[PATCH xf86-input-synaptics 0/6] Multitouch support

Chase Douglas chase.douglas at canonical.com
Thu Jan 19 13:05:45 PST 2012

The following patch series adds multitouch support to synaptics. It
starts off by initializing touch support in synaptics.c. Then, we add
support to the eventcomm backend.

I had hoped to abstract all the touch support between the synaptics.c
core and all the backends. This wasn't too hard for initializing the
touch device class, but became very difficult for posting the actual
events. I can see the following three approaches:

1. Really hack it into the existing backend interface
2. Rewrite the backend interface
3. Post touch events out of band in each backend

Option 1 would merely make a bad situation worse, so I didn't attempt
it. I did attempt option 2, but the changes were drastic enough that I
couldn't be sure all the backends would still function correctly, and I
don't have all the hardware required to test it. So I chose option 3 for

In a sense, posting the touches out of band may not be a terrible thing
anyways. For indirect touch devices, which is all this input module will
ever be used for, touch events are extra data unrelated to pointer
events. They will be handled out of band by clients, so maybe this isn't
a terrible approach.

-- Chase

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