Scarlett 8i6 (3rd gen) interface is supported in kernel v5.14 and support has also been back-ported to LTS kernel v5.10, but the interface has to be enabled at boot time
There has been an ongoing discussion about support for 2nd gen and 3rd gen devices in another forum
Focusrite Scarlett 2nd and 3rd Gen mixer driver - LinuxMusicians
Users with these devices should follow this discussion as there might be an ALSA mixer and patchbay GUI released in the near future
To enable the driver when system is booted and audio module loaded requires a modprobe option device_setup=1 with the correct Vendor and product ID code to identify the device
Use this command to create the modprobe file:
echo `options snd_usb_audio vid=0x1235 pid=0x8213 device_setup=1` | sudo tee --append /etc/modprobe.d/scarlett8i6.conf
Release Linux 5.14.0 · geoffreybennett/scarlett-gen2 · GitHub
Reboot system to ensure the modprobe option is loaded
The modprobe option should allow ALSA to detect all the interface channels in ALSA
All the channels should be accessible (and patchable) in JACK
However, PulseAudio will probably need a custom profile to access more than one channel