Hey,
>
>
> I'm running into trouble with ModemManager, there seems to be no way to
> disable probing for certain devices.
> I have found countless threads discussing the lack of this feature, but none
> of them refer to my specific troubles.
>
We did have lots of problems in the past with blocklisting certain
type of devices automatically, we were too optimistic trying to look
for TTY modems. I guess that is what you are referring to, bu that has
changed a lot in the past years.
>
> We have some CDC devices that implement ACM and ether.
> We want to communicate on the ttyACM of these devices, but our data keeps
> getting corrupted.
Are those ttyACM ports AT ports, or some other protocol? ModemManager
would only probe ttyACM ports that report themselves as using the AT
protocol in the USB descriptors.
> After many hours we finally found out ModemManager is probing the devices, so
> we added the udev rules:
>
> /etc/udev/rules.d/78-custom-mm-blacklist-internal-modem.rules :
>
> ACTION!="add|change|move", GOTO="custom_mm_blacklist_internal_modem_end"
> ATTRS{idVendor}=="[redacted1]" ATTRS{idProduct}=="[redacted2]",
> ENV{ID_MM_DEVICE_IGNORE}="1"
> ATTRS{idVendor}=="[redacted1]" ATTRS{idProduct}=="[redacted3]",
> ENV{ID_MM_DEVICE_IGNORE}="1"
> LABEL="custom_mm_blacklist_internal_modem_end"
>
> but looking at the logs I see:
>
> ModemManager[3751]: <debug> [filter] (tty/ttyACM0): port filtered: device is
> blocklisted
> ModemManager[3751]: <debug> [filter] (net/enxd[redacted4]) port allowed: net
> device
> ModemManager[3751]: <debug> [filter] (net/enxd[redacted4]) port allowed: net
> device
> ModemManager[3751]: <debug> [filter] (tty/ttyACM0): port allowed: device also
> exports a net interface
>
> So if ModemManager successfully found the device is blocklisted, why does it
> continue to probe the port?
This is definitely a bug. I've opened
https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/833
> What is the recommended mechanism to disable the probing of these devices?
>
> I would prefer to exclude these specific devices, and not have to resort to
> heavy handed solutions that alter the global rules.
>
Your udev rules should have fully blocklisted the device, but they
didn't, sorry for that :/
Let's get this fixed.
--
Aleksander
