[systemd-devel] Use a specific device ?

[Mantas Mikulėnas]

On Fri, Jun 5, 2015 at 4:22 PM, Harald Hoyer <harald.hoyer at gmail.com> wrote:

> On 05.06.2015 15:09, poma wrote:
> > 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?
> >
>
> Wouldn't it be nicer to have symlinks like in /dev/disk ?
> /dev/tty/by-path/....


60-serial.rules:16:ENV{ID_PATH}=="?*", ENV{.ID_PORT}=="",
SYMLINK+="serial/by-path/$env{ID_PATH}"
60-serial.rules:17:ENV{ID_PATH}=="?*", ENV{.ID_PORT}=="?*",
SYMLINK+="serial/by-path/$env{ID_PATH}-port$env{.ID_PORT}"

-- 
Mantas Mikulėnas <grawity at gmail.com>
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