10

I want to execute a script on headphones disconnect but I resent the idea of constant polling of the status when there is already some code executed when it's changed.

Community
  • 1
int_ua
  • 8,892

2 Answers2

12

In most systems if not all, ACPI can handle this event. To test that:

  1. Run acpi_listen

  2. Unplug & replug headphones, example output: (mic/ears share in same jack on my laptop)

    jack/headphone HEADPHONE unplug
jack/microphone MICROPHONE unplug
jack/headphone HEADPHONE plug
jack/microphone MICROPHONE plug

  3. Put your-script.sh in /etc/acpi/

  4. Add an event trigger file for your script in /etc/acpi/events/

    event=jack/headphone HEADPHONE unplug
action=/etc/acpi/your-script.sh

    Check the other files there to learn from.

  5. You may need to restart acpid service to reload changed rules in /etc/acpi/events/

    sudo service acpid restart

Reference: man acpid

user.dz
  • 49,176
1

The current version of your script now contains a sleep 0.25 command.

sleep is timer-based so doesn't use any processing cycles while sleeping…

It does use a very tiny bit of CPU to set up the timer, but sleep 1 (sleep 1 second), sleep 60 (sleep for a minute) and sleep 86400 (sleep for a day) all use the same number CPU cycles.

Using ACPI however is the perfect solution as ACPI is event-driven instead of polling-driven.

Community
  • 1
Fabby
  • 35,017