[alsa-devel] calling snd_ctl_notify from mixer ctl_put

[Raymond Yau]

2012-10-14 上午5:24 於 "Ondrej Zary" <linux at rainbow-software.org> 寫道：
>
> On Friday 12 October 2012 08:03:13 Clemens Ladisch wrote:
> > Ondrej Zary wrote:
> > > I want to enable/disable some mixer controls based on state of another
> > > control (switching between limiter and AGC mode). So I (re)set the
> > > SNDRV_CTL_ELEM_ACCESS_INACTIVE flag in kctl->vd[0].access
> > > and then call snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO,
&kctl->id);
> > > Everyting from ctl_put() mixer callback.
> > >
> > > When changing the control value in alsamixer, it crashes with:
> > > alsamixer: simple.c:948: snd_mixer_selem_get_enum_item: Assertion
> > > `(elem)->type == SND_MIXER_ELEM_SIMPLE' failed.
> >
> > Looks like a bug in alsamixer.
>
> Thanks. I've now tried some other mixers that are present in Debian and
most
> of them are unusable:
> alsamixergui: does not understand ENUM controls
> gnome-alsamixer: does not understand ENUM controls
> gnome-volume-control: crashes like alsamixer
> xfce4-mixer: crashes like alsamixer
> kmix (TDE 3.5.13): does not update controls when switching limiter/AGC
> kmix (KDE 4): crashes like alsamixer
> (other mixers won't even run as they seem to be OSS-only)
>
> But there's one that works fine: QasMixer.
>

the alsamixer also crash only when "independent headphone" enum of ad1988
is visible in alsamixer when the analog or headphone playback stream
close/open in ubuntu 12.4