linux-kernel - Re: [PATCH 2/2] HID: multitouch: enable palm rejection for Windows Precision Touchpad

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Date:	Mon, 27 Jun 2016 16:18:05 +0200
From:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:	Allen Hung <allen_hung@...l.com>
Cc:	Jiri Kosina <jikos@...nel.org>, linux-input@...r.kernel.org,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] HID: multitouch: enable palm rejection for Windows
 Precision Touchpad

On Jun 23 2016 or thereabouts, Allen Hung wrote:
> The usage Confidence is mandary to Windows Precision Touchpad devices. If
> it is examined in input_mapping on a WIndows Precision Touchpad, a new add
> quirk MT_QUIRK_CONFIDENCE desgned for such devices will be applied to the
> device. A touch with the confidence bit is not set is determined as
> invalid.
> 
> Tested on Dell XPS13 9343
> 
> Signed-off-by: Allen Hung <allen_hung@...l.com>

Thanks Allen for taking care of that.

For the series:
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>

Cheers,
Benjamin

> ---
>  drivers/hid/hid-multitouch.c | 18 +++++++++++++++---
>  1 file changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index 4ef7006..fb6f1f4 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -61,6 +61,7 @@ MODULE_LICENSE("GPL");
>  #define MT_QUIRK_ALWAYS_VALID		(1 << 4)
>  #define MT_QUIRK_VALID_IS_INRANGE	(1 << 5)
>  #define MT_QUIRK_VALID_IS_CONFIDENCE	(1 << 6)
> +#define MT_QUIRK_CONFIDENCE		(1 << 7)
>  #define MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE	(1 << 8)
>  #define MT_QUIRK_NO_AREA		(1 << 9)
>  #define MT_QUIRK_IGNORE_DUPLICATES	(1 << 10)
> @@ -78,6 +79,7 @@ struct mt_slot {
>  	__s32 contactid;	/* the device ContactID assigned to this slot */
>  	bool touch_state;	/* is the touch valid? */
>  	bool inrange_state;	/* is the finger in proximity of the sensor? */
> +	bool confidence_state;  /* is the touch made by a finger? */
>  };
>  
>  struct mt_class {
> @@ -502,6 +504,9 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>  			mt_store_field(usage, td, hi);
>  			return 1;
>  		case HID_DG_CONFIDENCE:
> +			if (cls->name == MT_CLS_WIN_8 &&
> +				field->application == HID_DG_TOUCHPAD)
> +				cls->quirks |= MT_QUIRK_CONFIDENCE;
>  			mt_store_field(usage, td, hi);
>  			return 1;
>  		case HID_DG_TIPSWITCH:
> @@ -614,6 +619,7 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
>  		return;
>  
>  	if (td->curvalid || (td->mtclass.quirks & MT_QUIRK_ALWAYS_VALID)) {
> +		int active;
>  		int slotnum = mt_compute_slot(td, input);
>  		struct mt_slot *s = &td->curdata;
>  		struct input_mt *mt = input->mt;
> @@ -628,10 +634,14 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
>  				return;
>  		}
>  
> +		if (!(td->mtclass.quirks & MT_QUIRK_CONFIDENCE))
> +			s->confidence_state = 1;
> +		active = (s->touch_state || s->inrange_state) &&
> +							s->confidence_state;
> +
>  		input_mt_slot(input, slotnum);
> -		input_mt_report_slot_state(input, MT_TOOL_FINGER,
> -			s->touch_state || s->inrange_state);
> -		if (s->touch_state || s->inrange_state) {
> +		input_mt_report_slot_state(input, MT_TOOL_FINGER, active);
> +		if (active) {
>  			/* this finger is in proximity of the sensor */
>  			int wide = (s->w > s->h);
>  			/* divided by two to match visual scale of touch */
> @@ -696,6 +706,8 @@ static void mt_process_mt_event(struct hid_device *hid, struct hid_field *field,
>  			td->curdata.touch_state = value;
>  			break;
>  		case HID_DG_CONFIDENCE:
> +			if (quirks & MT_QUIRK_CONFIDENCE)
> +				td->curdata.confidence_state = value;
>  			if (quirks & MT_QUIRK_VALID_IS_CONFIDENCE)
>  				td->curvalid = value;
>  			break;
> -- 
> 2.7.4
>