Comment 16 for bug 1414706

https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/sound/pci/hda/patch_realtek.c?id=73bdd597823e2231dc882577dbbaf8df92fe1775

you need to use debug version of alsa driver to check the system log to find out whether your codec alc292 can automatcally differentiate headset and headphone as your thinkpad does not support conventional mic

http://voices.canonical.com/david.henningsson/2014/03/07/headset-jacks-on-newer-laptops/