Asus S400CA inverted microphone (Skype not usable)

[J.J. Berkhout]

System: Asus S400CA with Linux Mint 17.3 Rosa, kernel 3.19.0-39-generic #44~14.04.1-Ubuntu SMP Wed Dec 2 10:00:35 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Running Skype, sound input from microphone does not work. When (in alsa-mixer OR in pavucontrol) one channel is reduced and the other is maximized, sound input works although not at full volume.

Alsa information:
http://www.alsa-project.org/db/?f=4fd8506e1121c53b192c73150ba74fb24075314e

Edit:
This is NOT a bug in the alsa-driver, but a problem with the settings of my system. I changed the /etc/modprobe.d/alsa-base.conf by adding the line:

options snd-hda-intel model=auto

which repaired the microphone response in alsamixer and pavucontrol.
Skype still did not work, but after fiddling around with the settings under "Recording" in pavucontrol I got it working. My excuses if I wasted anyone's time. Please accept that I use this system for only the last week and have no experience with Linux whatsoever.

Further edit:
As for the problem and the solution see http://forums.linuxmint.com/viewtopic.php?f=49&t=177730.