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

[Glenn Golden]

Raymond Yau <superquad.vortex2 at gmail.com> [2015-04-19 10:47:11 +0800]:
> 
> You have not posted alsa-info of working 3.18
> 

Here are alsa-info.sh reports for both kernels:

    http://misc.postpro.net/t510led/alsa_info_3.18.6.txt
    http://misc.postpro.net/t510led/alsa_info_3.19.3_soft0.txt
    http://misc.postpro.net/t510led/alsa_info_3.19.3_soft1.txt

The difference between the 3.19 "soft0" and "soft1" versions is that "soft0"
version was booted with the kernel commandline parameter

	thinkpad_acpi.software_mute=0

This just reverts the muting behavior back to 3.18 (which is my preference).
The "soft1" version does not supply this parameter, so you get the default
3.19 behavior (i.e., software muting enabled, HW muting disabled.)


>
> Refer to alsa-info found in t510 speaker powersave regression
> 
> https://lkml.org/lkml/2012/12/22/113
> 

Superficially, to my eyes anyway, it doesn't seem related to this issue.
Do you think it might be?  If so, please be more explicit, I don't see
the connection.

>
> Simple mixer control 'Console',0
>   Capabilities: pswitch pswitch-joined
>   Playback channels: Mono
   Mono: Playback [on]
> 
> Do this console playback switch has any effect on your schematic view ?
> 

It's a read-only card, so it has no "effect", but its state does reflect
the HW mute state. See further below for details.

> 
> AFAIK, pulseaudio ignore card  29 "ThinkPadEC"
> 

Yes, that seems to be right. But it can be seen via amixer -c29: Here's the
observed behavior under 3.18, using the terminology from the kernel bug
report:

  0.  Toggle MUTEKEY until MUTELED = off.
  1.  Start audio source, verify SPK_SOUND = on
  2.  'amixer -c29 get Console' reports "Mono: Playback [on]"
  3.  Toggle MUTEKEY, verify MUTELED = on, SPK_SOUND = off
  4.  'amixer -c29 get Console' reports "Mono: Playback [off]"

That's all I see.