[dpdk-dev] i40e rte_eth_link_get_nowait() on X722 returns wrong link_speed value 20000 instead of 10000

[Martin Weiser]

Hi,

just bumping this since there has been no reply at all for a long time.
Would it be better if I opened a bug for this?

Best,
Martin


Am 22.01.19 um 16:07 schrieb Martin Weiser:
> Hi,
>
> We are using a Xeon D with an integrated X722 NIC that provides two
> ports of 8086:37d2 and two ports of 8086:37d0. All four ports show the
> same behavior: they return a link speed value of 20000 for a 10Gbps link.
>
> This only seems to happen when internally the update_link_reg() function
> in i40e_ethdev.c is used. This requires the application to use the
> rte_eth_link_get_nowait() function and not use link status change
> interrupts.
> If you use e.g. testpmd with the option --no-lsc-interrupt you can
> reproduce the behavior since it will suddenly show a link speed of 20000
> Mbps instead of 10000 Mbps.
>
>
> Here are two examples of the register values read by update_link_reg():
>
> A 10Gbps link which produces the wrong link speed value:
>
> I40E_PRTMAC_LINKSTA: 0x60000080
> I40E_PRTMAC_MACC:    0x3d00
>
>
> A 1Gbps link which produces the correct link speed value:
>
> I40E_PRTMAC_LINKSTA: 0x48000081
> I40E_PRTMAC_MACC:    0x3d00
>
>
> Best regards,
> Martin
>