Forums - Quectel RM502QAE (5G Mezzanine board) not detected

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Quectel RM502QAE (5G Mezzanine board) not detected
alejandro
Join Date: 16 Mar 23
Posts: 3
Posted: Thu, 2023-03-16 07:12

Hello everyone,

We recently purchased an RB5 development kit along with the optional 5G Mezzanine board, which mounts the Quectel RM502QAE 5G modem. We followed the steps on the startup guide (https://developer.qualcomm.com/qualcomm-robotics-rb5-kit/quick-start-gui...): downloaded the SDK manager and flashed a fresh Ubuntu 18 image (more specifically, the "QRB5165.UBUN.1.0-220923_debug"). We then connected the 5G Mezzanine board on top of the development kit.

The Quectel modem, however, is not detected. We know from the output of lsusb that the first ID it shows (2c7c:0800) corresponds to the Quectel RM502QAE modem, because we have other devices with Quectel modems attached to them that report the same ID. However, the RB5 development kit does not seem recognize it, as it does not provide a description for it.
 

We have investigated and we have found no documentation related to setting up this 5G Mezzanine, neither in the startup guide nor the forums. We would appreciate any pointers to what could be the source of this issue and a possible way to solve it.

Kind regards,

Alejandro

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alejandro
Join Date: 16 Mar 23
Posts: 3
Posted: Mon, 2023-03-20 07:25

Hello again,

The issue has been solved. The modem was indeed not being identified by lsusb nor mmcli -L; however, dmesg output showed that the system recognized it, so we concluded that the issue was lying with the modem manager. Removing the --filter-policy=strict on the service file (in /lib/systemd/system/ModemManager.service) was necessary; when running mmcli -M afterwards, the modem is added to the list and given a number e.g.
mmcli -M
/org/freedesktop/ModemManager1/Modem/0 [Quectel] RM502Q-AE

From this point onwards, mmcli works as expected.

With regards,

Alejandro

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alejandro
Join Date: 16 Mar 23
Posts: 3
Posted: Tue, 2023-03-21 09:24

Hello everyone,

The situation with the Quectel modem still persists. The base Ubuntu 18 image flashed from the SDK manager does not seem to include USB serial nor Quectel drivers. The output of mmcli -m 0 (assuming the modem is in ID 0) is the following:

  --------------------------------
  General  |            dbus path: /org/freedesktop/ModemManager1/Modem/0
           |            device id: 7996b6407f1a94da3cf3384527da5a27a29a0bdb
  --------------------------------
  Hardware |         manufacturer: Quectel
           |                model: RM502Q-AE
           |             revision: RM502QAEAAR11A02M4G
           |            supported: gsm-umts, lte
           |              current: gsm-umts, lte
           |         equipment id: 867826050502558
  --------------------------------
  System   |               device: /sys/devices/platform/soc/a800000.ssusb/a800000.dwc3/xhci-hcd.0.auto/usb2/2-1/2-1.4
           |              drivers: option1
           |               plugin: Generic
           |         primary port: ttyUSB2
           |                ports: ttyUSB0 (qcdm), ttyUSB2 (at), ttyUSB3 (at)
  --------------------------------
  Status   |       unlock retries: sim-pin (3), sim-pin2 (3), sim-puk (10), sim-puk2 (10)
           |                state: enabled
           |          power state: on
           |       signal quality: 0% (cached)
  --------------------------------
  Modes    |            supported: allowed: 2g, 3g, 4g; preferred: none
           |              current: allowed: 2g, 3g, 4g; preferred: none
  --------------------------------
  IP       |            supported: ipv4, ipv6, ipv4v6
  --------------------------------
  3GPP     |                 imei: 867826050502558
           |         registration: idle
  --------------------------------
  3GPP EPS | ue mode of operation: csps-2
  --------------------------------
  SIM      |            dbus path: /org/freedesktop/ModemManager1/SIM/0

The system identifies it as a Generic plugin, rather than a Quectel plugin with associated option and usb_wwan drivers. Also, we would expect the cdc-wdm0 and wwan0 interfaces / ports to be open, but they are not. Am I correct in assuming that this should be the case if the Quectel drivers were installed?

In parallel, we also reached out to Quectel and received the drivers for this modem model, which we have successfully installed using the custom kernel (4.19.125-perf). However, modprobe does not seem to start the driver even if it reports no issues; we conclude this from running lsmod and seeing these drivers missing. What would be the correct way of doing this?

With regards,

Alejandro

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