Input: synaptics - fix resolution for manually provided min/max

commit d49cb7ae upstream.

commit 421e08c4 fixed the reported min/max for the X and Y axis,
but unfortunately, it broke the resolution of those same axis.

On the t540p, the resolution is the same regarding X and Y. It is not
a problem for xf86-input-synaptics because this driver is only interested
in the ratio between X and Y.
Unfortunately, xf86-input-cmt uses directly the resolution, and having a
null resolution leads to some divide by 0 errors, which are translated by
-infinity in the resulting coordinates.
Reported-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
[bwh: Backported to 3.2: I didn't apply the PNP ID changes, so the
 code being moved looks different]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/input/mouse/synaptics.c

@@ -245,14 +245,6 @@ static int synaptics_resolution(struct psmouse *psmouse)
 	struct synaptics_data *priv = psmouse->private;
 	unsigned char resp[3];
 
-	if (quirk_min_max) {
-		priv->x_min = quirk_min_max[0];
-		priv->x_max = quirk_min_max[1];
-		priv->y_min = quirk_min_max[2];
-		priv->y_max = quirk_min_max[3];
-		return 0;
-	}
-
 	if (SYN_ID_MAJOR(priv->identity) < 4)
 		return 0;
 
@@ -263,6 +255,14 @@ static int synaptics_resolution(struct psmouse *psmouse)
 		}
 	}
 
+	if (quirk_min_max) {
+		priv->x_min = quirk_min_max[0];
+		priv->x_max = quirk_min_max[1];
+		priv->y_min = quirk_min_max[2];
+		priv->y_max = quirk_min_max[3];
+		return 0;
+	}
+
 	if (SYN_EXT_CAP_REQUESTS(priv->capabilities) >= 5 &&
 	    SYN_CAP_MAX_DIMENSIONS(priv->ext_cap_0c)) {
 		if (synaptics_send_cmd(psmouse, SYN_QUE_EXT_MAX_COORDS, resp)) {