https://docs.kernel.org/sound/designs/powersave.html
The default value of timeout is given via CONFIG_SND_AC97_POWER_SAVE_DEFAULT and CONFIG_SND_HDA_POWER_SAVE_DEFAULT Kconfig options. Setting this to 1 (the minimum value) isn’t recommended because many applications try to reopen the device frequently. 10 would be a good choice for normal operations.