Le 13 août 10 à 01:15, Jiri Kosina a écrit :
i Chris,
has this patch been really tested?
I am almost certain that we need to have the device ID to be added to
hid_blacklist[] in drivers/hid/hid-core.c as well. Otherwise the
hid-egalax driver wouldn't bind to the device automatically in a
proper
way.
Guys,
I happen to have gathered information about this during the last five
days:
- Mathieu Virbel, author of PyMT, has reported that with the above
patch (and probably the corresponding change to hid-core.c) the
multitouch panel of the Joojoo kind of works, but with a strange
behaviour: SYNC messages are inserted between fingers.
- after checking HID report descriptors, it appears that the
protocol used by this device is fairly different from that of the
eGalax found in the T101MT. Basically, it uses what Microsoft
describes as 'serial' multitouch events instead of the 'parallel'
multitouch events we ususally see. This means that each finger is
reported in a message of its own.
- after checking with the maker of these panels, it appears that
they have two independent product lines. One, with product IDs 48xx,
is resistive and has a classical 'parallel' protocol. The other, with
product IDs 72xx, is capacitive and has an unusual 'serial' protocol.
The Joojoo has the latter.
In summary this is a new kind of panel with an unusual HID prototol
and the hid-egalax driver fails at producing a proper event sequence.
The major issue here is that the key to resolving the problem does
*not* lie in the driver: SYNC messages are produced in hid-input.c
and drivers cannot block them. To address this, one would need to
make the <HID event> -> <input event> + <sync> mapping less
systematic. This could converge with the efforts required if we were
to have a more generic management of multitouch devices (we need one
driver for each device because hid-core.c was not designed with this
kind of device in mind).
My suggestions:
- accept the patch, after adding a few comments in the code about
this device requiring future care for its 'serial' protocol.
- start thinking about what changes are required in hid-input and/
or hid-core for a more generic management of multitouch devices.
Cheers,
St.
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