly, Woojung said he was seeing duplication of
broadcasts. So it could be the Microchip hardware is forwarding
broadcast in the hardware.

	  Andrew