Re: [PATCH net] net: dsa: b53: be VLAN unaware when not filtering

[Semih Baskan]

Hi Jonas,

On Thu, Aug 13, 2026 at 10:08 AM Jonas Gorski <jonas.gorski@xxxxxxxxx> wrote:
> There is also a (global) bit in VLAN_CTRL5 to configure something
> similar to MV88E6XXX_G1_VTU_DATA_MEMBER_TAG_UNMODIFIED:
>
>  *     PRESV_NON1Q      - en_preserv_non_1q_frame: (default 0)

Measured on the BCM53011: the bit preserves both frame types.
Setup: vlan_filtering=1, VID 1 with the egress port dropped from
the untag map, external endpoints on two front ports.

- Bit clear (the running default): an untagged frame egresses tagged
  VID 1, 12 of 12, and a priority tagged frame egresses tagged VID 1,
  10 of 10.
- Bit set: the same untagged frames egress untagged, 10 of 10, and
  the same priority tagged frames egress with VID 0 preserved, 10 of
  10.

The description's untag-map=1 case for priority tagged frames
measures differently: they also egress with VID 0 kept, 10 of 10,
where the text says they would be untagged. So with the bit set the
preservation of non 1Q frames is unconditional.

Best regards,
Semih