> 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]>
