[dpdk-dev] Questions about reporting auto-negotiation capability

[Thomas Monjalon]

29/03/2021 06:02, Huisong Li:
> Hi, all
> 
>          'speed_capa' in struct rte_eth_dev_info is defined as follows:
> 
> uint32_t speed_capa;  /**< Supported speeds bitmap (ETH_LINK_SPEED_). */
> 
> 
>        Most PMD drivers use this field to report the speeds capability 
> supported by the device to the upper-layer app.
> 
> But it seems that few NICs report their auto-negotiation capability 
> through this field. If NIC also uses it to report
> 
> their auto-negotiation capability through this field, and should set it 
> to ETH_LINK_SPEED_AUTONEG(0) based on
> 
> the definition of ETH_LINK_SPEED_xxx. In this case, it conflicts the 
> report of the speeds capability .
> 
> 
> I don't know how to correctly report the auto-negotiation capability of 
> the device. Thanks for your reply.

ETH_LINK_SPEED_AUTONEG is not for capabilities.
Anyway, if it is set, it changes nothing (0) in the bitmap.
I see mlx5 is wrongly using it.

speed_capa is only for enumerating speeds.