[PATCH] Fix coasting speed

[Pierre Lulé]

Hello,

I'm bringing back up this issue since I still think coasting is broken
on synaptics touchpad. Can anybody reproduce the issue ? Is there
anything wrong with the report or the patch ? (first time I use
git-send-mail, I'm sorry if there is a problem...)

It affects versions 1.5.99.901 and 1.5.99.902 which are included in
Archlinux and Fedora (I could not confirm on Fedora though).

Best regards,
Pierre Lulé

Le 28 mars 2012 00:13, Pierre Lulé <pierre at lule.fr> a écrit :
>
> Oops, left a typo in previous patch. Here's the correction.
>
> Fixes a bug introduced in commit 2603ad69b997c999404ecc441e0d64ea2cc22018 (Use the scroll distances as increment for scrolling valuator axes)
>
> Since this commit, scroll distance was set with SetScrollValuator function but it was still used as a divisor to calculate coasting,
> thus making coasting too slow. (at least on my computer)
>
> Deleting the divisor fixes the issue.
>
> A report of the same bug : https://bugs.archlinux.org/task/28955
> ---
>  src/synaptics.c |   23 ++++++++++-------------
>  1 file changed, 10 insertions(+), 13 deletions(-)
>
> diff --git a/src/synaptics.c b/src/synaptics.c
> index 99b5085..696a1f6 100644
> --- a/src/synaptics.c
> +++ b/src/synaptics.c
> @@ -2330,39 +2330,36 @@ start_coasting(SynapticsPrivate *priv, struct SynapticsHwState *hw,
>        double pkt_time = HIST_DELTA(0, 3, millis) / 1000.0;
>        if (vert && !circ) {
>            double dy = estimate_delta(HIST(0).y, HIST(1).y, HIST(2).y, HIST(3).y);
> -           int sdelta = para->scroll_dist_vert;
> -           if (pkt_time > 0 && sdelta > 0) {
> -               double scrolls_per_sec = dy / pkt_time / sdelta;
> +           if (pkt_time > 0) {
> +               double scrolls_per_sec = dy / pkt_time;
>                if (fabs(scrolls_per_sec) >= para->coasting_speed) {
>                    priv->scroll.coast_speed_y = scrolls_per_sec;
> -                   priv->scroll.coast_delta_y = (hw->y - priv->scroll.last_y) / (double)sdelta;
> +                   priv->scroll.coast_delta_y = (hw->y - priv->scroll.last_y);
>                }
>            }
>        }
>        if (horiz && !circ){
>            double dx = estimate_delta(HIST(0).x, HIST(1).x, HIST(2).x, HIST(3).x);
> -           int sdelta = para->scroll_dist_horiz;
> -           if (pkt_time > 0 && sdelta > 0) {
> -               double scrolls_per_sec = dx / pkt_time / sdelta;
> +           if (pkt_time > 0) {
> +               double scrolls_per_sec = dx / pkt_time;
>                if (fabs(scrolls_per_sec) >= para->coasting_speed) {
>                    priv->scroll.coast_speed_x = scrolls_per_sec;
> -                   priv->scroll.coast_delta_x = (hw->x - priv->scroll.last_x) / (double)sdelta;
> +                   priv->scroll.coast_delta_x = (hw->x - priv->scroll.last_x);
>                }
>            }
>        }
>        if (circ) {
>            double da = estimate_delta_circ(priv);
> -           double sdelta = para->scroll_dist_circ;
> -           if (pkt_time > 0 && sdelta > 0) {
> -               double scrolls_per_sec = da / pkt_time / sdelta;
> +           if (pkt_time > 0) {
> +               double scrolls_per_sec = da / pkt_time;
>                if (fabs(scrolls_per_sec) >= para->coasting_speed) {
>                    if (vert) {
>                        priv->scroll.coast_speed_y = scrolls_per_sec;
> -                       priv->scroll.coast_delta_y = diffa(priv->scroll.last_a, angle(priv, hw->x, hw->y)) / sdelta;
> +                       priv->scroll.coast_delta_y = diffa(priv->scroll.last_a, angle(priv, hw->x, hw->y));
>                    }
>                    else if (horiz) {
>                        priv->scroll.coast_speed_x = scrolls_per_sec;
> -                       priv->scroll.coast_delta_x = diffa(priv->scroll.last_a, angle(priv, hw->x, hw->y)) / sdelta;
> +                       priv->scroll.coast_delta_x = diffa(priv->scroll.last_a, angle(priv, hw->x, hw->y));
>                    }
>                }
>            }
> --
> 1.7.9.4
>