Headset Microphone not working

I experienced a version of this on Fedora 40, but the current issue is showing up on Fedora 41. My laptop is the Framework 13 with Ryzen 7840U mainboard.

Headsets that are plugged into the headphone jack don’t appear to get any input from the headset microphone. I’ve tested that:

  1. the headset itself is not broken, using another device
  2. the built-in microphone functions, so it’s not a generalized audio issue
  3. the headset microphone input is maxed out in volume in alsamixer (not where I’d normally keep it, but good to reduce the problem space)

I had similar, but not identical, issues in Fedora 40 and a Ubuntu 24.04 live image I tested. There, enabling the headset microphone (rather than treating the headset as headphones only) caused sound to become mono rather than stereo, and speaking into the earpiece produced a microphone input, so maybe my laptop just has issues. But I suspect it’s a software issue, given that the behavior changed in Fedora 41 (no more mono sound and earpiece mic).