From ed29e073ba93f2d52832804cabdd831d5d357d33 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 10 Jun 2025 08:43:19 +0200 Subject: [PATCH] ALSA: sb: Don't allow changing the DMA mode during operations When a PCM stream is already running, one shouldn't change the DMA mode via kcontrol, which may screw up the hardware. Return -EBUSY instead. Link: https://bugzilla.kernel.org/show_bug.cgi?id=218185 Link: https://patch.msgid.link/20250610064322.26787-1-tiwai@suse.de Signed-off-by: Takashi Iwai --- sound/isa/sb/sb16_main.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/sound/isa/sb/sb16_main.c b/sound/isa/sb/sb16_main.c index 74db11525003..c4930efd44e3 100644 --- a/sound/isa/sb/sb16_main.c +++ b/sound/isa/sb/sb16_main.c @@ -703,6 +703,9 @@ static int snd_sb16_dma_control_put(struct snd_kcontrol *kcontrol, struct snd_ct unsigned char nval, oval; int change; + if (chip->mode & (SB_MODE_PLAYBACK | SB_MODE_CAPTURE)) + return -EBUSY; + nval = ucontrol->value.enumerated.item[0]; if (nval > 2) return -EINVAL; -- 2.50.1