Re: [PATCH] net/mlx5e: Again mutually exclude RX-FCS and RX-port-timestamp

[Tariq Toukan <ttoukan.linux@gmail.com>]

On 06/10/2023 8:37, Will Mortensen wrote:
> Commit 1e66220948df8 ("net/mlx5e: Update rx ring hw mtu upon each rx-fcs
> flag change") seems to have accidentally inverted the logic added in
> commit 0bc73ad46a76 ("net/mlx5e: Mutually exclude RX-FCS and
> RX-port-timestamp").
> 
> The impact of this is a little unclear since it seems the FCS scattered
> with RX-FCS is (usually?) correct regardless.
> 

Thanks for your patch.

> Fixes: 1e66220948df8 ("net/mlx5e: Update rx ring hw mtu upon each rx-fcs flag change")
> Tested-by: Charlotte Tan <charlotte@extrahop.com>
> Reviewed-by: Charlotte Tan <charlotte@extrahop.com>
> Cc: Adham Faris <afaris@nvidia.com>
> Cc: Aya Levin <ayal@nvidia.com>
> Cc: Tariq Toukan <tariqt@nvidia.com>
> Cc: Moshe Shemesh <moshe@nvidia.com>
> Cc: Saeed Mahameed <saeedm@nvidia.com>
> Signed-off-by: Will Mortensen <will@extrahop.com>
> ---
> For what it's worth, regardless of this change the PCMR register behaves
> unexpectedly in our testing on NICs where rx_ts_over_crc_cap is 1 (i.e.
> where rx_ts_over_crc is supported), such as ConnectX-7 running firmware
> 28.37.1014. For example, fcs_chk is always 0, and rx_ts_over_crc can
> never be set to 1 after being set to 0. On ConnectX-5, where
> rx_ts_over_crc_cap is 0, fcs_chk behaves as expected.
> 
> We'll probably be opening a support case about that after we test more,
> but I mention it here because it makes FCS-related testing confusing.
> 

Please open the case and we'll analyze.

>   drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> index a2ae791538ed..acb40770cf0c 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
> @@ -3952,13 +3952,14 @@ static int set_feature_rx_fcs(struct net_device *netdev, bool enable)
>   	struct mlx5e_channels *chs = &priv->channels;
>   	struct mlx5e_params new_params;
>   	int err;
> +	bool rx_ts_over_crc = !enable;

nit:  Please maintain the reserved Christmas tree.

>   
>   	mutex_lock(&priv->state_lock);
>   
>   	new_params = chs->params;
>   	new_params.scatter_fcs_en = enable;
>   	err = mlx5e_safe_switch_params(priv, &new_params, mlx5e_set_rx_port_ts_wrap,
> -				       &new_params.scatter_fcs_en, true);
> +				       &rx_ts_over_crc, true);
>   	mutex_unlock(&priv->state_lock);
>   	return err;
>   }

Reviewed-by: Tariq Toukan <tariqt@nvidia.com>

Regards,
Tariq