[systemd-devel] About stable network interface names

[Martin Wilck]

On Tue, 2017-06-06 at 21:40 +0300, Andrei Borzenkov wrote:
> 
> Can device and function really change? My understanding is that
> device
> part is determined by bus physical wiring and function by PCI card
> design; this leaves bus as volatile run-time enumeration value.

For PCIe, that's only true for the "function" part.
https://superuser.com/questions/1060808/how-is-the-device-determined-in
-pci-enumeration-bus-device-function

The systemd docs are a bit misleading for PCIe, as they talk about
"physical/geographical location" for the common enp$Xs$Yf$Z scheme,
which is actually just the BDF. The interface on my laptop is called
enp0s31f6 although the laptop doesn't have "slot 31". (1)

Martin

(1) Well, that's actually because the manufacturer saved the money to
implement the DMI BIOS correctly: there is even a DMI type 41 entry for
onboard LAN, but the PCI device number (sic!) is wrong.

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