ALSA: ice1724 - pro-rate-locking makes sense only for internal clock mode

* pro-rate-locking applies to internal clock mode only
* required rate and current rate are compared for internal clock mode only
Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/ice1712/ice1724.c

@@ -118,9 +118,12 @@ static inline int stdclock_is_spdif_master(struct snd_ice1712 *ice)
 	return (inb(ICEMT1724(ice, RATE)) & VT1724_SPDIF_MASTER) ? 1 : 0;
 }
 
+/*
+ * locking rate makes sense only for internal clock mode
+ */
 static inline int is_pro_rate_locked(struct snd_ice1712 *ice)
 {
-	return ice->is_spdif_master(ice) || PRO_RATE_LOCKED;
+	return (!ice->is_spdif_master(ice)) && PRO_RATE_LOCKED;
 }
 
 /*
@@ -668,10 +671,15 @@ static int snd_vt1724_set_pro_rate(struct snd_ice1712 *ice, unsigned int rate,
 		return -EBUSY;
 	}
 	if (!force && is_pro_rate_locked(ice)) {
+		/* comparing required and current rate - makes sense for
+		 * internal clock only */
 		spin_unlock_irqrestore(&ice->reg_lock, flags);
 		return (rate == ice->cur_rate) ? 0 : -EBUSY;
 	}
 
+	if (force || !ice->is_spdif_master(ice)) {
+		/* force means the rate was switched by ucontrol, otherwise
+		 * setting clock rate for internal clock mode */
 		old_rate = ice->get_rate(ice);
 		if (force || (old_rate != rate))
 			ice->set_rate(ice, rate);
@@ -679,6 +687,7 @@ static int snd_vt1724_set_pro_rate(struct snd_ice1712 *ice, unsigned int rate,
 			spin_unlock_irqrestore(&ice->reg_lock, flags);
 			return 0;
 		}
+	}
 
 	ice->cur_rate = rate;