diff --git a/libs/ardour/ardour/disk_reader.h b/libs/ardour/ardour/disk_reader.h
index 7ccfa0b3d9..a170fba766 100644
--- a/libs/ardour/ardour/disk_reader.h
+++ b/libs/ardour/ardour/disk_reader.h
@@ -84,8 +84,8 @@ public:
 
 	void adjust_buffering ();
 
-	int can_internal_playback_seek (samplecnt_t distance);
-	int internal_playback_seek (samplecnt_t distance);
+	bool can_internal_playback_seek (sampleoffset_t distance);
+	void internal_playback_seek (sampleoffset_t distance);
 	int seek (samplepos_t sample, bool complete_refill = false);
 
 	static PBD::Signal0<void> Underrun;
diff --git a/libs/ardour/ardour/track.h b/libs/ardour/ardour/track.h
index b6abece1f0..e9d9a60380 100644
--- a/libs/ardour/ardour/track.h
+++ b/libs/ardour/ardour/track.h
@@ -137,8 +137,8 @@ public:
 	int do_flush (RunContext, bool force = false);
 	void set_pending_overwrite (bool);
 	int seek (samplepos_t, bool complete_refill = false);
-	int can_internal_playback_seek (samplecnt_t);
-	int internal_playback_seek (samplecnt_t);
+	bool can_internal_playback_seek (samplecnt_t);
+	void internal_playback_seek (samplecnt_t);
 	void non_realtime_locate (samplepos_t);
 	void realtime_handle_transport_stopped ();
 	int overwrite_existing_buffers ();
diff --git a/libs/ardour/disk_reader.cc b/libs/ardour/disk_reader.cc
index c87f04daf2..973cd33e3c 100644
--- a/libs/ardour/disk_reader.cc
+++ b/libs/ardour/disk_reader.cc
@@ -623,8 +623,8 @@ DiskReader::seek (samplepos_t sample, bool complete_refill)
 	return ret;
 }
 
-int
-DiskReader::can_internal_playback_seek (samplecnt_t distance)
+bool
+DiskReader::can_internal_playback_seek (sampleoffset_t distance)
 {
 	/* 1. Audio */
 
@@ -632,11 +632,15 @@ DiskReader::can_internal_playback_seek (samplecnt_t distance)
 	boost::shared_ptr<ChannelList> c = channels.reader();
 
 	for (chan = c->begin(); chan != c->end(); ++chan) {
-		if ((*chan)->rbuf->read_space() < (size_t) distance) {
+		if (!(*chan)->rbuf->can_seek (distance)) {
 			return false;
 		}
 	}
 
+	if (distance < 0) {
+		return true; // XXX TODO un-seek MIDI
+	}
+
 	/* 2. MIDI */
 
 	uint32_t samples_read    = g_atomic_int_get(&_samples_read_from_ringbuffer);
@@ -645,19 +649,26 @@ DiskReader::can_internal_playback_seek (samplecnt_t distance)
 	return ((samples_written - samples_read) < distance);
 }
 
-int
-DiskReader::internal_playback_seek (samplecnt_t distance)
+void
+DiskReader::internal_playback_seek (sampleoffset_t distance)
 {
-	ChannelList::iterator chan;
-	boost::shared_ptr<ChannelList> c = channels.reader();
-
-	for (chan = c->begin(); chan != c->end(); ++chan) {
-		(*chan)->rbuf->increment_read_ptr (::llabs(distance));
+	if (distance == 0) {
+		return;
 	}
 
-	playback_sample += distance;
+	sampleoffset_t off = distance;
 
-	return 0;
+	ChannelList::iterator chan;
+	boost::shared_ptr<ChannelList> c = channels.reader();
+	for (chan = c->begin(); chan != c->end(); ++chan) {
+		if (distance < 0) {
+			off = 0 - (sampleoffset_t) (*chan)->rbuf->decrement_read_ptr (llabs (distance));
+		} else {
+			off = (*chan)->rbuf->increment_read_ptr (distance);
+		}
+	}
+
+	playback_sample += off;
 }
 
 static
diff --git a/libs/ardour/track.cc b/libs/ardour/track.cc
index d5902be50e..f4161ebb06 100644
--- a/libs/ardour/track.cc
+++ b/libs/ardour/track.cc
@@ -506,13 +506,13 @@ Track::seek (samplepos_t p, bool complete_refill)
 	return _disk_writer->seek (p, complete_refill);
 }
 
-int
+bool
 Track::can_internal_playback_seek (samplecnt_t p)
 {
 	return _disk_reader->can_internal_playback_seek (p);
 }
 
-int
+void
 Track::internal_playback_seek (samplecnt_t p)
 {
 	return _disk_reader->internal_playback_seek (p);