Headphone mic (TRRS) not working

[lonewsk]

Microphone input via 3-point jack (TRRS) not woking on Arch.

Alsa seems to detect the input, some config is applied and device is showing up on pipewire. But no audio input is detected.

I think it is related to the forked alsa ucm profile (the one from Manjaro repos). Don't know if it works on CPI OS.

Will add more documenation and investigate.

[lonewsk]

Asked about it on CPi's Discord server, seems like it's not working on provided OS either.

I'll try to contact Clockwork directly.

Also tried to build the audio package from Manjaro's repo, but still not working.

[lonewsk]

Config files are located under /usr/share/alsa/ucm2/Rockchip/es8388/

File HiFi.conf gives alsa some directions on where to find the microphone input :

SectionDevice."Mic" {
    Comment "Headphone Mic"

    EnableSequence [
        cset "name='Differential Mux' 'Line 2'"
    ]

    Value {
        CapturePriority 100
        CapturePCM "hw:${CardId},0"
    }
}

[lonewsk]

Looks like microphone input is connected to GPIO 124, 126 and 128, as seen in schematics.

[lonewsk]

Clockwork's forum thread