On 26/09/14 11:47, Samuli Suominen wrote: > On 26/09/14 11:22, Canek Peláez Valdés wrote: >> On Fri, Sep 26, 2014 at 3:07 AM, Neil Bothwick <n...@digimed.co.uk> wrote: >>> On Fri, 26 Sep 2014 05:27:15 +0200, Alan McKinnon wrote: >>> >>>>> I buy machines with one ethernet interface. What I find >>>>> particularly annoying is this doublespeak about calling it >>>>> "predictable". Before the change, it was predicatbly "eth0". Now, >>>>> it's different on every different model. >>>> It's not doublespeak, the interfaces are named exactly according to >>>> where they are on the PCI bus. If you had two interfaces, they show up >>>> to the kernel in random order by time and sometimes eth0/eth1 are nto >>>> the same they were before the reboot. >>> That may be true for PCI devices but not for USB ones. If you unplug a >>> USB device and plug it back into the same port, it will get a different >>> device number. The naming is more predictable, but it's not there yet. >> That doesn't sound right. If unplugging a USB net device and plugging >> it again *in the same port* results in a different device *name*, then >> it is a bug and should be reported; the description of the algorithm >> in [1] sounds like it should get always the same name for the same >> port, unless I'm misunderstanding something. >> >> Regards. >> >> [1] >> http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n51 > I've seen this happening once on a cheap laptop with a stripped down > BIOS I can't > even recall brand for, it had a kludge in the BIOS settings for > hotplugging, turning > it off, allowed the port to remain same, turning it on, some machine > specific code > gets executed and the kernel interprets the same port as different port > > Bad hardware, bad hardware settings, maybe missing exception for that > particular > hardware type in the code that determines the name... I'm not sure, I > don't have > the machine anymore > > - Samuli >
Later kernels *can mark interfaces predictable in a new form of metadata*, and udev >= 209 can pick that information up, and then it won't do anykind of userspace renaming on it, since kernel has declared the interface name to be steady...predictable...always same, so I hope we are moving towards kernel assigning predictable names for all drivers and we can get rid of the userspace renaming of interfaces all together at some point I really believe this is a task for the kernel to provide predictable names, and all this userspace renaming is just a bandage we can hopefully soon rip off - Samuli
