From 08a46b4190d345544d04ce4fe2e1844b772b8535 Mon Sep 17 00:00:00 2001

From: Ping Cheng <pinglinux@gmail.com>

Date: Sun, 9 Apr 2023 09:42:29 -0700

Subject: [PATCH] HID: wacom: Set a default resolution for older tablets

Git-commit: 08a46b4190d345544d04ce4fe2e1844b772b8535

Patch-mainline: v6.4-rc1

References: git-fixes

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@wacom.com>

Link: https://lore.kernel.org/r/20230409164229.29777-1-ping.cheng@wacom.com

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/hid/wacom_wac.c | 12 ++++++++++--

 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c

index 4cfa51416dbc..0c6a82c665c1 100644

--- a/drivers/hid/wacom_wac.c

+++ b/drivers/hid/wacom_wac.c

@@ -1921,6 +1921,7 @@ static void wacom_map_usage(struct input_dev *input, struct hid_usage *usage,

 	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;

@@ -1941,8 +1942,15 @@ static void wacom_map_usage(struct input_dev *input, struct hid_usage *usage,

 	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:

 	case EV_MSC:

-- 

2.35.3