I was hitting a problem that sometimes when I brought the laptop out of hibernate it would not recognise the headphones being plugged in. As I sometimes watch training courses on the my commute this was a problem as I didn’t think the other commuters would want to hear about some of the low level idiosyncrasies of C#.
However I now have a fix. If it fails to recognise the headphones launch “Control Panel” and then “Device Manager”. Once this is open expand the “Sound, video and game controllers” entry and there should be a “Cirrus Logic High Definition Audio” entry under that. Right click and select Disable. Once it is disabled right click again and re-enable it. Your headphones should now be recognised again.