[PATCH net-next] net: dsa: mt7530: drop untagged frames on VLAN-aware ports without PVID

[DENG Qingfang]

On Fri, Aug 06, 2021 at 03:17:40AM +0300, Vladimir Oltean wrote:
> 
> Good catch with this condition, sja1105 and ocelot are buggy in this
> regard, it seems, probably others too. Need to fix them. Although
> honestly I would probably rather spend the time patching the bridge
> already to not accept duplicate VLAN entries from user space, just with
> different flags, it's just too complex to handle the overwrites everywhere...
> Plus, bridge accepting duplicate VLANs means we cannot refcount them on
> DSA and CPU ports at the cross-chip level, which in turn means we can
> never delete them from those ports.
> 
> Anyhow, enough rambling.
> 
> Reviewed-by: Vladimir Oltean <olteanv at gmail.com>

Please allow me to send a v2. This sets the CPU port's PVID to 0
on boot, which causes some undefined behaviour..