diff --git a/sys/dev/atkbdc/atkbdc.c b/sys/dev/atkbdc/atkbdc.c
index b53de3ef299..adf55ec54d1 100644
--- a/sys/dev/atkbdc/atkbdc.c
+++ b/sys/dev/atkbdc/atkbdc.c
@@ -296,6 +296,7 @@ atkbdc_setup(atkbdc_softc_t *sc, bus_space_tag_t tag, bus_space_handle_t h0,
 	    sc->lock = FALSE;
 	    sc->kbd.head = sc->kbd.tail = 0;
 	    sc->aux.head = sc->aux.tail = 0;
+	    sc->aux_mux_enabled = FALSE;
 #if KBDIO_DEBUG >= 2
 	    sc->kbd.call_count = 0;
 	    sc->kbd.qcount = sc->kbd.max_qcount = 0;
@@ -639,7 +640,12 @@ write_kbd_command(KBDC p, int c)
 int
 write_aux_command(KBDC p, int c)
 {
-    if (!write_controller_command(p, KBDC_WRITE_TO_AUX))
+    int f;
+
+    f = aux_mux_is_enabled(p) ?
+        KBDC_WRITE_TO_AUX_MUX + kbdcp(p)->aux_mux_port : KBDC_WRITE_TO_AUX;
+
+    if (!write_controller_command(p, f))
 	return FALSE;
     return write_controller_data(p, c);
 }
@@ -1201,3 +1207,78 @@ set_controller_command_byte(KBDC p, int mask, int command)
 
     return TRUE;
 }
+
+/*
+ * Rudimentary support for active PS/2 AUX port multiplexing.
+ * Only write commands can be routed to a selected AUX port.
+ * Source port of data processed by read commands is totally ignored.
+ */
+static int
+set_aux_mux_state(KBDC p, int enabled)
+{
+	int command, version;
+
+	if (write_controller_command(p, KBDC_FORCE_AUX_OUTPUT) == 0 ||
+	    write_controller_data(p, 0xF0) == 0 ||
+	    read_controller_data(p) != 0xF0)
+		return (-1);
+
+	if (write_controller_command(p, KBDC_FORCE_AUX_OUTPUT) == 0 ||
+	    write_controller_data(p, 0x56) == 0 ||
+	    read_controller_data(p) != 0x56)
+		return (-1);
+
+	command = enabled ? 0xa4 : 0xa5;
+	if (write_controller_command(p, KBDC_FORCE_AUX_OUTPUT) == 0 ||
+	    write_controller_data(p, command) == 0 ||
+	    (version = read_controller_data(p)) == command)
+		return (-1);
+
+	return (version);
+}
+
+int
+set_active_aux_mux_port(KBDC p, int port)
+{
+
+	if (!aux_mux_is_enabled(p))
+		return (FALSE);
+
+	if (port < 0 || port >= KBDC_AUX_MUX_NUM_PORTS)
+		return (FALSE);
+
+	kbdcp(p)->aux_mux_port = port;
+
+	return (TRUE);
+}
+
+/* Checks for active multiplexing support and enables it */
+int
+enable_aux_mux(KBDC p)
+{
+	int version;
+
+	version = set_aux_mux_state(p, TRUE);
+	if (version >= 0) {
+		kbdcp(p)->aux_mux_enabled = TRUE;
+		set_active_aux_mux_port(p, 0);
+	}
+
+	return (version);
+}
+
+int
+disable_aux_mux(KBDC p)
+{
+
+	kbdcp(p)->aux_mux_enabled = FALSE;
+
+	return (set_aux_mux_state(p, FALSE));
+}
+
+int
+aux_mux_is_enabled(KBDC p)
+{
+
+	return (kbdcp(p)->aux_mux_enabled);
+}
diff --git a/sys/dev/atkbdc/atkbdcreg.h b/sys/dev/atkbdc/atkbdcreg.h
index 576dec96739..43486cb6248 100644
--- a/sys/dev/atkbdc/atkbdcreg.h
+++ b/sys/dev/atkbdc/atkbdcreg.h
@@ -51,6 +51,8 @@
 /* controller commands (sent to KBD_COMMAND_PORT) */
 #define KBDC_SET_COMMAND_BYTE 	0x0060
 #define KBDC_GET_COMMAND_BYTE 	0x0020
+#define KBDC_WRITE_TO_AUX_MUX	0x0090
+#define KBDC_FORCE_AUX_OUTPUT	0x00d3
 #define KBDC_WRITE_TO_AUX    	0x00d4
 #define KBDC_DISABLE_AUX_PORT 	0x00a7
 #define KBDC_ENABLE_AUX_PORT 	0x00a8
@@ -209,6 +211,8 @@ typedef struct atkbdc_softc {
 #define KBDC_QUIRK_IGNORE_PROBE_RESULT	(1 << 1)
 #define KBDC_QUIRK_RESET_AFTER_PROBE	(1 << 2)
 #define KBDC_QUIRK_SETLEDS_ON_INIT	(1 << 3)
+    int aux_mux_enabled;	/* active PS/2 multiplexing is enabled */
+    int aux_mux_port;		/* current aux mux port */
 } atkbdc_softc_t; 
 
 enum kbdc_device_ivar {
@@ -223,6 +227,8 @@ typedef caddr_t KBDC;
 #define KBDC_RID_KBD	0
 #define KBDC_RID_AUX	1
 
+#define KBDC_AUX_MUX_NUM_PORTS	4
+
 /* function prototypes */
 
 atkbdc_softc_t *atkbdc_get_softc(int unit);
@@ -268,6 +274,11 @@ void kbdc_set_device_mask(KBDC kbdc, int mask);
 int get_controller_command_byte(KBDC kbdc);
 int set_controller_command_byte(KBDC kbdc, int command, int flag);
 
+int set_active_aux_mux_port(KBDC p, int port);
+int enable_aux_mux(KBDC p);
+int disable_aux_mux(KBDC p);
+int aux_mux_is_enabled(KBDC p);
+
 #endif /* _KERNEL */
 
 #endif /* !_DEV_ATKBDC_ATKBDCREG_H_ */
diff --git a/sys/dev/atkbdc/psm.c b/sys/dev/atkbdc/psm.c
index 79ebf9c51f0..1c03b7e17e2 100644
--- a/sys/dev/atkbdc/psm.c
+++ b/sys/dev/atkbdc/psm.c
@@ -150,6 +150,9 @@ struct psmcpnp_softc {
 #define	PSM_LEVEL_MIN		PSM_LEVEL_BASE
 #define	PSM_LEVEL_MAX		PSM_LEVEL_NATIVE
 
+/* Active PS/2 multiplexing */
+#define	PSM_NOMUX		(-1)
+
 /* Logitech PS2++ protocol */
 #define	MOUSE_PS2PLUS_CHECKBITS(b)	\
     ((((b[2] & 0x03) << 2) | 0x02) == (b[1] & 0x0f))
@@ -438,6 +441,11 @@ struct psm_softc {		/* Driver status information */
 	int		cmdcount;
 	struct sigio	*async;		/* Processes waiting for SIGIO */
 	int		extended_buttons;
+	int		muxport;	/* MUX port with attached Synaptics */
+	u_char		muxsave[3];	/* 3->6 byte proto conversion buffer */
+	int		muxtpbuttons;	/* Touchpad button state */
+	int		muxmsbuttons;	/* Mouse (trackpoint) button state */
+	struct timeval	muxmidtimeout;	/* middle button supression timeout */
 #ifdef EVDEV_SUPPORT
 	struct evdev_dev *evdev_a;	/* Absolute reporting device */
 	struct evdev_dev *evdev_r;	/* Relative reporting device */
@@ -603,6 +611,7 @@ static void	proc_mmanplus(struct psm_softc *, packetbuf_t *,
 		    mousestatus_t *, int *, int *, int *);
 static int	proc_synaptics(struct psm_softc *, packetbuf_t *,
 		    mousestatus_t *, int *, int *, int *);
+static int	proc_synaptics_mux(struct psm_softc *, packetbuf_t *);
 static void	proc_versapad(struct psm_softc *, packetbuf_t *,
 		    mousestatus_t *, int *, int *, int *);
 static int	proc_elantech(struct psm_softc *, packetbuf_t *,
@@ -632,6 +641,7 @@ static probefunc_t	enable_4dmouse;
 static probefunc_t	enable_4dplus;
 static probefunc_t	enable_mmanplus;
 static probefunc_t	enable_synaptics;
+static probefunc_t	enable_synaptics_mux;
 static probefunc_t	enable_trackpoint;
 static probefunc_t	enable_versapad;
 static probefunc_t	enable_elantech;
@@ -652,6 +662,8 @@ static struct {
 	 * WARNING: the order of probe is very important.  Don't mess it
 	 * unless you know what you are doing.
 	 */
+	{ MOUSE_MODEL_SYNAPTICS,	/* Synaptics Touchpad on Active Mux */
+	  0x00, MOUSE_PS2_PACKETSIZE, enable_synaptics_mux },
 	{ MOUSE_MODEL_NET,		/* Genius NetMouse */
 	  0x08, MOUSE_PS2INTELLI_PACKETSIZE, enable_gmouse },
 	{ MOUSE_MODEL_NETSCROLL,	/* Genius NetScroll */
@@ -1082,6 +1094,7 @@ static int
 doopen(struct psm_softc *sc, int command_byte)
 {
 	int stat[3];
+	int mux_enabled = FALSE;
 
 	/*
 	 * FIXME: Synaptics TouchPad seems to go back to Relative Mode with
@@ -1096,6 +1109,15 @@ doopen(struct psm_softc *sc, int command_byte)
 	 * doesn't show any evidence of such a command.
 	 */
 	if (sc->hw.model == MOUSE_MODEL_SYNAPTICS) {
+		if (sc->muxport != PSM_NOMUX) {
+			mux_enabled = enable_aux_mux(sc->kbdc) >= 0;
+			if (mux_enabled)
+				set_active_aux_mux_port(sc->kbdc, sc->muxport);
+			else
+				log(LOG_ERR, "psm%d: failed to enable "
+				    "active multiplexing mode.\n",
+				    sc->unit);
+		}
 		mouse_ext_command(sc->kbdc, 1);
 		get_mouse_status(sc->kbdc, stat, 0, 3);
 		if ((SYNAPTICS_VERSION_GE(sc->synhw, 7, 5) ||
@@ -1106,6 +1128,8 @@ doopen(struct psm_softc *sc, int command_byte)
 			    "hopefully restored\n",
 			    sc->unit));
 		}
+		if (mux_enabled)
+			disable_aux_mux(sc->kbdc);
 	}
 
 	/*
@@ -1354,6 +1378,7 @@ psmprobe(device_t dev)
 #endif
 #endif /* PSM_HOOKRESUME | PSM_HOOKAPM */
 	sc->flags = 0;
+	sc->muxport = PSM_NOMUX;
 	if (bootverbose)
 		++verbose;
 
@@ -1823,7 +1848,7 @@ psm_register_synaptics(device_t dev)
 			evdev_support_key(evdev_a, BTN_0 + i);
 
 	error = evdev_register_mtx(evdev_a, &Giant);
-	if (!error && sc->synhw.capPassthrough) {
+	if (!error && (sc->synhw.capPassthrough || sc->muxport != PSM_NOMUX)) {
 		guest_model = sc->tpinfo.sysctl_tree != NULL ?
 		    MOUSE_MODEL_TRACKPOINT : MOUSE_MODEL_GENERIC;
 		error = psm_register(dev, guest_model);
@@ -2931,6 +2956,9 @@ psmintr(void *arg)
 	int c;
 	packetbuf_t *pb;
 
+	if (aux_mux_is_enabled(sc->kbdc))
+		VLOG(2, (LOG_DEBUG, "psmintr: active multiplexing mode is not "
+		    "supported!\n"));
 
 	/* read until there is nothing to read */
 	while((c = read_aux_data_no_wait(sc->kbdc)) != -1) {
@@ -3282,7 +3310,7 @@ proc_synaptics(struct psm_softc *sc, packetbuf_t *pb, mousestatus_t *ms,
 		 * Handle packets from the guest device. See:
 		 * Synaptics PS/2 TouchPad Interfacing Guide, Section 5.1
 		 */
-		if (sc->synhw.capPassthrough) {
+		if (sc->synhw.capPassthrough || sc->muxport != PSM_NOMUX) {
 			*x = ((pb->ipacket[1] & 0x10) ?
 			    pb->ipacket[4] - 256 : pb->ipacket[4]);
 			*y = ((pb->ipacket[1] & 0x20) ?
@@ -3581,6 +3609,83 @@ SYNAPTICS_END:
 	return (0);
 }
 
+static int
+proc_synaptics_mux(struct psm_softc *sc, packetbuf_t *pb)
+{
+	int butt;
+
+	/*
+	 * Convert 3-byte interleaved mixture of Synaptics and generic mouse
+	 * packets into plain 6-byte Synaptics packet protocol.
+	 * While in hidden multiplexing mode KBC does some editing of the
+	 * packet stream. It remembers the button bits from the last packet
+	 * received from each device, and replaces the button bits of every
+	 * packet with the logical OR of all devices’ most recent button bits.
+	 * This button crosstalk should be filtered out as Synaptics and
+	 * generic mouse encode middle button presses in a different way.
+	 */
+	switch (pb->ipacket[0] & 0xc0) {
+	case 0x80:	/* First 3 bytes of Synaptics packet */
+		bcopy(pb->ipacket, sc->muxsave, 3);
+		/* Compute middle mouse button supression timeout. */
+		sc->muxmidtimeout.tv_sec  = 0;
+		sc->muxmidtimeout.tv_usec = 50000;	/* ~2-3 ints */
+		timevaladd(&sc->muxmidtimeout, &sc->lastsoftintr);
+		return (1);
+
+	case 0xc0:	/* Second 3 bytes of Synaptics packet */
+		/* Join two 3-bytes absolute packets */
+		bcopy(pb->ipacket, pb->ipacket + 3, 3);
+		bcopy(sc->muxsave, pb->ipacket, 3);
+		/* Prefer trackpoint buttons over touchpad's */
+		pb->ipacket[0] &= ~(0x08 | sc->muxmsbuttons);
+		pb->ipacket[3] &= ~(0x08 | sc->muxmsbuttons);
+		butt = (pb->ipacket[3] & 0x03) << 2 | (pb->ipacket[0] & 0x03);
+		/* Add hysteresis to remove spurious middle button events */
+		if (butt != sc->muxtpbuttons && sc->fpcount < 1) {
+			pb->ipacket[0] &= 0xfc;
+			pb->ipacket[0] |= sc->muxtpbuttons & 0x03;
+			pb->ipacket[3] &= 0xfc;
+			pb->ipacket[3] |= sc->muxtpbuttons >> 2 & 0x03;
+			++sc->fpcount;
+		} else {
+			sc->fpcount = 0;
+			sc->muxtpbuttons = butt;
+		}
+		/* Filter out impossible w induced by middle trackpoint btn */
+		if (sc->synhw.capExtended && !sc->synhw.capPassthrough &&
+		    (pb->ipacket[0] & 0x34) == 0x04 &&
+		    (pb->ipacket[3] & 0x04) == 0x04) {
+			pb->ipacket[0] &= 0xfb;
+			pb->ipacket[3] &= 0xfb;
+		}
+		sc->muxsave[0] &= 0x30;
+		break;
+
+	default:	/* Generic mouse (Trackpoint) packet */
+		/* Filter out middle button events induced by some w values */
+		if (sc->muxmsbuttons & 0x03 || pb->ipacket[0] & 0x03 ||
+		    (timevalcmp(&sc->lastsoftintr, &sc->muxmidtimeout, <=) &&
+		     (sc->muxsave[0] & 0x30 || sc->muxsave[2] > 8)))
+			pb->ipacket[0] &= 0xfb;
+		sc->muxmsbuttons = pb->ipacket[0] & 0x07;
+		/* Convert to Synaptics pass-through protocol */
+		pb->ipacket[4] = pb->ipacket[1];
+		pb->ipacket[5] = pb->ipacket[2];
+		pb->ipacket[1] = pb->ipacket[0];
+		pb->ipacket[2] = 0;
+		pb->ipacket[0] = 0x84 | (sc->muxtpbuttons & 0x03);
+		pb->ipacket[3] = 0xc4 | (sc->muxtpbuttons >> 2 & 0x03);
+	}
+
+	VLOG(4, (LOG_DEBUG, "synaptics: %02x %02x %02x %02x %02x %02x\n",
+	    pb->ipacket[0], pb->ipacket[1], pb->ipacket[2],
+	    pb->ipacket[3], pb->ipacket[4], pb->ipacket[5]));
+
+	pb->inputbytes = MOUSE_SYNAPTICS_PACKETSIZE;
+	return (0);
+}
+
 static int
 psmpalmdetect(struct psm_softc *sc, finger_t *f, int nfingers)
 {
@@ -4919,6 +5024,10 @@ psmsoftintr(void *arg)
 			break;
 
 		case MOUSE_MODEL_SYNAPTICS:
+			if (pb->inputbytes == MOUSE_PS2_PACKETSIZE)
+				if (proc_synaptics_mux(sc, pb))
+					goto next;
+
 			if (proc_synaptics(sc, pb, &ms, &x, &y, &z) != 0) {
 				VLOG(3, (LOG_DEBUG, "synaptics: "
 				    "packet rejected\n"));
@@ -6029,6 +6138,60 @@ synaptics_set_mode(struct psm_softc *sc, int mode_byte) {
 	}
 }
 
+/*
+ * AUX MUX detection code should be placed at very beginning of probe sequence
+ * at least before 4-byte protocol mouse probes e.g. MS IntelliMouse probe as
+ * latter can trigger switching the MUX to incompatible state.
+ */
+static int
+enable_synaptics_mux(struct psm_softc *sc, enum probearg arg)
+{
+	KBDC kbdc = sc->kbdc;
+	int port, version;
+	int probe = FALSE;
+	int active_ports_count = 0;
+	int active_ports_mask = 0;
+
+	version = enable_aux_mux(kbdc);
+	if (version == -1)
+		return (FALSE);
+
+	for (port = 0; port < KBDC_AUX_MUX_NUM_PORTS; port++) {
+		VLOG(3, (LOG_DEBUG, "aux_mux: ping port %d\n", port));
+		set_active_aux_mux_port(kbdc, port);
+		if (enable_aux_dev(kbdc) && disable_aux_dev(kbdc)) {
+			active_ports_count++;
+			active_ports_mask |= 1 << port;
+		}
+	}
+
+	if (verbose >= 2)
+		printf("Active Multiplexing PS/2 controller v%d.%d with %d "
+		    "active port(s)\n", version >> 4 & 0x0f, version & 0x0f,
+		    active_ports_count);
+
+	/* psm has a special support for GenMouse + SynTouchpad combination */
+	if (active_ports_count >= 2) {
+		for (port = 0; port < KBDC_AUX_MUX_NUM_PORTS; port++) {
+			if ((active_ports_mask & 1 << port) == 0)
+				continue;
+			VLOG(3, (LOG_DEBUG, "aux_mux: probe port %d\n", port));
+			set_active_aux_mux_port(kbdc, port);
+			probe = enable_synaptics(sc, arg);
+			if (probe) {
+				if (arg == PROBE)
+					sc->muxport = port;
+				break;
+			}
+		}
+	}
+
+	/* IRQ handler does not support active multiplexing mode */
+	disable_aux_mux(kbdc);
+
+	return (probe);
+}
+
 static int
 enable_synaptics(struct psm_softc *sc, enum probearg arg)
 {