Comment 37 for bug 874535

The problem only happens with the front panel headphone jack, the debugging did not show any plugged events for the front mic. I do not see the problem with the rear audio jacks.

With debugging still enabled, I plugged in cables to the motherboard rear audio ports and it showed plugged events for 'Rear Mic Jack' and 'Line Jack', but not for the any of the Front/Center/Rear/Side audio out jacks (so I assume either the hardware or the default ALSA/PulseAudio config does not do jack detection for those).

Given removing the front audio connector from the motherboard fixed the problem, I have not changed any Alsa or PulseAudio settings like jack_detect (and don't plan to). I'm guessing the front headphone jack in my chassis is bad, or perhaps there is some sort of electromagnetic interference through the unshielded cable going to the front audio jacks.