Asus eee-top touch screen

From: Gabriele Turchi
Date: Sun May 24 2009 - 03:39:22 EST

Hi all.

I've done some tests to use the touch screen included in the Asus eee-top PC under Fedora 10/11. From the first results, the touch screen was detected, but only the mouse button events are generated. I've googled around a bit to find a solution, but found nothing.

Looking into kernel and X sources, the more viable solution for me was to write a little kernel module, to modify a bit the event's stream to make them compatible with X needs.

My module is attached, even if I fully understand that this module could be the worst conceived and worst written ever... :-)

To be serious: my choice was to make the less invasive solution, and this module appear to reach the goal: my touch screen works well now. Maybe mine was the wrong approach, but I've found so little documentation on how to make a better one. I'll obviously accept any useful suggestion.

I hope this could be useful.

Gabriele Turchi

P.S.: Please CC me, I'm not subscribed, and my apologies for my horrible English.

* HID driver for TouchPack touchscreen
* (ASUS eee top touch screen)
* Copyright (c) 2009 Gabriele Turchi - gabriele.turchi@xxxxxxxx

* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.

#include <linux/device.h>
#include <linux/hid.h>
#include <linux/module.h>

#include "hid-ids.h"

static int tp_input_mapping(struct hid_device *device, struct hid_input *hi,
struct hid_field *field, struct hid_usage *usage,
unsigned long **bit, int *max)
/* This is needed for evdev compatibility: these events are (apparently) never generated, but
* X11 evdev driver goes mad with it.

if ( (usage->hid & HID_USAGE_PAGE) == HID_UP_DIGITIZER) {
printk(KERN_INFO "tp_input_mapping: discard HID_UP_DIGITIZER => 0x%04X\n", usage->hid);
return -1;

return 0;

static int tp_event(struct hid_device *device, struct hid_field *field, struct hid_usage *usage, __s32 value)
/* "Somewere" the right axis number is changed with the wrong one.
* Here we restore the correct values.

if ( (usage->code == 0x02) || (usage->code == 0x03) )
usage->code -= 2;
return 0;

static const struct hid_device_id tp_devices[] = {
{ HID_USB_DEVICE( 0x1bfd, 0x1688) },
{ }
MODULE_DEVICE_TABLE(hid, tp_devices);

static struct hid_driver tp_driver = {
.name = "touchpack",
.id_table = tp_devices,
.input_mapping = tp_input_mapping,
.event = tp_event,

static int tp_init(void)
return hid_register_driver(&tp_driver);

static void tp_exit(void)



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