[PATCH v3 2/2] ALSA: usb-audio: Check connector value on resume

[Takashi Iwai]

On Thu, 25 Mar 2021 17:59:13 +0100,
Kai-Heng Feng wrote:
> 
> Rear Mic on Lenovo P620 cannot record after S3, despite that there's no
> error and the other two functions of the USB audio, Line In and Line
> Out, work just fine.
> 
> The mic starts to work again after running userspace app like "alsactl
> store". Following the lead, the evidence shows that as soon as connector
> status is queried, the mic can work again.
> 
> So also check connector value on resume to "wake up" the USB audio to
> make it functional.
> 
> This can be device specific, however I think this generic approach may
> benefit more than one device.
> 
> Now the resume callback checks connector, and a new callback,
> reset_resume, to also restore switches and volumes.
> 
> Suggested-by: Takashi Iwai <tiwai at suse.de>
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>

Applied now.  Thanks.


Takashi

> ---
> v3:
>  - New callback to handle resume and reset-resume separately.
> 
> v2:
>  - Remove reset-resume.
>  - Fold the connector checking to the mixer resume callback.
> 
>  sound/usb/mixer.c        | 44 +++++++++++++++++++++++++++++++---------
>  sound/usb/mixer.h        |  1 +
>  sound/usb/mixer_quirks.c |  2 +-
>  3 files changed, 36 insertions(+), 11 deletions(-)
> 
> diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
> index 5a2d9a768f70..2faf5767c7f8 100644
> --- a/sound/usb/mixer.c
> +++ b/sound/usb/mixer.c
> @@ -3631,20 +3631,43 @@ static int restore_mixer_value(struct usb_mixer_elem_list *list)
>  	return 0;
>  }
>  
> +static int default_mixer_resume(struct usb_mixer_elem_list *list)
> +{
> +	struct usb_mixer_elem_info *cval = mixer_elem_list_to_info(list);
> +
> +	/* get connector value to "wake up" the USB audio */
> +	if (cval->val_type == USB_MIXER_BOOLEAN && cval->channels == 1)
> +		get_connector_value(cval, NULL, NULL);
> +
> +	return 0;
> +}
> +
> +static int default_mixer_reset_resume(struct usb_mixer_elem_list *list)
> +{
> +	int err = default_mixer_resume(list);
> +
> +	if (err < 0)
> +		return err;
> +	return restore_mixer_value(list);
> +}
> +
>  int snd_usb_mixer_resume(struct usb_mixer_interface *mixer, bool reset_resume)
>  {
>  	struct usb_mixer_elem_list *list;
> +	usb_mixer_elem_resume_func_t f;
>  	int id, err;
>  
> -	if (reset_resume) {
> -		/* restore cached mixer values */
> -		for (id = 0; id < MAX_ID_ELEMS; id++) {
> -			for_each_mixer_elem(list, mixer, id) {
> -				if (list->resume) {
> -					err = list->resume(list);
> -					if (err < 0)
> -						return err;
> -				}
> +	/* restore cached mixer values */
> +	for (id = 0; id < MAX_ID_ELEMS; id++) {
> +		for_each_mixer_elem(list, mixer, id) {
> +			if (reset_resume)
> +				f = list->reset_resume;
> +			else
> +				f = list->resume;
> +			if (f) {
> +				err = f(list);
> +				if (err < 0)
> +					return err;
>  			}
>  		}
>  	}
> @@ -3663,6 +3686,7 @@ void snd_usb_mixer_elem_init_std(struct usb_mixer_elem_list *list,
>  	list->id = unitid;
>  	list->dump = snd_usb_mixer_dump_cval;
>  #ifdef CONFIG_PM
> -	list->resume = restore_mixer_value;
> +	list->resume = default_mixer_resume;
> +	list->reset_resume = default_mixer_reset_resume;
>  #endif
>  }
> diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h
> index c29e27ac43a7..e5a01f17bf3c 100644
> --- a/sound/usb/mixer.h
> +++ b/sound/usb/mixer.h
> @@ -69,6 +69,7 @@ struct usb_mixer_elem_list {
>  	bool is_std_info;
>  	usb_mixer_elem_dump_func_t dump;
>  	usb_mixer_elem_resume_func_t resume;
> +	usb_mixer_elem_resume_func_t reset_resume;
>  };
>  
>  /* iterate over mixer element list of the given unit id */
> diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
> index ffd922327ae4..b7f9c2fded05 100644
> --- a/sound/usb/mixer_quirks.c
> +++ b/sound/usb/mixer_quirks.c
> @@ -151,7 +151,7 @@ static int add_single_ctl_with_resume(struct usb_mixer_interface *mixer,
>  		*listp = list;
>  	list->mixer = mixer;
>  	list->id = id;
> -	list->resume = resume;
> +	list->reset_resume = resume;
>  	kctl = snd_ctl_new1(knew, list);
>  	if (!kctl) {
>  		kfree(list);
> -- 
> 2.30.2
>