ALSA: hda: Notify IEC958 Default PCM switch state changes

The "IEC958 Default PCM Playback Switch" control is backed directly by
mout->share_spdif. The share-switch callbacks currently access that state
without serialization, and spdif_share_sw_put() always returns 0, so
normal userspace writes never emit the standard ALSA control value
notification.

snd_hda_multi_out_analog_open() may also clear mout->share_spdif when the
analog PCM capabilities and the SPDIF capabilities no longer intersect.
That fallback is still needed to avoid creating an impossible hw
constraint set, but it changes the mixer backing value without notifying
subscribers.

Protect the share-switch callbacks with spdif_mutex like the other SPDIF
control handlers, return the actual change value from spdif_share_sw_put(),
and notify the cached control when the open path forcibly disables
shared SPDIF mode after dropping spdif_mutex.

This keeps the existing auto-disable behavior while making switch state
changes visible to userspace.

Fixes: 9a08160bdbe3 ("[ALSA] hda-codec - Add "IEC958 Default PCM" switch")
Fixes: 022b466fc353 ("ALSA: hda - Avoid invalid formats and rates with shared SPDIF")
Suggested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260403-hda-spdif-share-notify-v3-1-4eb1356b0f17@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

0 files changed, 0 insertions, 0 deletions