2012/3/15 Thorsten Wissmann <re06huxa@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>: > Hi, > > 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?) > > Information about our context: We took the partial working and GPL > licensed driver code out of /usr/src/ of [3] and enabled the multitouch > parts of it. > 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. 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. Chris -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
