Why got XEvent type 84 in _x11_fd_callback?

Peter Hutterer peter.hutterer at who-t.net
Wed Jan 15 03:44:56 PST 2014

On Wed, Jan 15, 2014 at 02:22:11PM +0800, Leslie Zhai wrote:
> Hi synaptics developers,
> In geis-2.2.16, libgeis/backend/grail/geis_grail_backend.c source
> code file, about the 1143 line,
> http://bazaar.launchpad.net/~oif-team/geis/trunk/view/head:/libgeis/backend/grail/geis_grail_backend.c#L1147
> it would get error XEvent type, printf the XEvent type is 84.
> My development enviorment shown as below:
> 3.12.7-2-ARCH i686
> xf86-input-synaptics-1.7.3
> geis-2.2.16
> touchegg svn reversion 189
> gnome-shell 3.10.2
> I used touchegg, a qt4 gesture recognition application based on
> geis, to debug gesture recognition, and my touchpad supports
> multitouch, for example mtdev_has_mt_event(mtdev, ABS_MT_SLOT), when
> I used 3 fingers to drag, geis got error XEvent type 84 in
> _x11_fd_callback function.

84 is probably some XInput event, just take the base event you get from
xdpyinfo -ext XInputExtension, then subtract that from 84 and it'll tell you
what the matching XI_* event from XIproto.h is.

other than that I don't know much about geis, there was a multitouch-dev
list or so when geis came out, maybe someone on there knows though it's
pretty dead these days
> I argued that it might be xf86-input-synaptics-1.7.3`s issue,
> because geis backend only received XEvent, then classified the
> gesture, but synaptics post the multitouch event by
> xf86PostTouchEvent, in xf86-input-synaptics=1.7.3 src/synaptics.c,
> about the line 2710,
> http://cgit.freedesktop.org/xorg/driver/xf86-input-synaptics/tree/src/synaptics.c?h=synaptics-1.7-branch#n2710

synaptics only sends touch events under very specific conditions and
configurations. unless you've enabled those configurations you may be
following the wrong lead.

> And why ubuntu phone with multitouch touchscreen works well? It is
> based on Mir, utouch-geis, sort of gesture recognition utils, is not
> it? or it is android-based, different from Linux multitouch
> protocol?
> https://www.kernel.org/doc/Documentation/input/multi-touch-protocol.txt

I have no idea what the question is here, sorry.


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