I’m running Manjaro on an Alienware 15 R4, and it has dual audio jacks. It has a mic jack and the other one is a headphone/headset jack. When I first installed Manjaro it worked well, when I plugged in my separate cables, it used the right jacks and the audio worked fine, but I updated it once and then it stopped working as it should. The issue consists in the mic and headphones working in exclusion to the other. When I select the headphones the mic won’t work, and when I select the mic the headphones don’t play any audio, even though pulse shows it outputting sound.
Do an errors check and see what comes up. System and Journal. I’m new to manjaro but not new to solving PC issues and hacking windows. I also have Alienware 13 R3 and the 15 R4. I am in the same situation and are experiencing the same issues that you stated above. Also noticing Bluetooth headphone connectivity has lost functionality. USB 3.0 recognition issues with ADB/Android devices. Using terminal I see errors with BIOS. Will research Linux versions of the Alienware 3.5 audio/mic jack and Bluetooth drivers. I’m reading posts that suggest that BIOS errors aren’t necessarily something that will be remedied with a BIOS update. I will also remove the audio/BT packets and re-install them to see if I regain functionality. Could also revert back to a previous software. Alienware Manjaro users are an extremely niche group. Ill put updates here on my progress.