[systemd-devel] Match section of .link file not working

[Kay Sievers]

On Mon, Aug 25, 2014 at 7:25 PM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Sun, 24.08.14 06:49, Simon Peeters (peeters.simon at gmail.com) wrote:
>
>> >> This should be the value of ID_PATH property, not sysfs path. Check with
>> >>
>> >> udevadm info --query
>> >> property /sys/devices/ocp.3/47400000.usb/musb-hdrc.1.auto/usb1/1-1/1-1:1.0/net/wlv3
>> >
>> > oops, I confused ID_PATH with DEVPATH, now i feel like an idiot.
>
> ID_PATH is basically the "reduced + stable" part of the full sysfs path.
>
>> Ok, so there is only one problem now:
>> ID_PATH is the same for all my vif interfaces, and i need to select
>> only one of them.

ID_PATH usually describes the "parent hardware", and the same hardware
can have multiple independent devices. Unique names for several
devices need to be composed by appending something to the "parent
hardware".

I don't have a good idea what a working model for your case would be,
where multiple devices share the same parent. This is not a common
model.

> This is some embedded device with your hw connected to some platform
> bus?
>
> Currently the ID_PATH logic doesn't understand platform busses (since it
> is not clear how "stable" they are). This has come up before, and could
> probably be fixed. Maybe we should assume that platform busses are
> always enuemrated in a stable way, dunno.
>
> Kay probably has something useful to say here. Kay?

Special buses need explicit support in the code if ID_PATH is not
generated, but that does not look like the problem here.

Seems the USB interface exports 3 different network devices. Do they
have any unique property? Like dev_id, dev_port in /sys? Or are the
types of the netifs unique?

If anything like that is available, that could be appended to the
parent ID_PATH string and identify the device uniquely, if you get
what I mean.

Kay