Comment 80 for bug 874535

Same here, Gigabyte GA-B250M-DS3H with HDA Intel PCH, ALC887-VD. Ubuntu 18.04.

On my machine, once this starts happening it survives a reboot but goes away for a while after a _cold_ reboot.

Clicks every few seconds and debounce might indeed be a workaround (~20 ms plug/unplug in my case):

$ ./pulseaudio -vvvv --log-time=1 2>&1 | grep -P 'Front Headphone.*is now'
( 0.120| 0.000) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
( 3.134| 0.000) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
( 3.155| 0.000) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
( 5.161| 0.000) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
( 5.182| 0.000) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
( 6.324| 0.000) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
( 6.345| 0.000) D: [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged

I'm yet to see anything other than 21-22 ms. I set jackpoll_ms=40 in snd_hda_intel options but still seeing the same plug/unplug interval.

Similar reports on this pulseaudio bug: https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1585084