Thank You for your quick answer!
On Thu, Mar 15, 2012 at 12:27:22PM -0500, Chris Bagwell wrote:
> 2012/3/15 Thorsten Wissmann <re06huxa@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>:
> > we are working on already existing multitouch driver for a Promethean
> > ActivBoard, which supports both multiple fingers and pens. The pens
> > behave Wacom-like, i.e. the device actually can tell a cursor position
> > without a button action.
> >
> > Because of the (up to 4) fingers, we use the input_mt_* functions. Is it
> > possible to just update the cursor position without a button action? (As
> > it is can be done with plain input_* functions?) Or do we have to create
> > two input devices? (one with multitouch input_mt_* and one for the pens?)
>
> I'm not quite sure what you mean by updating cursor position without a
> button action. By button action, do you mean BTN_TOOL_*? It is true
> you need to set correct BTN_TOOL_* before updating any X/Y coordinates
> so user land knows that X/Y maps to.
With "updating cursor position without a button action" we meant
something like moving a "normal" mouse without pressing any button.
(Which generates just mouse motion events for X applications)
> Its also true that sharing ABS_X/Y events between both a BTN_TOOL_PEN
> and a BTN_TOOL_FINGER will confuse most user land apps (they think
> only touchpads can declare BTN_TOOL_FINGER's but this is a
> touchscreen) and it also has bad side affects to the kernel's MT
> pointer emulation functions.
>
> You can look at kernel drivers/input/touchscreen/wacom_w8001.c for an
> example touchscreen that supports pen and at least 2 MT touches on a
> single /dev/input device (because HW packets come over single serial
> interface). It does not declare a BTN_TOOL_FINGER nor use pointer
> emulation to overcome issues I mentioned and xf86-input-wacom
> understands how to handle this device.
>
> If you want to work with other unmodified user land apps (perhaps
> xf86-input-evdev for touches) then its probably easiest to split pen
> and touch to separate input devices. drivers/input/tablet/wacom_wac.c
> shows some examples of that approach but that driver doesn't have to
> work to hard to split in to 2 input devices because the USB device
> already puts the events on separate USB interfaces.
OK. We want the device to work with the xf86-input-evdev driver. So we
will split it into two devices.
Thorsten
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