On Wed, Apr 1, 2020 at 11:23 PM Gerecke, Jason killertofu@gmail.com wrote:

From: Jason Gerecke jason.gerecke@wacom.com

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.

Ref: https://github.com/linuxwacom/input-wacom/issues/155

I think the official tag is "Link", not "Ref". I changed it.

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+

---

I really wish we had regression tests for Wacom devices too. This could have been avoided in the first place.

Anyway, applied to for-5.7/upstream-fixes

Thanks!

Cheers, Benjamin

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

diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c index 5ded94b7bf68..cd71e7133944 100644 --- a/drivers/hid/wacom_sys.c +++ b/drivers/hid/wacom_sys.c @@ -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: "
  

-- 2.26.0