[systemd-devel] Use a specific device ?

[poma]

On 05.06.2015 16:12, Harald Hoyer wrote:
> On 05.06.2015 15:41, poma wrote:
>> On 05.06.2015 15:29, Harald Hoyer wrote:
>>> On 05.06.2015 15:28, Mantas Mikulėnas wrote:
>>>> On Fri, Jun 5, 2015 at 4:22 PM, Harald Hoyer <harald.hoyer at gmail.com
>>>> <mailto: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
>>>>     <mailto: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 <mailto:grawity at gmail.com>>
>>>
>>> There we go.. already implemented :)
>>
>>
>> But not dracut-mented:
>> # lsinitrd initramfs-4.1.0-0.rc5.git0.1.fc23.x86_64.img | grep 60-serial.rules ; echo $?
>> 1
>>
>>
>> https://github.com/systemd/systemd/blob/master/rules/60-serial.rules
>>
>>
> 
> no modem-manager in there also
> 


Thank you.