The Speed shows 65535 Mbps when the ethernet cable is unplug

[chnguyen-ampere]

• Description

The Speed property from /xyz/openbmc_project/network/ethX dbus object shows 65535 (decimal number) Mbps when unplug the ethernet cable.

• Reproduce the issue:

1. Unplug the ethernet cable
2. Check the Speed property from /xyz/openbmc_project/network/ethX dbus object.

root@board:~# busctl introspect xyz.openbmc_project.Network /xyz/openbmc_project/network/eth0 | grep "Speed"
.Speed                                            property  u         65535                                                                  emits-change

• Analyst issue

The phosphor-networkd will report Speed property by int type from the Ethernet PHY Linux driver (https://elixir.bootlin.com/linux/v6.6/source/include/linux/phy.h#L682)

But the Speed property was defined as a uint32 type (phosphor-dbus-interfaces/yaml/xyz/openbmc_project/Network/EthernetInterface.interface.yaml at master · openbmc/phosphor-dbus-interfaces)

A mismatch value type will happen when unplug the RJ45 cable, the Ethernet PHY Linux driver will return -1 value (SPEED_UNKNOWN macro) but the phosphor-networkd reports an uint32 value to the Speed property (phosphor-dbus-interfaces/yaml/xyz/openbmc_project/Network/EthernetInterface.interface.yaml at master · openbmc/phosphor-dbus-interfaces ). So, the Speed property will be 65535 (decimal number).

[williamspatrick]

phosphor-networkd should probably catch the -1 condition and set the property to either 0 or max_int to indicate unknown.

[chnguyen-ampere]

phosphor-networkd should probably catch the -1 condition and set the property to either 0 or max_int to indicate unknown.

Thank @williamspatrick , I'll push a patch to support probably catching the -1 condition and then set the property to 0 to indicate unknown.

[chnguyen-ampere]

Hi @williamspatrick , I pushed a patch to fix this issue https://gerrit.openbmc.org/c/openbmc/phosphor-networkd/+/76647 . Please help me take look it!