diff --git a/sndiod/dev.c b/sndiod/dev.c
index 54bd854..61dd802 100644
--- a/sndiod/dev.c
+++ b/sndiod/dev.c
@@ -1197,7 +1197,7 @@ dev_exitall(struct dev *d)
 void
 dev_close_do(struct dev *d)
 {
-	struct ctl *c;
+	struct ctl *c, **pc;
 
 #ifdef DEBUG
 	if (log_level >= 3) {
@@ -1205,9 +1205,18 @@ dev_close_do(struct dev *d)
 		log_puts(": closing\n");
 	}
 #endif
-	while ((c = d->ctl_list) != NULL) {
-		d->ctl_list = c->next;
-		xfree(c);
+	pc = &d->ctl_list;
+	while ((c = *pc) != NULL) {
+		if (c->addr >= CTLADDR_END) {
+			if (c->refs_mask == 0) {
+				*pc = c->next;
+				xfree(c);
+				continue;
+			}
+			c->type = CTL_NONE;
+			c->desc_mask = ~0;
+		}
+		pc = &c->next;
 	}
 	d->pstate = DEV_CFG;
 	dev_sio_close(d);
@@ -1229,8 +1238,16 @@ dev_close_do(struct dev *d)
 void
 dev_close(struct dev *d)
 {
+	struct ctl *c;
+
 	dev_exitall(d);
 	dev_close_do(d);
+
+	/* there are no clients, just free remaining local controls */
+	while ((c = d->ctl_list) != NULL) {
+		d->ctl_list = c->next;
+		xfree(c);
+	}
 }
 
 /*
@@ -2154,6 +2171,7 @@ struct ctlslot *
 ctlslot_new(struct dev *d, struct ctlops *ops, void *arg)
 {
 	struct ctlslot *s;
+	struct ctl *c;
 	int i;
 
 	i = 0;
@@ -2171,6 +2189,8 @@ ctlslot_new(struct dev *d, struct ctlops *ops, void *arg)
 		return NULL;
 	s->ops = ops;
 	s->arg = arg;
+	for (c = d->ctl_list; c != NULL; c = c->next)
+		c->refs_mask |= s->mask;
 	return s;
 }
 
@@ -2180,6 +2200,17 @@ ctlslot_new(struct dev *d, struct ctlops *ops, void *arg)
 void
 ctlslot_del(struct ctlslot *s)
 {
+	struct ctl *c, **pc;
+
+	pc = &s->dev->ctl_list;
+	while ((c = *pc) != NULL) {
+		c->refs_mask &= ~s->mask;
+		if (c->refs_mask == 0) {
+			*pc = c->next;
+			xfree(c);
+		} else
+			pc = &c->next;
+	}
 	s->ops = NULL;
 	dev_unref(s->dev);
 }
@@ -2225,7 +2256,8 @@ struct ctl *
 dev_addctl(struct dev *d, char *gstr, int gunit, int type, int addr,
     char *str0, int unit0, char *func, char *str1, int unit1, int val)
 {
-	struct ctl *c;
+	struct ctl *c, **pc;
+	int i;
 
 	c = xmalloc(sizeof(struct ctl));
 	c->type = type;
@@ -2242,10 +2274,17 @@ dev_addctl(struct dev *d, char *gstr, int gunit, int type, int addr,
 	c->addr = addr;
 	c->val_mask = ~0;
 	c->desc_mask = ~0;
-	c->next = d->ctl_list;
-	d->ctl_list = c;
 	c->curval = val;
 	c->dirty = 0;
+	c->refs_mask = 0;
+	for (i = 0; i < DEV_NCTLSLOT; i++) {
+		if (d->ctlslot[i].ops != NULL)
+			c->refs_mask |= 1 << i;
+	}
+	for (pc = &d->ctl_list; *pc != NULL; pc = &(*pc)->next)
+		; /* nothing */
+	c->next = NULL;
+	*pc = c;
 #ifdef DEBUG
 	if (log_level >= 3) {
 		dev_log(d);
@@ -2267,18 +2306,23 @@ dev_rmctl(struct dev *d, int addr)
 		c = *pc;
 		if (c == NULL)
 			return;
-		if (c->addr == addr)
+		if (c->type != CTL_NONE && c->addr == addr)
 			break;
 		pc = &c->next;
 	}
+	c->type = CTL_NONE;
 #ifdef DEBUG
 	if (log_level >= 3) {
 		dev_log(d);
 		log_puts(": removing ");
 		ctl_log(c);
+		log_puts(", refs_mask = 0x");
+		log_putx(c->refs_mask);
 		log_puts("\n");
 	}
 #endif
+	if (c->refs_mask != 0)
+		return;
 	*pc = c->next;
 	xfree(c);
 }
@@ -2309,7 +2353,7 @@ dev_setctl(struct dev *d, int addr, int val)
 			}
 			return 0;
 		}
-		if (c->addr == addr)
+		if (c->type != CTL_NONE && c->addr == addr)
 			break;
 		c = c->next;
 	}
@@ -2344,7 +2388,7 @@ dev_onctl(struct dev *d, int addr, int val)
 	for (;;) {
 		if (c == NULL)
 			return 0;
-		if (c->addr == addr)
+		if (c->type != CTL_NONE && c->addr == addr)
 			break;
 		c = c->next;
 	}
diff --git a/sndiod/dev.h b/sndiod/dev.h
index bd0ef12..1d3e93d 100644
--- a/sndiod/dev.h
+++ b/sndiod/dev.h
@@ -120,6 +120,7 @@ struct opt {
 
 struct ctl {
 	struct ctl *next;
+#define CTL_NONE	0		/* deleted */
 #define CTL_NUM		2		/* number (aka integer value) */
 #define CTL_SW		3		/* on/off switch, only bit 7 counts */
 #define CTL_VEC		4		/* number, element of vector */
@@ -134,6 +135,7 @@ struct ctl {
 	} group, chan0, chan1;			/* affected channels */
 	unsigned int val_mask;
 	unsigned int desc_mask;
+	unsigned int refs_mask;
 	unsigned int curval;
 	int dirty;
 };
diff --git a/sndiod/sock.c b/sndiod/sock.c
index c60e5b8..3577720 100644
--- a/sndiod/sock.c
+++ b/sndiod/sock.c
@@ -1370,7 +1370,7 @@ sock_buildmsg(struct sock *f)
 {
 	unsigned int size, mask;
 	struct amsg_mix_desc *desc;
-	struct ctl *c;
+	struct ctl *c, **pc;
 
 	/*
 	 * If pos changed (or initial tick), build a MOVE message.
@@ -1520,9 +1520,13 @@ sock_buildmsg(struct sock *f)
 		desc = f->ctldesc;
 		mask = f->ctlslot->mask;
 		size = 0;
-		for (c = f->ctlslot->dev->ctl_list; c != NULL; c = c->next) {
-			if ((c->desc_mask & mask) == 0)
+		pc = &f->ctlslot->dev->ctl_list;
+		while ((c = *pc) != NULL) {
+			if ((c->desc_mask & mask) == 0 ||
+			    (c->refs_mask & mask) == 0) {
+				pc = &c->next;
 				continue;
+			}
 			if (size == SOCK_CTLDESC_SIZE *
 				sizeof(struct amsg_mix_desc))
 				break;
@@ -1543,6 +1547,18 @@ sock_buildmsg(struct sock *f)
 			desc->curval = htons(c->curval);
 			size += sizeof(struct amsg_mix_desc);
 			desc++;
+
+			/* if this is a deleted entry unref it */
+			if (c->type == CTL_NONE) {
+				c->refs_mask &= ~mask;
+				if (c->refs_mask == 0) {
+					*pc = c->next;
+					xfree(c);
+					continue;
+				}
+			}
+
+			pc = &c->next;
 		}
 		if (size > 0) {
 			AMSG_INIT(&f->wmsg);