[arch-general] x220 external mic

This is a question for those who have or still are using a Thinkpad x220. I've been trying to get an external 3.5mm headphone+mic combo to work in a way that the mic is picked up, but so far nothing fixed it and I cannot find anything relevant on the internet. I've tried enable/disabling the mic i/o port in BIOS, but I'm fairly certain that the setting is just for the built-in mic under the monitor and not anything connected via the a combo inline external device. Any hints what I can try? I've tried with ALSA and ALSA plus PulseAudio and never been able to see any device that would pick up sound.