[alsa-devel] [GIT PULL] dummy: allow disabling mixer controls

[Raymond Yau]

2012-10-21 下午7:13 於 "Clemens Ladisch" <clemens at ladisch.de> 寫道：
>
> Raymond Yau wrote:
> > 2012-10-21 上午6:11 於 "Clemens Ladisch" <clemens at ladisch.de> 寫道：
> >> Quite a few mixer applications do not handle deactivated controls
> >> correctly.
> >
> > what is the meaning of deactivated control ?
>
> A control where writes do not have an (immediate) effect.

why do you not implement this kind of control by disable/enable the write
access ?

>
> > amixer still can change the value of the deactivated cd volume control
if
> > write access is no disabled
>
> Yes, when write access is enabled, the control can be written to.
> This is necessary for "alsactl (re)store".

if the control can be write when the driver is loaded, the write access of
the control can be disable/enable instead of using active/inactive

>
> Alsamixer displays such controls as gray and read-only because changing
> them would not make sense at the moment, but allowing changes would
> actually be possible (if confusing).

alsamixer can also display non writable control in different color