4.3-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jason Gerecke <killertofu@xxxxxxxxx>
commit 499522c8c015de995aabce3d0f0bf4b9b17f44c3 upstream.
The cached indicies 'cc_index' and 'cc_value_index' introduced in 1b5d514
are only valid for a single report ID. If a touchscreen has multiple
reports with a HID_DG_CONTACTCOUNT usage, its possible that the values
will not be correct for the report we're handling, resulting in an
incorrect value for 'num_expected'. This has been observed with the Cintiq
Companion 2.
To address this, we store the ID of the report those indicies are valid
for in a new 'cc_report' variable. Before using them to get the expected
contact count, we first check if the ID of the report we're processing
matches 'cc_report'. If it doesn't, we update the indicies to point to
the HID_DG_CONTACTCOUNT usage of the current report (if it has one).
Signed-off-by: Jason Gerecke <jason.gerecke@xxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/hid/wacom_wac.c | 26 ++++++++++++++++++++++++++
drivers/hid/wacom_wac.h | 1 +
2 files changed, 27 insertions(+)
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -1628,6 +1628,7 @@ static void wacom_wac_finger_usage_mappi
wacom_map_usage(input, usage, field, EV_KEY, BTN_TOUCH, 0);
break;
case HID_DG_CONTACTCOUNT:
+ wacom_wac->hid_data.cc_report = field->report->id;
wacom_wac->hid_data.cc_index = field->index;
wacom_wac->hid_data.cc_value_index = usage->usage_index;
break;
@@ -1715,6 +1716,31 @@ static void wacom_wac_finger_pre_report(
struct wacom_wac *wacom_wac = &wacom->wacom_wac;
struct hid_data* hid_data = &wacom_wac->hid_data;
+ if (hid_data->cc_report != 0 &&
+ hid_data->cc_report != report->id) {
+ int i;
+
+ hid_data->cc_report = report->id;
+ hid_data->cc_index = -1;
+ hid_data->cc_value_index = -1;
+
+ for (i = 0; i < report->maxfield; i++) {
+ struct hid_field *field = report->field[i];
+ int j;
+
+ for (j = 0; j < field->maxusage; j++) {
+ if (field->usage[j].hid == HID_DG_CONTACTCOUNT) {
+ hid_data->cc_index = i;
+ hid_data->cc_value_index = j;
+
+ /* break */
+ i = report->maxfield;
+ j = field->maxusage;
+ }
+ }
+ }
+ }
+
if (hid_data->cc_index >= 0) {
struct hid_field *field = report->field[hid_data->cc_index];
int value = field->value[hid_data->cc_value_index];
--- a/drivers/hid/wacom_wac.h
+++ b/drivers/hid/wacom_wac.h
@@ -198,6 +198,7 @@ struct hid_data {
int width;
int height;
int id;
+ int cc_report;
int cc_index;
int cc_value_index;
int num_expected;
--
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