[oss-devel] ALC268 hdaudio auto detect headphone presence ?

[Hannu Savolainen]

Wannabe Tsotsi kirjoitti:
> Hannu wrote:
>
> > This is something that needs to be done when the hdaudio driver is
> > rewritten (during this year). However before that it may not be 
> possible.
>
> Do you have a particular approach in mind ?

There are few things that need to be done.

1) Finding out when something gets plugged or unpluged to the jacks. 
This can be done by implementing support for "unsolicited responses" 
sent by the codec when
something gets plugged/unplugged. Otherwise the driver could use 
timeout() callbacks to check the jack precense detection bits every 
(say) 10 seconds.

2) Finding out which jack (pin widget) is the headphone and which jacks 
are connected to the speaker(s). In most systems this can be done by 
observing the association/sequence fields of the CONFIG_DEFAULT 
registers of the pin widgets. My current understanding is that sequence 
value of 0xe (or was it 0xf) tells that this jack is the headphone. When 
something gets plugged to it then all other pin widgets sharing the same 
association number should be muted.

3) Muting/unmuting the speakers can be done by clearing the output (amp) 
enable bits of the pin widgets.

Best regards,

Hannu