[Bug 220331] FTDI serial IO - unknown device type: 0x8312

bugzilla-daemon
2025-08-27T08:37:16Z

--- Comment #4 from Johan Hovold (johan@kernel.org) ---
On Thu, Jul 10, 2025 at 09:11:14AM +0000, bugzilla-daemon@kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=220331

> Issue with a newer hardware with USB DisplayLink adapter, syslog throws
> following error about unrecognized device type 0x8312:
>
> > [ 4.447826] usb 1-8.2.1: New USB device found, idVendor=17e9,
> > idProduct=ff00, bbcdDevice=83.12
> > [ 4.447833] usb 1-8.2.1: New USB device strings: Mfr=1, Product=2,
> > SerialNumber
> > =3
> > [ 4.447835] usb 1-8.2.1: Product: PM1000
> > [ 4.447836] usb 1-8.2.1: Manufacturer: DisplayLink
> > [ 4.447837] usb 1-8.2.1: SerialNumber: 9638293100007141

This does not look like an FTDI device and as far as I can see ftdi_sio
driver should not even try to bind to it currently as the VID/PID is not
in the driver's match table.

> > [ 4.479297] usbcore: registered new interface driver ftdi_sio
> > [ 4.479363] usbserial: USB Serial support registered for FTDI USB Serial
> > Device
> > [ 4.480786] ftdi_sio 1-8.2.1:1.0: FTDI USB Serial Device converter
> > detected
> > [ 4.480848] ftdi_sio ttyUSB0: unknown device type: 0x8312
> > [ 4.480923] ftdi_sio 1-8.2.1:1.1: FTDI USB Serial Device converter
> > detected
> > [ 4.480957] ftdi_sio ttyUSB1: unknown device type: 0x8312
> > [ 4.486014] ftdi_sio ttyUSB0: unknown device type: 0x8312
> > [ 4.486049] ftdi_sio ttyUSB1: unknown device type: 0x8312

Please post the output of "lsusb -v" for this device.

Johan