I just installed 4.13.0-36-generic on a spare drive. MB is a Supermicro C2SEA, so RealTek ALC888. Everything is working, but my headphones. I have searched around on Google and found little information that was helpful. Sound works on my regular speakers. When I plug in the headphones into front headphone jack, I still hear sounds from speakers only. Sound settings show only Line Out and Digital Output (S/PDIF). No Headphones listed. I have tried the suggestion: alsactl restore but no change. Any suggestions? Thanks in advance, it's been a long time since I worked with Linux.