diff mbox series

[4.14,016/114] HID: wacom: Read HID_DG_CONTACTMAX directly for non-generic devices

Message ID 20200518173506.610881590@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman May 18, 2020, 5:35 p.m. UTC 
From: Jason Gerecke <jason.gerecke@wacom.com>

commit 778fbf4179991e7652e97d7f1ca1f657ef828422 upstream.

We've recently switched from extracting the value of HID_DG_CONTACTMAX
at a fixed offset (which may not be correct for all tablets) to
injecting the report into the driver for the generic codepath to handle.
Unfortunately, this change was made for *all* tablets, even those which
aren't generic. Because `wacom_wac_report` ignores reports from non-
generic devices, the contact count never gets initialized. Ultimately
this results in the touch device itself failing to probe, and thus the
loss of touch input.

This commit adds back the fixed-offset extraction for non-generic devices.

Link: https://github.com/linuxwacom/input-wacom/issues/155
Fixes: 184eccd40389 ("HID: wacom: generic: read HID_DG_CONTACTMAX from any feature report")
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Reviewed-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com>
CC: stable@vger.kernel.org # 5.3+
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/hid/wacom_sys.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -132,9 +132,11 @@  static void wacom_feature_mapping(struct
 			data[0] = field->report->id;
 			ret = wacom_get_report(hdev, HID_FEATURE_REPORT,
 					       data, n, WAC_CMD_RETRIES);
-			if (ret == n) {
+			if (ret == n && features->type == HID_GENERIC) {
 				ret = hid_report_raw_event(hdev,
 					HID_FEATURE_REPORT, data, n, 0);
+			} else if (ret == 2 && features->type != HID_GENERIC) {
+				features->touch_max = data[1];
 			} else {
 				features->touch_max = 16;
 				hid_warn(hdev, "wacom_feature_mapping: "