[PATCH 4.19 02/79] HID: wacom: generic: read HID_DG_CONTACTMAX from any feature report

Greg Kroah-Hartman
2019-09-19T22:12:30Z

From: Aaron Armstrong Skomra <skomra@gmail.com>

commit 184eccd40389df29abefab88092c4ff33191fd0c upstream.

In the generic code path, HID_DG_CONTACTMAX was previously
only read from the second byte of report 0x23.

Another report (0x82) has the HID_DG_CONTACTMAX in the
higher nibble of the third byte. We should support reading the
value of HID_DG_CONTACTMAX no matter what report we are reading
or which position that value is in.

To do this we submit the feature report as a event report
using hid_report_raw_event(). Our modified finger event path
records the value of HID_DG_CONTACTMAX when it sees that usage.

Fixes: 8ffffd5212846 ("HID: wacom: fix timeout on probe for some wacoms")
Signed-off-by: Aaron Armstrong Skomra <aaron.skomra@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/hid/wacom_sys.c | 10 ++++++----
drivers/hid/wacom_wac.c | 4 ++++
2 files changed, 10 insertions(+), 4 deletions(-)

--- a/drivers/hid/wacom_sys.c
+++ b/drivers/hid/wacom_sys.c
@@ -282,14 +282,16 @@ static void wacom_feature_mapping(struct
/* leave touch_max as is if predefined */
if (!features->touch_max) {
/* read manually */
- data = kzalloc(2, GFP_KERNEL);
+ n = hid_report_len(field->report);
+ data = hid_alloc_report_buf(field->report, GFP_KERNEL);
if (!data)
break;
data[0] = field->report->id;
ret = wacom_get_report(hdev, HID_FEATURE_REPORT,
- data, 2, WAC_CMD_RETRIES);
- if (ret == 2) {
- features->touch_max = data[1];
+ data, n, WAC_CMD_RETRIES);
+ if (ret == n) {
+ ret = hid_report_raw_event(hdev,
+ HID_FEATURE_REPORT, data, n, 0);
} else {
features->touch_max = 16;
hid_warn(hdev, "wacom_feature_mapping: "
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -2533,6 +2533,7 @@ static void wacom_wac_finger_event(struc
struct wacom *wacom = hid_get_drvdata(hdev);
struct wacom_wac *wacom_wac = &wacom->wacom_wac;
unsigned equivalent_usage = wacom_equivalent_usage(usage->hid);
+ struct wacom_features *features = &wacom->wacom_wac.features;

switch (equivalent_usage) {
case HID_GD_X:
@@ -2553,6 +2554,9 @@ static void wacom_wac_finger_event(struc
case HID_DG_TIPSWITCH:
wacom_wac->hid_data.tipswitch = value;
break;
+ case HID_DG_CONTACTMAX:
+ features->touch_max = value;
+ return;
}