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Date:   Fri, 31 May 2019 14:19:14 -0400
Message-ID: <20190531141914.GB26582@t480s.localdomain>
From:   Vivien Didelot <vivien.didelot@gmail.com>
To:     Florian Fainelli <f.fainelli@gmail.com>
Cc:     Nikita Yushchenko <nikita.yoush@cogentembedded.com>,
        Andrew Lunn <andrew@lunn.ch>,
        "David S. Miller" <davem@davemloft.net>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Marek =?UTF-8?B?QmVow7pu?= <marek.behun@nic.cz>,
        Russell King <rmk+kernel@armlinux.org.uk>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Chris Healy <cphealy@gmail.com>
Subject: Re: [PATCH] net: dsa: mv88e6xxx: avoid error message on remove from
 VLAN 0
In-Reply-To: <38a5dbac-a8e7-325a-225f-b97774f7bb81@gmail.com>
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Hi Florian,

On Fri, 31 May 2019 09:36:13 -0700, Florian Fainelli <f.fainelli@gmail.com> wrote:
> > But VID 0 has a special meaning for the kernel, it means the port's private
> > database (when it is isolated, non-bridged), it is not meant to be programmed
> > in the switch. That's why I would've put that knowledge into the DSA layer,
> > which job is to translate the kernel operations to the (dumb) DSA drivers.
> > 
> > I hope I'm seeing things correctly here.
> 
> Your first part about the fact that it's the port private database is
> true, the fact that it is not programmed into the HW actually depends on
> what the switch is capable of doing. With mv88e6xxx you have per-port
> VLAN filtering controls, but other switches that do not have that
> capability need to program VID == 0 into the HW to continue maintaining
> VLAN filtering on a non bridged port while a bridge has enslaved other
> ports of the switch.

Are you saying that switches without per-port VLAN filtering controls
will program VID 0, and thus put all non bridged ports into the same VLAN,
allowing them to talk to each other?


Thanks,
Vivien