[systemd-devel] Use a specific device ?

[Dan Williams]

On Fri, 2015-06-05 at 16:16 +0200, Jean-Christian de Rivaz wrote:
> Le 05. 06. 15 15:51, poma a écrit :
> > On 05.06.2015 15:37, Jean-Christian de Rivaz wrote:
> >> Le 05. 06. 15 15:09, poma a écrit :
> >>> On 05.06.2015 14:14, Jean-Christian de Rivaz wrote:
> >>>> Le 05. 06. 15 13:18, Aleksander Morgado a écrit :
> >>>>> On Tue, May 26, 2015 at 12:19 AM, Jean-Christian de Rivaz <jc at eclis.ch> wrote:
> >>>>>> I have a system where the modem have multiple /dev/ttyACMx ports where x is
> >>>>>> not constant because of the dynamic nature of others serial devices.
> >>>>> It may be worth noting that a very similar issue with the one faced
> >>>>> here is the one with network interface names, where interface names
> >>>>> were created as kernel drivers probed the different interfaces, ending
> >>>>> up with "eth0", "eth1" and so on. Then, there would be network
> >>>>> interface configurations for each network interface based on the name,
> >>>>> but no one really ensured that the name was the same upon reboots. The
> >>>>> solution provided by systemd to ensure that the proper configuration
> >>>>> is applied always to the proper interface is to make the device names
> >>>>> "predictable", see:
> >>>>> http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/
> >>>>>
> >>>>> This solution avoids the need of any other udev rules to e.g. create
> >>>>> network interface names containing the device MAC address or what not.
> >>>>>
> >>>>> I'm wondering whether the same could be applied not only to network
> >>>>> interfaces, but also to ttyACMs, ttyUSBs and cdc-wdms, and end up
> >>>>> having predictable tty names like e.g. /dev/ttyACMp0s20u4i0. Sure,
> >>>>> those names are a nightmare to type, but they are predictable (e.g. in
> >>>>> this case by including the physical location of the connector of the
> >>>>> hardware).
> >>>>>
> >>>> This would be a wonderful solution. The only problem is when will this
> >>>> feature be available in a stable Linux kernel widely used by all majors
> >>>> distributions? Until this dream happens (probably not before severals
> >>>> years I guess), an other option must be implemented.
> >>>>
> >>>> Jean-Christian
> >>> Face your broadband modem, live your dreams?
> >>>
> >>> Kay, when this would happen - Predictable Broadband Modem Interface Names?
> >>>
> >> I must emphasis that this solution will still not solve the ModemManager
> >> problem of automatically probing any added serial devices, requiring all
> >> non-modem serial device to add the ID_MM_IGNORE hack in udev rules. This
> >> must change as soon as possible.
> >>
> >> Jean-Christian
> >>
> >
> > MM probing various hardware, not much of a news.
> >
> 
> But still a problem. The lack of proper use of udev by ModemManager 

What is "proper" use of udev here?

Dan