Re: [PATCH net] net: dsa: b53: prevent standalone from trying to forward to other ports

[Florian Fainelli <florian.fainelli@broadcom.com>]

On 2/26/26 12:24, Rafał Miłecki wrote:
> W dniu 8.05.2025 o 11:14, Jonas Gorski pisze:
>> When bridged ports and standalone ports share a VLAN, e.g. via VLAN
>> uppers, or untagged traffic with a vlan unaware bridge, the ASIC will
>> still try to forward traffic to known FDB entries on standalone ports.
>> But since the port VLAN masks prevent forwarding to bridged ports, this
>> traffic will be dropped.
>>
>> This e.g. can be observed in the bridge_vlan_unaware ping tests, where
>> this breaks pinging with learning on.
>>
>> Work around this by enabling the simplified EAP mode on switches
>> supporting it for standalone ports, which causes the ASIC to redirect
>> traffic of unknown source MAC addresses to the CPU port.
>>
>> Since standalone ports do not learn, there are no known source MAC
>> addresses, so effectively this redirects all incoming traffic to the CPU
>> port.
> 
> This change broke standalone ports (those not being part of bridge) on 
> Northstar (BCM5301X) devices. We got reports from users about WAN ports 
> on routers not working anymore:
> https://github.com/openwrt/openwrt/issues/21187
> https://github.com/openwrt/openwrt/issues/21349
> 
> Can you take another look at those changes, see if something me be 
> wrong / missing?

Checking the BCM5301X datasheet, the register definitions look correct.

The first report appears to be for a Netgear R7000 which AFAICT would 
utilize port 8 of the switch as the CPU port, which would be correct.

The other report is for a Netgear R6250 where port 5 would be acting as 
the CPU port, that could be an issue unless the switch is also 
programmed to use port 5 as the IMP port.

Could you try to program GMNGCFG (page 0x02, offset 0) bits 7:6 to have 
the value 0b11 which is dual IMP port (IMPO is port 8 and IMP1 is port 
5) and see if that helps?
-- 
Florian