ALSA: usb-audio: Resume mixer values properly

Implement reset_resume callback so that the mixer values are properly
restored.  Still no boot quirks are called, so it might not work well
on some devices.

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

1 files changed, 79 insertions, 20 deletions

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 44b0ba4..aa9bc19 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -2299,26 +2299,6 @@ requeue:
 	}
 }
 
-/* stop any bus activity of a mixer */
-void snd_usb_mixer_inactivate(struct usb_mixer_interface *mixer)
-{
-	usb_kill_urb(mixer->urb);
-	usb_kill_urb(mixer->rc_urb);
-}
-
-int snd_usb_mixer_activate(struct usb_mixer_interface *mixer)
-{
-	int err;
-
-	if (mixer->urb) {
-		err = usb_submit_urb(mixer->urb, GFP_NOIO);
-		if (err < 0)
-			return err;
-	}
-
-	return 0;
-}
-
 /* create the handler for the optional status interrupt endpoint */
 static int snd_usb_mixer_status_create(struct usb_mixer_interface *mixer)
 {
@@ -2417,3 +2397,82 @@ void snd_usb_mixer_disconnect(struct list_head *p)
 	usb_kill_urb(mixer->urb);
 	usb_kill_urb(mixer->rc_urb);
 }
+
+#ifdef CONFIG_PM
+/* stop any bus activity of a mixer */
+static void snd_usb_mixer_inactivate(struct usb_mixer_interface *mixer)
+{
+	usb_kill_urb(mixer->urb);
+	usb_kill_urb(mixer->rc_urb);
+}
+
+static int snd_usb_mixer_activate(struct usb_mixer_interface *mixer)
+{
+	int err;
+
+	if (mixer->urb) {
+		err = usb_submit_urb(mixer->urb, GFP_NOIO);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+int snd_usb_mixer_suspend(struct usb_mixer_interface *mixer)
+{
+	snd_usb_mixer_inactivate(mixer);
+	return 0;
+}
+
+static int restore_mixer_value(struct usb_mixer_elem_info *cval)
+{
+	int c, err, idx;
+
+	if (cval->cmask) {
+		idx = 0;
+		for (c = 0; c < MAX_CHANNELS; c++) {
+			if (!(cval->cmask & (1 << c)))
+				continue;
+			if (cval->cached & (1 << c)) {
+				err = set_cur_mix_value(cval, c + 1, idx,
+							cval->cache_val[idx]);
+				if (err < 0)
+					return err;
+			}
+			idx++;
+		}
+	} else {
+		/* master */
+		if (cval->cached) {
+			err = set_cur_mix_value(cval, 0, 0, *cval->cache_val);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+int snd_usb_mixer_resume(struct usb_mixer_interface *mixer, bool reset_resume)
+{
+	struct usb_mixer_elem_info *cval;
+	int id, err;
+
+	/* FIXME: any mixer quirks? */
+
+	if (reset_resume) {
+		/* restore cached mixer values */
+		for (id = 0; id < MAX_ID_ELEMS; id++) {
+			for (cval = mixer->id_elems[id]; cval;
+			     cval = cval->next_id_elem) {
+				err = restore_mixer_value(cval);
+				if (err < 0)
+					return err;
+			}
+		}
+	}
+
+	return snd_usb_mixer_activate(mixer);
+}
+#endif