Hi David,
First of all, thank you for your work on subwoofer issues. I've had a chance to test them on my system lately, and they do really fix the bug reported, but another one (more serious, in my opinion) remains: subwoofer is not muted via normal mute button (more precisely, by muting Master ALSA mixer). The problem is that during autoconfiguration procedure, subwoofer is mapped on PCM channel, and there seems (at least to me) to be no reliable way to distinguish subwoofer from other possibly existing outputs on a general system and change this behavior. Creating dedicated presets for the machines with a subwoofer seems to be right way to workaround this, but then _quirks you've implemented should be merged with this preset.
Does this sound reasonable to you or I am missing anything?
Thanks.
Regards, Valentine Sinitsyn