Comment # 7 on bug 940717 from Stanislav Brabec

I just tested openSUSE 13.1, and the problem exists there as well. So it is not
a regression. I always used rear connector with a long cable, but now cable was
broken and I tested front one.

Rear connector is controlled by Speaker+LO and Line Out mute switch and works
well. But surprisingly Auto-Mute Mode does not disable rear connector in any of
three choices.

It look like a problem of routing of 'Headphone Playback Volume' to the chip.
It has no effect.

Guessing from the pop sound, 'Headphone Playback Switch' apparently handles
headphones and does something.