Re: [PATCH net v4 2/7] net: dsa: mt7530: fix trapping frames with multiple CPU ports on MT7530

[Arınç ÜNAL]

On 13.06.2023 00:09, Russell King (Oracle) wrote:
> On Mon, Jun 12, 2023 at 10:59:40AM +0300, arinc9.unal@xxxxxxxxx wrote:
> > From: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
> >
> > The CPU_PORT bits represent the CPU port to trap frames to for the MT7530
> > switch. This switch traps frames received from a user port to the CPU port
> > set on the CPU_PORT bits, regardless of the affinity of the user port from
> > which the frames are received.
>
> I think:
>
> "On the MT7530, the CPU_PORT() field indicates which CPU port to trap
> frames to, regardless of the affinity of the inbound user port."
>
> covers everything necessary in the first paragraph? Sorry to be a pain
> about this, but commit logs should be understandable.

Sounds good to me.

> > When multiple CPU ports are being used, the trapped frames won't be
> > received when the DSA conduit interface, which the frames are supposed to
> > be trapped to, is down because it's not affine to any user port. This
> > requires the DSA conduit interface to be manually set up for the trapped
> > frames to be received.
>
> "When multiple CPU ports are in use, if the DSA conduit interface is
> down, trapped frames won't be passed to the conduit interface."

Ok.

> > To fix this, implement ds->ops->master_state_change() on this subdriver and
> > set the CPU_PORT bits to the CPU port which the DSA conduit interface its
>
> ... "to the first CPU port" - isn't that what the code is doing with
> __ffs(priv->active_cpu_ports)? You're giving priority to the lowest
> numbered port, and I think that should be stated in the commit message.

Will do.

Arınç