Re: [PATCH v2 1/2] ALSA: usb-audio: Add QUIRK_FLAG_MIXER_GET_CUR_BROKEN

[Rong Zhang]

Hi Takashi,

Thanks for your review.

On Thu, 2026-05-28 at 09:44 +0200, Takashi Iwai wrote:
> On Wed, 27 May 2026 20:56:27 +0200,
> Rong Zhang wrote:
> > 
> > @@ -1258,6 +1261,16 @@ static int check_sticky_volume_control(struct usb_mixer_elem_info *cval,
> >  			return 0;
> >  	}
> >  
> > +	if (cval->head.mixer->chip->quirk_flags & QUIRK_FLAG_MIXER_GET_CUR_BROKEN) {
> > +		usb_audio_warn(cval->head.mixer->chip,
> > +			       "%d:%d: broken mixer GET_CUR (%d/%d/%d => %d)\n",
> > +			       cval->head.id, mixer_ctrl_intf(cval->head.mixer),
> > +			       cval->min, cval->max, cval->res, saved);
> > +
> 
> IMO, it's better to be usb_audio_info().  Otherwise it leads to an
> unnecessary caution.  Basically the behavior is expected, so there is
> nothing to worry about that.

Hmm, makes sense.

With your suggestion, I also just realized that it makes no sense to
restore a garbage volume using snd_usb_set_cur_mix_value(..., saved)
when GET_CUR is broken. It would be probably better to rely on
init_cur_mix_raw() to initialize the mixer to cval->min instead, just
like what it does for mixers that return errors for GET_CUR.

Hence, I will turn it into a usb_audio_info(), clear cval->cached and
goto no_checks, so that init_cur_mix_raw() will initialize it properly.
The usb_audio_warn() in init_cur_mix_raw() will need to be gated by
cval->get_cur_broken in this case too.

Thanks for your suggestion,
Rong

> 
> 
> thanks,
> 
> Takashi