Hello. I have a 4XC1Q24438 (Lenovo P/N) wired up to a T480.
Said modem works nice and all but it completely disappears (/dev/cdc-wdm0 disappears and no more functionality till reboot) when I suspend to RAM or hibernate.
What do I do? AT is disabled or i don’t know how to access it since there’s no /dev/ttyUSBXYZ
Could you show the dmesg log?
It is not sure what hapened. Maybe the Lenovo not support USB suspend and resume. And maybe there is someproblem with the hardware, so after the Linux resume but the USB device lost connection.
I checked again, /dev/cdc-wdm0 appears after resuming from S3 but not S2idle.
This is my dmesg log:
[34645.858991] PM: suspend entry (deep)
[34646.491848] Filesystems sync: 0.632 seconds
[34646.593992] Freezing user space processes
[34646.595480] Freezing user space processes completed (elapsed 0.001 seconds)
[34646.595484] OOM killer disabled.
[34646.595485] Freezing remaining freezable tasks
[34646.596696] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
[34646.596707] printk: Suspending console(s) (use no_console_suspend to debug)
[34646.764391] e1000e: EEE TX LPI TIMER: 00000011
[34646.853675] ACPI: EC: interrupt blocked
[34646.874738] ACPI: PM: Preparing to enter system sleep state S3
[34646.876204] ACPI: EC: event blocked
[34646.876205] ACPI: EC: EC stopped
[34646.876206] ACPI: PM: Saving platform NVS memory
[34646.876252] Disabling non-boot CPUs ...
[34646.877617] smpboot: CPU 3 is now offline
[34646.879745] smpboot: CPU 2 is now offline
[34646.881835] smpboot: CPU 1 is now offline
[34646.884750] ACPI: PM: Low-level resume complete
[34646.884801] ACPI: EC: EC started
[34646.884803] ACPI: PM: Restoring platform NVS memory
[34646.885546] Enabling non-boot CPUs ...
[34646.885637] smpboot: Booting Node 0 Processor 1 APIC 0x2
[34646.886737] CPU1 is up
[34646.886788] smpboot: Booting Node 0 Processor 2 APIC 0x4
[34646.887479] CPU2 is up
[34646.887520] smpboot: Booting Node 0 Processor 3 APIC 0x6
[34646.888241] CPU3 is up
[34646.889200] ACPI: PM: Waking up from system sleep state S3
[34646.891332] ACPI: EC: interrupt unblocked
[34646.902945] ACPI: EC: event unblocked
[34647.101514] nvme nvme0: 4/0/0 default/read/poll queues
[34647.122175] usb 2-3: reset SuperSpeed USB device number 2 using xhci_hcd
[34647.249137] usb 1-6: reset high-speed USB device number 2 using xhci_hcd
[34647.277896] iwlwifi 0000:01:00.0: WFPM_UMAC_PD_NOTIFICATION: 0x20
[34647.277935] iwlwifi 0000:01:00.0: WFPM_LMAC2_PD_NOTIFICATION: 0x1f
[34647.277952] iwlwifi 0000:01:00.0: WFPM_AUTH_KEY_0: 0x90
[34647.277962] iwlwifi 0000:01:00.0: CNVI_SCU_SEQ_DATA_DW9: 0x0
[34647.484170] usb 1-7: reset full-speed USB device number 3 using xhci_hcd
[34647.690327] psmouse serio1: synaptics: queried max coordinates: x [..5678], y [..4690]
[34647.719107] usb 1-8: reset high-speed USB device number 4 using xhci_hcd
[34647.724753] psmouse serio1: synaptics: queried min coordinates: x [1266..], y [1160..]
[34647.880629] OOM killer enabled.
[34647.880630] Restarting tasks: Starting
[34647.880674] usb 1-9: USB disconnect, device number 5
[34647.881688] Restarting tasks: Done
[34647.881706] random: crng reseeded on system resumption
[34647.882071] Bluetooth: hci0: Device revision is 0
[34647.882073] Bluetooth: hci0: Secure boot is enabled
[34647.882075] Bluetooth: hci0: OTP lock is enabled
[34647.882076] Bluetooth: hci0: API lock is enabled
[34647.882077] Bluetooth: hci0: Debug lock is disabled
[34647.882078] Bluetooth: hci0: Minimum firmware build 1 week 10 2014
[34647.882079] Bluetooth: hci0: Bootloader timestamp 2019.40 buildtype 1 build 38
[34647.882083] Bluetooth: hci0: No support for _PRR ACPI method
[34647.884149] Bluetooth: hci0: Found device firmware: intel/ibt-0041-0041.sfi
[34647.884239] Bluetooth: hci0: Boot Address: 0x100800
[34647.884241] Bluetooth: hci0: Firmware Version: 133-20.25
[34647.898683] video LNXVIDEO:00: Restoring backlight state
[34647.900546] PM: suspend exit
[34647.995932] usb 1-9: new full-speed USB device number 7 using xhci_hcd
[34648.121498] usb 1-9: New USB device found, idVendor=06cb, idProduct=009a, bcdDevice= 1.64
[34648.121503] usb 1-9: New USB device strings: Mfr=0, Product=0, SerialNumber=1
[34648.121505] usb 1-9: SerialNumber: XXXXXXXXXXXX
[34649.506085] Bluetooth: hci0: Waiting for firmware download to complete
[34649.506088] Bluetooth: hci0: Firmware loaded in 1583941 usecs
[34649.506181] Bluetooth: hci0: Waiting for device to boot
[34649.531232] Bluetooth: hci0: Device booted in 24550 usecs
[34649.533223] Bluetooth: hci0: Found Intel DDC parameters: intel/ibt-0041-0041.ddc
[34649.535192] Bluetooth: hci0: Applying Intel DDC parameters completed
[34649.538205] Bluetooth: hci0: Firmware timestamp 2025.20 buildtype 1 build 82053
[34649.538209] Bluetooth: hci0: Firmware SHA1: 0x937bca4a
[34649.542187] Bluetooth: hci0: Fseq status: Success (0x00)
[34649.542190] Bluetooth: hci0: Fseq executed: 00.00.02.41
[34649.542192] Bluetooth: hci0: Fseq BT Top: 00.00.02.41
[34649.615298] Bluetooth: MGMT ver 1.23
[34650.871629] e1000e 0000:00:1f.6 eno0: NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx
[34651.751454] wlp1s0: authenticate with XX:XX:XX:XX:XX:XX (local address=ea:2e:f7:ee:34:ba)
[34651.753575] wlp1s0: send auth to XX:XX:XX:XX:XX:XX (try 1/3)
[34651.801906] wlp1s0: authenticated
[34651.802947] wlp1s0: associate with XX:XX:XX:XX:XX:XX (try 1/3)
[34651.806964] wlp1s0: RX AssocResp from XX:XX:XX:XX:XX:XX (capab=0x1011 status=0 aid=24)
[34651.834393] wlp1s0: associated
[34651.858065] wlp1s0: Limiting TX power to 30 (30 - 0) dBm as advertised by XX:XX:XX:XX:XX:XX
From the log we can know that the Linux do not support USB suspend.
So once the Linux resume, the USB lost connection.
You can reset the USB controller and then you can see the USB modem.
echo 0 > /sys/bus/usb/drivers/usb/usb1/authorized
sleep 1
echo 1 > /sys/bus/usb/drivers/usb/usb1/authorized
How does Bluetooth work then? It seems to share the same controller
We can see that the Bluetooth USB device enumerate again.It still not connection after the resume.
I didn’t see the USB modem from the log.
As of now I am able to send AT commands. Seems like the modem responds after S3 sleep without restarting USB bus especially if i set QT+QSCLK to 1. It doesn’t save when I set it to 1,1 though, it returns (1,0),(1,0) when I query it
AT+QSCLK=1 cannot save the params. It need to be set every time.