Index: sys/dev/usb/input/ums.c
===================================================================
--- sys/dev/usb/input/ums.c
+++ sys/dev/usb/input/ums.c
@@ -118,6 +118,9 @@
 #define	UMS_FLAG_SBU        0x0010	/* spurious button up events */
 #define	UMS_FLAG_REVZ	    0x0020	/* Z-axis is reversed */
 #define	UMS_FLAG_W_AXIS     0x0040
+#define	UMS_FLAG_X_ABS      0x0100
+#define	UMS_FLAG_Y_ABS      0x0200
+#define	UMS_FLAG_Z_ABS      0x0400
 
 	uint8_t	sc_iid_w;
 	uint8_t	sc_iid_x;
@@ -225,13 +228,15 @@
 	int32_t buttons_reported = 0;
 #endif
 	int32_t dw = 0;
-	int32_t dx = 0;
-	int32_t dy = 0;
-	int32_t dz = 0;
+	int32_t dx = sc->sc_status.dx;
+	int32_t dy = sc->sc_status.dy;
+	int32_t dz = sc->sc_status.dz;
 	int32_t dt = 0;
 	uint8_t i;
 	uint8_t id;
 	int len;
+	int changed = 0;
+	uint32_t abs_flags = 0;
 
 	usbd_xfer_status(xfer, &len, NULL, NULL, NULL);
 
@@ -273,17 +278,35 @@
 		}
 
 	repeat:
+		abs_flags |= info->sc_flags & (UMS_FLAG_X_ABS | UMS_FLAG_Y_ABS | UMS_FLAG_Z_ABS);
+
 		if ((info->sc_flags & UMS_FLAG_W_AXIS) &&
-		    (id == info->sc_iid_w))
+		    (id == info->sc_iid_w)) {
 			dw += hid_get_data(buf, len, &info->sc_loc_w);
+			changed += dw != 0;
+		}
 
 		if ((info->sc_flags & UMS_FLAG_X_AXIS) && 
-		    (id == info->sc_iid_x))
-			dx += hid_get_data(buf, len, &info->sc_loc_x);
+		    (id == info->sc_iid_x)) {
+
+			if (info->sc_flags & UMS_FLAG_X_ABS)
+				dx = hid_get_data(buf, len, &info->sc_loc_x);
+			else
+				dx += hid_get_data(buf, len, &info->sc_loc_x);
+
+			changed += dx != sc->sc_status.dx;
+		}
 
 		if ((info->sc_flags & UMS_FLAG_Y_AXIS) &&
-		    (id == info->sc_iid_y))
-			dy = -hid_get_data(buf, len, &info->sc_loc_y);
+		    (id == info->sc_iid_y)) {
+
+			if (info->sc_flags & UMS_FLAG_Y_ABS)
+				dy = -hid_get_data(buf, len, &info->sc_loc_y);
+			else
+				dy -= hid_get_data(buf, len, &info->sc_loc_y);
+
+			changed += dy != sc->sc_status.dy;
+		}
 
 		if ((info->sc_flags & UMS_FLAG_Z_AXIS) &&
 		    (id == info->sc_iid_z)) {
@@ -291,7 +314,13 @@
 			temp = hid_get_data(buf, len, &info->sc_loc_z);
 			if (info->sc_flags & UMS_FLAG_REVZ)
 				temp = -temp;
-			dz -= temp;
+
+			if (info->sc_flags & UMS_FLAG_Z_ABS)
+				dz = -temp;
+			else
+				dz -= temp;
+
+			changed += dz != sc->sc_status.dz;
 		}
 
 		if ((info->sc_flags & UMS_FLAG_T_AXIS) &&
@@ -299,6 +328,7 @@
 			dt -= hid_get_data(buf, len, &info->sc_loc_t);
 			/* T-axis is translated into button presses */
 			buttons_found |= (1UL << 5) | (1UL << 6);
+			changed += dt != 0;
 		}
 
 		for (i = 0; i < info->sc_buttons; i++) {
@@ -322,9 +352,12 @@
 #endif
 		/* keep old button value(s) for non-detected buttons */
 		buttons |= sc->sc_status.button & ~buttons_found;
+		changed += buttons != sc->sc_status.button;
 
-		if (dx || dy || dz || dt || dw ||
-		    (buttons != sc->sc_status.button)) {
+		if (changed) {
+			int32_t old_dx = sc->sc_status.dx;
+			int32_t old_dy = sc->sc_status.dy;
+			int32_t old_dz = sc->sc_status.dz;
 
 			DPRINTFN(6, "x:%d y:%d z:%d t:%d w:%d buttons:0x%08x\n",
 			    dx, dy, dz, dt, dw, buttons);
@@ -339,14 +372,21 @@
 			}
 
 			sc->sc_status.button = buttons;
-			sc->sc_status.dx += dx;
-			sc->sc_status.dy += dy;
-			sc->sc_status.dz += dz;
+			sc->sc_status.dx = dx;
+			sc->sc_status.dy = dy;
+			sc->sc_status.dz = dz;
 			/*
 			 * sc->sc_status.dt += dt;
 			 * no way to export this yet
 			 */
 
+			if (!(abs_flags & UMS_FLAG_X_ABS))
+				dx -= old_dx;
+			if (!(abs_flags & UMS_FLAG_Y_ABS))
+				dy -= old_dy;
+			if (!(abs_flags & UMS_FLAG_Z_ABS))
+				dz -= old_dz;
+
 			/*
 		         * The Qtronix keyboard has a built in PS/2
 		         * port for a mouse.  The firmware once in a
@@ -367,7 +407,10 @@
 
 				usb_callout_stop(&sc->sc_callout);
 
-				ums_put_queue(sc, dx, dy, dz, dt, buttons);
+				/* sysmouse does not support absolute positioning */
+				if (!(abs_flags & (UMS_FLAG_X_ABS | UMS_FLAG_Y_ABS | UMS_FLAG_Z_ABS)))
+					ums_put_queue(sc, dx, dy, dz, dt, buttons);
+
 #ifdef EVDEV_SUPPORT
 				ums_evdev_push(sc, dx, dy, dz, dt,
 				    buttons_reported);
@@ -470,14 +513,20 @@
 	if (hid_locate(buf, len, HID_USAGE2(HUP_GENERIC_DESKTOP, HUG_X),
 	    hid_input, index, &info->sc_loc_x, &flags, &info->sc_iid_x)) {
 
-		if ((flags & MOUSE_FLAGS_MASK) == MOUSE_FLAGS) {
+		switch (flags & MOUSE_FLAGS_MASK) {
+		case 0:
+			info->sc_flags |= UMS_FLAG_X_ABS;
+		case MOUSE_FLAGS:
 			info->sc_flags |= UMS_FLAG_X_AXIS;
 		}
 	}
 	if (hid_locate(buf, len, HID_USAGE2(HUP_GENERIC_DESKTOP, HUG_Y),
 	    hid_input, index, &info->sc_loc_y, &flags, &info->sc_iid_y)) {
 
-		if ((flags & MOUSE_FLAGS_MASK) == MOUSE_FLAGS) {
+		switch (flags & MOUSE_FLAGS_MASK) {
+		case 0:
+			info->sc_flags |= UMS_FLAG_Y_ABS;
+		case MOUSE_FLAGS:
 			info->sc_flags |= UMS_FLAG_Y_AXIS;
 		}
 	}
@@ -488,7 +537,11 @@
 	    hid_locate(buf, len, HID_USAGE2(HUP_GENERIC_DESKTOP,
 	    HUG_TWHEEL), hid_input, index, &info->sc_loc_z, &flags,
 	    &info->sc_iid_z)) {
-		if ((flags & MOUSE_FLAGS_MASK) == MOUSE_FLAGS) {
+
+		switch (flags & MOUSE_FLAGS_MASK) {
+		case 0:
+			info->sc_flags |= UMS_FLAG_Z_ABS;
+		case MOUSE_FLAGS:
 			info->sc_flags |= UMS_FLAG_Z_AXIS;
 		}
 		/*
@@ -507,7 +560,10 @@
 	    HUG_Z), hid_input, index, &info->sc_loc_z, &flags, 
 	    &info->sc_iid_z)) {
 
-		if ((flags & MOUSE_FLAGS_MASK) == MOUSE_FLAGS) {
+		switch (flags & MOUSE_FLAGS_MASK) {
+		case 0:
+			info->sc_flags |= UMS_FLAG_Z_ABS;
+		case MOUSE_FLAGS:
 			info->sc_flags |= UMS_FLAG_Z_AXIS;
 		}
 	}
@@ -563,13 +619,14 @@
 		return;
 
 	/* announce information about the mouse */
-	device_printf(dev, "%d buttons and [%s%s%s%s%s] coordinates ID=%u\n",
+	device_printf(dev, "%d buttons and [%s%s%s%s%s]%s coordinates ID=%u\n",
 	    (info->sc_buttons),
 	    (info->sc_flags & UMS_FLAG_X_AXIS) ? "X" : "",
 	    (info->sc_flags & UMS_FLAG_Y_AXIS) ? "Y" : "",
 	    (info->sc_flags & UMS_FLAG_Z_AXIS) ? "Z" : "",
 	    (info->sc_flags & UMS_FLAG_T_AXIS) ? "T" : "",
 	    (info->sc_flags & UMS_FLAG_W_AXIS) ? "W" : "",
+	    (info->sc_flags & (UMS_FLAG_X_ABS | UMS_FLAG_Y_ABS | UMS_FLAG_Z_ABS)) ? " (absolute)" : "",
 	    info->sc_iid_x);
 }
 
@@ -713,6 +770,8 @@
 		goto detach;
 
 #ifdef EVDEV_SUPPORT
+	info = &sc->sc_info[0];
+
 	sc->sc_evdev = evdev_alloc();
 	evdev_set_name(sc->sc_evdev, device_get_desc(dev));
 	evdev_set_phys(sc->sc_evdev, device_get_nameunit(dev));
@@ -722,19 +781,31 @@
 	evdev_set_methods(sc->sc_evdev, sc, &ums_evdev_methods);
 	evdev_support_prop(sc->sc_evdev, INPUT_PROP_POINTER);
 	evdev_support_event(sc->sc_evdev, EV_SYN);
+	if (info->sc_flags & (UMS_FLAG_X_ABS | UMS_FLAG_Y_ABS | UMS_FLAG_Z_ABS))
+		evdev_support_event(sc->sc_evdev, EV_ABS);
 	evdev_support_event(sc->sc_evdev, EV_REL);
 	evdev_support_event(sc->sc_evdev, EV_KEY);
 
-	info = &sc->sc_info[0];
-
-	if (info->sc_flags & UMS_FLAG_X_AXIS)
-		evdev_support_rel(sc->sc_evdev, REL_X);
+	if (info->sc_flags & UMS_FLAG_X_AXIS) {
+		if (info->sc_flags & UMS_FLAG_X_ABS)
+			evdev_support_abs(sc->sc_evdev, ABS_X, 0, 0, 0x7fff, 0, 0, 0);
+		else
+			evdev_support_rel(sc->sc_evdev, REL_X);
+	}
 
-	if (info->sc_flags & UMS_FLAG_Y_AXIS)
-		evdev_support_rel(sc->sc_evdev, REL_Y);
+	if (info->sc_flags & UMS_FLAG_Y_AXIS) {
+		if (info->sc_flags & UMS_FLAG_Y_ABS)
+			evdev_support_abs(sc->sc_evdev, ABS_Y, 0, 0, 0x7fff, 0, 0, 0);
+		else
+			evdev_support_rel(sc->sc_evdev, REL_Y);
+	}
 
-	if (info->sc_flags & UMS_FLAG_Z_AXIS)
-		evdev_support_rel(sc->sc_evdev, REL_WHEEL);
+	if (info->sc_flags & UMS_FLAG_Z_AXIS) {
+		if (info->sc_flags & UMS_FLAG_Z_ABS)
+			evdev_support_abs(sc->sc_evdev, ABS_Z, 0, 0, 0x7fff, 0, 0, 0);
+		else
+			evdev_support_rel(sc->sc_evdev, REL_Z);
+	}
 
 	if (info->sc_flags & UMS_FLAG_T_AXIS)
 		evdev_support_rel(sc->sc_evdev, REL_HWHEEL);
@@ -925,9 +996,21 @@
 {
 	if (evdev_rcpt_mask & EVDEV_RCPT_HW_MOUSE) {
 		/* Push evdev event */
-		evdev_push_rel(sc->sc_evdev, REL_X, dx);
-		evdev_push_rel(sc->sc_evdev, REL_Y, -dy);
-		evdev_push_rel(sc->sc_evdev, REL_WHEEL, -dz);
+		if (sc->sc_info[0].sc_flags & UMS_FLAG_X_ABS)
+			evdev_push_event(sc->sc_evdev, EV_ABS, ABS_X, dx);
+		else
+			evdev_push_rel(sc->sc_evdev, REL_X, dx);
+
+		if (sc->sc_info[0].sc_flags & UMS_FLAG_Y_ABS)
+			evdev_push_event(sc->sc_evdev, EV_ABS, ABS_Y, -dy);
+		else
+			evdev_push_rel(sc->sc_evdev, REL_Y, -dy);
+
+		if (sc->sc_info[0].sc_flags & UMS_FLAG_Z_ABS)
+			evdev_push_event(sc->sc_evdev, EV_ABS, ABS_WHEEL, -dx);
+		else
+			evdev_push_rel(sc->sc_evdev, REL_WHEEL, -dz);
+
 		evdev_push_rel(sc->sc_evdev, REL_HWHEEL, dt);
 		evdev_push_mouse_btn(sc->sc_evdev,
 		    (buttons & ~MOUSE_STDBUTTONS) |