[systemd-devel] Proposal: Add biosdevname naming scheme to systemd

[Andrei Borzenkov]

On Tue, Oct 20, 2015 at 7:46 AM, Jordan Hargrave <jharg93 at gmail.com> wrote:
> On Mon, Mar 2, 2015 at 1:17 PM, Tom Gundersen <teg at jklm.no> wrote:
>> Hi Jordan,
>>
>> On Mon, Mar 2, 2015 at 4:45 PM, Jordan Hargrave <jharg93 at gmail.com> wrote:
>>> There are currently two competing naming mechanisms for network cards,
>>> biosdevname and systemd.  Systemd currently has some limitations on naming
>>> cards that use network partitioning or support SR-IOV.
>>
>> Could you point to an example so we can fix it? I thought all bug
>> reports had been handled, but maybe I lost track of something.
>>
>
> I have a quad-port NIC:
> 0000:40:00.0 = PCIE bridge (SMBIOS Slot 2)
> 0000:41:00.0 = Ethernet Device (port1)
> 0000:41:00.1 = Ethernet Device (port2)
> 0000:42:00.0 = Ethernet Device (port3)
> 0000:42:00.1 = Ethernet Device (port4)
>
> biosdevname would name these p2p1, p2p2, p2p3, p2p4 respectively.
>

How does it determine that 41 and 42 are the same device? I.e. how
does it differ from real bridge with two independent two-port cards
behind? Could you explain what information it is using? Is it exported
in sysfs?

...
>
> That could be possible. I've tried submitting a patch upstream for
> kernel but hasn't been accepted yet.  So SMBIOS parsing would have to
> be part of systemd.
>

udev is already using SMBIOS type 41 to obtain slot number for
on-board devices. As long as this information is exported via sysfs
for other PCI cards it should be straightforward to extend.