Hi Mark,
> On Mon, Jun 06, 2022 at 05:44:41PM +0200, Lukasz Majewski wrote:
>
> > Without this change the BTL speaker produces some
> > "distortion" noise when test program
> > (speaker-test -t waw) is ended with ctrl+c.
>
> > As our design uses speaker outputs to drive BTL speaker,
> > it was necessary to also mute the speaker via the codec
> > internal WM8940_SPKVOL register with setting
> > WM8940_SPKMUTE bit.
>
> This will not interact well with both the user visible control of the
> speaker volume via the Speaker Playback Volume control and the analog
> bypass paths that the device has - it'll change the state of the
> control without generating any events, and cut off any bypassed audio
> that's mixed in.
>
I'm wondering why it is safe to call DAI's .digital_mute()
callback, which explicitly changes state of the "DAC soft mute enable"
bit (DACMU) ?
And on the other hand it is not correct to just mute the speakers?
> You can probably achieve a similar effect by making the control an
> _AUTODISABLE one which will allow the core to mute the control when
> it's not being used in a way that's not visible to userspace.
The exact definition for the event, which I'm forcing above:
SOC_SINGLE("Speaker Playback Switch", WM8940_SPKVOL, 6, 1, 1),
And there is no SOC_SINGLE_AUTODISABLE() macro available.
The issue I'm trying to fix:
- The mclk clock is stopped (after some time) by imx SOC when I end
'speaker-test' program with ctrl+c.
- When the clock is not provided (after ~1sec) I do hear a single short
noise from speakers.
- The other solution (which also works) would be to enable clock once
(during probe) and then do not disable it till system is powered
off (yes it is a hack :-) ).
I'm wondering if this can be fixed by some 'amixer' user space switch?
Thanks in advance for help.
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@xxxxxxx
Attachment:
pgpcqdO4AI66y.pgp
Description: OpenPGP digital signature
