Score:0

Device "/dev/ttyUSB0" suddenly missing

py flag

I have a very basic server Ubuntu 22.04.2 LTS on Proxmox running Docker with a USB 3G Modem used as a SMS Gateway. It worked for a couple of weeks, but today it stopped working as device "/dev/ttyUSB0". I didn't installed nothing recently, maybe I just upgraded the OS, but the device is seen on dmesg once I connect it:

[  290.515190] usb 2-1: new high-speed USB device number 2 using xhci_hcd
[  290.668094] usb 2-1: New USB device found, idVendor=05c6, idProduct=1000, bcdDevice= 0.00
[  290.668104] usb 2-1: New USB device strings: Mfr=3, Product=2, SerialNumber=4
[  290.668107] usb 2-1: Product: Qualcomm CDMA Technologies MSM
[  290.668109] usb 2-1: Manufacturer: Qualcomm, Incorporated
[  290.668111] usb 2-1: SerialNumber: 35***********60
[  290.684334] usb-storage 2-1:1.0: USB Mass Storage device detected
[  290.686380] scsi host3: usb-storage 2-1:1.0
[  290.686555] usbcore: registered new interface driver usb-storage
[  290.691327] usbcore: registered new interface driver uas

And after some time:

[  312.783760] usb 2-1: reset high-speed USB device number 2 using xhci_hcd
[  359.157508] usbcore: registered new interface driver usbserial_generic
[  359.157528] usbserial: USB Serial support registered for generic
[  364.179931] usbcore: registered new interface driver qcserial
[  364.179957] usbserial: USB Serial support registered for Qualcomm USB modem

Here some other output:

# lsusb
Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 002 Device 002: ID 05c6:1000 Qualcomm, Inc. Mass Storage Device
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd QEMU USB Tablet
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
# modprobe usbserial
# modprobe qcserial
#

I can reinstall the OS, and it would be the second time with the same issue, and if I don't find the root cause it may happen again. Does someone has any ideas of the root cause?

UPDATE: Once replicating the behavior (connecting the USB device trough ProxMox), journalctl -b doesn't seem to show anything useful:

Apr 02 19:23:48 DOCKER-01 kernel: usb 2-1: new high-speed USB device number 2 using xhci_hcd
Apr 02 19:23:48 DOCKER-01 kernel: usb 2-1: New USB device found, idVendor=05c6, idProduct=1000, bcdDevice= 0.00
Apr 02 19:23:48 DOCKER-01 kernel: usb 2-1: New USB device strings: Mfr=3, Product=2, SerialNumber=4
Apr 02 19:23:48 DOCKER-01 kernel: usb 2-1: Product: Qualcomm CDMA Technologies MSM
Apr 02 19:23:48 DOCKER-01 kernel: usb 2-1: Manufacturer: Qualcomm, Incorporated
Apr 02 19:23:48 DOCKER-01 kernel: usb 2-1: SerialNumber: 35***********60
Apr 02 19:23:48 DOCKER-01 kernel: usb-storage 2-1:1.0: USB Mass Storage device detected
Apr 02 19:23:48 DOCKER-01 kernel: scsi host3: usb-storage 2-1:1.0
Apr 02 19:23:48 DOCKER-01 kernel: usbcore: registered new interface driver usb-storage
Apr 02 19:23:48 DOCKER-01 kernel: usbcore: registered new interface driver uas
Apr 02 19:23:53 DOCKER-01 systemd[1]: run-docker-runtime\[REDACTED]-runc.LcuTxY.mount: Deactivated successfully.
Apr 02 19:24:10 DOCKER-01 kernel: usb 2-1: reset high-speed USB device number 2 using xhci_hcd
Apr 02 19:24:45 DOCKER-01 systemd[1]: run-docker-runtime\[REDACTED]-runc.s4nLGm.mount: Deactivated successfully.

Then, brltty is not installed (and I have already checked):

# dpkg -l | grep brltty
#

UPDATE

user1686 avatar
us flag
Are there any messages in `journalctl -b` surrounding those kernel messages? In particular, when udev detects the device in its "storage" mode, it's supposed to invoke "usb_modeswitch" which then does some magic to switch it to "modem" mode; look for messages related to that.
nobody avatar
gh flag
Can you plug the device in an usb2 port? And for a long shot `dpkg -l | grep brltty ` please.
David avatar
cn flag
Device may also be going bad can you replace it?
Masterlog_ITA avatar
py flag
On Windows, it seems working.
Masterlog_ITA avatar
py flag
I was able to fix the issue by following those instructions: https://askubuntu.com/a/1295507/1685859 That doesn't explain why it was working for weeks without the UDEV rule, but it's fine it's fixed now.
I sit in a Tesla and translated this thread with Ai:

mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.