[alsa-devel] [PATCH 2/5] ALSA: hda/generic - Fix wrong initial power state for fixed pins

[Takashi Iwai]

At Fri, 10 Apr 2015 16:51:58 +0800,
Raymond Yau wrote:
> 
> >
> > When the widget power-saving is enabled, the first automute hook
> > invocation checks through the whole pins and it also tries to
> > synchronize the power state.  However, this results in a wrong state
> > because it calls unconditionally snd_hda_jack_detect_state().
> > This patch adds a check of jack detectability before the actual jack
> > detection call.
> 
> What happen when the computer has no headphone jack ?

Nothing wrong happens.  The logic of widget power saving is to power
down unused paths.  It includes the paths with pins that aren't
plugged and paths with the DAC/ADCs that aren't enabled (no stream
running).  Fixed pins are handled as always plugged.


Takashi

> 
> No mic jack and internal mic
> 
> Those  thin mini itx motherboard use firmware to disable mixer and remove
> all input pins
> 
> # Prevent the AA-loopback from being enabled which can pull in white noise
> (ACI#380)
> [hint]
> mixer_nid = 0
> 
> Will the driver still power down the audio mixer and audio inputs ?
> 
> Seem driver still create capture device when there is no input pins
> 
> https://bugs.freedesktop.org/show_bug.cgi?id=54881#c16
> 
> https://bugs.freedesktop.org/show_bug.cgi?id=54881#c16