[alsa-devel] [pulseaudio-discuss] ThinkPad T-510 audio output mute LED non-workingness

[Raymond Yau]

> >
> > Well, your firmware does not have SSMS, at all.  It is not that
> thinkpad-acpi
> > can't find it due to some change in the acpi core, it simply isn't there
> to
> > be found.
> >
>
> OK, thanks for the detective work, Henrique.
>
> In the interest of documenting what's been learned here (at least by me),
> what follows is an attempt at a detailed summary/guide to ThinkPad mute key
> and mute LED behavior when transitioning from 3.18 to 3.19 kernels. Perhaps
> it may be useful to others who are also head-scratching about this issue,
> since it involves quite a few moving parts.
>
> It would be great if you could look it over when you have a chance, and
> correct or bless it as you see fit. I'll also pass it by the PA folks and
> then
> post the result to both the original PA ML thread and to the ThinkPad ACPI
> ML
> as well (if you want).
>
>
>
> =============================================================================
> For TP models like the T-510 (and others without the SSMS mute LED
> interface):
>
>  0.  If you want your mute LED to do anything (other than be permanently
> off)
>      you have no choice but to set acpi.software_mute=0 at boot time, which
>      reverts to 3.18 behavior.  If you do this, then 1-3 below apply.  If
> you
>      don't care whether your mute LED works, then 4-8 further below apply.
>
>  1.  The embedded controller (EC) fields mute key events directly, and in
>      response, toggles both the hardware speaker mute gate and the mute LED
>      (if you have one). The kernel is not involved in these actions at all.
>
>  2.  "Mute LED on" means, unequivocally, that the hardware mute gate is
>      clamped, i.e. no sound can emit from the speaker, period.  The
> hardware
>      mute gate has no effect on headphone mute state.
>
>  3.  If you happen to already have the mute key mapped via userspace event
>      to do something with the mixer mute state (e.g. via
> amixer/pactl/pacmd,
>      etc.) you should probably disable that mapping in order to avoid
>      unintended conflicts and/or mild insanity.
>
>
> Do your volume up/down key still work with soft_mute=1 ?

https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1450947

It seem that Thinkpad X60 's volume up/down key has no effect

Do thinkpad_acpi need to check whether thinkpad support "HAUM" and "SAUM"
interface before enable software mute ?