Re: [PATCH] ASoC: codecs: lpass-wsa-macro: rewrite the interpolator volume after enabling clocks

[Jonathan Marek]

this is just papering over the real problem, which would be the regmap 
cache being out of sync with the HW registers. there's no requirement 
that the volume register be written after the int/path clock enable

(fwiw, this problem doesn't reproduce on my setup, where this driver 
does not autosuspend and the regmap doesn't go into cache-only mode)

On 9/24/26 8:59 AM, Liviu Nicoara wrote:
> Commit 902f497a1ff5 ("ASoC: codecs: lpass-wsa-macro: remove useless
> gain read/write sequence") removed the read and write of the digital
> volume register in wsa_macro_enable_interpolator(), on the grounds that
> writing back the value just read does nothing. The comment above it,
> "apply gain after int clk is enabled", was left in place.
>
> On the Dell XPS 13 9345 (X1E80100, four WSA8845 amplifiers on two WSA
> macros) the write does something: a volume change made while the path
> is idle does not take effect when playback starts. Lowering the digital
> volume from 81 to 63 with nothing playing, then playing a test tone,
> gave about the same level as before the change. With the rewrite
> restored, lowering it from 81 to 69 while idle played audibly quieter,
> and restoring 81 while idle brought the level back. Changes made during
> playback take effect with or without the rewrite.
>
> This is the behaviour described in commit 46188db080bd ("ASoC: codecs:
> lpass-wsa-macro: fix compander volume hack"): "the volume registers
> still need to be written after enabling clocks in order for any prior
> updates to take effect." The value read comes from the register cache,
> so the write pushes the last requested volume to the hardware once its
> clock runs.
>
> Restore the rewrite in the interpolator's POST_PMU event only. The mix
> path event removed later in the same series is not brought back.
>
> Fixes: 902f497a1ff5 ("ASoC: codecs: lpass-wsa-macro: remove useless gain read/write sequence")
> Assisted-by: Claude:claude-opus-5-5
> Signed-off-by: Liviu Nicoara <lnicoara@xxxxxxxxxxxx>
> ---
>
> Notes:
>      Tested on v7.2.6 on the machine above, by listening. This function is
>      unchanged between v7.2 and for-next; the driver's clocks moved to the
>      PM clock framework in cd054a6e272c after v7.2, which was not tested
>      here. Build-tested on broonie/for-next (arm64 defconfig).
>
>   sound/soc/codecs/lpass-wsa-macro.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/sound/soc/codecs/lpass-wsa-macro.c b/sound/soc/codecs/lpass-wsa-macro.c
> index 4242366601a5..899c8bee4645 100644
> --- a/sound/soc/codecs/lpass-wsa-macro.c
> +++ b/sound/soc/codecs/lpass-wsa-macro.c
> @@ -1849,6 +1849,7 @@ static int wsa_macro_enable_interpolator(struct snd_soc_dapm_widget *w,
>   					 int event)
>   {
>   	struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
> +	unsigned int gain;
>   	u16 gain_reg;
>   	u16 reg;
>   	struct wsa_macro *wsa = snd_soc_component_get_drvdata(component);
> @@ -1890,6 +1891,8 @@ static int wsa_macro_enable_interpolator(struct snd_soc_dapm_widget *w,
>   					CDC_WSA_RX_PGA_HALF_DB_MASK,
>   					CDC_WSA_RX_PGA_HALF_DB_ENABLE);
>   		}
> +		gain = snd_soc_component_read(component, gain_reg);
> +		snd_soc_component_write(component, gain_reg, gain);
>   		wsa_macro_config_ear_spkr_gain(component, wsa,
>   						event, gain_reg);
>   		break;