[pulseaudio-discuss] Dealing with the ThinkPad hardware mixer

[Tom Gundersen]

On Mon, May 23, 2011 at 7:50 PM, Colin Guthrie <gmane at colin.guthr.ie> wrote:
> 'Twas brillig, and Andrew Lutomirski at 23/05/11 18:21 did gyre and gimble:
>> What is the kernel supposed to do to get PulseAudio to DTRT?  On some,
>> but not (I think) all, models, we can disable hardware mixer control
>> and make all of the buttons act like ordinary buttons, but that will
>> cause the light (if present) to malfunction, and I don't know if all
>> models can do this.  So as it stands, PulseAudio would have to
>> understand that the mixer is special and watch for ALSA change
>> notifications.
>>
>> I'm willing to change the thinkpad-acpi driver to make it work better,
>> but I know nothing at all about PulseAudio internals.  What should I
>> do?
>
> Can you give some more details?
>
> e.g. does it show up under the same alsa card as the HDA or is it separate?
>
> amixer -c0 (or appropriate number) would be useful to begin with :)

I have a ThinkPad X60 which I think is one of the relevant models. I
have a mute botton and two volume buttons, but no light. Pressing vol
up/down unmutes and changes the volume.

As explained by Andy,
alsamixer -c29
shows the thinkpad mixer and it works as expected (read-only).

Below are the outputs of amixer for my system (running 2.6.39 fwiw).
I'd be happy to try patches or help in any other way to make this work
nicely with PA.

Cheers,

Tom

teg at x60 ~ % amixer -c29
Simple mixer control 'Console',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
  Playback channels: Mono
  Limits: Playback 0 - 14
  Mono: Playback 10 [71%] [off]



teg at x60 ~ % amixer -c0
Simple mixer control 'Master',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 63
  Mono:
  Front Left: Playback 61 [97%] [0.00dB] [on]
  Front Right: Playback 61 [97%] [0.00dB] [on]
Simple mixer control 'PCM',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 23 [74%] [0.00dB] [on]
  Front Right: Playback 23 [74%] [0.00dB] [on]
Simple mixer control 'CD',0
  Capabilities: pvolume pswitch cswitch cswitch-joined cswitch-exclusive penum
  Capture exclusive group: 0
  Playback channels: Front Left - Front Right
  Capture channels: Mono
  Limits: Playback 0 - 31
  Mono: Capture [off]
  Front Left: Playback 23 [74%] [0.00dB] [on]
  Front Right: Playback 23 [74%] [0.00dB] [on]
Simple mixer control 'Mic',0
  Capabilities: pvolume pswitch cswitch cswitch-joined cswitch-exclusive penum
  Capture exclusive group: 0
  Playback channels: Front Left - Front Right
  Capture channels: Mono
  Limits: Playback 0 - 31
  Mono: Capture [on]
  Front Left: Playback 0 [0%] [-34.50dB] [off]
  Front Right: Playback 0 [0%] [-34.50dB] [off]
Simple mixer control 'Mic Boost',0
  Capabilities: volume penum
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: 0 - 3
  Front Left: 1 [33%] [10.00dB]
  Front Right: 1 [33%] [10.00dB]
Simple mixer control 'IEC958',0
  Capabilities: pswitch pswitch-joined penum
  Playback channels: Mono
  Mono: Playback [on]
Simple mixer control 'IEC958 Default PCM',0
  Capabilities: pswitch pswitch-joined penum
  Playback channels: Mono
  Mono: Playback [on]
Simple mixer control 'IEC958 Playback Source',0
  Capabilities: enum
  Items: 'PCM' 'ADC'
  Item0: 'PCM'
Simple mixer control 'Beep',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
  Playback channels: Mono
  Limits: Playback 0 - 15
  Mono: Playback 0 [0%] [-45.00dB] [off]
Simple mixer control 'Capture',0
  Capabilities: cvolume cswitch penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 15
  Front Left: Capture 15 [100%] [22.50dB] [on]
  Front Right: Capture 15 [100%] [22.50dB] [on]
Simple mixer control 'Mix',0
  Capabilities: cswitch cswitch-joined cswitch-exclusive penum
  Capture exclusive group: 0
  Capture channels: Mono
  Mono: Capture [off]