Only init abs axes if we don't have acceleration

A lot of devices (mainly MS input devices) have abs axes on top of the
relative axes. Those axes are usually mute but with the current code we set up
absolute axes for those devices. Relative events are then scaled by the server
which makes the device appear slow.

As an immediate fix always prefer relative axes and only set up absolute axes
if the device has a calibration matrix but no pointer acceleration.
This may mess up other devices where the relative axes are dead, we'll deal
with this when it comes.

https://bugs.freedesktop.org/show_bug.cgi?id=90322

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>

src/libinput.c

@@ -85,6 +85,8 @@ struct xf86libinput {
 		double y_remainder;
 	} scale;
 
+	BOOL has_abs;
+
 	ValuatorMask *valuators;
 
 	struct options {
@@ -526,6 +528,8 @@ xf86libinput_init_pointer_absolute(InputInfoPtr pInfo)
 	SetScrollValuator(dev, 2, SCROLL_TYPE_HORIZONTAL, driver_data->scroll.hdist, 0);
 	SetScrollValuator(dev, 3, SCROLL_TYPE_VERTICAL, driver_data->scroll.vdist, 0);
 
+	driver_data->has_abs = TRUE;
+
 	return Success;
 }
 static void
@@ -636,7 +640,8 @@ xf86libinput_init(DeviceIntPtr dev)
 	if (libinput_device_has_capability(device, LIBINPUT_DEVICE_CAP_KEYBOARD))
 		xf86libinput_init_keyboard(pInfo);
 	if (libinput_device_has_capability(device, LIBINPUT_DEVICE_CAP_POINTER)) {
-		if (libinput_device_config_calibration_has_matrix(device))
+		if (libinput_device_config_calibration_has_matrix(device) &&
+		    !libinput_device_config_accel_is_available(device))
 			xf86libinput_init_pointer_absolute(pInfo);
 		else
 			xf86libinput_init_pointer(pInfo);
@@ -709,6 +714,13 @@ xf86libinput_handle_absmotion(InputInfoPtr pInfo, struct libinput_event_pointer
 	ValuatorMask *mask = driver_data->valuators;
 	double x, y;
 
+	if (!driver_data->has_abs) {
+		xf86IDrvMsg(pInfo, X_ERROR,
+			    "Discarding absolute event from relative device. "
+			    "Please file a bug\n");
+		return;
+	}
+
 	x = libinput_event_pointer_get_absolute_x_transformed(event, TOUCH_AXIS_MAX);
 	y = libinput_event_pointer_get_absolute_y_transformed(event, TOUCH_AXIS_MAX);