[PATCH] HID: wacom: Work around HID descriptor bug in DTK-2451 and DTH-2452

[Jason Gerecke <killertofu@gmail.com>]

The DTK-2451 and DTH-2452 have a buggy HID descriptor which incorrectly
contains a Cintiq-like report, complete with pen tilt, rotation, twist,
serial number, etc. The hardware doesn't actually support this data but
our driver duitifully sets up the device as though it does. To ensure
userspace has a correct view of devices without updated firmware, we clean
up this incorrect data in wacom_setup_device_quirks.

We're also careful to clear the WACOM_QUIRK_TOOLSERIAL flag since its
presence causes the driver to wait for serial number information (via
wacom_wac_pen_serial_enforce) that never comes, resulting in the pen
being non-responsive.

Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Fixes: 8341720642 ("HID: wacom: Queue events with missing type/serial data for later processing")
Cc: stable@vger.kernel.org # v4.16+
---
 drivers/hid/wacom_wac.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index e0a06be5ef5c..b4b4a30e3982 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -3335,6 +3335,7 @@ static void wacom_setup_intuos(struct wacom_wac *wacom_wac)
 
 void wacom_setup_device_quirks(struct wacom *wacom)
 {
+	struct wacom_wac *wacom_wac = &wacom->wacom_wac;
 	struct wacom_features *features = &wacom->wacom_wac.features;
 
 	/* The pen and pad share the same interface on most devices */
@@ -3464,6 +3465,25 @@ void wacom_setup_device_quirks(struct wacom *wacom)
 
 	if (features->type == REMOTE)
 		features->device_type |= WACOM_DEVICETYPE_WL_MONITOR;
+
+	/* HID descriptor for DTK-2451 / DTH-2452 claims to report lots
+	 * of things it shouldn't. Lets fix up the damage...
+	 */
+	if (wacom->hdev->product == 0x382 || wacom->hdev->product == 0x37d) {
+		features->quirks &= ~WACOM_QUIRK_TOOLSERIAL;
+		__clear_bit(BTN_TOOL_BRUSH, wacom_wac->pen_input->keybit);
+		__clear_bit(BTN_TOOL_PENCIL, wacom_wac->pen_input->keybit);
+		__clear_bit(BTN_TOOL_AIRBRUSH, wacom_wac->pen_input->keybit);
+		__clear_bit(ABS_Z, wacom_wac->pen_input->absbit);
+		__clear_bit(ABS_DISTANCE, wacom_wac->pen_input->absbit);
+		__clear_bit(ABS_TILT_X, wacom_wac->pen_input->absbit);
+		__clear_bit(ABS_TILT_Y, wacom_wac->pen_input->absbit);
+		__clear_bit(ABS_WHEEL, wacom_wac->pen_input->absbit);
+		__clear_bit(ABS_MISC, wacom_wac->pen_input->absbit);
+		__clear_bit(MSC_SERIAL, wacom_wac->pen_input->mscbit);
+		__clear_bit(EV_MSC, wacom_wac->pen_input->evbit);
+	}
 }
 
 int wacom_setup_pen_input_capabilities(struct input_dev *input_dev,
-- 
2.19.1