HID: wacom: Properly report negative values from Intuos Pro 2 Bluetooth

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>

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index f8ddcaaa2ac6956bed87778e60d19b4925550a61..1d9e32d2bc63e02ec91b2a6232a01f7c6518e496 100644 (file)
--- 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]));