Re: /dev/ttyUSB0 file disappears on Ubuntu 22.04

[Greg KH <greg@kroah.com>]

On Thu, Jun 02, 2022 at 11:47:50AM +0300, Yuri wrote:
> Thanks for a quick reply, Greg. No, no error here. No matter when I execute
> this on my PC under Ubuntu 22.04
> 
> ls -l /dev/ttyUSB*
> 
> I get this
> 
> ls: cannot access '/dev/ttyUSB*': No such file or directory

Is the device node actually there?

What does /dev/serial/ contain?

> I made this log after attaching and removing the device. Here's dmesg output
> 
> [ 2276.613198] usb 2-1.5: new full-speed USB device number 5 using ehci-pci
> [ 2276.727502] usb 2-1.5: New USB device found, idVendor=0403,
> idProduct=6001, bcdDevice= 6.00
> [ 2276.727511] usb 2-1.5: New USB device strings: Mfr=1, Product=2,
> SerialNumber=3
> [ 2276.727514] usb 2-1.5: Product: USB Serial
> [ 2276.727516] usb 2-1.5: Manufacturer: FTDI
> [ 2276.727518] usb 2-1.5: SerialNumber: FT0KKBIF
> [ 2276.729550] ftdi_sio 2-1.5:1.0: FTDI USB Serial Device converter detected
> [ 2276.729626] usb 2-1.5: Detected FT232RL
> [ 2276.730487] usb 2-1.5: FTDI USB Serial Device converter now attached to
> ttyUSB0
> [ 3173.152415] usb 2-1.5: USB disconnect, device number 5
> [ 3173.152974] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now
> disconnected from ttyUSB0
> [ 3173.153005] ftdi_sio 2-1.5:1.0: device disconnected
> [ 3182.847132] kauditd_printk_skb: 1 callbacks suppressed
> [ 3396.861511] usb 2-1.5: new full-speed USB device number 6 using ehci-pci
> [ 3396.975858] usb 2-1.5: New USB device found, idVendor=0403,
> idProduct=6001, bcdDevice= 6.00
> [ 3396.975866] usb 2-1.5: New USB device strings: Mfr=1, Product=2,
> SerialNumber=3
> [ 3396.975870] usb 2-1.5: Product: USB Serial
> [ 3396.975872] usb 2-1.5: Manufacturer: FTDI
> [ 3396.975874] usb 2-1.5: SerialNumber: FT0KKBIF
> [ 3396.978651] ftdi_sio 2-1.5:1.0: FTDI USB Serial Device converter detected
> [ 3396.978714] usb 2-1.5: Detected FT232RL
> [ 3396.979568] usb 2-1.5: FTDI USB Serial Device converter now attached to
> ttyUSB0
> [ 3553.309826] usb 2-1.5: USB disconnect, device number 6
> [ 3553.310371] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now
> disconnected from ttyUSB0
> [ 3553.310404] ftdi_sio 2-1.5:1.0: device disconnected
> 
> 
> And here's the syslog output echoing log above
> 
> Jun  2 10:41:54 qgs-comp kernel: [ 3173.152415] usb 2-1.5: USB disconnect,
> device number 5
> Jun  2 10:41:54 qgs-comp kernel: [ 3173.152974] ftdi_sio ttyUSB0: FTDI USB
> Serial Device converter now disconnected from ttyUSB0
> Jun  2 10:41:54 qgs-comp kernel: [ 3173.153005] ftdi_sio 2-1.5:1.0: device
> disconnected
> Jun  2 10:42:02 qgs-comp systemd[1786]: Started Application launched by
> gnome-shell.
> Jun  2 10:42:03 qgs-comp libreoffice-writer.desktop[7821]: Warning: failed
> to launch javaldx - java may not function correctly
> Jun  2 10:42:04 qgs-comp kernel: [ 3182.847132] kauditd_printk_skb: 1
> callbacks suppressed
> Jun  2 10:42:04 qgs-comp kernel: [ 3182.847137] audit: type=1400
> audit(1654155724.011:126): apparmor="ALLOWED" operation="file_mmap"
> profile="libreoffice-soffice" name="/tmp/.glQ6PDw2" pid=7839
> comm="soffice.bin" requested_mask="m" denied_mask="m" fsuid=1000 ouid=1000
> Jun  2 10:42:04 qgs-comp kernel: [ 3183.137037] audit: type=1400
> audit(1654155724.303:127): apparmor="ALLOWED" operation="connect"
> profile="libreoffice-soffice" name="/run/user/1000/at-spi/bus_1" pid=7838
> comm="soffice.bin" requested_mask="wr" denied_mask="wr" fsuid=1000 ouid=1000
> Jun  2 10:42:04 qgs-comp kernel: [ 3183.137207] audit: type=1400
> audit(1654155724.303:128): apparmor="ALLOWED" operation="file_perm"
> profile="libreoffice-soffice" name="/run/user/1000/at-spi/bus_1" pid=7838
> comm="soffice.bin" requested_mask="r" denied_mask="r" fsuid=1000 ouid=1000
> Jun  2 10:42:04 qgs-comp kernel: [ 3183.137218] audit: type=1400
> audit(1654155724.303:129): apparmor="ALLOWED" operation="file_perm"
> profile="libreoffice-soffice" name="/run/user/1000/at-spi/bus_1" pid=7838
> comm="soffice.bin" requested_mask="r" denied_mask="r" fsuid=1000 ouid=1000
> Jun  2 10:42:14 qgs-comp systemd[1786]:
> app-gnome-libreoffice\x2dwriter-7821.scope: Consumed 3.025s CPU time.
> Jun  2 10:45:38 qgs-comp kernel: [ 3396.861511] usb 2-1.5: new full-speed
> USB device number 6 using ehci-pci
> Jun  2 10:45:38 qgs-comp kernel: [ 3396.975858] usb 2-1.5: New USB device
> found, idVendor=0403, idProduct=6001, bcdDevice= 6.00
> Jun  2 10:45:38 qgs-comp kernel: [ 3396.975866] usb 2-1.5: New USB device
> strings: Mfr=1, Product=2, SerialNumber=3
> Jun  2 10:45:38 qgs-comp kernel: [ 3396.975870] usb 2-1.5: Product: USB
> Serial
> Jun  2 10:45:38 qgs-comp kernel: [ 3396.975872] usb 2-1.5: Manufacturer:
> FTDI
> Jun  2 10:45:38 qgs-comp kernel: [ 3396.975874] usb 2-1.5: SerialNumber:
> FT0KKBIF
> Jun  2 10:45:38 qgs-comp kernel: [ 3396.978651] ftdi_sio 2-1.5:1.0: FTDI USB
> Serial Device converter detected
> Jun  2 10:45:38 qgs-comp kernel: [ 3396.978714] usb 2-1.5: Detected FT232RL
> Jun  2 10:45:38 qgs-comp kernel: [ 3396.979568] usb 2-1.5: FTDI USB Serial
> Device converter now attached to ttyUSB0
> Jun  2 10:45:38 qgs-comp mtp-probe: checking bus 2, device 6:
> "/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5"
> Jun  2 10:45:38 qgs-comp mtp-probe: bus: 2, device: 6 was not an MTP device
> Jun  2 10:45:38 qgs-comp systemd-udevd[7907]: 2-1.5: Failed to create/update
> device symlink '/dev/ttyUSB0', ignoring: File exists
> Jun  2 10:45:38 qgs-comp snapd[938]: hotplug.go:199: hotplug device add
> event ignored, enable experimental.hotplug
> Jun  2 10:45:38 qgs-comp mtp-probe: checking bus 2, device 6:
> "/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5"
> Jun  2 10:45:38 qgs-comp mtp-probe: bus: 2, device: 6 was not an MTP device
> Jun  2 10:45:40 qgs-comp ModemManager[1055]: <info>  [base-manager] couldn't
> check support for device
> '/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5': not supported by any
> plugin
> Jun  2 10:45:47 qgs-comp kernel: [ 3406.230869] [UFW BLOCK] IN=enp5s0 OUT=
> MAC=01:00:5e:00:00:01:c4:6e:1f:70:4f:f4:08:00 SRC=192.168.0.1 DST=224.0.0.1
> LEN=32 TOS=0x00 PREC=0xC0 TTL=1 ID=0 DF PROTO=2
> Jun  2 10:46:34 qgs-comp systemd[1786]: Started Application launched by
> gnome-shell.
> Jun  2 10:46:34 qgs-comp systemd[1786]: Started VTE child process 7940
> launched by gnome-terminal-server process 5736.
> Jun  2 10:46:34 qgs-comp gnome-shell[2070]: Can't update stage views actor
> <unnamed>[<MetaWindowGroup>:0x55cea707c320] is on because it needs an
> allocation.
> Jun  2 10:46:34 qgs-comp gnome-shell[2070]: Can't update stage views actor
> <unnamed>[<MetaWindowActorX11>:0x55ceb6917ed0] is on because it needs an
> allocation.
> Jun  2 10:46:34 qgs-comp gnome-shell[2070]: Can't update stage views actor
> <unnamed>[<MetaSurfaceActorX11>:0x55cea8afc6c0] is on because it needs an
> allocation.
> Jun  2 10:46:37 qgs-comp systemd[1786]: Started Application launched by
> gnome-shell.
> Jun  2 10:46:37 qgs-comp systemd[1786]: Started VTE child process 7958
> launched by gnome-terminal-server process 5736.
> Jun  2 10:46:37 qgs-comp gnome-shell[2070]: Can't update stage views actor
> <unnamed>[<MetaWindowGroup>:0x55cea707c320] is on because it needs an
> allocation.
> Jun  2 10:46:37 qgs-comp gnome-shell[2070]: Can't update stage views actor
> <unnamed>[<MetaWindowActorX11>:0x55cea8e32360] is on because it needs an
> allocation.
> Jun  2 10:46:37 qgs-comp gnome-shell[2070]: Can't update stage views actor
> <unnamed>[<MetaSurfaceActorX11>:0x55cea8afca40] is on because it needs an
> allocation.
> Jun  2 10:48:14 qgs-comp kernel: [ 3553.309826] usb 2-1.5: USB disconnect,
> device number 6
> Jun  2 10:48:14 qgs-comp kernel: [ 3553.310371] ftdi_sio ttyUSB0: FTDI USB
> Serial Device converter now disconnected from ttyUSB0
> Jun  2 10:48:14 qgs-comp kernel: [ 3553.310404] ftdi_sio 2-1.5:1.0: device
> disconnected
> 
> 
> No problems on the same PC working under Ubuntu 18.04 and 16.04 whatsoever:
> 
> ls -l /dev/ttyUSB*
> crw-rw---- 1 root dialout 188, 0 Jun  2 10:36 /dev/ttyUSB0

I think you are going to have to contact ubuntu for this issue and get
support from them as it's their kernel and overall system configuration
here, the kernel looks like it is working just fine.

good luck!

greg k-h