[alsa-devel] alsactl adds volume controls?

[Raymond Yau]

2010/10/1 Clemens Ladisch <clemens at ladisch.de>

> Takashi Iwai wrote:
> > Mark Brown wrote:
> > > On Thu, Sep 30, 2010 at 04:09:56PM +0100, Colin Guthrie wrote:
> > > > *shouldn't* use them, but at present it does and they *are* active
> and
> > > > used, so it's not an issue for me), the problem is rather one of
> setting
> > > > Master (not PCM) to 0% aka -46.5dB causes some kind of auto-mute that
> > > > cuts off all sound. It shouldn't do that.
> > >
> > > Is this perhaps just an error in the TLV information - should it be
> > > flagging that the minimim gain is mute but isn't?
> >
> > There is no clear (or consistent) definition in HD-audio codec, I guess.
>
> The HDA spec is quite clear that muting is done only with the mute bit.
>
> > Some chips do mute at 0 and some not.
>
> Those that do are violating the specification.
>
> But we have to support them anyway.
> Colin, please tell us the IDs of your codec so that we can add a TLV
> workaround to the driver.
>
>
> Regards,
> Clemens
>
>
Actually, the softvol plugin behave as the same way as Colin describe since
when the resolution is 2 , the softvol become a mute switch

http://git.alsa-project.org/?p=alsa-lib.git;a=commit;h=f78af4ab0412052aabb74c9122a8d8f3ab6d45e6

So the question is why -51dB is selected as min_dB

Is this value enough for S16_LE or  S32_LE for hda-intel ?

http://git.alsa-project.org/?p=alsa-kernel.git;a=commitdiff;h=eacbb9dba6b4c982a0217ea2c7d15db88d4fda37;hp=d91b424d6d7bda0773b6b6b606d48d089c4f5115

As those DACs support -120dB to 0dB , but the driver can actually limit the
dB range to -60dB to 0dB . so the minimum volume -60dB is definitly not mute
in this case

why -60dB is selected  ?