[PATCH] ALSA: cs8427: read the PCM stream IEC958 status from its own buffer

[PATCH] ALSA: cs8427: read the PCM stream IEC958 status from its own buffer

[raoxu]

From: Xu Rao <raoxu@uniontech.com>

The IEC958 Playback PCM Stream control writes pcm_status, but its
get callback always returns def_status.  As a result, userspace
reads back the default status instead of the PCM stream status after
writing the stream control.  Rate changes also update pcm_status
without being reflected in the value returned by the control.

Select the status buffer using the same private_value as the put
callback.  The default control continues to return def_status,
while the PCM stream control now returns its own current status.

Signed-off-by: Xu Rao <raoxu@uniontech.com>
---
 sound/i2c/cs8427.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sound/i2c/cs8427.c b/sound/i2c/cs8427.c
index 1de985ba85d9..773383471f17 100644
--- a/sound/i2c/cs8427.c
+++ b/sound/i2c/cs8427.c
@@ -424,9 +424,11 @@ static int snd_cs8427_spdif_get(struct snd_kcontrol *kcontrol,
 {
 	struct snd_i2c_device *device = snd_kcontrol_chip(kcontrol);
 	struct cs8427 *chip = device->private_data;
+	const char *status = kcontrol->private_value ?
+		chip->playback.pcm_status : chip->playback.def_status;
 	
 	snd_i2c_lock(device->bus);
-	memcpy(ucontrol->value.iec958.status, chip->playback.def_status, 24);
+	memcpy(ucontrol->value.iec958.status, status, 24);
 	snd_i2c_unlock(device->bus);
 	return 0;
 }
-- 
2.50.1

Re: [PATCH] ALSA: cs8427: read the PCM stream IEC958 status from its own buffer

[Takashi Iwai]

On Wed, 04 Nov 2026 09:33:04 +0100,
raoxu wrote:
> 
> From: Xu Rao <raoxu@uniontech.com>
> 
> The IEC958 Playback PCM Stream control writes pcm_status, but its
> get callback always returns def_status.  As a result, userspace
> reads back the default status instead of the PCM stream status after
> writing the stream control.  Rate changes also update pcm_status
> without being reflected in the value returned by the control.
> 
> Select the status buffer using the same private_value as the put
> callback.  The default control continues to return def_status,
> while the PCM stream control now returns its own current status.
> 
> Signed-off-by: Xu Rao <raoxu@uniontech.com>

Applied to for-next branch now, as this is no urgent fix.


thanks,

Takashi