Eu coloquei isso:
options snd-hda-intel model=dell-vostro-3560
No final de "/etc/modprobe.d/alsa-base.conf"
E meu som está funcionando novamente:)
$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: CONEXANT Analog [CONEXANT Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0