From mboxrd@z Thu Jan  1 00:00:00 1970
From: Filippo Sironi <filippo.sironi@gmail.com>
Subject: writing a touchscreen device driver
Date: Fri, 30 May 2014 18:54:21 +0200
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Hi everyone,

I'm writing a touchscreen device driver for the PIXCIR Tango C series (http://www.pixcir.com.cn/english/products.asp?Action=Detail&ID=95) for Linux 4 Tegra 3.1.10 (I'm using a Tegra 2 series platform).

I went through the documentation and I came up with the code you can find in this gist: https://gist.github.com/filipposironi/d9ab11e232d8cae9b8f4 .
To test the touchscreen I'm using a set of X11/Qt applications and a X11/Qt/QtWebKit browser. The touchscreen works fine with Qt controls (e.g., buttons and text areas); unfortunately, the same doesn't happen with HTML controls inside the Qt/QtWebKit browser, they struggle to get the focus (sometimes they do and sometimes they don't). Everything else (scrolling with one finger, pinch and zoom, etc. works great).

I initially thought the problem was inside QtWebKit; however, an eGalax touchscreen working with the device driver implemented inside drivers/hid/hid-multitouch.c behaves like a charm even with the Qt/QtWebKit browser.
The evtest (http://cgit.freedesktop.org/evtest/) output I get from the two touchscreens is definitely the same.

I'm wondering if there is something fundamentally wrong with my device driver (https://gist.github.com/filipposironi/d9ab11e232d8cae9b8f4) that I'm not seeing.

Thanks,
Filippo

PS: I'm using Xorg 1.14.1 and evdev 2.7.3 with mtdev 1.1.3 support.