2 files changed, 47 insertions, 19 deletions

diff --git a/include/sound/control.h b/include/sound/control.h
index 4721b4bba053..4cf8f7aaa13f 100644
--- a/include/sound/control.h
+++ b/include/sound/control.h
@@ -171,6 +171,22 @@ int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
  */
 struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
                                                  const unsigned int *tlv);
-int snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave);
-                      
+int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
+                       unsigned int flags);
+/* optional flags for slave */
+#define SND_CTL_SLAVE_NEED_UPDATE       (1 << 0)
+
+static inline int
+snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave)
+{
+        return _snd_ctl_add_slave(master, slave, 0);
+}
+
+static inline int
+snd_ctl_add_slave_uncached(struct snd_kcontrol *master,
+                           struct snd_kcontrol *slave)
+{
+        return _snd_ctl_add_slave(master, slave, SND_CTL_SLAVE_NEED_UPDATE);
+}
+
 #endif  /* __SOUND_CONTROL_H */
diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c
index 4cc57f902e2c..d51b198d06d9 100644
--- a/sound/core/vmaster.c
+++ b/sound/core/vmaster.c
@@ -50,18 +50,38 @@ struct link_slave {
         struct link_master *master;
         struct link_ctl_info info;
         int vals[2];            /* current values */
+        unsigned int flags;
         struct snd_kcontrol slave; /* the copy of original control entry */
 };
 
+static int slave_update(struct link_slave *slave)
+{
+        struct snd_ctl_elem_value *uctl;
+        int err, ch;
+
+        uctl = kmalloc(sizeof(*uctl), GFP_KERNEL);
+        if (!uctl)
+                return -ENOMEM;
+        uctl->id = slave->slave.id;
+        err = slave->slave.get(&slave->slave, uctl);
+        for (ch = 0; ch < slave->info.count; ch++)
+                slave->vals[ch] = uctl->value.integer.value[ch];
+        kfree(uctl);
+        return 0;
+}
+
 /* get the slave ctl info and save the initial values */
 static int slave_init(struct link_slave *slave)
 {
         struct snd_ctl_elem_info *uinfo;
-        struct snd_ctl_elem_value *uctl;
-        int err, ch;
+        int err;
 
-        if (slave->info.count)
-                return 0; /* already initialized */
+        if (slave->info.count) {
+                /* already initialized */
+                if (slave->flags & SND_CTL_SLAVE_NEED_UPDATE)
+                        return slave_update(slave);
+                return 0;
+        }
 
         uinfo = kmalloc(sizeof(*uinfo), GFP_KERNEL);
         if (!uinfo)
@@ -85,15 +105,7 @@ static int slave_init(struct link_slave *slave)
         slave->info.max_val = uinfo->value.integer.max;
         kfree(uinfo);
 
-        uctl = kmalloc(sizeof(*uctl), GFP_KERNEL);
-        if (!uctl)
-                return -ENOMEM;
-        uctl->id = slave->slave.id;
-        err = slave->slave.get(&slave->slave, uctl);
-        for (ch = 0; ch < slave->info.count; ch++)
-                slave->vals[ch] = uctl->value.integer.value[ch];
-        kfree(uctl);
-        return 0;
+        return slave_update(slave);
 }
 
 /* initialize master volume */
@@ -229,7 +241,8 @@ static void slave_free(struct snd_kcontrol *kcontrol)
  * - logarithmic volume control (dB level), no linear volume
  * - master can only attenuate the volume, no gain
  */
-int snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave)
+int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
+                       unsigned int flags)
 {
         struct link_master *master_link = snd_kcontrol_chip(master);
         struct link_slave *srec;
@@ -241,6 +254,7 @@ int snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave)
         srec->slave = *slave;
         memcpy(srec->slave.vd, slave->vd, slave->count * sizeof(*slave->vd));
         srec->master = master_link;
+        srec->flags = flags;
 
         /* override callbacks */
         slave->info = slave_info;
@@ -254,8 +268,7 @@ int snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave)
         list_add_tail(&srec->list, &master_link->slaves);
         return 0;
 }
-
-EXPORT_SYMBOL(snd_ctl_add_slave);
+EXPORT_SYMBOL(_snd_ctl_add_slave);
 
 /*
  * ctl callbacks for master controls
@@ -367,5 +380,4 @@ struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
 
         return kctl;
 }
-
 EXPORT_SYMBOL(snd_ctl_make_virtual_master);