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<div>Hi,<br></div><div dir="auto"><br></div><div dir="auto">I am a developer working on a board with a Quectel Modem, and I am in charge of replacing our old abstraction layer with ModemManager to communicate with this modem.<br></div><div dir="auto"><br></div><div dir="auto">I have been playing with ModemManager for a few days to be familiar with it. I have read the documentation and I have been reading also the source code to better understand how it works. <br></div><div dir="auto"><br></div><div dir="auto">However, a few fundamental questions remain for me, and I hope some people here may give me some clue.<br></div><div dir="auto"><br></div><div dir="auto">First of all, when I list the modems found by MM, it returns not one, but two modems:<br></div><div dir="auto"><br></div><div dir="auto"># mmcli -L<br></div><div dir="auto"> /org/freedesktop/ModemManager1/Modem/1 [Quectel] SG520TM<br></div><div dir="auto"> /org/freedesktop/ModemManager1/Modem/0 [Quectel] SG520TM<br></div><div dir="auto"><br></div><div dir="auto">One of them is linked to tty USB port and communicates only with AT commands (ttyUSBx), the other one is linked to the PCIe port and communicates only with QMI (wwan0qmi0).<br></div><div dir="auto">I do not have a wwan0at0 driver. The only way to have AT commands is through the ttyUSBx port.<br></div><div dir="auto"><br></div><div dir="auto">It looks like I have two separate modems, whereas I have only one physical modem, connected to the board with two physical ports (usb & pcie).<br></div><div dir="auto"><br></div><div dir="auto">The diagrams here suggest that MM can have single modems with more than one protocol, but on the same physical port:<br></div><div dir="auto"><a href="https://modemmanager.org/docs/modemmanager/wwan-device-types/">https://modemmanager.org/docs/modemmanager/wwan-device-types/</a><br></div><div dir="auto"><br></div><div dir="auto">Is it possible to have MM create only one modem using two different physical ports (ttyUSBx on USB & wwan0qmi0 on PCIe), in order to have AT & QMI simultaneously?<br></div><div dir="auto"><br></div><div dir="auto">If not, does it mean that in order to have one modem with AT & QMI, I would need to have a working wwan0at0 driver?<br></div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto">My second question is about the cache handling. <br></div><div dir="auto">I could see that MM may use cached AT results, meaning that your plugin can have the result of an AT command without actually sending it (with the allow_cached parameter).<br></div><div dir="auto">This is a great feature, and experience showed us that it improves dramatically your application latencies.<br></div><div dir="auto"><br></div><div dir="auto">Are QMI or Dbus requests cached as well?<br></div><div dir="auto"><br></div><div dir="auto">Regards,<br></div><div dir="auto">Alex<br></div><div dir="auto">-- <br></div><div> Sent with Tutanota, enjoy secure & ad-free emails. <br></div> </body>
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