From 7284788743121ec8bed556b00f830dc52ad9955d Mon Sep 17 00:00:00 2001 From: HyeongJun An Date: Tue, 8 Sep 2026 22:41:53 +0900 Subject: [PATCH] ALSA: hda: Report a change when only the channel status bytes move The put() callback of "IEC958 Playback Default" returns whether the converted register value moved. The convert_from_spdif_status() helper reads part of the first two channel status bytes and none of the last two, while the get() callback returns all four. So a write that lands only in the bits it does not read changes what userspace reads back and reports no change. Of the 31 bits above the mode bit, 20 are such bits in consumer mode and 29 in professional mode. The core notifies only on a positive return. Toggling status[2] bit 0 on an HDA HDMI codec moves the read-back from 04 00 00 00 to 04 00 01 00 with no event. Toggling the non-audio bit in status[0] gives one. Compare the stored status as well, the way the ac97 code does. The write to the codec stays gated on the converted value. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: HyeongJun An Assisted-by: Claude:claude-opus-5 Link: https://patch.msgid.link/20260908134153.1614273-1-sammiee5311@gmail.com Signed-off-by: Takashi Iwai --- sound/hda/common/codec.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/sound/hda/common/codec.c b/sound/hda/common/codec.c index 7d17d773cfbf..5d9b53bd64ea 100644 --- a/sound/hda/common/codec.c +++ b/sound/hda/common/codec.c @@ -2277,6 +2277,7 @@ static int snd_hda_spdif_default_put(struct snd_kcontrol *kcontrol, int idx = kcontrol->private_value; struct hda_spdif_out *spdif; hda_nid_t nid; + unsigned int old_status; unsigned short val; int change; @@ -2285,6 +2286,7 @@ static int snd_hda_spdif_default_put(struct snd_kcontrol *kcontrol, guard(mutex)(&codec->spdif_mutex); spdif = snd_array_elem(&codec->spdif_out, idx); nid = spdif->nid; + old_status = spdif->status; spdif->status = ucontrol->value.iec958.status[0] | ((unsigned int)ucontrol->value.iec958.status[1] << 8) | ((unsigned int)ucontrol->value.iec958.status[2] << 16) | @@ -2295,7 +2297,7 @@ static int snd_hda_spdif_default_put(struct snd_kcontrol *kcontrol, spdif->ctls = val; if (change && nid != (u16)-1) set_dig_out_convert(codec, nid, val & 0xff, (val >> 8) & 0xff); - return change; + return change || spdif->status != old_status; } #define snd_hda_spdif_out_switch_info snd_ctl_boolean_mono_info