/dev/ttyUSB0 doesn't appear for an FTDI on fresh Ubuntu 22.04

[Yuri Yorick]

Hi all,

This problem appeared on a freshly installed Ubuntu 22.04 desktop.

When I'm attaching a ftdi device into usb everything looks great but there's no /dev/ttyUSB0 file. Looks like it's created and then disappears immediately. I tried to remove brltty package (as some recommends https://bugs.launchpad.net/ubuntu/+source/brltty/+bug/1958224) but it didn't help.

The same ftdi device works on older Ubuntu version w/o any problems. So hardware is ok.

I'm having this in syslog:

Jun 1 16:58:09 qgs-comp kernel: [ 538.642086] usb 2-1.5: new full-speed USB device number 5 using ehci-pci
Jun 1 16:58:10 qgs-comp kernel: [ 538.756437] usb 2-1.5: New USB device found, idVendor=0403, idProduct=6001, bcdDevice= 6.00
Jun 1 16:58:10 qgs-comp kernel: [ 538.756445] usb 2-1.5: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Jun 1 16:58:10 qgs-comp kernel: [ 538.756448] usb 2-1.5: Product: USB Serial
Jun 1 16:58:10 qgs-comp kernel: [ 538.756450] usb 2-1.5: Manufacturer: FTDI
Jun 1 16:58:10 qgs-comp kernel: [ 538.756452] usb 2-1.5: SerialNumber: FT0KKBIF
Jun 1 16:58:10 qgs-comp kernel: [ 538.759677] ftdi_sio 2-1.5:1.0: FTDI USB Serial Device converter detected
Jun 1 16:58:10 qgs-comp kernel: [ 538.759713] usb 2-1.5: Detected FT232RL
Jun 1 16:58:10 qgs-comp kernel: [ 538.760546] usb 2-1.5: FTDI USB Serial Device converter now attached to ttyUSB0
Jun 1 16:58:01 qgs-comp colord-sane: message repeated 2 times: [ io/hpmud/musb.c 2101: Invalid usb_open: Permission denied]
Jun 1 16:58:10 qgs-comp mtp-probe: checking bus 2, device 5: "/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5"
Jun 1 16:58:10 qgs-comp mtp-probe: bus: 2, device: 5 was not an MTP device
Jun 1 16:58:10 qgs-comp systemd-udevd[5394]: 2-1.5: Failed to create/update device symlink '/dev/ttyUSB0', ignoring: File exists
Jun 1 16:58:10 qgs-comp snapd[942]: hotplug.go:199: hotplug device add event ignored, enable experimental.hotplug
Jun 1 16:58:10 qgs-comp mtp-probe: checking bus 2, device 5: "/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5"
Jun 1 16:58:10 qgs-comp mtp-probe: bus: 2, device: 5 was not an MTP device
Jun 1 16:58:10 qgs-comp colord-sane: io/hpmud/musb.c 2101: Invalid usb_open: Permission denied

I noticed this line:

Jun 1 16:58:10 qgs-comp systemd-udevd[5394]: 2-1.5: Failed to create/update device symlink '/dev/ttyUSB0', ignoring: File exists

Why is it happening? There's no /dev/ttyUSB0 neither before nor after I attach ftdi device to a USB port.

Let's take a look in /dev/serial folder:

cd /dev/serial ; ls -LR

.:
by-id
by-path

./by-id:
ls: cannot access './by-id/usb-FTDI_USB_Serial_FT0KKBIF-if00-port0': No such file or directory
usb-FTDI_USB_Serial_FT0KKBIF-if00-port0

./by-path:
ls: cannot access './by-path/pci-0000:00:1d.0-usb-0:1.5:1.0-port0': No such file or directory
pci-0000:00:1d.0-usb-0:1.5:1.0-port0

So the folders and links are there but there's no /dev/ttyUSB0 file the links point to.

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Libera.chat.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1976534/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]