From: Ping Cheng <pinglinux@xxxxxxxxx> commit 08a46b4190d345544d04ce4fe2e1844b772b8535 upstream. Some older tablets may not report physical maximum for X/Y coordinates. Set a default to prevent undefined resolution. Signed-off-by: Ping Cheng <ping.cheng@xxxxxxxxx> Link: https://lore.kernel.org/r/20230409164229.29777-1-ping.cheng@xxxxxxxxx Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/hid/wacom_wac.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/drivers/hid/wacom_wac.c +++ b/drivers/hid/wacom_wac.c @@ -1791,6 +1791,7 @@ static void wacom_map_usage(struct input int fmax = field->logical_maximum; unsigned int equivalent_usage = wacom_equivalent_usage(usage->hid); int resolution_code = code; + int resolution = hidinput_calc_abs_res(field, resolution_code); if (equivalent_usage == HID_DG_TWIST) { resolution_code = ABS_RZ; @@ -1813,8 +1814,15 @@ static void wacom_map_usage(struct input switch (type) { case EV_ABS: input_set_abs_params(input, code, fmin, fmax, fuzz, 0); - input_abs_set_res(input, code, - hidinput_calc_abs_res(field, resolution_code)); + + /* older tablet may miss physical usage */ + if ((code == ABS_X || code == ABS_Y) && !resolution) { + resolution = WACOM_INTUOS_RES; + hid_warn(input, + "Wacom usage (%d) missing resolution \n", + code); + } + input_abs_set_res(input, code, resolution); break; case EV_KEY: input_set_capability(input, EV_KEY, code);
