HID: wacom: Read HID_DG_CONTACTMAX directly for non-generic devices

commit 778fbf4179 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: 184eccd403 ("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>
This commit is contained in:
Jason Gerecke 2020-04-01 14:23:29 -07:00 committed by Greg Kroah-Hartman
parent 0aeae7ad94
commit 3fc16b5b19
1 changed files with 3 additions and 1 deletions

View File

@ -319,9 +319,11 @@ static void wacom_feature_mapping(struct hid_device *hdev,
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: "