Re: DSA Switch: query: Switch configuration, data plane doesn't work whereas control plane works

[Vladimir Oltean <olteanv@gmail.com>]

On Tue, Dec 24, 2024 at 03:00:17PM +0530, sai kumar wrote:
> Hi Team,
> 
> This could be basic question related to DSA, if possible please help
> to share your feedback,. Thanks.
> 
> 
> External CPU eth1 ---RGMII---- Switch Port 0 (cpu port)
> Switch Port 1 (lan1) --- DHCP client
> 
> I am using marvell 88E6390 evaluation board, modified the device tree
> to support MDIO control over USB.
> The switch control plane works, we are unable to dump registers and

unable -> able, right?

> see port status.
> 
> The kernel version on board with external cpu is 6.1
> 
> I have connected a dhcp client to port 1 of the switch and the
> discover packet is not reaching the cpu port (port 0) and external cpu
> interface eth1.
> Using the bridge without vlan to configure, able to see the client
> device mac addr in bridge fdb show
> with vlan id as 4095.
> 
> tcpdump on external cpu port eth1 and bridge br0 to listen for
> incoming packets from the client . No discover packets are being
> received on those interfaces.
> 
> Could you please let us know if any configuration is being missed for
> switch data plane to work ? Thanks.
> 
> 
> The below are the commands used to configure the bridge:

I don't immediately see something obviously wrong. Could you run
ethtool -S on lan1 and on eth0, and try to find a positive correlation
between the DHCP requests and a certain packet counter incrementing in
the switch? We should determine whether there is packet loss in the
switch or whether there is some other reason for the lack of connectivity.