Re: [PATCH] Input: Change BTN_TOOL_FINGER flag when hover event trigger

['Dmitry Torokhov' <dmitry.torokhov@gmail.com>]

Hi KT,

On Mon, May 23, 2016 at 10:28:59PM +0800, 廖崇榮 wrote:
> Hi Dmitry,
> 
> Thanks for your confirmation.
> 
> I think the best and simplest way is to add below code to emit BTN_TOOL_FINGER if hover condition meets.
> 
> input_report_key(dev, BTN_TOOL_FINGER, input_mt_get_value(dev, ABS_DISTANCE));
> 
> Is it ok for you?
> 
> 	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) {
> 
> 			/* Emit BTN_TOOL_FINGER*/
> 			input_report_key(dev, BTN_TOOL_FINGER, input_mt_get_value(dev, ABS_DISTANCE));

I do not see why we need to emit BTN_TOOL_FINGER event twice, once
here, and second time in input_mt_report_finger_count():

- If distance is non-zero (and all other conditions are true) then count
  will be 1 and will be calling input_mt_report_finger_count(dev, 1)
  which will result in sending EV_KEY/BTN_TOOL_FINGER/1 event.

- If distance is 0 then count will remain 0 and
  input_mt_report_finger_count(dev, 0) will result in
  EV_KEY/BTN_TOOL_FINGER/0.

which is exactly what we need as far as I can see.

Thanks.

> 
> 			count = 1;
> 		}
> 
> B.R  KT
> -----Original Message-----
> From: 'Dmitry Torokhov' [mailto:dmitry.torokhov@gmail.com] 
> Sent: Friday, May 20, 2016 8:52 AM
> To: 廖崇榮
> Cc: linux-input@vger.kernel.org; linux-kernel@vger.kernel.org; zac.hsieh@emc.com.tw; '黃世鵬 經理'; 'Charles Mooney'; 'Agnes Cheng'; 'jeff'
> Subject: Re: [PATCH] Input: Change BTN_TOOL_FINGER flag when hover event trigger
> 
> 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
> 

-- 
Dmitry
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