Comment 75 for bug 1935850

workaround for me to get sound, not mic:
/etc/modprobe.d/alsa-base.conf
options snd-intel-dspcfg dsp_driver=1

reference : https://bbs.archlinux.org/viewtopic.php?id=260139

still no mic though.
Some more dmesg :

dmesg | grep audio
[ 5.670976] snd_hda_intel 0000:00:1f.3: bound 0000:00:02.0 (ops i915_audio_component_bind_ops [i915])
[ 5.751918] snd_hda_codec_realtek hdaudioC0D0: autoconfig for ALC215: line_outs=1 (0x14/0x0/0x0/0x0/0x0) type:speaker
[ 5.751928] snd_hda_codec_realtek hdaudioC0D0: speaker_outs=0 (0x0/0x0/0x0/0x0/0x0)
[ 5.751932] snd_hda_codec_realtek hdaudioC0D0: hp_outs=1 (0x21/0x0/0x0/0x0/0x0)
[ 5.751937] snd_hda_codec_realtek hdaudioC0D0: mono: mono_out=0x0
[ 5.751939] snd_hda_codec_realtek hdaudioC0D0: inputs:
[ 5.751942] snd_hda_codec_realtek hdaudioC0D0: Mic=0x19
vinger@vinger-HP-EliteBook-830-G6:~$ dmesg | grep firm
[ 4.444306] i915 0000:00:02.0: [drm] Finished loading DMC firmware i915/kbl_dmc_ver1_04.bin (v1.4)
[ 4.498913] iwlwifi 0000:3a:00.0: loaded firmware version 59.601f3a66.0 cc-a0-59.ucode op_mode iwlmvm