[PATCH net v2 0/2] net: dsa: mt7530: fix trapped frame forwarding and egress tagging

[Paolo Abeni]

On 9/23/26 07:51, Tao Gong wrote:
> This series resolves two issues in the MT7530 DSA switch driver preventing
> trapped link-local control frames (such as STP BPDUs) from reaching the CPU
> host when bridge VLAN filtering is enabled:
> 
> 1. Commit 3ac85bcfd404 ("net: dsa: mt7530: preserve VLAN tags on trapped
>     link-local frames") set MT7530_VLAN_EG_DISABLED to preserve VLAN tags,
>     but in hardware this disables the per-packet override and causes
>     trapped frames to follow the CPU port's active VLAN table (VAWD2) rule.
>     When bridge VLAN filtering is active, the CPU port is in stack mode,
>     causing incoming untagged BPDUs (01:80:C2:00:00:00) to be egressed with
>     a VLAN tag, which userspace STP daemons (such as ustpd) and the kernel
>     bridge drop. MT7530_VLAN_EG_CONSISTENT correctly preserves wire state
>     (untagged frames stay untagged, tagged frames stay tagged).
> 
> 2. On Airoha EN7581 and AN7583 switch IP, setting MT7531_CFC (0x04)
>     CPU_PMAP alone is insufficient; the switch MAC forwarding control
>     (MT753X_MFC, 0x10) must also have CPU_EN and CPU_PORT configured for
>     trapped frames to exit to the CPU conduit.
It's unclear to me if you are observing the issue with real H/W or if the
patches comes from LLMs or static analysis. Please clarify such info
in the next iteration.

Also clashiko feedback looks relevant, please have a look. You should
address LLM's feedback proactively.

/P