Messages in this thread |  | | Date | Fri, 10 Jun 2022 11:23:31 +0200 | From | Lukasz Majewski <> | Subject | Re: [PATCH 3/3] ASoC: wm8940: Mute also the speaker output |
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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
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