[alsa-devel] alsactl adds volume controls?

[Raymond Yau]

2010/10/4 Colin Guthrie <gmane at colin.guthr.ie>

> 'Twas brillig, and Raymond Yau at 04/10/10 12:09 did gyre and gimble:
> > 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  ?
>
>
> Just for clarity, the 0 -> -51dB range is for the PCM control (i.e.
> softvol) only. The Master control gives me -46.5dB in addtiion to that
> giving a total of -97.5dB. This still isn't as high as the -120dB you
> are mentioning, but it's a lot closer.
>
> Of course I am lucky in that my Master apparently works fine but for
> those souls without any Master control, I presume the full range should
> be offered by the PCM softvol?
>
> Col
>
>
Did it happen on both channels or only left channel ?

The workaround mentioned in errata is to lock the sample rate