Re: [PATCH iwl-net] idpf: preserve tcp-data-split setting across hard resets

[Brian Vazquez]

Thanks for the patch Ray,

Since header-split is on by default on this device, and vport_config
is allocated zeroed, what about fliping the the user_flag meaning?

  __IDPF_USER_FLAG_HSPLIT -> __IDPF_USER_FLAG_HSPLIT_DIS

If we do that then config starts with the right value on the
user_config, if it's flipped user_config is already persistent acrros
hard resets.  And then we can just delete the call
idpf_vport_set_hsplit(vport, ETHTOOL_TCP_DATA_SPLIT_ENABLED) from
idpf_vport_init and do not worry about where it should be.

On Wed, Nov 11, 2026 at 8:11 PM Ray Zhang <sgzhang@xxxxxxxxxx> wrote:
>
> idpf_vport_init() runs on both initial probe and hard reset, and
> unconditionally calls idpf_vport_set_hsplit() with
> ETHTOOL_TCP_DATA_SPLIT_ENABLED. If a user disabled header split via
> 'ethtool -G <dev> tcp-data-split off', a subsequent hard reset sets
> __IDPF_USER_FLAG_HSPLIT again and silently re-enables header split.
>
> Move the default idpf_vport_set_hsplit() call to idpf_cfg_netdev(),
> which runs after idpf_vport_init() sets rxq_model and returns early on
> hard reset when IDPF_VPORT_REG_NETDEV is already set.
>
> Found by code inspection. Reproduced and verified on an Intel IPU PF
> (8086:1452) by disabling tcp-data-split via ethtool and triggering a
> function reset from a test module via idpf_idc_request_reset(): before
> this change tcp-data-split reverted to 'on' after reset, and with this
> change it stays 'off' (with rx-hsplit remaining 0).
>
> Fixes: 9b1aa3ef2328 ("idpf: add get/set for Ethtool's header split ringparam")
> Signed-off-by: Ray Zhang <sgzhang@xxxxxxxxxx>
> ---
>  drivers/net/ethernet/intel/idpf/idpf_lib.c      | 1 +
>  drivers/net/ethernet/intel/idpf/idpf_virtchnl.c | 2 --
>  2 files changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/idpf/idpf_lib.c b/drivers/net/ethernet/intel/idpf/idpf_lib.c
> index cd1b173e3b27..db6603711be4 100644
> --- a/drivers/net/ethernet/intel/idpf/idpf_lib.c
> +++ b/drivers/net/ethernet/intel/idpf/idpf_lib.c
> @@ -945,6 +945,7 @@ static int idpf_cfg_netdev(struct idpf_vport *vport)
>         netdev->vlan_features |= netdev->features | other_offloads;
>         netdev->hw_enc_features |= dflt_features | other_offloads;
>         idpf_xdp_set_features(vport);
> +       idpf_vport_set_hsplit(vport, ETHTOOL_TCP_DATA_SPLIT_ENABLED);
>
>         idpf_set_ethtool_ops(netdev);
>         netif_set_affinity_auto(netdev);
> diff --git a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> index 928de868fa62..fc56437b01ab 100644
> --- a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> +++ b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> @@ -3381,8 +3381,6 @@ int idpf_vport_init(struct idpf_vport *vport, struct idpf_vport_max_q *max_q)
>         memcpy(vport->rx_itr_profile, rx_itr, IDPF_DIM_PROFILE_SLOTS);
>         memcpy(vport->tx_itr_profile, tx_itr, IDPF_DIM_PROFILE_SLOTS);
>
> -       idpf_vport_set_hsplit(vport, ETHTOOL_TCP_DATA_SPLIT_ENABLED);
> -
>         idpf_vport_init_num_qs(vport, vport_msg, rsrc);
>         idpf_vport_calc_num_q_desc(vport, rsrc);
>         idpf_vport_calc_num_q_groups(rsrc);
> --
> 2.56.0.611.g1030f0b940-goog
>