Hello, I am using a Quectel EC21 modem, connected to an imx6ul soc via usb (UART is also available), everything works fine and I have connectivity without issues.
So my usecase is putting both the cpu and the modem, and I am able to do that, but the wakeup should be from a remote MQTT message coming from my server which will wakeup the modem first, that in turn wakeup the cpu using the RI pin. I have played around with this and it is only possible if I use the modem's MQTT stack, as it will maintain the TCP connection even in sleep mode. I am configuring the MQTT endpoint using AT commands (through mmcli --commands). The problem is that I am not able to receive the messages when subscribing to a topic, even though I know the message arrived (I can see the raw data when putting modemmanager in Debug mode). So my question is, is it possible to receive the MQTT URCs (+QMTRECV for example) over DBUS so that my application could handle them after wakeup, and if not what path should I follow ? Note: I tried probing the USB AT interface for incoming URCs but I wasn't able to receive them, probably because modemmanager is concurrently using it as well ? Regards, Mohamed
