[PATCH synaptics] Don't assume that touch devices report per finger width and pressure

[Peter Hutterer]

On Wed, Jan 07, 2015 at 02:12:33PM +0100, Gabriele Mazzotta wrote:
> The palm detection relies on both the width and the pressure.
> a897147be04 ("Use ABS_MT events for the palm detection when supported")
> assumed that all the touch devices can report both ABS_MT_TOUCH_MAJOR
> and ABS_MT_PRESSURE, but this is not necessarily true. This assumption
> could hence break the palm detection when at least one of the mentioned
> events is not declared but both ABS_TOOL_WIDTH and ABS_PRESSURE are
> reported.
> 
> Signed-off-by: Gabriele Mazzotta <gabriele.mzt at gmail.com>

merged and pushed, thanks.

Cheers,
   Peter

> ---
>  src/eventcomm.c    | 10 ++++++++--
>  src/synaptics.c    |  2 +-
>  src/synapticsstr.h |  1 +
>  3 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/src/eventcomm.c b/src/eventcomm.c
> index 931859b..9d98feb 100644
> --- a/src/eventcomm.c
> +++ b/src/eventcomm.c
> @@ -626,9 +626,11 @@ EventProcessTouchEvent(InputInfoPtr pInfo, struct SynapticsHwState *hw,
>                      hw->cumulative_dx += ev->value - last_val;
>                  else if (ev->code == ABS_MT_POSITION_Y)
>                      hw->cumulative_dy += ev->value - last_val;
> -                else if (ev->code == ABS_MT_TOUCH_MAJOR)
> +                else if (ev->code == ABS_MT_TOUCH_MAJOR &&
> +                         priv->has_mt_palm_detect)
>                      hw->fingerWidth = ev->value;
> -                else if (ev->code == ABS_MT_PRESSURE)
> +                else if (ev->code == ABS_MT_PRESSURE &&
> +                         priv->has_mt_palm_detect)
>                      hw->z = ev->value;
>              }
>  
> @@ -886,6 +888,10 @@ event_query_touch(InputInfoPtr pInfo)
>              return;
>          }
>  
> +        if (libevdev_has_event_code(dev, EV_ABS, ABS_MT_TOUCH_MAJOR) &&
> +            libevdev_has_event_code(dev, EV_ABS, ABS_MT_PRESSURE))
> +            priv->has_mt_palm_detect = TRUE;
> +
>          axnum = 0;
>          for (axis = ABS_MT_SLOT + 1; axis <= ABS_MT_MAX; axis++) {
>              int axis_idx = axis - ABS_MT_TOUCH_MAJOR;
> diff --git a/src/synaptics.c b/src/synaptics.c
> index 2746565..3b11fda 100644
> --- a/src/synaptics.c
> +++ b/src/synaptics.c
> @@ -1857,7 +1857,7 @@ SynapticsDetectFinger(SynapticsPrivate * priv, struct SynapticsHwState *hw)
>      if ((hw->z > para->palm_min_z) && (hw->fingerWidth > para->palm_min_width))
>          return FS_BLOCKED;
>  
> -    if (priv->has_touch)
> +    if (priv->has_mt_palm_detect)
>          return finger;
>  
>      if (hw->x == 0 || priv->finger_state == FS_UNTOUCHED)
> diff --git a/src/synapticsstr.h b/src/synapticsstr.h
> index dcc7cd0..9a5542f 100644
> --- a/src/synapticsstr.h
> +++ b/src/synapticsstr.h
> @@ -331,6 +331,7 @@ struct _SynapticsPrivateRec {
>      Bool has_width;             /* device reports finger width */
>      Bool has_scrollbuttons;     /* device has physical scrollbuttons */
>      Bool has_semi_mt;           /* device is only semi-multitouch capable */
> +    Bool has_mt_palm_detect;    /* device reports per finger width and pressure */
>  
>      enum TouchpadModel model;   /* The detected model */
>      unsigned short id_vendor;   /* vendor id */
> -- 
> 2.1.4
>