Can't switch to HDMI audio output

[RidgeA]

Hello,

I have a laptop with 2 GPU and use an optimus-manager to switch between inte/nvidia GPU.

For some reason after switching to NVIDIA and turning on nvhda, I can't switch the audio output to HDMI.
HDMI output appears in a list of audio devices, however after switching to HDMI nothing happens, and I can't see any errors and nothing suspicions in dmesg...

What could I do to debug this issue and find out what goes wrong?

Arch linux, kernel - 5.1.15

[RidgeA]

I found a log record that could be related to the issue

systemd-udevd[2545]: Process '/usr/bin/alsactl restore 1' failed with exit code 99.

udev rule

cat /usr/lib/udev/rules.d/90-alsa-restore.rules 
ACTION=="add", SUBSYSTEM=="sound", KERNEL=="controlC*", KERNELS!="card*", TEST=="/usr/bin", TEST=="/usr/share/alsa", GOTO="alsa_restore_go"
GOTO="alsa_restore_end"

LABEL="alsa_restore_go"
TEST!="/etc/alsa/state-daemon.conf", RUN+="/usr/bin/alsactl restore $attr{device/number}"
TEST=="/etc/alsa/state-daemon.conf", RUN+="/usr/bin/alsactl nrestore $attr{device/number}"

LABEL="alsa_restore_end"

and I don't have /etc/alsa/state-daemon.conf

here is my full log after enabling nvhda

kernel: nvhda: enabling audio
kernel: pci 0000:01:00.1: [10de:1aeb] type 00 class 0x040300
kernel: pci 0000:01:00.1: reg 0x10: [mem 0xad080000-0xad083fff]
kernel: nvhda: Audio found, adding
kernel: pci 0000:01:00.1: BAR 0: assigned [mem 0xad080000-0xad083fff]
kernel: snd_hda_intel 0000:01:00.1: Disabling MSI
kernel: snd_hda_intel 0000:01:00.1: Handle vga_switcheroo audio client
kernel: input: HDA NVidia HDMI/DP,pcm=3 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input29
kernel: input: HDA NVidia HDMI/DP,pcm=7 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input30
kernel: input: HDA NVidia HDMI/DP,pcm=8 as /devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card1/input31
systemd-udevd[3888]: Process '/usr/bin/alsactl restore 1' failed with exit code 99.

[vfbsilva]

@RidgeA I stumbled on your post cause I was facing the same issue with manjaro. I've installed installed https://aur.archlinux.org/packages/nvhda-dkms-git/ and now it works. Hope it helps.