[PATCH] HID: wacom: generic: sync pad events only for actual packets

[Ping Cheng <pinglinux@gmail.com>]

Commits d793ff8 and 4082da8 introduced two pad usages which do not
actually send pad input events. To make sure we do not post empty
pad packets, pad_input_event_flag is introduced. Turn on the flag
for real pad input events so we can synchronize them properly.

Signed-off-by: Ping Cheng <ping.cheng@wacom.com>
---
Jiri: this patch is based on your for-4.12/wacom branch
---
 drivers/hid/wacom_wac.c | 6 +++++-
 drivers/hid/wacom_wac.h | 1 +
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index f136038..ffef32a 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -1881,6 +1881,7 @@ static void wacom_wac_pad_event(struct hid_device *hdev, struct hid_field *field
 		 /* fall through*/
 	default:
 		input_event(input, usage->type, usage->code, value);
+		if (value) features->pad_input_event_flag = true;
 		break;
 	}
 }
@@ -1919,11 +1920,14 @@ static void wacom_wac_pad_report(struct hid_device *hdev,
 	struct wacom_wac *wacom_wac = &wacom->wacom_wac;
 	struct input_dev *input = wacom_wac->pad_input;
 	bool active = wacom_wac->hid_data.inrange_state != 0;
+	struct wacom_features *features = &wacom_wac->features;
 
 	/* report prox for expresskey events */
-	if (wacom_equivalent_usage(report->field[0]->physical) == HID_DG_TABLETFUNCTIONKEY) {
+	if ((wacom_equivalent_usage(report->field[0]->physical) == HID_DG_TABLETFUNCTIONKEY) &&
+	    features->pad_input_event_flag) {
 		input_event(input, EV_ABS, ABS_MISC, active ? PAD_DEVICE_ID : 0);
 		input_sync(input);
+		if (!active) features->pad_input_event_flag = false;
 	}
 
 }
diff --git a/drivers/hid/wacom_wac.h b/drivers/hid/wacom_wac.h
index 839bd4b..ff09609 100644
--- a/drivers/hid/wacom_wac.h
+++ b/drivers/hid/wacom_wac.h
@@ -263,6 +263,7 @@ struct wacom_features {
 	int pktlen;
 	bool check_for_hid_type;
 	int hid_type;
+	bool pad_input_event_flag;
 };
 
 struct wacom_shared {
-- 
2.7.4