Dell WYSE 7040 thin client (Intel i5 6500TE) built-in sound ALC255 mini how-to

[razif]

Hi everyone,
I usually browse this forum to find solutions, but now I’d like to share something that might be useful to others. I am running FreeBSD 15-RELEASE.
After testing many different fixes found online, I finally found a working solution. My computer has three sound outputs:
1- HDMI
2- Internal built-in speaker
3- Headphone jack

if you
dmesg | grep pcm :

pcm0: <Realtek ALC255 (Front Analog Line-out)> at nid 27 on hdaa0
pcm1: <Intel Skylake (HDMI/DP 8ch)> at nid 3 on hdaa1

then this lines should be added in the /boot/device.hints :
hint.hdaa.0.nid20.config="as=1 seq=0 device=Speaker"
hint.hdaa.0.nid27.config="as=1 seq=15 device=Headphones"

when rebooted, you should see this lines when you dmesg | grep pcm :

pcm0: <Realtek ALC255 (Front Analog Headphones)> at nid 27 on hdaa0
pcm1: <Realtek ALC255 (Front Analog Headphones)> at nid 33 on hdaa0
pcm2: <Intel Skylake (HDMI/DP 8ch)> at nid 3 on hdaa1
pcm0: <Realtek ALC255 (Analog 2.0+HP)> at nid 20,27 on hdaa0
pcm1: <Realtek ALC255 (Front Analog Headphones)> at nid 33 on hdaa0
pcm2: <Intel Skylake (HDMI/DP 8ch)> at nid 3 on hdaa1

and when you cat /dev/sndstat :
Installed devices:
pcm0: <Realtek ALC255 (Analog 2.0+HP)> (play) default
pcm1: <Realtek ALC255 (Front Analog Headphones)> (play)
pcm2: <Intel Skylake (HDMI/DP 8ch)> (play)

each of those pcm should be functional if tested when you switch it with:
sysctl hw.snd.default_unit=n
n = the pcm (0 or 1 or 2)