Re: [PATCH net-next v8 2/3] net: dsa: mv88e6xxx: use the hw tx queues

[Cedric Jehasse]

On Mon, Aug 17, 2026 at 10:50:24AM -0700, Jakub Kicinski wrote:
> On Tue, 11 Aug 2026 13:45:48 +0200 Cedric Jehasse via B4 Relay wrote:
> > When transmitting fill in the PRI field in the dsa tag to select the
> > egress queue is sent to.
> > From the datasheets i've looked at these switches have 4 or 8 transmit
> > queues per port.
> > Note: skbs with skb->offload_fwd_mark set use the DSA_CMD_FORWARD
> > tag. These are processed as normal ingress frames, meaning the queue
> > they end up in can still be altered by other switch config. eg. priority
> > overrides, tcam policies.
> > This isn't done for vlan tagged frames because this would overwrite the
> > PCP value in the vlan tag (The PRI field in the dsa
> > tag is used as the PCP value in the vlan tag).
>
> Pretending that a DSA device has multiple Tx queues _from the stack_
> makes no sense. You should be offloading PRIO as the root qdisc,
> like mlxsw does. Then the rate limiters should be attached as children
> of PRIO.

This patch follows what the implementation i found in other dsa drivers.
mlxsw seems to be the only driver handling TC_SETUP_QDISC_PRIO.
Wouldn't that mean setting up cbs for a mv88e6xxx switch would use different
tc commands than setting it up for another dsa switch (prio vs mqprio)?
Is your comment specific to this driver, or for dsa drivers in general?