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From:   DENG Qingfang <dqfext@gmail.com>
To:     Vladimir Oltean <olteanv@gmail.com>
Cc:     Sean Wang <sean.wang@mediatek.com>,
        Landen Chao <Landen.Chao@mediatek.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        Eric Woudstra <ericwouds@gmail.com>,
        =?iso-8859-1?Q?Ren=E9?= van Dorst <opensource@vdorst.com>,
        Frank Wunderlich <frank-w@public-files.de>
Subject: Re: [RFC net-next v2 4/4] Revert "mt7530 mt7530_fdb_write only set ivl bit vid larger than 1"
Date:   Mon,  2 Aug 2021 23:48:38 +0800
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On Mon, Aug 02, 2021 at 04:44:09PM +0300, Vladimir Oltean wrote:
> Would you mind explaining what made VID 1 special in Eric's patch in the
> first place?

The default value of all ports' PVID is 1, which is copied into the FDB
entry, even if the ports are VLAN unaware. So running `bridge fdb show`
will show entries like `dev sw0p0 vlan 1 self` even on a VLAN-unaware
bridge.

Eric probably thought VID 1 is the FDB of all VLAN-unaware bridges, but
that is not true. And his patch probably cause a new issue that FDB is
inaccessible in a VLAN-**aware** bridge with PVID 1.

This series sets PVID to 0 on VLAN-unaware ports, so `bridge fdb show`
will no longer print `vlan 1` on VLAN-unaware bridges, and we don't
need special case in port_fdb_{add,del} for assisted learning.