[alsa-devel] HD Audio with 'mute light'

Arnout Engelen alsalist at bzzt.net
Sat Sep 22 20:54:11 CEST 2012


I've got a laptop with a HD Audio onboard sound card: the CX20590.

It seems like this card has a sort of 'hardware mute state': the 'mute button'
has a light, and when this light is on, no sound is heard, regardless of
whether or not the channel is muted in the ALSA mixer.

The hardware mute button switches the 'hardware mute state', and also sends a
keyboard event which I can use to also update the ALSA mixer mute.

This doesn't, however, work the other way around: I haven't found any way yet
to manipulate the 'hardware mute state' from software.

Looking with hda_analyzer, I notice this card has a 'Vendor Defined Widget'.
Might this be something that could be used to manipulate the hardware mute
state? I can use hda-verb but I wouldn't know how to discover which verb to
use. Anything else to try?

Attached is the codec info.

Kind regards,


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