HD Audio with 'mute light'

HD Audio with 'mute light'

[Arnout Engelen]

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Hi,

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,

Arnout

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Re: HD Audio with 'mute light'

[Takashi Iwai]

At Sat, 22 Sep 2012 20:54:11 +0200,
Arnout Engelen wrote:
> 
> Hi,
> 
> 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.

Such a hardware mute isn't always related with the codec itself.
For example, Lenovo laptops have controls of the sound in the ACPI
over the sound chip.  OTOH, some machines (like HP laptops) use EAPD
for controlling the mute LED.  This is bound with the Master switch in
the recent driver.

So, without knowing the hardware detail, it's hard to tell more.


Takashi

> 
> 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,
> 
> Arnout

Re: HD Audio with 'mute light'

[David Henningsson]

On 09/22/2012 08:54 PM, Arnout Engelen wrote:
> Hi,
>
> 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.

We generally recommend people to submit the entire alsa-info, rather 
than just the codec info (which, btw, was an empty attachment). In 
particular; if you're having a thinkpad, the mute LED is controlled 
through thinkpad-acpi, and if you're having an HP, it's usually 
connected to the codec in a way hinted by BIOS. Given that you have a 
conexant codec, I'm guessing it's a thinkpad.


-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic

Re: HD Audio with 'mute light'

[Arnout Engelen]

On Mon, Sep 24, 2012 at 10:12:19AM +0200, David Henningsson wrote:
> >Attached is the codec info.
> 
> We generally recommend people to submit the entire alsa-info, rather
> than just the codec info (which, btw, was an empty attachment).

woops :)

> In particular; if you're having a thinkpad, the mute LED is controlled
> through thinkpad-acpi, and if you're having an HP, it's usually
> connected to the codec in a way hinted by BIOS. Given that you have
> a conexant codec, I'm guessing it's a thinkpad.

Thanks (also to Takashi) for this explanation. Indeed this is a ThinkPad
(W520). I'll look into thinkpad-acpi :)


Kind regards,

Arnout