Comment 33 for bug 874535

Thank you so much to: Jim for submitting this bug report; Luke for pointing out the PulseAudio logging wiki; and David for providing the workaround details for PulseAudio and snd-hda-intel. I've had the volume pop-up problem (easily 50+ times a day) since I built my system in late 2012 and only bummed that I finally found this bug report today instead of a long time ago.

I confirmed I was affected by the same jack sensing issue by using PulseAudio logging this way (based on the wiki; you might want to confirm you don't have an existing client.conf file):

echo autospawn = no > ~/.config/pulse/client.conf
pkill pulseaudio
pulseaudio --daemonize -vv --log-time=1 --log-target=file:/tmp/pulseaudio.log
tail -f /tmp/pulseaudio.log

Searching the logs with:
grep is.now /tmp/pulseaudio.log

showed repeated messages like this:
D (1565.604| 634.163) [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
D (1565.626| 0.020) [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged
D (1712.599| 146.972) [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now plugged in
D (1712.621| 0.020) [pulseaudio] module-alsa-card.c: Jack 'Front Headphone Jack' is now unplugged

I was thinking I'd use the snd-hda-intel jackpoll_ms workaround, until I thought about actually checking the hardware setup on my system. First I connected/disconnected headphones to the front panel headphone jack to confirm the jack shown in the debug output above indeed toggled again while tailing the log. Then I disconnected the cable from my case to the motherboard "Front panel audio connector (AAFP)" since I never use those jacks anyway. This simple hardware fix worked for me and so I thought I'd share this information in case anyone else has the issue and wants to go this route so the kernel sound drivers don't have to process any interrupts generated by (phantom) audio jack plug events.

To restore the standard PulseAudio daemon process without debugging, I re-enabled autospawn, killed the debug daemon process and after a few seconds it is restarted automatically:

rm ~/.config/pulse/client.conf
pkill pulseaudio