[PATCH libinput] touchpad: detect fake finger overflow after BTN_TOOL_QUINTTAB

[Hans de Goede]

Hi,

On 09-04-15 06:23, Peter Hutterer wrote:
> Up to QUINTTAP, we count fake fingers through the BTN_TOOL_*TAP kernel defines.
> Once we exceed QUINTTAP, the nfake_finger count returns to 0 and
> tp_unhover_touches terminates all touch sequences. The most visible effect of
> this was stopped in 591a41f but the problem remained.
>
> Since we're not using 5 fingers for anything, use that to set the
> overflow flag. The kernel gives us either a BTN_TOUCH 0 (all
> released) or a lower BTN_TOOL_*TAP to unset the flag when we go below 5
> fingers again.
>
> And if we overflow, we can skip the unhovering of touch points since we a)
> have a decent touchpad that gives us real touchpoints and b) hovering isn't
> supported for 5 touches anyway.
>
> https://bugs.freedesktop.org/show_bug.cgi?id=89800
>
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>

Looks good, I've added my Rev-by and pushed this one.

Regards,

Hans


> ---
>   src/evdev-mt-touchpad.c | 29 +++++++++++++++++++++++++----
>   1 file changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
> index 724fd32..19ec99e 100644
> --- a/src/evdev-mt-touchpad.c
> +++ b/src/evdev-mt-touchpad.c
> @@ -34,6 +34,7 @@
>   #define DEFAULT_ACCEL_NUMERATOR 3000.0
>   #define DEFAULT_HYSTERESIS_MARGIN_DENOMINATOR 700.0
>   #define DEFAULT_TRACKPOINT_ACTIVITY_TIMEOUT 500 /* ms */
> +#define FAKE_FINGER_OVERFLOW (1 << 7)
>
>   static inline int
>   tp_hysteresis(int in, int center, int margin)
> @@ -127,8 +128,10 @@ tp_get_touch(struct tp_dispatch *tp, unsigned int slot)
>   static inline unsigned int
>   tp_fake_finger_count(struct tp_dispatch *tp)
>   {
> -	/* don't count BTN_TOUCH */
> -	return ffs(tp->fake_touches >> 1);
> +	if (tp->fake_touches & FAKE_FINGER_OVERFLOW)
> +		return FAKE_FINGER_OVERFLOW;
> +	else /* don't count BTN_TOUCH */
> +		return ffs(tp->fake_touches >> 1);
>   }
>
>   static inline bool
> @@ -146,6 +149,8 @@ tp_fake_finger_set(struct tp_dispatch *tp,
>
>   	switch (code) {
>   	case BTN_TOUCH:
> +		if (!is_press)
> +			tp->fake_touches &= ~FAKE_FINGER_OVERFLOW;
>   		shift = 0;
>   		break;
>   	case BTN_TOOL_FINGER:
> @@ -156,14 +161,24 @@ tp_fake_finger_set(struct tp_dispatch *tp,
>   	case BTN_TOOL_QUADTAP:
>   		shift = code - BTN_TOOL_DOUBLETAP + 2;
>   		break;
> +	/* when QUINTTAP is released we're either switching to 6 fingers
> +	   (flag stays in place until BTN_TOUCH is released) or
> +	   one of DOUBLE/TRIPLE/QUADTAP (will clear the flag on press) */
> +	case BTN_TOOL_QUINTTAP:
> +		if (is_press)
> +			tp->fake_touches |= FAKE_FINGER_OVERFLOW;
> +		return;
>   	default:
>   		return;
>   	}
>
> -	if (is_press)
> +	if (is_press) {
> +		tp->fake_touches &= ~FAKE_FINGER_OVERFLOW;
>   		tp->fake_touches |= 1 << shift;
> -	else
> +
> +	} else {
>   		tp->fake_touches &= ~(0x1 << shift);
> +	}
>   }
>
>   static inline void
> @@ -325,6 +340,8 @@ tp_process_fake_touches(struct tp_dispatch *tp,
>   	unsigned int i, start;
>
>   	nfake_touches = tp_fake_finger_count(tp);
> +	if (nfake_touches == FAKE_FINGER_OVERFLOW)
> +		return;
>
>   	start = tp->has_mt ? tp->real_touches : 0;
>   	for (i = start; i < tp->ntouches; i++) {
> @@ -387,6 +404,7 @@ tp_process_key(struct tp_dispatch *tp,
>   		case BTN_TOOL_DOUBLETAP:
>   		case BTN_TOOL_TRIPLETAP:
>   		case BTN_TOOL_QUADTAP:
> +		case BTN_TOOL_QUINTTAP:
>   			tp_fake_finger_set(tp, e->code, !!e->value);
>   			break;
>   		case BTN_0:
> @@ -494,6 +512,9 @@ tp_unhover_touches(struct tp_dispatch *tp, uint64_t time)
>   		return;
>
>   	nfake_touches = tp_fake_finger_count(tp);
> +	if (nfake_touches == FAKE_FINGER_OVERFLOW)
> +		return;
> +
>   	if (tp->nfingers_down == nfake_touches &&
>   	    ((tp->nfingers_down == 0 && !tp_fake_finger_is_touching(tp)) ||
>   	     (tp->nfingers_down > 0 && tp_fake_finger_is_touching(tp))))
>