Re: [RFC PATCH v2 2/3] ALSA: hda/realtek: Add support for Legion 7 16ACHg6 laptop Speakers

[Takashi Iwai <tiwai@suse.de>]

On Wed, 20 Oct 2021 10:59:43 +0200,
Lucas Tanure wrote:
> 
> Find the associated Amps by dai name, and use dai ops to configure it.
> Disable support for Amps if ASoC not built.

Hrm, it's the question whether such a sneaking into DAI access in open
code is a good idea.  If any, it could be done by some helper function
instead.

And some more details:

> +static int alc_add_soc_dai_list(struct alc_spec *spec, const char *dai_name)
> +{
> +#if IS_ENABLED(CONFIG_SND_SOC)
> +	struct snd_soc_dai_link_component dlc;
> +	struct alc_soc_dai_node *dai_node;
> +	//struct snd_soc_component *comp;
> +	struct snd_soc_dai *dai;
> +
> +	dlc.dai_name = dai_name;
> +	dlc.of_node = NULL;
> +	dlc.name = NULL;
> +
> +	dai = snd_soc_find_dai(&dlc);
> +	if (!dai)
> +		return -EPROBE_DEFER;

The deferred probe won't work at this stage for HD-audio codecs unlike
many ASoC codec drivers.  And moreover, the fixup action doesn't
handle the error at all...

Second, this way may lead to use-after-free if the ASoC stuff is
unbound while the usage from HD-audio codec side.

Also, the dependency mess is still there.  Even if we allow the hard
binding to ASoC core here, IS_ENABLED() wouldn't work properly.  It
must be IS_REACHABLE().


thanks,

Takashi