Re: [PATCH net V2 10/11] net/mlx5e: Update and set Xon/Xoff upon port speed set

Jakub Kicinski
2025-09-11T13:47:38Z

On Wed, 10 Sep 2025 17:00:11 -0700 Jakub Kicinski wrote:
> On Mon, 25 Aug 2025 17:34:33 +0300 Mark Bloch wrote:
> > Xon/Xoff sizes are derived from calculations that include
> > the port speed.
> > These settings need to be updated and applied whenever the
> > port speed is changed.
> > The port speed is typically set after the physical link goes down
> > and is negotiated as part of the link-up process between the two
> > connected interfaces.
> > Xon/Xoff parameters being updated at the point where the new
> > negotiated speed is established.
>
> Hi, this is breaking dual host CX7 w/ 28.45.1300 (but I think most
> older FW versions, too). Looks like the host is not receiving any
> mcast (ping within a subnet doesn't work because the host receives
> no ndisc), and most traffic slows down to a trickle.
> Lost of rx_prio0_buf_discard increments.
>
> Please TAL ASAP, this change went to LTS last week.

Any news on this? I heard that it also breaks DCB/QoS configuration
on 6.12.45 LTS.