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

Mark Bloch
2025-09-11T14:25:30Z

On 11/09/2025 16:47, Jakub Kicinski wrote:
> 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.

Hi Jakub,

We are looking into this, once we have anything I'll update.
Just to make sure, reverting this is one commit solves the
issue you are seeing?

Mark