From a780e5b3638a0ff81301fc68aca15b47ba0befb7 Mon Sep 17 00:00:00 2001
From: Benjamin Tissoires <tissoire@cena.fr>
Date: Wed, 14 Apr 2010 17:27:51 +0200
Subject: [PATCH] xf86ScaleAxis: support for high resolution devices

High resolution devices was generating integer overflow.
For instance the wacom Cintiq 21UX has an axis value up to
87000. Thus the term (dSx * (Cx - Rxlow)) is greater than
MAX_INT32.

Using 64bits integer avoids such problem.

Signed-off-by: Philippe Ribet <ribet@cena.fr>
Signed-off-by: Benjamin Tissoires <tissoire@cena.fr>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
---
 hw/xfree86/common/xf86Xinput.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/xfree86/common/xf86Xinput.c b/hw/xfree86/common/xf86Xinput.c
index 7723ba683..dba3370f3 100644
--- a/hw/xfree86/common/xf86Xinput.c
+++ b/hw/xfree86/common/xf86Xinput.c
@@ -86,6 +86,7 @@
 #include "windowstr.h"	/* screenIsSaved */
 
 #include <stdarg.h>
+#include <stdint.h>          /* for int64_t */
 
 #include <X11/Xpoll.h>
 
@@ -1177,12 +1178,11 @@ xf86ScaleAxis(int	Cx,
               int	Rxlow )
 {
     int X;
-    int dSx = Sxhigh - Sxlow;
-    int dRx = Rxhigh - Rxlow;
+    int64_t dSx = Sxhigh - Sxlow;
+    int64_t dRx = Rxhigh - Rxlow;
 
-    dSx = Sxhigh - Sxlow;
     if (dRx) {
-	X = ((dSx * (Cx - Rxlow)) / dRx) + Sxlow;
+	X = (int)(((dSx * (Cx - Rxlow)) / dRx) + Sxlow);
     }
     else {
 	X = 0;