Re: [PATCH 2/2] ALSA: Integrate control based jack reporting with core jack reporting

[Mark Brown <broonie@opensource.wolfsonmicro.com>]

On Tue, Feb 14, 2012 at 09:29:27AM +0800, Raymond Yau wrote:

I really shouldn't have ot remind you to not remove people from the CC
list, this is really basic stuff...

> 1) The problem of core jack api which is tailor made for embedded
> device, it assume there is only one sound card

This is not the case at all, there is no such assumption and indeed many
embedded devices have multiple sound cards.

> when the desktop computer have more than one sound cards which have jack detect
> there is no mapping to which sound card has the events.

The jack device is a child of the sound card, userspace can look at the
parent to see which sound card a given jack is associated with.

> 2) if the objective of adding jack detection is for trapping
> plug/unplug event to trigger the reconfiguration of audio server

> http://thread.gmane.org/gmane.linux.alsa.devel/89781/focus=89788

> does the audio server require to know the initial state of the hdmi
> or just need the trigger event ?

For all three of the accessory detection mechanisms the state can be
read at any time.