Hi, I am running kernel 4.19.75 on iMX6 with a uBlox SARA-R4 LTE modem, the modem manager is oFono, connect manager is connman. It could connect to LTE between half hours to hours, then it dropped LTE connection randomly, here are error messages, what could cause the qmi_wwan status received: -71 and qmi_wwan usb_submit_urb failed with result -19 errors? [ 1018.944840] usb 1-1: USB disconnect, device number 2 [ 1019.072845] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0 [ 1019.130834] option 1-1:1.0: device disconnected [ 1019.142012] qmi_wwan 1-1:1.3: nonzero urb status received: -71 [ 1019.147909] qmi_wwan 1-1:1.3: wdm_int_callback - 0 bytes [ 1019.153254] qmi_wwan 1-1:1.3: wdm_int_callback - usb_submit_urb failed with result -19 [ 1019.228197] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1 [ 1019.274475] option 1-1:1.2: device disconnected [ 1019.340442] qmi_wwan 1-1:1.3 wwan0: unregister 'qmi_wwan' usb-ci_hdrc.1-1, WWAN/QMI device [ 1022.827992] usb 1-1: new high-speed USB device number 3 using ci_hdrc [ 1023.057165] option 1-1:1.0: GSM modem (1-port) converter detected [ 1023.097815] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0 [ 1023.157293] option 1-1:1.2: GSM modem (1-port) converter detected [ 1023.178163] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1 [ 1023.201251] qmi_wwan 1-1:1.3: cdc-wdm0: USB WDM device [ 1023.243783] qmi_wwan 1-1:1.3 wwan0: register 'qmi_wwan' at usb-ci_hdrc.1-1, WWAN/QMI device, 16:ed:38:aa:c5:90 Thank you. Kind regards, - jh
