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From: Takashi Iwai <tiwai@suse.de>
To: linux-sound@vger.kernel.org
Subject: [PATCH 1/2] ALSA: sb: Don't allow changing the DMA mode during operations
Date: Tue, 10 Jun 2025 08:43:19 +0200	[thread overview]
Message-ID: <20250610064322.26787-1-tiwai@suse.de> (raw)

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
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 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;
-- 
2.49.0


             reply	other threads:[~2025-06-10  6:43 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-10  6:43 Takashi Iwai [this message]
2025-06-10  6:43 ` [PATCH 2/2] ALSA: sb: Force to disable DMAs once when DMA mode is changed Takashi Iwai

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