How can I enable ftdi_sio on Ubuntu server 21.10 on Raspberry Pi (ARM64)?

I'm trying to get a USB serial device working. I can see the device using 'lsusb' but it never appears in '/dev'. From what I understand there's this "extra" kernel package that I downloaded which contains ftdi_sio.ko which will make the device visible in /dev.

I tried to install the module in the kernel with 'insmod /lib/modules/5.13.0-20-generic/kernel/drivers/usb/serial/ftdi_sio.ko'. However, when I try this I get the error ERROR: could not insert module ftdi_sio.ko: Invalid module format.

I think this is because my actual kernel is in /lib/modules/5.13.0-1009-raspi/kernel/drivers/usb... But there's not much in there, and I have no clue how to find, download and install the correct "extra" package that will work.

The documentation that comes with the serial USB device mentions the need to patch the kernel, but that seems like too much work to get it to recognize a serial USB device which it already sees. Not to mention that this is way beyond my skill level.

Appreciate any help.

I'm experiencing the exact same issue, and so is Rumancz on the Raspberry Pi forums.

Edit: As OP @Gordeon_Lee points out below—and as I discovered from Bug #1947723 on Ubuntu's linux-raspi package Launchpad—the solution was to simply run sudo apt install linux-modules-extra-raspi (or if you're not using a Raspberry Pi: sudo apt install linux-modules-extra-$(uname -r)). Additionally, I have confirmed the fix (in the above link) in the latest -proposed 5.13.0-1011-raspi kernel image, so this should be resolved when the 5.13.0-1011-raspi kernel image is released, without having to even do that.

Thanks for your help, Gordon!

Cheers, Jonathan