[PATCH 3/5] HID:hid-lg4ff: ensure ConstantForce is disabled when set to 0

[Simon Wood <simon@mungewell.org>]

When 'Constant Force' is set to 0 it is not turned off completely,
the wheel feels 'heavy'. This patch issues the '13 00..' command
to ensure that the force in slot 1 (the Constant Force) is
deactivated.

Reported-by: Elias Vanderstuyft <elias.vds@gmail.com>
Signed-off-by: Simon Wood <simon@mungewell.org>
---
 drivers/hid/hid-lg4ff.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/hid/hid-lg4ff.c b/drivers/hid/hid-lg4ff.c
index 49f6cc0..5d140b7 100644
--- a/drivers/hid/hid-lg4ff.c
+++ b/drivers/hid/hid-lg4ff.c
@@ -196,6 +196,21 @@ static int hid_lg4ff_play(struct input_dev *dev, void *data, struct ff_effect *e
 	case FF_CONSTANT:
 		x = effect->u.ramp.start_level + 0x80;	/* 0x80 is no force */
 		CLAMP(x);
+
+		if (x == 0x80) {
+			/* De-activate force in slot-1*/
+			value[0] = 0x13;
+			value[1] = 0x00;
+			value[2] = 0x00;
+			value[3] = 0x00;
+			value[4] = 0x00;
+			value[5] = 0x00;
+			value[6] = 0x00;
+
+			hid_hw_request(hid, report, HID_REQ_SET_REPORT);
+			return 0;
+		}
+
 		value[0] = 0x11;	/* Slot 1 */
 		value[1] = 0x08;
 		value[2] = x;
-- 
1.8.1.2