EC25-EU modem problems when host resumes from sleep

Hello,

we are currently facing issues with a EC25-EU modem when the host resumes from sleep.

We are using a SBC (SBC-IOT-iMX8 | NXP i.MX8M Mini | Internet of Things Gateway SBC | Compulab) with the EC25-EU connected via Mini PCIe. The SBC runs yocto kirkstone with ModemManager 1.18.8. Modem-firmware: EG25GGBR07A08M2G_30.202.30.202

Our application requires the system to enter sleep mode frequently (suspend to RAM). The system wakes up every 90s and stays awake for about 15s before it enters sleep mode again.

We frequently encounter multiple different issues with the modem after the host resumes from sleep (every few suspend-resume cyles):

QMI-communication problem:

Dec 10 22:01:33 afgi-device ModemManager[279452]: <info>  [sleep-monitor] system is resuming                                                                                                                                               
Dec 10 22:01:33 afgi-device ModemManager[279452]: <info>  [modem0] resume synchronization state (1/4): modem interface sync                                                                                                                
Dec 10 22:01:33 afgi-device ModemManager[279452]: <info>  [modem0] simple connect started...                                                                                                                                               
Dec 10 22:01:33 afgi-device ModemManager[279452]: <info>  [modem0] simple connect state (4/8): wait to get fully enabled                                                                                                                   
Dec 10 22:01:33 afgi-device ModemManager[279452]: <info>  [modem0] simple connect state (5/8): register                                                                                                                                    
Dec 10 22:01:33 afgi-device ModemManager[279452]: <info>  [modem0] simple connect state (6/8): bearer                                                                                                                                      
Dec 10 22:01:33 afgi-device ModemManager[279452]: <info>  [modem0] simple connect state (7/8): connect                                                                                                                                     
Dec 10 22:01:33 afgi-device ModemManager[279452]: <info>  [modem0] state changed (registered -> connecting)                                                                                                                                
Dec 10 22:01:38 afgi-device ModemManager[279452]: transaction 0x6c6 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:39 afgi-device ModemManager[279452]: transaction 0x6c7 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:40 afgi-device ModemManager[279452]: transaction 0x6c8 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:41 afgi-device ModemManager[279452]: transaction 0x6c9 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:42 afgi-device ModemManager[279452]: transaction 0x6ca aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:43 afgi-device ModemManager[279452]: transaction 0x73 aborted, but message is not abortable                                                                                                                                   
Dec 10 22:01:43 afgi-device ModemManager[279452]: transaction 0x6cb aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:43 afgi-device ModemManager[279452]: transaction 0x6cc aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:43 afgi-device ModemManager[279452]: <warn>  [modem0] could not load SIM identifier: QMI operation failed: Transaction timed out (3 retries left)                                                                             
Dec 10 22:01:43 afgi-device ModemManager[279452]: <warn>  [modem0] couldn't load extended signal information: No way to load extended signal information                                                                                   
Dec 10 22:01:44 afgi-device ModemManager[279452]: transaction 0x18c aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:44 afgi-device ModemManager[279452]: transaction 0x6cd aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:44 afgi-device ModemManager[279452]: transaction 0x6ce aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:44 afgi-device ModemManager[279452]: <warn>  [modem0] couldn't load extended signal information: No way to load extended signal information                                                                                   
Dec 10 22:01:45 afgi-device ModemManager[279452]: transaction 0x6cf aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:45 afgi-device ModemManager[279452]: transaction 0x6d0 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:45 afgi-device ModemManager[279452]: <warn>  [modem0] couldn't load extended signal information: No way to load extended signal information                                                                                   
Dec 10 22:01:46 afgi-device ModemManager[279452]: transaction 0x6d1 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:46 afgi-device ModemManager[279452]: transaction 0x6d2 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:46 afgi-device ModemManager[279452]: <warn>  [modem0] couldn't load extended signal information: No way to load extended signal information                                                                                   
Dec 10 22:01:47 afgi-device ModemManager[279452]: transaction 0x6d3 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:47 afgi-device ModemManager[279452]: transaction 0x6d4 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:47 afgi-device ModemManager[279452]: <warn>  [modem0] couldn't load extended signal information: No way to load extended signal information                                                                                   
Dec 10 22:01:48 afgi-device ModemManager[279452]: transaction 0x6d5 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:48 afgi-device ModemManager[279452]: transaction 0x6d6 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:48 afgi-device ModemManager[279452]: <warn>  [modem0] couldn't load extended signal information: No way to load extended signal information                                                                                   
Dec 10 22:01:49 afgi-device ModemManager[279452]: transaction 0x6d7 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:49 afgi-device ModemManager[279452]: transaction 0x18d aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:49 afgi-device ModemManager[279452]: transaction 0x6d8 aborted, but message is not abortable                                                                                                                                  
Dec 10 22:01:49 afgi-device ModemManager[279452]: <warn>  [modem0/bearer1] connection attempt #54 failed: Transaction timed out

The ModemManager automatically recovers from that error-state by resetting the modem.

USB connection lost:
Sometimes after the host resumes from sleep, the USB device for the EC25-EU modem does not appear anymore (lsusb). The only way to recover from that situation, is to restart the system or hard-reset the modem (Reset-Pin).

I’ve already tried many things which did not solve the problem:

  • Upgrading ModemManager to 1.22
  • Starting the ModemManager with the ‘–test-quick-suspend-resume’ -flag (without that flag, the ModemManager resets the modem on every system-resume)
  • Blacklisting/ unloading the “option”-driver → This has at least reduced the frequency with which the problems occurs.
  • Applying some kernerl patches based on ‘Quectel_UMTS_LTE_5G_Linux_USB_Driver_User_Guide_V3.1-1.pdf’ I’ve found somwhere on this forum.
  • Putting the modem to low power state before suspending the system
      mmcli -m "${MODEM_NAME}" --disable
      mmcli -m "${MODEM_NAME}" --set-power-state-low

I constanly try to find a solution by trying different configurations on 10 devices in parallel. The problem appears on all of them.
You could you please assist me in troublshooting this issue.

I recommend you try pulling up the DTR pin to see if it can solve this problem.

It is better to provide the dmesg log.