Re: [PATCH] ASoC: mediatek: mt8195: Re-add codec entry for ETDM1_OUT_BE dai link

[AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>]

Il 20/06/24 11:25, Chen-Yu Tsai ha scritto:
> This partially reverts commit e70b8dd26711704b1ff1f1b4eb3d048ba69e29da.
>
> Said commit removes the codec entry for the ETDM1_OUT_BE dai link for
> some reason. This does not have the intended effect, as the remaining
> DAILINK_COMP_ARRAY(COMP_EMPTY()) platform entry becomes the codec
> entry, and the platform entry is completely gone.
>
> This causes in a KASAN out-of-bounds warning in mtk_soundcard_common_probe()
> in sound/soc/mediatek/common/mtk-soundcard-driver.c:
>
> 	for_each_card_prelinks(card, i, dai_link) {
> 		if (adsp_node && !strncmp(dai_link->name, "AFE_SOF", strlen("AFE_SOF")))
> 			dai_link->platforms->of_node = adsp_node;
> 		else if (!dai_link->platforms->name && !dai_link->platforms->of_node)
> 			dai_link->platforms->of_node = platform_node;
> 	}
>
> where the code expects the platforms array to have space for at least one entry.
>
> Re-add the entry so that dai_link->platforms has space.

Ok, but wait a minute... the commit that you're pointing at in the Fixes tag is
a commit that fixes a problem identified in commit

13f58267cda3 ("ASoC: soc.h: don't create dummy Component via COMP_DUMMY()")

to keep it short, after that one, without removing the COMP_DUMMY(), the audio
was broken in .. some way, I don't currently remember specifically what was
happening, but I had no sound at all.

If the problem is not showing up anymore, backporting this commit to the kernels
kernels affected by the issue that I solved... will break sound!

So... well.. that's the "some reason".... :-)

Cheers,
Angelo

> Fixes: e70b8dd26711 ("ASoC: mediatek: mt8195: Remove afe-dai component and rework codec link")
> Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
> ---
>   sound/soc/mediatek/mt8195/mt8195-mt6359.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/sound/soc/mediatek/mt8195/mt8195-mt6359.c b/sound/soc/mediatek/mt8195/mt8195-mt6359.c
> index ca8751190520..2832ef78eaed 100644
> --- a/sound/soc/mediatek/mt8195/mt8195-mt6359.c
> +++ b/sound/soc/mediatek/mt8195/mt8195-mt6359.c
> @@ -827,6 +827,7 @@ SND_SOC_DAILINK_DEFS(ETDM2_IN_BE,
>   
>   SND_SOC_DAILINK_DEFS(ETDM1_OUT_BE,
>   		     DAILINK_COMP_ARRAY(COMP_CPU("ETDM1_OUT")),
> +		     DAILINK_COMP_ARRAY(COMP_EMPTY()),
>   		     DAILINK_COMP_ARRAY(COMP_EMPTY()));
>   
>   SND_SOC_DAILINK_DEFS(ETDM2_OUT_BE,