[alsa-devel] alsa-lib: snd_mixer_selem_is_active changes - which event?

[Raymond Yau]

2011/2/16 Sebastian H. <vand2 at gmx.de>

> Hello
>
> I wonder which event mask notifies an application that
> snd_mixer_selem_is_active() may have changed.
>
> SND_CTL_EVENT_MASK_VALUE
> or
> SND_CTL_EVENT_MASK_INFO
>
> or something else?
>
> I'd be glad for any insights?
>
>
qasmixer display the following message when play audio through front device
of emu10k1

alsa_callback_hctl_elem: Unknown mask ( 3 )
[EE] snd_hctl_handle_events : Operation not permitted


which event mask "SND_CTL_EVENT_MASK_VALUE" or "SND_CTL_EVENT_MASK_VALUE "
should the mixer application handle first ?

e.g. it is possible that the driver may change access of  the control

 & ~SNDRV_CTL_ELEM_ACCESS_READ