From 83162eeaf78c71ff6f6fa31dc95e3b6e90ee593f Mon Sep 17 00:00:00 2001 From: HyeongJun An Date: Wed, 2 Sep 2026 00:39:21 +0900 Subject: [PATCH] ALSA: dummy: Report a change when one capture switch channel moves The snd_dummy_capsrc_put() builds its change flag with &&, so it reports a change only when both channels move at once. Writing a single channel stores the new value and returns 0, the control core then sends no SNDRV_CTL_EVENT_MASK_VALUE, and a second reader keeps showing the old setting until it polls again. The volume put a few lines above compares the same pair of channels with ||. The mixer selftest already reports this. With snd-dummy loaded it fails event_missing on all five capture switches: # CD Capture Switch.1 orig 0 read 1, is_volatile 0 not ok 13 event_missing.Dummy.9 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Assisted-by: Claude:claude-opus-5 Signed-off-by: HyeongJun An Link: https://patch.msgid.link/20260901153921.3971-1-sammiee5311@gmail.com Signed-off-by: Takashi Iwai --- sound/drivers/dummy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c index b908d2564aee..3f6bfee29986 100644 --- a/sound/drivers/dummy.c +++ b/sound/drivers/dummy.c @@ -808,7 +808,7 @@ static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_el left = ucontrol->value.integer.value[0] & 1; right = ucontrol->value.integer.value[1] & 1; guard(spinlock_irq)(&dummy->mixer_lock); - change = dummy->capture_source[addr][0] != left && + change = dummy->capture_source[addr][0] != left || dummy->capture_source[addr][1] != right; dummy->capture_source[addr][0] = left; dummy->capture_source[addr][1] = right;