[PATCH evdev 4/5] Dummy process MT events.

[Peter Hutterer]

On Tue, Apr 13, 2010 at 10:39:44AM +0200, Benjamin Tissoires wrote:
> 
> 
> Le 09/04/2010 07:44, Peter Hutterer a écrit :
> >On Sun, Mar 28, 2010 at 01:58:12PM +0200, Benjamin Tissoires wrote:
> >>In case the driver receive a mt event, it stores it at the first
> >>available place, i.e. it does not overrides older mt values.
> >>
> >>At the end, in the EV_SYNC event, it only send the values it has
> >>filled.
> >>
> >>Signed-off-by: Benjamin Tissoires<tissoire at cena.fr>
> >>---
> >>  src/evdev.c |   31 ++++++++++++++++++++++++++++---
> >>  src/evdev.h |    1 +
> >>  2 files changed, 29 insertions(+), 3 deletions(-)
> >>
> >>diff --git a/src/evdev.c b/src/evdev.c
> >>index 7e59601..76af8dc 100644
> >>--- a/src/evdev.c
> >>+++ b/src/evdev.c
> >>@@ -422,6 +422,8 @@ EvdevProcessValuators(InputInfoPtr pInfo, int v[MAX_VALUATORS], int *num_v,
> >>       */
> >>      else if (pEvdev->abs&&  pEvdev->tool) {
> >>          memcpy(v, pEvdev->vals, sizeof(int) * pEvdev->num_vals);
> >>+        if (pEvdev->current_num_multitouch>  EVDEV_MAX_TOUCHPOINTS)
> >>+            pEvdev->current_num_multitouch = EVDEV_MAX_TOUCHPOINTS;
> >
> >do I understand this correctly that if you get 6 touchpoints the last one
> >overwrites touchpoint 5? is this preferable to just dropping them once they
> >overflow?
> 
> not exactly. What you propose is already occurring: this assignment
> is made in the function EvdevProcessValuators which is called at the
> end of the frame (on an EV_SYNC event).
> When mt-values are coming, the EvdevProcessAbsoluteMotionEvent
> function is called and this function drops them if
> current_num_multitouch > EVDEV_MAX_TOUCHPOINTS.
> 
> I had to clamp current_num_multitouch at the end as I rely on it to
> know how many valuators do I need to send

ah, I see. that confusion was caused by the variable naming, I'd really
prefer a different variable name. Thanks for clarifying this.

Cheers,
  Peter
 
> >also, can we rename current_num_multitouch to mt_current_touchpoint?
> >otherwise this may get confused with the number of touchpoints supported by
> >the device.
> 
> ack.
>