[pulseaudio-discuss] [PATCH 6/6] ucm: Add support for "JackHWMute"

[Tanu Kaskinen]

On Tue, 2015-03-31 at 20:32 +0300, Tanu Kaskinen wrote:
> On Mon, 2015-03-30 at 09:54 +0200, David Henningsson wrote:
> > Also, we would then get automatic support for use cases like "Line Out" 
> > which should only be available if both a) "Line Out Jack" is plugged in 
> > and b) "Headphone Jack" is unplugged.
> 
> In my patch I decided to not support a situation where one jack makes a
> device available and another jack makes it unavailable, because of the
> ambiguity. If we want to support the use case you mention, I guess the
> UCM spec should explicitly say that JackHWMute overrides JackControl,
> otherwise we'd be relying on undefined behaviour.

I started to write a documentation patch for alsa-lib to address this
concern, but I think the current documentation might already be good
enough: "If JackHWMute is set, it indicates that when the jack is
plugged in, the hardware automatically mutes some other device." If the
other device is muted, it's natural to assume that the other device will
stay silent regardless of its own jack status.

-- 
Tanu