[PATCH] ALSA: usb-audio: Fix imbalance per-channel volume of sticky mixers

[PATCH] ALSA: usb-audio: Fix imbalance per-channel volume of sticky mixers

[Rong Zhang]

I accidentally made an off-by-a-line mistake when mimicking other code
paths that set all channels. The mistake breaks sticky mixers with
multiple channels.

I didn't realize this mistake at that time, as my device's mixer is
single-channel.

Fix it, so that per-channel volume of sticky mixers is balanced.

Fixes: aa2f4addab44 ("ALSA: usb-audio: Set the value of potential sticky mixers to maximum")
Signed-off-by: Rong Zhang <i@rong.moe>
---
 sound/usb/mixer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index b4c855c25eef..703c118f9d4e 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1473,8 +1473,8 @@ static int get_min_max_with_quirks(struct usb_mixer_elem_info *cval,
 	if (!cval->cmask) {
 		snd_usb_set_cur_mix_value(cval, 0, 0, cval->max);
 	} else {
+		idx = 0;
 		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++;

---
base-commit: 7404ce51637231382873d0b55edabc2f3b841a9d
change-id: ceff7816-uac-sticky-channels-fix-12f145cb9cec

Thanks,
Rong

Re: [PATCH] ALSA: usb-audio: Fix imbalance per-channel volume of sticky mixers

[Takashi Iwai]

On Sun, 05 Jul 2026 20:19:31 +0200,
Rong Zhang wrote:
> 
> I accidentally made an off-by-a-line mistake when mimicking other code
> paths that set all channels. The mistake breaks sticky mixers with
> multiple channels.
> 
> I didn't realize this mistake at that time, as my device's mixer is
> single-channel.
> 
> Fix it, so that per-channel volume of sticky mixers is balanced.
> 
> Fixes: aa2f4addab44 ("ALSA: usb-audio: Set the value of potential sticky mixers to maximum")
> Signed-off-by: Rong Zhang <i@rong.moe>

Applied now.  Thanks.


Takashi