diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 5fba456eb4a9..fb37bb8ad9a9 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -1371,10 +1371,8 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval, goto no_checks; ret = check_sticky_volume_control(cval, minchn, saved); - if (ret < 0) { - snd_usb_set_cur_mix_value(cval, minchn, 0, saved); - return ret; - } + if (ret < 0) + goto sticky; if (cval->min + cval->res < cval->max) check_volume_control_res(cval, minchn, saved); @@ -1431,6 +1429,33 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval, } return 0; + +sticky: + /* + * It makes no sense to restore the saved value for a sticky mixer, + * since setting any value is a no-op. + * + * However, in some rare cases, SET_CUR is effective despite GET_CUR + * always returns a constant value. These mixers are not sticky, but + * there's no way to distinguish them. Without any additional + * information, the best thing we can do is to set the mixer value to + * the maximum before bailing out, so that a soft mixer can still reach + * the maximum hardware volume if the mixer turns out to be non-sticky. + * Meanwhile, all channels must be synchronized to prevent imbalance + * volume. + */ + if (!cval->cmask) { + snd_usb_set_cur_mix_value(cval, 0, 0, cval->max); + } else { + for (i = 0; i < MAX_CHANNELS; i++) { + idx = 0; + if (cval->cmask & BIT(i)) { + snd_usb_set_cur_mix_value(cval, i + 1, idx, cval->max); + idx++; + } + } + } + return ret; } #define get_min_max(cval, def) get_min_max_with_quirks(cval, def, NULL)