Re: [PATCH v7 01/14] ALSA: hda: hda_cs_dsp_ctl: Add Library to support CS_DSP ALSA controls

[Takashi Iwai <tiwai@suse.de>]

On Wed, 22 Jun 2022 10:40:20 +0200,
Amadeusz Sławiński wrote:
> 
> > +static int hda_cs_dsp_add_kcontrol(struct hda_cs_dsp_coeff_ctl *ctl)
> > +{
> > +	struct cs_dsp_coeff_ctl *cs_ctl = ctl->cs_ctl;
> > +	struct snd_kcontrol_new *kcontrol;
> > +	struct snd_kcontrol *kctl;
> > +	int ret = 0;
> > +
> > +	if (cs_ctl->len > ADSP_MAX_STD_CTRL_SIZE) {
> > +		dev_err(cs_ctl->dsp->dev, "Control %s: length %zu exceeds maximum %d\n", ctl->name,
> > +			cs_ctl->len, ADSP_MAX_STD_CTRL_SIZE);
> > +		return -EINVAL;
> > +	}
> > +
> > +	kcontrol = kzalloc(sizeof(*kcontrol), GFP_KERNEL);
> > +	if (!kcontrol)
> > +		return -ENOMEM;
> > +
> > +	kcontrol->name = ctl->name;
> > +	kcontrol->info = hda_cs_dsp_coeff_info;
> > +	kcontrol->iface = SNDRV_CTL_ELEM_IFACE_MIXER;
> > +	kcontrol->private_value = (unsigned long)ctl;
> > +	kcontrol->access = wmfw_convert_flags(cs_ctl->flags);
> > +
> > +	kcontrol->get = hda_cs_dsp_coeff_get;
> > +	kcontrol->put = hda_cs_dsp_coeff_put;
> > +
> > +	kctl = snd_ctl_new1(kcontrol, NULL);
> 
> Wouldn't
> kctl = snd_ctl_new1(kcontrol, ctl);
> work instead of
> kcontrol->private_value = (unsigned long)ctl;
> ...
> kctl = snd_ctl_new1(kcontrol, NULL);
> ?

The second argument to snd_ctl_new1() is set to private_data field,
while private_value is taken from snd_kcontrol_new template.


Takashi