How do I make Ubuntu select my headset mic as default input automatically?

Solution 1:

Why it doesn't work

My system, Kubuntu 19.10 on a Dell XPS 13 9350, detects headphones and sets the correct output automatically.

As fas as I know it doesn't know if the headset has a microphone or not. This is why it only changes the output and not the input.

How to make it work

This is how to automatically switch the microphone on plug/unplug:

acpi_listen is the tool to detect when you plug/unplug the headset. This is what it detects:

jack/headphone HEADPHONE unplug
jack/headphone HEADPHONE plug

pulseaudio is where we can switch source ports

In my system to select headset microphone:

pacmd set-source-port alsa_input.pci-0000_00_1f.3.analog-stereo analog-input-headset-mic

To select internal microphone:

pacmd set-source-port alsa_input.pci-0000_00_1f.3.analog-stereo analog-input-internal-mic

You can use pacmd list-cards to get a list of sources names and ports names.
You can also use the terminal auto-complete feature to help craft the commands.

Now, let's bring everything together:

Switch to root with sudo su and create the script /etc/acpi/headset-microphone.sh

#!/bin/sh
export PULSE_RUNTIME_PATH="/run/user/1000/pulse/"
if [ "$1" = plug ]; then
  sudo -u you -E pacmd set-source-port alsa_input.pci-0000_00_1f.3.analog-stereo analog-input-headset-mic
else
  sudo -u you -E pacmd set-source-port alsa_input.pci-0000_00_1f.3.analog-stereo analog-input-internal-mic
fi

be sure to:

change you to your username
replace the pulseaudio source and ports with your values
make the script executable, chmod a+x /etc/acpi/headset-microphone.sh

then create the event listener, creating a file ´/etc/acpi/events/headset-microphone-plug´:

event=jack/headphone HEADPHONE plug
action=/etc/acpi/headset-microphone.sh plug

and the unplug event listener, creating a file ´/etc/acpi/events/headset-microphone-unplug´:

event=jack/headphone HEADPHONE unplug
action=/etc/acpi/headset-microphone.sh unplug

and, as last thing, restart the acpi listening events service

systemctl restart acpid.service