incompatibility of hidio with Multi-touch (MT) Protocol (version B) Hid touchscreens.

[jyg]

Trying to use hid/ hidio with a touchscreen on linux laptop, it appears that the current vesrion of hidio (as found here) is incompatible with my Multi-touch (MT) Protocol (version B) touchscreen.

In hidio.c, on line 526 some events are filtered (when they appear several times) and not sent to Pd. Furthermore, some events are duplicated as there is an instruction hidio_output_event(x, output_element) both in the parent function (hidio.c, line 528) and in the called function (hidio_linux.c, line 361).

For a correct use of the MT Protocol, each incoming event has to be transmitted, only one time, in order of arrival. (for an presentation of the protocol, see https://www.kernel.org/doc/Documentation/input/multi-touch-protocol.txt)

To solve this issue In my case, I commented the lines 519-533 of hidio.c, but this may generate some issues with other hid-devices types. However, I don't think that the instruction hidio_output_event shoud be present in both hidio.c and hidio_linux.c.

As I don't know if there is an active mainainer for hid/hidio, I posted this issue here too : avilleret/hid#3
(from https://github.com/jyg/PdMultitouch/blob/master/hidio/Readme.md)

[Benitoite]

I will have a look at the fork and try to test with my game controllers.