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Date: Thu, 19 May 2016 17:51:37 -0700
From: "'Dmitry Torokhov'" <dmitry.torokhov@gmail.com>
To: =?utf-8?B?5buW5bSH5qau?= <kt.liao@emc.com.tw>
Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
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        "'jeff'" <jeff.chuang@emc.com.tw>
Subject: Re: [PATCH] Input: Change BTN_TOOL_FINGER flag when hover event
 trigger
Message-ID: <20160520005137.GA39923@dtor-ws>
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On Tue, May 17, 2016 at 10:20:40PM +0800, 廖崇榮 wrote:
> Hi Dmitry,
> 
> I want to confirm my thought for your idea to avoid misunderstanding.
> I think you want to encapsulate " BTN_TOOL_FINGER" in the [input_mt_report_pointer_emulation] if hover happen.
> Vendor driver only report "ABS_DISTANCE" and let [input_mt_report_pointer_emulation] emit BTN_TOOL_FINGER report without change function parameter.
> 
> Please let me know if my misunderstand about your idea.

Yes, that is correct. Something like this:

diff --git a/drivers/input/input-mt.c b/drivers/input/input-mt.c
index 54fce56..a1bbec9 100644
--- a/drivers/input/input-mt.c
+++ b/drivers/input/input-mt.c
@@ -218,8 +218,23 @@ void input_mt_report_pointer_emulation(struct input_dev *dev, bool use_count)
 	}
 
 	input_event(dev, EV_KEY, BTN_TOUCH, count > 0);
-	if (use_count)
+
+	if (use_count) {
+		if (count == 0 &&
+		    !test_bit(ABS_MT_DISTANCE, dev->absbit) &&
+		    test_bit(ABS_DISTANCE, dev->absbit) &&
+		    input_abs_get_val(dev, ABS_DISTANCE) != 0) {
+			/*
+			 * Force reporting BTN_TOOL_FINGER for devices that
+			 * only report general hover (and not per-contact
+			 * distance) when contact is in proximity but not
+			 * on the surface.
+			 */
+			count = 1;
+		}
+
 		input_mt_report_finger_count(dev, count);
+	}
 
 	if (oldest) {
 		int x = input_mt_get_value(oldest, ABS_MT_POSITION_X);

-- 
Dmitry