From 2c27caa66ce843e019ff5281718096b828b5cb6c Mon Sep 17 00:00:00 2001 From: Jason Gerecke Date: Thu, 24 Oct 2024 11:41:17 -0700 Subject: [PATCH] wacom: Interpret tilt data from Intuos Pro BT as signed values The tilt data contained in the Bluetooth packets of an Intuos Pro are supposed to be interpreted as signed values. Simply casting the values to type `char` is not guaranteed to work since it is implementation- defined whether it is signed or unsigned. At least one user has noticed the data being reported incorrectly on their system. To ensure that the data is interpreted properly, we specifically cast to `signed char` instead. Link: https://github.com/linuxwacom/input-wacom/issues/445 Fixes: 4922cd26f03c ("HID: wacom: Support 2nd-gen Intuos Pro's Bluetooth classic interface") CC: stable@vger.kernel.org # 4.11+ Signed-off-by: Jason Gerecke --- 4.18/wacom_wac.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/4.18/wacom_wac.c b/4.18/wacom_wac.c index d89f9a72..29baf481 100644 --- a/4.18/wacom_wac.c +++ b/4.18/wacom_wac.c @@ -1373,9 +1373,9 @@ static void wacom_intuos_pro2_bt_pen(struct wacom_wac *wacom) rotation -= 1800; input_report_abs(pen_input, ABS_TILT_X, - (char)frame[7]); + (signed char)frame[7]); input_report_abs(pen_input, ABS_TILT_Y, - (char)frame[8]); + (signed char)frame[8]); input_report_abs(pen_input, ABS_Z, rotation); input_report_abs(pen_input, ABS_WHEEL, get_unaligned_le16(&frame[11]));