11 May
2015
11 May
'15
3:56 p.m.
On 2015-05-07 02:15, Glenn Golden wrote:
- ...because [Alsa? Pulseaudio?] maintains two independent mixer mute state variables -- one for headphone port, one for speaker port -- the semantics of both the mute key and the mute LED become less straightforward than with the hardware-based mute in 3.18.
The mute LED follows the state of ALSA's "Master Playback Switch". When that one is off, neither 3.5 mm headphone nor internal speakers have output - they're both muted.
PulseAudio's abstraction layer sets "Master Playback Switch" according to its active port's mute state. PulseAudio's active port (here speaker or headphone) will, by default, change automatically as headphones are plugged in or unplugged.
--
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic