freebsd hdmi audio

I have two HP's, a Slimline with an i7, and an Envy with an i7. Both are 
small towers (desktops).

I use drm-kmod, snd_hda.

dmesg:

hdacc0: <Realtek ALC671 HDA CODEC> at cad 0 on hdac0
hdaa0: <Realtek ALC671 Audio Function Group> at nid 1 on hdacc0
pcm0: <Realtek ALC671 (Rear Analog)> at nid 20 and 27 on hdaa0
pcm1: <Realtek ALC671 (Analog)> at nid 33 and 24 on hdaa0
hdacc1: <Intel Kaby Lake HDA CODEC> at cad 2 on hdac0
hdaa1: <Intel Kaby Lake Audio Function Group> at nid 1 on hdacc1
pcm2: <Intel Kaby Lake (HDMI/DP 8ch)> at nid 3 on hdaa1

  From the command line, I can output to the front or rear realtek 
outputs, but not hdmi.

cat /dev/sndstat
FreeBSD Audio Driver
Installed devices:
pcm0: <Realtek ALC671 (Rear Analog)> on hdaa0 (1p:1v/1r:1v)
        snddev flags=0x2e2<AUTOVCHAN,BUSY,MPSAFE,REGISTERED,VPC>
        [pcm0:play:dsp0.p0]: spd 48000, fmt 0x00200010, flags 
0x00002100, 0x00000004
        interrupts 0, underruns 0, feed 0, ready 0 
[b:2048/1024/2|bs:2048/1024/2]
        channel flags=0x2100<BUSY,HAS_VCHAN>
        {userland} -> feeder_mixer(0x00200010) -> {hardware}
pcm0:play:dsp0.p0[pcm0:virtual_play:dsp0.vp0]: spd 8000, fmt 0x00100008, 
flags 0x10000000, 0x00000000
        interrupts 0, underruns 0, feed 0, ready 0 [b:0/0/0|bs:0/0/0]
        channel flags=0x10000000<VIRTUAL>
        {userland} -> feeder_root(0x00000000) -> {hardware}
        [pcm0:record:dsp0.r0]: spd 48000, fmt 0x00200010, flags 
0x00002100, 0x00000005
        interrupts 0, overruns 0, feed 0, hfree 512, sfree 512 
[b:512/256/2|bs:512/256/2]
        channel flags=0x2100<BUSY,HAS_VCHAN>
        {hardware} -> feeder_root(0x00200010) -> 
feeder_mixer(0x00200010) -> {userland}
pcm0:record:dsp0.r0[pcm0:virtual_record:dsp0.vr0]: spd 8000, fmt 
0x00100008, flags 0x10000000, 0x00000000
        interrupts 0, overruns 0, feed 0, hfree 0, sfree 0 
[b:0/0/0|bs:0/0/0]
        channel flags=0x10000000<VIRTUAL>
        {hardware} -> feeder_root(0x00000000) -> {userland}
pcm1: <Realtek ALC671 (Analog)> on hdaa0 (1p:1v/1r:1v)
        snddev flags=0x2e2<AUTOVCHAN,BUSY,MPSAFE,REGISTERED,VPC>
        [pcm1:play:dsp1.p0]: spd 48000, fmt 0x00200010, flags 
0x00002100, 0x00000004
        interrupts 0, underruns 0, feed 0, ready 0 
[b:2048/1024/2|bs:2048/1024/2]
        channel flags=0x2100<BUSY,HAS_VCHAN>
        {userland} -> feeder_mixer(0x00200010) -> {hardware}
pcm1:play:dsp1.p0[pcm1:virtual_play:dsp1.vp0]: spd 8000, fmt 0x00100008, 
flags 0x10000000, 0x00000000
        interrupts 0, underruns 0, feed 0, ready 0 [b:0/0/0|bs:0/0/0]
        channel flags=0x10000000<VIRTUAL>
        {userland} -> feeder_root(0x00000000) -> {hardware}
        [pcm1:record:dsp1.r0]: spd 48000, fmt 0x00200010, flags 
0x00002100, 0x00000005
        interrupts 0, overruns 0, feed 0, hfree 512, sfree 512 
[b:512/256/2|bs:512/256/2]
        channel flags=0x2100<BUSY,HAS_VCHAN>
        {hardware} -> feeder_root(0x00200010) -> 
feeder_mixer(0x00200010) -> {userland}
pcm1:record:dsp1.r0[pcm1:virtual_record:dsp1.vr0]: spd 8000, fmt 
0x00100008, flags 0x10000000, 0x00000000
        interrupts 0, overruns 0, feed 0, hfree 0, sfree 0 
[b:0/0/0|bs:0/0/0]
        channel flags=0x10000000<VIRTUAL>
        {hardware} -> feeder_root(0x00000000) -> {userland}
pcm2: <Intel Kaby Lake (HDMI/DP 8ch)> on hdaa1 (1p:1v/0r:0v) default
        snddev 
flags=0x2e7<SIMPLEX,AUTOVCHAN,SOFTPCMVOL,BUSY,MPSAFE,REGISTERED,VPC>
        [pcm2:play:dsp2.p0]: spd 48000, fmt 0x00200010, flags 
0x00006100, 0x00000004
        interrupts 0, underruns 0, feed 0, ready 0 
[b:2048/1024/2|bs:2048/1024/2]
        channel flags=0x6100<BUSY,HAS_VCHAN,VCHAN_PASSTHROUGH>
        {userland} -> feeder_mixer(0x00200010) -> {hardware}
pcm2:play:dsp2.p0[pcm2:virtual_play:dsp2.vp0]: spd 8000, fmt 0x00100008, 
flags 0x10000000, 0x00000000
        interrupts 0, underruns 0, feed 0, ready 0 [b:0/0/0|bs:0/0/0]
        channel flags=0x10000000<VIRTUAL>
        {userland} -> feeder_root(0x00000000) -> {hardware}
No devices installed from userspace.

    BTW, I've been using FreeBSD since 1.x days.

These same systems give me sound on every output on linux mint, kde 
neon, debian12.

I'm running 14stable, but I've had this issue since 2017 (Dell Inspiron 
3668 (i3).