Comment # 2 on bug 1180651 from Takashi Iwai

Likely a known regression in 5.10.4 kernel.  See bug 1180543.

If that's the case, the workaround is to pass the boot option
    snd_hda_codec_hdmi.enable_silent_stream=0
or upgrade to 5.10.5 kernel in OBS Kernel:stable repo.  Please check it.