Simtech plugin filtering out Waveshare Raspberry Pi 4G HAT

Aleksander Morgado aleksander at
Wed Nov 17 15:54:13 UTC 2021


> I've just bought one of these
> and I'm trying to get it to work with ModemManager using (at the moment) the default version available in Raspberry Pi OS (mm 1.14.12). I'm also having some trouble convincing meson to build the latest version to try making changes, but I think that's a separate problem entirely due to my lack of understanding of meson.
> ModemManager v1.14.12 works if I switch the jumpers around to "control the SIM7600 via USB to UART" and plug in an additional USB cable from the Pi to the HAT's onboard USB connection, but I'm trying to get it to work without this cable and in its default "Raspberry Pi control" jumper setting (mainly because it's neater, honestly).
> I believe that the Hat's serial port is being filtered out because the Simtech plugin expects the Hat to have a Vendor/Product ID. However, when plugged in via the GPIO header, I see only a serial (ttyS0) interface, and thus no Vendor/Product IDs can match.
> Can I force the Simtech plugin to be used, or would it make no sense because of the single serial port? Should it be claimed and usable by the AT plugin instead? I'm more than happy to change stuff on this, because it has no other use at the moment.

You should tag the ttyS0 interface with the "ID_MM_DEVICE_PROCESS"
udev tag, so that MM can process the port.

The Simtech plugin doesn't support non-USB modems, though, so you'll
probably end up with the generic plugin managing the modem. If you do
need the Simtech plugin, we could probably update it to have "vendor
and product string filters" as some other plugins supporting RS232


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