No Audio from Stereo Mix

Hello everybody, I'm trying since some days to solve this problem but I can't get rid of it.
I'm using an Asus K550JK notebook with a 2in1 output/input jack (it can be used for external mic or line-in).
I'm on win8.1, I have smart audio software (conexant smartaudiohd).
I can't use any input source. There is internal mic and stereo mix in recording devices, I can enable stereo mix but it don't rec any audio.
I've set stereo mix as communication and as default device.
I've tried to reinstall drivers from asus support. No way to solve this problem.
In smart audio software I see only output jack. I'll attach some images.
Can you help me?

Update: I've just found out that I can use stereo mix to record computer sounds and music, but there's still no way to use external mic or line-in.