Re: [PATCH RFC 1/6] ASoC: qcom: sdm845: Demystify TDM masks a bit

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] The CPU DAI's capture mask is incorrectly configured to 0x0F (slots 0-3) instead of 0xF0 (slots 4-7), breaking the V/I sense capture path. The patch exacerbates this by using the playback macro `SPK_TDM_RX_MASK` to construct the capture mask, which creates a false semantic link and obfuscates the underlying bug.
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commit 7636e0a7627a4449334c3af3eda079faca90b76e
Author: David Heidelberg <david@ixit.cz>

ASoC: qcom: sdm845: Demystify TDM masks a bit

This commit updates the hardcoded TDM masks in the sdm845 machine driver
by defining them as bitmasks and utilizing them in the hw_params function.
It aims to describe which bits are used for each RX/TX slot.

> diff --git a/sound/soc/qcom/sdm845.c b/sound/soc/qcom/sdm845.c
> index 0ce9dff4dc525..edd2cc7a1c74f 100644
> --- a/sound/soc/qcom/sdm845.c
> +++ b/sound/soc/qcom/sdm845.c
[ ... ]
> @@ -129,8 +131,10 @@ static int sdm845_tdm_snd_hw_params(struct snd_pcm_substream *substream,
>  			goto end;
>  		}
>  	} else {
> -		ret = snd_soc_dai_set_tdm_slot(cpu_dai, 0xf, 0,
> -				8, slot_width);
> +		ret = snd_soc_dai_set_tdm_slot(cpu_dai,
> +					       SPK_TDM_RX_MASK | BIT(2) |
> +					       BIT(3), 0,
> +					       NUM_TDM_SLOTS, slot_width);

[Severity: High]
This is a pre-existing issue, but does using SPK_TDM_RX_MASK here conflate
the CPU DAI capture mask with the playback RX macros?

Looking at the capture path in sdm845_tdm_snd_hw_params(), the CPU DAI's
capture mask is currently configured to 0x0F (slots 0-3), but the codecs
are configured to transmit on slots 4-7 (mask 0xF0). This mismatch causes
the V/I sense capture path to receive silence.

Since the DSP channel mapping maps channels to slots 0, 4, 8, and 12, an
active mask of 0x0F completely disables slots 4 and 8 on the TDM port.

Could the capture mask be updated to use LEFT_SPK_TDM_TX_MASK and
RIGHT_SPK_TDM_TX_MASK to correctly configure 0xF0, rather than building
0x0F out of the playback mask?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260705-pixel3-audio-v1-0-3b66f33859f1@ixit.cz?part=1