From: Jason Gerecke <jason.gerecke@xxxxxxxxx> commit 49a397ad24ee5e2c53a59dada2780d7e71bd3f77 upstream. 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@xxxxxxxxxxxxxxx # 4.11+ Signed-off-by: Jason Gerecke <jason.gerecke@xxxxxxxxx> Signed-off-by: Jiri Kosina <jkosina@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/hid/wacom_wac.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/hid/wacom_wac.c +++ b/drivers/hid/wacom_wac.c @@ -1394,9 +1394,9 @@ static void wacom_intuos_pro2_bt_pen(str 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])); Patches currently in stable-queue which might be from jason.gerecke@xxxxxxxxx are queue-5.4/hid-wacom-interpret-tilt-data-from-intuos-pro-bt-as-signed-values.patch
