Re: [PATCH] Revert "ALSA: usb-audio: Name feature ctl using output if input is PCM"

[Niklāvs Koļesņikovs <pinkflames.linux@xxxxxxxxx>]

If it's relevant:

Reported-and-tested-by: Niklāvs Koļesņikovs <pinkflames.linux@xxxxxxxxx>

sestd., 2024. g. 16. marts, plkst. 10:37 — lietotājs Takashi Iwai
(<tiwai@xxxxxxx>) rakstīja:
>
> This reverts commit 1601cd53c7e3197181277326dbfc131d20a74e46.
>
> This fix is applied globally to all devices, and it may change the
> existing control names.  When the devices are managed with the fixed
> configuration like UCM, such control name mismatch may lead to
> significant regressions.
>
> For avoiding that kind of regression, we would need to apply such
> changes conditionally, but it'd take time to settle down.
> While the original fix is a good thing in general, in order to address
> the regression, let's revert the change for now.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=218605
> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> ---
>  sound/usb/mixer.c | 49 ++++++++++++++---------------------------------
>  1 file changed, 14 insertions(+), 35 deletions(-)
>
> diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
> index 81256ab56835..409fc1164694 100644
> --- a/sound/usb/mixer.c
> +++ b/sound/usb/mixer.c
> @@ -1652,34 +1652,6 @@ static const struct usb_feature_control_info *get_feature_control_info(int contr
>         return NULL;
>  }
>
> -static int feature_unit_mutevol_ctl_name(struct usb_mixer_interface *mixer,
> -                                        struct snd_kcontrol *kctl,
> -                                        struct usb_audio_term *iterm,
> -                                        struct usb_audio_term *oterm)
> -{
> -       struct usb_audio_term *aterm, *bterm;
> -       bool output_first;
> -       int len = 0;
> -
> -       /*
> -        * If the input terminal is USB Streaming, we try getting the name of
> -        * the output terminal first in hopes of getting something more
> -        * descriptive than "PCM".
> -        */
> -       output_first = iterm && !(iterm->type >> 16) && (iterm->type & 0xff00) == 0x0100;
> -
> -       aterm = output_first ? oterm : iterm;
> -       bterm = output_first ? iterm : oterm;
> -
> -       if (aterm)
> -               len = get_term_name(mixer->chip, aterm, kctl->id.name,
> -                                   sizeof(kctl->id.name), 1);
> -       if (!len && bterm)
> -               len = get_term_name(mixer->chip, bterm, kctl->id.name,
> -                                   sizeof(kctl->id.name), 1);
> -       return len;
> -}
> -
>  static void __build_feature_ctl(struct usb_mixer_interface *mixer,
>                                 const struct usbmix_name_map *imap,
>                                 unsigned int ctl_mask, int control,
> @@ -1761,15 +1733,22 @@ static void __build_feature_ctl(struct usb_mixer_interface *mixer,
>         case UAC_FU_MUTE:
>         case UAC_FU_VOLUME:
>                 /*
> -                * Determine the control name:
> -                * - If a name id is given in descriptor, use it.
> -                * - If input and output terminals are present, try to derive
> -                *   the name from either of these.
> -                * - Otherwise, make up a name using the feature unit ID.
> +                * determine the control name.  the rule is:
> +                * - if a name id is given in descriptor, use it.
> +                * - if the connected input can be determined, then use the name
> +                *   of terminal type.
> +                * - if the connected output can be determined, use it.
> +                * - otherwise, anonymous name.
>                  */
>                 if (!len) {
> -                       len = feature_unit_mutevol_ctl_name(mixer, kctl, iterm,
> -                                                           oterm);
> +                       if (iterm)
> +                               len = get_term_name(mixer->chip, iterm,
> +                                                   kctl->id.name,
> +                                                   sizeof(kctl->id.name), 1);
> +                       if (!len && oterm)
> +                               len = get_term_name(mixer->chip, oterm,
> +                                                   kctl->id.name,
> +                                                   sizeof(kctl->id.name), 1);
>                         if (!len)
>                                 snprintf(kctl->id.name, sizeof(kctl->id.name),
>                                          "Feature %d", unitid);
> --
> 2.43.0
>