I got this from a spanish website, but it's purported to work with your laptop model.
snd-pcsp index =- 2
alias snd-card-0 snd-hda-intel alias snd-card-0 snd-hda-intel
alias sound-slot-0 snd-hda-intel alias sound-slot-0 snd-hda-intel
options snd-hda-intel model=dell-m4-1 options snd-hda-intel model = dell-m4-1
options snd-hda-intel enable_msi=1 options snd-hda-intel enable_msi = 1
put those lines in /etc/modprobe.d/alsa-base.conf, then restart, then raise levels in alsamixer, then use speaker-test to check if it's worked