Re: [PATCH] ALSA: hda: intel-dsp-config: Prefer legacy driver as fallback

["Péter Ujfalusi" <peter.ujfalusi@linux.intel.com>]

On 10/12/2025 15:15, Takashi Iwai wrote:
> When config table entries don't match with the device to be probed,
> currently we fall back to SND_INTEL_DSP_DRIVER_ANY, which means to
> allow any drivers to bind with it.
> 
> This was set so with the assumption (or hope) that all controller
> drivers should cover the devices generally, but in practice, this
> caused a problem as reported recently.  Namely, when a specific
> kconfig for SOF isn't set for the modern Intel chips like Alderlake,
> a wrong driver (AVS) got probed and failed.  This is because we have
> entries like:
> 
>  #if IS_ENABLED(CONFIG_SND_SOC_SOF_ALDERLAKE)
>  /* Alder Lake / Raptor Lake */
>  	{
>  		.flags = FLAG_SOF | FLAG_SOF_ONLY_IF_DMIC_OR_SOUNDWIRE,
>  		.device = PCI_DEVICE_ID_INTEL_HDA_ADL_S,
>  	},
>  ....
>  #endif
> 
> so this entry is effective only when CONFIG_SND_SOC_SOF_ALDERLAKE is
> set.  If not set, there is no matching entry, hence it returns
> SND_INTEL_DSP_DRIVER_ANY as fallback.  OTOH, if the kconfig is set, it
> explicitly falls back to SND_INTEL_DSP_DRIVER_LEGACY when no DMIC or
> SoundWire is found -- that was the working scenario.  That being said,
> the current setup may be broken for modern Intel chips that are
> supposed to work with either SOF or legacy driver when the
> corresponding kconfig were missing.
> 
> For addressing the problem above, this patch changes the fallback
> driver to the legacy driver, i.e. return SND_INTEL_DSP_DRIVER_LEGACY
> type as much as possible.  When CONFIG_SND_HDA_INTEL is also disabled,
> the fallback is set to SND_INTEL_DSP_DRIVER_ANY type, just to be sure.

Makes sense.

> Reported-by: Askar Safin <safinaskar@gmail.com>
> Closes: https://lore.kernel.org/all/20251014034156.4480-1-safinaskar@gmail.com/
> Tested-by: Askar Safin <safinaskar@gmail.com>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>

Reviewed-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

> ---
>  sound/hda/core/intel-dsp-config.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/sound/hda/core/intel-dsp-config.c b/sound/hda/core/intel-dsp-config.c
> index c401c0658421..0c25e87408de 100644
> --- a/sound/hda/core/intel-dsp-config.c
> +++ b/sound/hda/core/intel-dsp-config.c
> @@ -718,7 +718,8 @@ int snd_intel_dsp_driver_probe(struct pci_dev *pci)
>  	/* find the configuration for the specific device */
>  	cfg = snd_intel_dsp_find_config(pci, config_table, ARRAY_SIZE(config_table));
>  	if (!cfg)
> -		return SND_INTEL_DSP_DRIVER_ANY;
> +		return IS_ENABLED(CONFIG_SND_HDA_INTEL) ?
> +			SND_INTEL_DSP_DRIVER_LEGACY : SND_INTEL_DSP_DRIVER_ANY;
>  
>  	if (cfg->flags & FLAG_SOF) {
>  		if (cfg->flags & FLAG_SOF_ONLY_IF_SOUNDWIRE &&

-- 
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