I have an early 2011 17" MBP that has had this unresponsive audio jack problem on and off for a long time--additionally it seems to be related to problems I have with the thunderbolt port:
- Sometimes I plug in headphones but only the internal speakers are seen/used.
- Most of the time when I plug a VGA or DVI adapter into the video port, the screen gets jitters or static every few seconds until I try unplugging and replugging one or more times.
- Sometimes when I plug in an HDMI adapter, one or both screens go crazy with video junk until I unplug and replug the adapter.
- Sometimes after unplugging from power, video, usb, audio, and walking around with my computer, I get kernel panics.
A while ago I had time to take it in to the Apple Store to get it looked (I tend to use it most of almost every day for work or otherwise, so not much opportunity to leave it at the shop) at but they didn't find anything immediately wrong with it and the tech had never heard of anything like the problems I was having.
I suspect that all these things have a common thread--that something is wrong with the electrical sensing capability of the ports. Maybe something is wrong with the voltage going to or from the ports? Maybe there's a circuitry defect.
The only other thing is, I had for a short while, the late 2010 version of this model and it exhibited the same video port weirdness. It also had a few unexplained kernel panics. The odds are pretty slim that I would get two different laptop editions with the same problems that no one has heard of. It IS possible but it's also possible that the cause is something inherent to me instead of the original hardware.. so I'm curious to see if anyone else has experienced all these things in the same computer.