How to configure touchscreen pressure sensitivity with evdev driver?

[Peter Hutterer]

On Wed, Jul 28, 2010 at 11:57:48AM +0200, Javi wrote:
> I've upgraded some machines with touchscreens to latest Xorg. The ones
> with USB EloGraphics touchscreens work like a charm with evdev driver
> and no extra configuration. The problem is with the ones with
> GeneralTouch USB touchscreens.
> 
> I managed to properly calibrate them, but now you need to exert hight
> pressure for the driver to detect click/drag events. I mean, you have
> to press so hard it becomes unusable. With the old Xorg I used the
> evtouch driver and touchscreens worked softly, but not anymore with
> evdev. I've tried to compile evtouch for latest Xorg but it fails with
> several errors.
> 
> So the question is...
> 
> Is there any way to configure pressure sensitivity with evdev driver?

no, evdev just passes the pressure on as an additional axis, it doesn't do
anything fancy with it.

the evtest output for your device will be useful to figure out the event
sequence that comes from the device and why the high pressure is necessary.

Cheers,
  Peter