diff --git a/sndiod/defs.h b/sndiod/defs.h
index b63335d..7fc782b 100644
--- a/sndiod/defs.h
+++ b/sndiod/defs.h
@@ -31,7 +31,7 @@ extern unsigned int log_level;
 /*
  * MIDI buffer size
  */
-#define MIDI_BUFSZ		125	/* 1 second at 31.25kbit/s */
+#define MIDI_BUFSZ		15	/* 1 second at 31.25kbit/s */
 
 /*
  * units used for MTC clock.
diff --git a/sndiod/dev.c b/sndiod/dev.c
index dcd7d3b..a62a60d 100644
--- a/sndiod/dev.c
+++ b/sndiod/dev.c
@@ -50,6 +50,7 @@ void zomb_exit(void *);
 
 void dev_midi_imsg(void *, unsigned char *, int);
 void dev_midi_omsg(void *, unsigned char *, int);
+void dev_midi_fill(void *, int);
 void dev_midi_exit(void *);
 
 struct midiops dev_midiops = {
@@ -465,6 +466,18 @@ dev_midi_omsg(void *arg, unsigned char *msg, int len)
 	}
 }
 
+void
+dev_midi_fill(void *arg, int count)
+{
+	struct dev *d = arg;
+
+#ifdef DEBUG
+	dev_log(d);
+	log_puts(": can't receive fill input\n");
+	panic();
+#endif
+}
+
 void
 dev_midi_exit(void *arg)
 {
@@ -663,7 +676,7 @@ dev_mix_cycle(struct dev *d)
 			*ps = s->next;
 			continue;
 		}
-		if (s->mix.buf.used < s->round * s->mix.bpf && 
+		if (s->mix.buf.used < s->round * s->mix.bpf &&
 		    !(s->pstate == SLOT_STOP)) {
 			if (s->xrun == XRUN_IGNORE) {
 				if (s->mode & MODE_RECMASK)
@@ -976,6 +989,13 @@ dev_new(char *path, struct aparams *par,
 	}
 	d = xmalloc(sizeof(struct dev), "dev");
 	d->num = dev_sndnum++;
+	/*
+	 * XXX
+	 * we don't use the input buffer, since we don't receive
+	 * raw midi data, so no need to allocate a input ibuf.
+	 * Possibly set imsg & fill callbacks to NULL and use this
+	 * to in midi_new() to check if buffers need to be allocated
+	 */
 	d->midi = midi_new(&dev_midiops, d, MODE_MIDIIN | MODE_MIDIOUT);
 	midi_tag(d->midi, d->num);
 	d->path = path;
diff --git a/sndiod/dsp.c b/sndiod/dsp.c
index fd4f143..963dab1 100644
--- a/sndiod/dsp.c
+++ b/sndiod/dsp.c
@@ -697,7 +697,7 @@ sqrtone(int ctx, adata_t *out, int period, int vol, int todo)
 			ctx = period / 2;
 		}
 		ctx--;
-		*(out++) = vol;
+		*(out++) += vol;
 	}
 	return ctx;
 }
diff --git a/sndiod/midi.c b/sndiod/midi.c
index e4f3d75..084d564 100644
--- a/sndiod/midi.c
+++ b/sndiod/midi.c
@@ -44,11 +44,13 @@
 int  port_open(struct port *);
 void port_imsg(void *, unsigned char *, int);
 void port_omsg(void *, unsigned char *, int);
+void port_fill(void *, int);
 void port_exit(void *);
 
 struct midiops port_midiops = {
 	port_imsg,
 	port_omsg,
+	port_fill,
 	port_exit
 };
 
@@ -83,11 +85,6 @@ midi_ontimo(void *arg)
 	struct midi *ep;
 	
 	for (i = MIDI_NEP, ep = midi_ep; i > 0; i--, ep++) {
-		ep->tickets = MIDI_XFER;
-		if (ep->ibuf.used > 0) {
-			while (midi_in(ep))
-				; /* nothing */
-		}
 	}
 	timo_add(&midi_timo, MIDI_TIMO);
 }
@@ -125,7 +122,6 @@ midi_new(struct midiops *ops, void *arg, int mode)
 	ep->st = 0;
 	ep->txmask = 0;
 	ep->rxmask = 1 << i;
-	ep->tickets = MIDI_XFER;
 	ep->mode = mode;
 	/*
 	 * client output is our input (ibuf) and our output (obuf) goes
@@ -236,30 +232,55 @@ midi_send(struct midi *iep, unsigned char *msg, int size)
 	}
 }
 
+
+void
+midi_fill(struct midi *oep)
+{
+	int i, count;
+	struct midi *iep;
+
+	for (i = 0; i < MIDI_NEP ; i++) {
+		if ((oep->rxmask & (1 << i)) == 0)
+			continue;
+		iep = midi_ep + i;
+		count = midi_in(iep);
+		if (count)
+			iep->ops->fill(iep->arg, count);
+	}
+}
+
 int
-midi_in(struct midi *ep)
+midi_in(struct midi *iep)
 {
 	unsigned char c, *idata;
-	int i, icount;
+	int i, icount, maxavail, avail;
+	struct midi *oep;
 
-	if (ep->ibuf.used == 0)
-		return 0;
-	if (ep->tickets == 0) {
-#ifdef DEBUG
-		if (log_level >= 4) {
-			midi_log(ep);
-			log_puts(": out of tickets, blocking\n");
-		}
-#endif
-		return 0;
+	/*
+	 * calculate the max message size we can process
+	 */
+	maxavail = MIDI_BUFSZ;
+	for (i = 0; i < MIDI_NEP ; i++) {
+		if ((iep->txmask & (1 << i)) == 0)
+			continue;
+		oep = midi_ep + i;
+		avail = oep->obuf.len - oep->obuf.used;
+		if (maxavail > avail)
+			maxavail = avail;
 	}
-	idata = abuf_rgetblk(&ep->ibuf, &icount);
-	//if (icount > ep->tickets)
-	//	icount = ep->tickets;
-	//ep->tickets -= icount;
+	
+	/*
+	 * in the works case output message is twice the 
+	 * input message (2-byte messages with running status)
+	 */
+	maxavail /= 2;
+
+	idata = abuf_rgetblk(&iep->ibuf, &icount);
+	if (icount > maxavail)
+		icount = maxavail;
 #ifdef DEBUG
 	if (log_level >= 4) {
-		midi_log(ep);
+		midi_log(iep);
 		log_puts(":  in:");
 		for (i = 0; i < icount; i++) {
 			log_puts(" ");
@@ -272,42 +293,42 @@ midi_in(struct midi *ep)
 		c = *idata++;
 		if (c >= 0xf8) {
 			if (c != MIDI_ACK)
-				ep->ops->imsg(ep->arg, &c, 1);
+				iep->ops->imsg(iep->arg, &c, 1);
 		} else if (c == SYSEX_END) {
-			if (ep->st == SYSEX_START) {
-				ep->msg[ep->idx++] = c;
-				ep->ops->imsg(ep->arg, ep->msg, ep->idx);
+			if (iep->st == SYSEX_START) {
+				iep->msg[iep->idx++] = c;
+				iep->ops->imsg(iep->arg, iep->msg, iep->idx);
 			}
-			ep->st = 0;
-			ep->idx = 0;
+			iep->st = 0;
+			iep->idx = 0;
 		} else if (c >= 0xf0) {
-			ep->msg[0] = c;
-			ep->len = common_len[c & 7];
-			ep->st = c;
-			ep->idx = 1;
+			iep->msg[0] = c;
+			iep->len = common_len[c & 7];
+			iep->st = c;
+			iep->idx = 1;
 		} else if (c >= 0x80) {
-			ep->msg[0] = c;
-			ep->len = voice_len[(c >> 4) & 7];
-			ep->st = c;
-			ep->idx = 1;
-		} else if (ep->st) {
-			if (ep->idx == 0 && ep->st != SYSEX_START)
-				ep->msg[ep->idx++] = ep->st;
-			ep->msg[ep->idx++] = c;
-			if (ep->idx == ep->len) {
-				ep->ops->imsg(ep->arg, ep->msg, ep->idx);
-				if (ep->st >= 0xf0)
-					ep->st = 0;
-				ep->idx = 0;
-			} else if (ep->idx == MIDI_MSGMAX) {
+			iep->msg[0] = c;
+			iep->len = voice_len[(c >> 4) & 7];
+			iep->st = c;
+			iep->idx = 1;
+		} else if (iep->st) {
+			if (iep->idx == 0 && iep->st != SYSEX_START)
+				iep->msg[iep->idx++] = iep->st;
+			iep->msg[iep->idx++] = c;
+			if (iep->idx == iep->len) {
+				iep->ops->imsg(iep->arg, iep->msg, iep->idx);
+				if (iep->st >= 0xf0)
+					iep->st = 0;
+				iep->idx = 0;
+			} else if (iep->idx == MIDI_MSGMAX) {
 				/* sysex continued */
-				ep->ops->imsg(ep->arg, ep->msg, ep->idx);
-				ep->idx = 0;
+				iep->ops->imsg(iep->arg, iep->msg, iep->idx);
+				iep->idx = 0;
 			}
 		}
 	}
-	abuf_rdiscard(&ep->ibuf, icount);
-	return 1;
+	abuf_rdiscard(&iep->ibuf, icount);
+	return icount;
 }
 
 void
@@ -319,7 +340,7 @@ midi_out(struct midi *oep, unsigned char *idata, int icount)
 	while (icount > 0) {
 		if (oep->obuf.used == oep->obuf.len) {
 #ifdef DEBUG
-			if (log_level >= 3) {
+			if (log_level >= 2) {
 				midi_log(oep);
 				log_puts(": overrun, discarding ");
 				log_putu(oep->obuf.used);
@@ -385,6 +406,12 @@ port_omsg(void *arg, unsigned char *msg, int size)
 	midi_out(p->midi, msg, size);
 }
 
+void
+port_fill(void *arg, int count)
+{
+	/* no flow control */
+}
+
 void
 port_exit(void *arg)
 {
@@ -423,6 +450,7 @@ port_del(struct port *c)
 
 	if (c->state != PORT_CFG)
 		port_close(c);
+	midi_del(c->midi);
 	for (p = &port_list; *p != c; p = &(*p)->next) {
 #ifdef DEBUG
 		if (*p == NULL) {
@@ -435,9 +463,18 @@ port_del(struct port *c)
 	xfree(c);
 }
 
-/*
- * Open a MIDI device and connect it to the thru box
- */
+struct port *
+port_bynum(int num)
+{
+	struct port *p;
+
+	for (p = port_list; p != NULL; p = p->next) {
+		if (num-- == 0)
+			return p;
+	}
+	return NULL;
+}
+
 int
 port_open(struct port *c)
 {
@@ -480,5 +517,6 @@ void
 port_done(struct port *c)
 {
 	/* XXX: drain */
-	port_close(c);
+	if (c->state != PORT_CFG)
+		port_close(c);
 }
diff --git a/sndiod/midi.h b/sndiod/midi.h
index 9287898..da8e7d7 100644
--- a/sndiod/midi.h
+++ b/sndiod/midi.h
@@ -56,6 +56,7 @@ struct midiops
 {
 	void (*imsg)(void *, unsigned char *, int);
 	void (*omsg)(void *, unsigned char *, int);
+	void (*fill)(void *, int);
 	void (*exit)(void *);
 };
 
@@ -70,7 +71,6 @@ struct midi {
 	unsigned int used;		/* bytes used in ``msg'' */
 	unsigned int idx;		/* current ``msg'' size */
 	unsigned int len;		/* expected ``msg'' length */
-	unsigned int tickets;		/* input throttling */
 	unsigned int txmask;		/* list of ep we send to */
 	unsigned int rxmask;		/* single ep we accept data for */
 	struct abuf ibuf;		/* input buffer */
@@ -105,10 +105,12 @@ void midi_log(struct midi *);
 int midi_in(struct midi *);
 void midi_out(struct midi *, unsigned char *, int);
 void midi_send(struct midi *, unsigned char *, int);
+void midi_fill(struct midi *);
 void midi_tag(struct midi *, unsigned int);
 void midi_untag(struct midi *, unsigned int);
 
 struct port *port_new(char *, unsigned int);
+struct port *port_bynum(int);
 void port_del(struct port *);
 int  port_init(struct port *);
 void port_done(struct port *);
diff --git a/sndiod/miofile.c b/sndiod/miofile.c
index 26adf52..a469dfd 100644
--- a/sndiod/miofile.c
+++ b/sndiod/miofile.c
@@ -124,6 +124,7 @@ port_mio_out(void *arg)
 		abuf_rdiscard(&ep->obuf, n);
 		if (n < count)
 			break;
+		midi_fill(ep);
 	}
 }
 
diff --git a/sndiod/sock.c b/sndiod/sock.c
index a038b9d..c3d2110 100644
--- a/sndiod/sock.c
+++ b/sndiod/sock.c
@@ -65,6 +65,7 @@ void sock_slot_mmcstop(void *);
 void sock_slot_mmcloc(void *, unsigned int);
 void sock_midi_imsg(void *, unsigned char *, int);
 void sock_midi_omsg(void *, unsigned char *, int);
+void sock_midi_fill(void *, int);
 void sock_exit(void *);
 
 struct fileops sock_fileops = {
@@ -91,6 +92,7 @@ struct slotops sock_slotops = {
 struct midiops sock_midiops = {
 	sock_midi_imsg,
 	sock_midi_omsg,
+	sock_midi_fill,
 	sock_exit
 };
 
@@ -272,6 +274,16 @@ sock_midi_omsg(void *arg, unsigned char *msg, int size)
 		;
 }
 
+void
+sock_midi_fill(void *arg, int count)
+{
+	struct sock *f = arg;
+
+	f->fillpending += count;
+	while (sock_write(f))
+		;
+}
+
 /*
  * Initialise socket in the SOCK_HELLO state with default
  * parameters.
@@ -540,9 +552,11 @@ sock_rdata(struct sock *f)
 	if (f->slot)
 		slot_write(f->slot);
 	if (f->midi) {
+		count = f->midi->ibuf.used;
 		while (midi_in(f->midi))
 			; /* nothing */
-		f->fillpending += f->midi->ibuf.len - f->midi->ibuf.used;
+		count -= f->midi->ibuf.used;
+		f->fillpending += count;
 	}
 	return 1;
 }
@@ -597,6 +611,8 @@ sock_wdata(struct sock *f)
 	}
 	if (f->slot)
 		slot_read(f->slot);
+	if (f->midi)
+		midi_fill(f->midi);
 #ifdef DEBUG
 	if (log_level >= 4) {
 		sock_log(f);
@@ -814,6 +830,7 @@ sock_hello(struct sock *f)
 {
 	struct amsg_hello *p = &f->rmsg.u.hello;
 	struct slot *s;
+	struct port *c;
 	struct dev *d;
 	unsigned int mode;
 
@@ -872,6 +889,14 @@ sock_hello(struct sock *f)
 			midi_tag(f->midi, p->devnum);
 		} else if (p->devnum < 32) {
 			midi_tag(f->midi, p->devnum);
+		} else if (p->devnum < 48) {
+			c = port_bynum(p->devnum - 32);
+			if (c == NULL)
+				return 0;
+			if (mode & MODE_MIDIOUT)
+				f->midi->txmask |= c->midi->rxmask;
+			if (mode & MODE_MIDIIN)
+				c->midi->txmask |= f->midi->rxmask;
 		} else
 			return 0;
 		if (mode & MODE_MIDIOUT)
@@ -1339,14 +1364,6 @@ sock_buildmsg(struct sock *f)
 	}
 
 	if (f->fillpending > 0) {
-#ifdef DEBUG
-		if (log_level >= 4) {
-			sock_log(f);
-			log_puts(": building FLOWCTL message, count = ");
-			log_puti(f->fillpending);
-			log_puts("\n");
-		}
-#endif
 		AMSG_INIT(&f->wmsg);
 		f->wmsg.cmd = htonl(AMSG_FLOWCTL);	       
 		f->wmsg.u.ts.delta = htonl(f->fillpending);
@@ -1354,6 +1371,16 @@ sock_buildmsg(struct sock *f)
 		if (f->slot)
 			size *= f->slot->mix.bpf;
 		f->rmax += size;
+#ifdef DEBUG
+		if (log_level >= 4) {
+			sock_log(f);
+			log_puts(": building FLOWCTL message, count = ");
+			log_puti(f->fillpending);
+			log_puts(", rmax -> ");
+			log_puti(f->rmax);
+			log_puts("\n");
+		}
+#endif
 		f->wtodo = sizeof(struct amsg);
 		f->wstate = SOCK_WMSG;
 		f->fillpending = 0;