I want to write a small program in C: When I plug my headphones in my notebook, it should turn the volume lower. Then, when I remove headphone from my notebook, it should turn the volume back up.
I am using the alsa driver, and I know how to control the volume.
The question is: How to get notified, when the headphone gets plugged in?
Before I asked this question, I tried to use IRQ. I used watch -d0.5 cat /proc/stat to see if any interrupts are experienced by the system when I plug in or remove my headphone, and I see 8 interrupts. I don't know with IRQ is the right one so, I have no idea.
Maybe you don't need to write any program. Alsamixer should let you specify the volume of the speaker and the volume of the headphones. You just set the headphones' volume a little lower, and that's all.