[PATCH 13/20] ALSA: scarlett2: Handle Gen 4 Direct Monitor mix updates

["Geoffrey D. Bennett" <g@xxxxx>]

When the Direct Monitor feature on the Scarlett 4th Gen Solo and 2i2
interfaces is used, the Mix A and B gains are updated by the
interface. This patch calls snd_ctl_notify() for the ALSA mix controls
when a Direct Monitor notification is received.

Signed-off-by: Geoffrey D. Bennett <g@xxxxx>
---
 sound/usb/mixer_scarlett2.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/sound/usb/mixer_scarlett2.c b/sound/usb/mixer_scarlett2.c
index 391ecacbc768..50899e81e00e 100644
--- a/sound/usb/mixer_scarlett2.c
+++ b/sound/usb/mixer_scarlett2.c
@@ -6285,11 +6285,23 @@ static void scarlett2_notify_direct_monitor(struct usb_mixer_interface *mixer)
 {
 	struct snd_card *card = mixer->chip->card;
 	struct scarlett2_data *private = mixer->private_data;
+	int count = private->num_mix_in * private->num_mix_out;
+	int i;
 
 	private->direct_monitor_updated = 1;
 
 	snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
 		       &private->direct_monitor_ctl->id);
+
+	if (!scarlett2_has_mixer(private))
+		return;
+
+	private->mix_updated = 1;
+
+	/* Notify of change to the mix controls */
+	for (i = 0; i < count; i++)
+		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE,
+			       &private->mix_ctls[i]->id);
 }
 
 /* Notify on power change */
-- 
2.43.0