On Mon, Jan 14, 2019 at 01:34:44PM +0200, Samu Nuutamo wrote:
> Hi,
>
> We have an imx6q-b450v3 board that has one of the switch ports configured as a
> fixed link. After upgrading the kernel to version 4.18 the link has
> experienced
> a small amount of packet loss, around 0.15%.
>
> The issue was bisected to a commit: aab9c4067d23 net: dsa: Plug in PHYLINK
> support
>
> After enabling debug we could see that the new phylink code causes the link to
> reset once every second:
>
> [ 309.992368] mv88e6085 gpio-0:00 enembc: phylink_mac_config:
> mode=fixed//100Mbps/Full adv=00000,00000208 pause=10 link=1 an=1
> [ 309.998451] mv88e6085 gpio-0:00: p5: Force link down
> [ 309.998869] mv88e6085 gpio-0:00: p5: Speed set to 100 Mbps
> [ 309.999280] mv88e6085 gpio-0:00: p5: Force full duplex
> [ 309.999895] mv88e6085 gpio-0:00: p5: Force link up
> [ 311.032400] mv88e6085 gpio-0:00 enembc: phylink_mac_config:
> mode=fixed//100Mbps/Full adv=00000,00000208 pause=10 link=1 an=1
> [ 311.038248] mv88e6085 gpio-0:00: p5: Force link down
> [ 311.038660] mv88e6085 gpio-0:00: p5: Speed set to 100 Mbps
> [ 311.039069] mv88e6085 gpio-0:00: p5: Force full duplex
> [ 311.039678] mv88e6085 gpio-0:00: p5: Force link up
> [ 312.072328] mv88e6085 gpio-0:00 enembc: phylink_mac_config:
> mode=fixed//100Mbps/Full adv=00000,00000208 pause=10 link=1 an=1
> [ 312.077603] mv88e6085 gpio-0:00: p5: Force link down
> [ 312.078010] mv88e6085 gpio-0:00: p5: Speed set to 100 Mbps
> [ 312.078417] mv88e6085 gpio-0:00: p5: Force full duplex
> [ 312.079026] mv88e6085 gpio-0:00: p5: Force link up
Hi Samu
Thanks for the report.
I think we should be fixing this from the other end. Why does PHYLINK
reset the link once per second? If you have time, please could you
investigate that.
Thanks
Andrew
