Bug#889294: alsa-utils: External mic via combo jack is not detected on Acer Aspire V3-372

[Vladimir K]

Seems to be fully fixed by adding:

    options snd_hda_intel model=alc255-acer

to a file in /etc/modrobe.d/

If there is a mechanism for assigning this model automatically based on dmi 
data, it might be a good idea to apply it.