evdev: workaround for missing ABS_X/Y on multitouch devices

[Colin Macdonald]

On 27/06/14 02:47, Peter Hutterer wrote:
> right idea, but I think this is too fancy for what we need. Something like
> this before the loop should be enough:
> 
> /* curse you, android! */
> if (libevdev_has_event_code(EV_ABS, ABS_MT_POSITION_X) &&
>     !libevdev_has_event_code(EV_ABS, ABS_X))
> {
>     const struct input_absinfo* abs;
>     abs = libevdev_get_abs_info(pEvdev->dev, axis);
>     libevdev_enable_event_code(pEvdev->dev, EV_ABS, ABS_X, abs);
>     num_axes++;
> }
> 
> repeat for ABS_Y

Hi Peter,

Sorry so long to get back to this, as I'm sure you've long forgotten.
But please find patch attached.  I followed your advice and did this
before the mapping loop.

However, I did the full mt_axis_mappings table, not just
ABS_MT_POSITION_X and _Y.  I think this is the right thing to do here in
case some driver has ABS_MT_PRESSURE or ABS_MT_DISTANCE.

I've lightly tested on an Android device where it does make the
touchscreen work.

It also seems ok (i.e., doesn't break) my touchscreen laptop (Fedora
GNU/Linux).

Colin
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