From b63c4c2718d641ba9bec888994f0cb0c23a1ef45 Mon Sep 17 00:00:00 2001
From: Jason Gerecke <killertofu@gmail.com>
Date: Wed, 30 Aug 2017 15:13:25 -0700
Subject: [PATCH] HID: wacom: Properly report negative values from Intuos Pro 2
 Bluetooth
Git-commit: b63c4c2718d641ba9bec888994f0cb0c23a1ef45
Patch-mainline: v4.14-rc4
References: bsc#1085536

The wacom driver's IRQ handler for Bluetooth reports from the 2nd-gen
Intuos Pro does not correctly process negative numbers. Values for
tilt and rotation (which can go negative) are instead interpreted as
unsigned and so jump to very large values when the data should be
negative. This commit properly casts the data to ensure we report
negative numbers when necessary.

Fixes: 4922cd2 ("HID: wacom: Support 2nd-gen Intuos Pro's Bluetooth classic interface")
Cc: stable@vger.kernel.org # v4.11
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/hid/wacom_wac.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index f8ddcaaa2ac6..1d9e32d2bc63 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -1229,9 +1229,9 @@ static void wacom_intuos_pro2_bt_pen(struct wacom_wac *wacom)
 		if (range) {
 			input_report_abs(pen_input, ABS_X, get_unaligned_le16(&frame[1]));
 			input_report_abs(pen_input, ABS_Y, get_unaligned_le16(&frame[3]));
-			input_report_abs(pen_input, ABS_TILT_X, frame[7]);
-			input_report_abs(pen_input, ABS_TILT_Y, frame[8]);
-			input_report_abs(pen_input, ABS_Z, get_unaligned_le16(&frame[9]));
+			input_report_abs(pen_input, ABS_TILT_X, (char)frame[7]);
+			input_report_abs(pen_input, ABS_TILT_Y, (char)frame[8]);
+			input_report_abs(pen_input, ABS_Z, (int16_t)get_unaligned_le16(&frame[9]));
 			input_report_abs(pen_input, ABS_WHEEL, get_unaligned_le16(&frame[11]));
 		}
 		input_report_abs(pen_input, ABS_PRESSURE, get_unaligned_le16(&frame[5]));
-- 
2.13.6