Arch Linux

lpatters1241

Member

Registered: 2022-06-03

Posts: 2

No device assigment for USB Uart

Below is the 'dmesg' output when a USB device using an FTDI-UART is plugged into the system.

[ 5670.372474] usb 5-1: new full-speed USB device number 2 using xhci_hcd
[ 5670.782144] usb 5-1: New USB device found, idVendor=0403, idProduct=b3a8, bcdDevice= 6.00
[ 5670.782153] usb 5-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 5670.782157] usb 5-1: Product: FT232R USB UART
[ 5670.782159] usb 5-1: Manufacturer: FTDI
[ 5670.782162] usb 5-1: SerialNumber: ST09r0Hu8w

In previous years, this would result in an assignment to /dev/ttyUSB0.

My search for a solution have been unsuccessful.

Suggestions?

Thank you.

dimich

Member

From: Kharkiv, Ukraine

Registered: 2009-11-03

Posts: 630

Re: No device assigment for USB Uart

Is ftdi_sio module loaded?

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,634

Re: No device assigment for USB Uart

Welcome to the forums.   Do the kernel revisions reported by uname -a and by pacman -Q linux  (Assuming you are using the stock kernel) match?

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dimich

Member

From: Kharkiv, Ukraine

Registered: 2009-11-03

Posts: 630

Re: No device assigment for USB Uart

Is this a new-purchased device? I don't see 0xB3A8 PID mentioned in ftdi_sio modalias. If installed and running kernel versions are the same and ftdi_sio is loaded, try to

# echo 0403 b3a8 >/sys/bus/usb-serial/drivers/ftdi_sio/new_id

before device insertion.

lpatters1241

Member

Registered: 2022-06-03

Posts: 2

Re: No device assigment for USB Uart

Thank you very much.

The module was not loaded. Loading it AND adding the device's PID information solved the problem.
It is once again available as /dev/ttyUSB0.

The device is not new; 6+ years old; used infrequently.