Add snd_ctl_sync_vmaster()

Taken from the upstream change (commit 1ca2f2ec).

2 files changed, 58 insertions, 25 deletions

diff --git a/include/sound/control.h b/include/sound/control.h
index 346ec79..47b92c5 100644
--- a/include/sound/control.h
+++ b/include/sound/control.h
@@ -160,7 +160,8 @@ snd_ctl_add_slave_uncached(struct snd_kcontrol *master,
 int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kctl,
 			     void (*hook)(void *, int),
 			     void *private_data);
-void snd_ctl_sync_vmaster_hook(struct snd_kcontrol *kctl);
+void snd_ctl_sync_vmaster(struct snd_kcontrol *kctl, bool hook_only);
+#define snd_ctl_sync_vmaster_hook(kctl)	snd_ctl_sync_vmaster(kctl, true)
 
 /*
  * Helper functions for jack-detection controls
diff --git a/snd-vmaster.c b/snd-vmaster.c
index 8b984d5..5df8dc2 100644
--- a/snd-vmaster.c
+++ b/snd-vmaster.c
@@ -44,7 +44,7 @@ struct link_master {
 /*
  * link slave - this contains a slave control element
  *
- * It fakes the control callbacks with additional attenuation by the
+ * It fakes the control callbacsk with additional attenuation by the
  * master control.  A slave may have either one or two channels.
  */
 
@@ -213,7 +213,10 @@ static int slave_put(struct snd_kcontrol *kcontrol,
 	}
 	if (!changed)
 		return 0;
-	return slave_put_val(slave, ucontrol);
+	err = slave_put_val(slave, ucontrol);
+	if (err < 0)
+		return err;
+	return 1;
 }
 
 static int slave_tlv_cmd(struct snd_kcontrol *kcontrol,
@@ -307,20 +310,10 @@ static int master_get(struct snd_kcontrol *kcontrol,
 	return 0;
 }
 
-static int master_put(struct snd_kcontrol *kcontrol,
-		      struct snd_ctl_elem_value *ucontrol)
+static int sync_slaves(struct link_master *master, int old_val, int new_val)
 {
-	struct link_master *master = snd_kcontrol_chip(kcontrol);
 	struct link_slave *slave;
 	struct snd_ctl_elem_value *uval;
-	int err, old_val;
-
-	err = master_init(master);
-	if (err < 0)
-		return err;
-	old_val = master->val;
-	if (ucontrol->value.integer.value[0] == old_val)
-		return 0;
 
 	uval = kmalloc(sizeof(*uval), GFP_KERNEL);
 	if (!uval)
@@ -329,11 +322,33 @@ static int master_put(struct snd_kcontrol *kcontrol,
 		master->val = old_val;
 		uval->id = slave->slave.id;
 		slave_get_val(slave, uval);
-		master->val = ucontrol->value.integer.value[0];
+		master->val = new_val;
 		slave_put_val(slave, uval);
 	}
 	kfree(uval);
-	if (master->hook && !err)
+	return 0;
+}
+
+static int master_put(struct snd_kcontrol *kcontrol,
+		      struct snd_ctl_elem_value *ucontrol)
+{
+	struct link_master *master = snd_kcontrol_chip(kcontrol);
+	int err, new_val, old_val;
+	bool first_init;
+
+	err = master_init(master);
+	if (err < 0)
+		return err;
+	first_init = err;
+	old_val = master->val;
+	new_val = ucontrol->value.integer.value[0];
+	if (new_val == old_val)
+		return 0;
+
+	err = sync_slaves(master, old_val, new_val);
+	if (err < 0)
+		return err;
+	if (master->hook && first_init)
 		master->hook(master->hook_private_data, master->val);
 	return 1;
 }
@@ -343,7 +358,7 @@ static void master_free(struct snd_kcontrol *kcontrol)
 	struct link_master *master = snd_kcontrol_chip(kcontrol);
 	struct link_slave *slave, *n;
 
-	/* free all slave links and restore the original slave kctls */
+	/* free all slave links and retore the original slave kctls */
 	list_for_each_entry_safe(slave, n, &master->slaves, list) {
 		struct snd_kcontrol *sctl = slave->kctl;
 		struct list_head olist = sctl->list;
@@ -363,7 +378,6 @@ static void master_free(struct snd_kcontrol *kcontrol)
  * @tlv: optional TLV int array for dB information
  *
  * Creates a virtual master control with the given name string.
- * Returns the created control element, or NULL for errors (ENOMEM).
  *
  * After creating a vmaster element, you can add the slave controls
  * via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
@@ -372,6 +386,8 @@ static void master_free(struct snd_kcontrol *kcontrol)
  * for dB scale of the master control.  It should be a single element
  * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
  * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
+ *
+ * Return: The created control element, or %NULL for errors (ENOMEM).
  */
 struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
 						 const unsigned int *tlv)
@@ -419,9 +435,12 @@ EXPORT_SYMBOL(snd_ctl_make_virtual_master);
  * snd_ctl_add_vmaster_hook - Add a hook to a vmaster control
  * @kcontrol: vmaster kctl element
  * @hook: the hook function
+ * @private_data: the private_data pointer to be saved
  *
  * Adds the given hook to the vmaster control element so that it's called
  * at each time when the value is changed.
+ *
+ * Return: Zero.
  */
 int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
 			     void (*hook)(void *private_data, int),
@@ -435,20 +454,33 @@ int snd_ctl_add_vmaster_hook(struct snd_kcontrol *kcontrol,
 EXPORT_SYMBOL_GPL(snd_ctl_add_vmaster_hook);
 
 /**
- * snd_ctl_sync_vmaster_hook - Sync the vmaster hook
+ * snd_ctl_sync_vmaster - Sync the vmaster slaves and hook
  * @kcontrol: vmaster kctl element
+ * @hook_only: sync only the hook
  *
- * Call the hook function to synchronize with the current value of the given
- * vmaster element.  NOP when NULL is passed to @kcontrol or the hook doesn't
- * exist.
+ * Forcibly call the put callback of each slave and call the hook function
+ * to synchronize with the current value of the given vmaster element.
+ * NOP when NULL is passed to @kcontrol.
  */
-void snd_ctl_sync_vmaster_hook(struct snd_kcontrol *kcontrol)
+void snd_ctl_sync_vmaster(struct snd_kcontrol *kcontrol, bool hook_only)
 {
 	struct link_master *master;
+	bool first_init = false;
+
 	if (!kcontrol)
 		return;
 	master = snd_kcontrol_chip(kcontrol);
-	if (master->hook)
+	if (!hook_only) {
+		int err = master_init(master);
+		if (err < 0)
+			return;
+		first_init = err;
+		err = sync_slaves(master, master->val, master->val);
+		if (err < 0)
+			return;
+	}
+
+	if (master->hook && !first_init)
 		master->hook(master->hook_private_data, master->val);
 }
-EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster_hook);
+EXPORT_SYMBOL_GPL(snd_ctl_sync_vmaster);