在 2021/3/29 15:19, Thomas Monjalon 写道:
29/03/2021 09:03, Thomas Monjalon:
29/03/2021 06:02, Huisong Li:
'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.
I see some drivers are advertising ETH_LINK_SPEED_FIXED in speed_capa
if the device cannot support autonegotiation.
Should we add a note in doxygen?
Can we use bit 0 to indicate whether the device supports auto-negotiation?
Like,
1/ If device doesn't support auto-negotiation, set bit(0) of the
'speed_capa' to 1, namely, "speed_capa |= ETH_LINK_SPEED_FIXED".
2/ Other bits of the 'speed_capa' report all the speed capabilities
supported by the device regardless of the value of bit(0) .
The above behavior is similar to cxgbe, bnxt, and mlx5. In this way,
users can know whether the device supports auto-negotiation
based on bit(0) and detect the supported speed capabilities based on
other bits.
After all, this 'speed_capa' and the 'link_speeds' in "rte_eth_conf"
struct have different purposes.
.
