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

Tao Gong gongtao0607 at gmail.com
Thu Oct 15 10:24:19 PDT 2026


Sorry, I overlooked the existing fix, commit 4cb3cd670b2a ("net: dsa:
mt7530: untag VLAN-aware bridge PVID"). I saw the issue on real
hardware (AN7581) running a 6.18 stable kernel, which doesn't have
that commit. After picking it up, the issue is gone and neither patch
is needed. Please drop this series.

On Tue, Sep 29, 2026 at 2:08 AM Paolo Abeni <pabeni at redhat.com> wrote:
>
> 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
>


-- 
~Tao



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