Multiple clicks with touchscreen

Kerrick Staley mail at kerrickstaley.com
Wed Aug 10 22:06:30 PDT 2011


Hello,
Basically, what I would like to do is prevent input events from my
touchscreen from appearing on /dev/input/mice.

I have a dual-head setup with a regular screen (built into my laptop) on the
left and a touchscreen on the right. When the touchscreen is touched, it
registers two clicks; this is undesirable. From what I can find in forums,
etc., the issue is that input events appear on both /dev/input/mice and
/dev/input/mouse0. Indeed, when the touchscreen is touched, both devices
show activity.

Earlier, the multiple-click issue did not occur, but there was another
issue: touchscreen events did not occur in the correct spot (they were
spread across both monitors). I fixed this using
$ xinput set-prop "QUANTA OpticalTouchScreen" --type=float "Coordinate
Transformation Matrix" 0.53333333 0 0.46666666667 0 1 0 0 0 1
n.b. The touchscreen is a HP Compaq L2105tm, which uses a touch sensor
manufactured by Quanta. The screen is 1920x1080 and is sitting to the right
of the laptop, which has a 1680x1050 display, so the transformation matrix
is correct.

Now that the touchscreen is properly calibrated, there are two clicks: one
in the correct spot, and one in the original spot (where it clicked before I
invoked xinput; this location corresponds to an identity transformation
matrix).

How can I fix this issue? I found 3 separate solutions, none of which worked
for me:

1. Disable /dev/input/mice, as described at
http://www.conan.de/touchscreen/evtouch.html
-There is no ServerLayout section in my xorg.conf. The dual-head layout is
configured dynamically by Gnome 3 when I log in or when the monitor is
attached; I'll eventually configure ivman or similar to automatically invoke
xinput when the display is attached.
-As I understand it, this will prevent the mouse (a TrackPoint) from
working; the mouse is needed for the regular display.

2. Patch the driver, per
http://www.linuxquestions.org/questions/linux-desktop-74/hal-vs-xserver-dev-input-mice-convincing-x-to-*not*-use-a-given-input-device-697802/#post3415561
-I don't know where in the driver I should insert this code; plus, the
driver is part of the kernel (module hid-quanta), so I'd have to recompile
my kernel.

3. Write a HAL rule, per
http://www.linuxquestions.org/questions/linux-desktop-74/hal-vs-xserver-dev-input-mice-convincing-x-to-*not*-use-a-given-input-device-697802/#post3625659
-I tried this, and it didn't work. I used <match key="info.product"
contains="OpticalTouchScreen">, but I'm not sure if this is correct.

I'm running X.Org 1.10.3.901 (1.10.4 RC 1) on Linux 3.0 (the distribution is
Arch Linux). If there is any additional information needed (log output,
etc.), please ask.

Thanks,
Kerrick Staley
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