On Mon, Nov 02, 2026 at 10:55:43AM +0000, Loftus, Ciara wrote:
> > Subject: [PATCH] net/ice: add explicit control of link auto-negotiation
> >
> > When selecting a fixed speed of the link, whether or not
> > autonegotiation (e.g. AN Clause 37, etc.), needs to be enabled depends
> > on the peer link. While commit 3dc2933866d9 ("net/ice: disable link
> > negotiation for fixed speed selection") would allow link setup when the
> > remote side also has a fixed link without AN37 auto-negotiation, it
> > causes the link to flap up and down when e.g. two ports are connected
> > back to back and only one is set to a fixed speed.
> >
> > Support both scenarios of auto-negotiation supported or unsupported on
> > the remote end by adding an explicit driver option for disabling
> > auto-negotiation when a fixed speed is selected. If no fixed speed
> > setting, then new option does nothing.
> >
> > Fixes: 3dc2933866d9 ("net/ice: disable link negotiation for fixed speed
> > selection")
> >
> > Signed-off-by: Bruce Richardson <[email protected]>
> > ---
> > doc/guides/nics/ice.rst | 10 ++++++++++
> > doc/guides/rel_notes/release_26_11.rst | 2 ++
> > drivers/net/intel/ice/ice_ethdev.c | 12 +++++++++++-
> > drivers/net/intel/ice/ice_ethdev.h | 1 +
> > 4 files changed, 24 insertions(+), 1 deletion(-)
> >
> > diff --git a/doc/guides/nics/ice.rst b/doc/guides/nics/ice.rst
> > index ca3a94655b..af36341c9a 100644
> > --- a/doc/guides/nics/ice.rst
> > +++ b/doc/guides/nics/ice.rst
> > @@ -107,6 +107,16 @@ Configuration
> > Runtime Configuration
> > ~~~~~~~~~~~~~~~~~~~~~
> >
> > +``auto_neg_disable`` (default ``0``)
> > + Control hardware link negotiation when a fixed speed is requested with
> > ``RTE_ETH_LINK_SPEED_FIXED``.
> > + By default, the firmware's negotiation settings are preserved,
> > + allowing a fixed-speed link to use negotiation such as Clause 37 when
> > required by its peer.
> > + Set ``auto_neg_disable=1`` to disable Clause 28, Clause 37 and Clause 73
> > negotiation.
> > + This option has no effect when automatic speed selection is requested.
> > + For example::
> > +
> > + -a 80:00.0,auto_neg_disable=1
> > +
>
> The approach looks good to me.
> Something my AI review flagged was the setting of "link.link_autoneg"
> in ice_link_update() - your patch doesn't update that setting, and it's still
> just based off the dev_conf.link_speeds value, and doesn't take into account
> the value of the devarg (unlike ice_apply_link_speed() which accounts for
> both). Perhaps it's not necessary, just something to check.
> Once that is addressed or ruled out:
>
> Acked-by: Ciara Loftus <[email protected]>
Yes, good catch. That is fixed in v2, but I've dropped your ack as some of
the logic has been moved to a subfunction to avoid copy-pasting too much.
