linux-kernel - Re: [PATCH] ASoC: codecs: lpass-rx-macro: Fix playback quality distortion

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Message-ID: <6889f493-f37b-43a5-add8-8e170e295492@linaro.org>
Date: Tue, 2 Sep 2025 08:08:30 +0200
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: Srinivas Kandagatla <srini@...nel.org>,
 Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>,
 Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
 linux-sound@...r.kernel.org, linux-arm-msm@...r.kernel.org,
 linux-kernel@...r.kernel.org, Alexey Klimov <alexey.klimov@...aro.org>
Subject: Re: [PATCH] ASoC: codecs: lpass-rx-macro: Fix playback quality
 distortion

On 02/09/2025 04:40, Dmitry Baryshkov wrote:
> On Mon, Sep 01, 2025 at 09:44:04AM +0200, Krzysztof Kozlowski wrote:
>> Commit bb4a0f497bc1 ("ASoC: codecs: lpass: Drop unused
>> AIF_INVALID first DAI identifier") removed first entry in enum with DAI
>> identifiers, because it looked unused.  Turns out that there is a
>> relation between DAI ID and "RX_MACRO RX0 MUX"-like kcontrols which use
>> "rx_macro_mux_text" array.  That "rx_macro_mux_text" array used first
>> three entries of DAI IDs enum, with value '0' being invalid.
>>
>> The value passed tp "RX_MACRO RX0 MUX"-like kcontrols was used as DAI ID
>> and set to configure active channel count and mask, which are arrays
>> indexed by DAI ID.
>>
>> After removal of first AIF_INVALID DAI identifier, this kcontrol was
>> updating wrong entries in active channel count and mask arrays which was
>> visible in reduced quality (distortions) during headset playback on the
>> Qualcomm SM8750 MTP8750 board.  It seems it also fixes recording silence
>> (instead of actual sound) via headset, even though that's different
>> macro codec.
> 
> Wouldn't it be easier to assign 1 to RX_MACRO_AIF1_PB,
> TX_MACRO_AIF1_CAP, etc.?

That would be basically revert of mentioned commit, so same arguments as
I used in that commit.

Best regards,
Krzysztof