Pre-note:
I wrote this mail for the linux kernel development list, and realized,
once finished writing the mail, that linux-input would be a better place
to post this. I searched the archives and found a few mails that I
missed before starting to write this driver and mail. So I understand
that some work is already going on, and some might require changes to
the HID system?
Anyway... I hope my mail may still be of some help to the process. My
(proof of concept) driver is functional for the Acer T230H. I am
currently using it to my great amusement :-D
Hi all of you,
This mail is in regard to an Acer T230H touchscreen, and aimed to
- Daniel Ritz, who is the maintainer of the usbtouchscreen kernel module
- Alex Custov, whom's friend also have this screen
- Linux kernel input list
You are all on the CC, because I hope that some of you can and will help
me finish the driver for this screen.
So... I got this screen, and in Linux it is recognized only as
/dev/hidraw0 and /dev/usb/hiddev0 devices. I really wanted to get it to
work, so I sat down and analyzed the output, and wrote a small program
as a proof-of-concept driver.
Once I got this working, I went to the kernel source of the
usbtouchscreen driver, and tried to expand it to include support for
this screen at kernel space - but failed. Ii could not get the driver to
properly register my screen - no matter what I did, it always ended up
as the hiddev and hidraw devices. (And kernel messages were not very
helpful).
Anyway... I have never hacked the kernel source before, and - due to
lack of time - I now give up, and hope some of you will take your time
to include my code in the driver.
I have attached my sample driver. It opens the hidraw device, reads
data, parses it, and passes it on to Xorg (via XTest). The parsing is
done in the decodeData()-function. The rest is done in mail(). I hope I
have written enough comments for my code to be readable by you.
What I hope you can do, is
- Expand the usbtouchscreen driver to register the screen
(vendor:product id 0408:3000)
- Copy the decodeData function and pass the raw data to it.
- Send the parsed data to the kernel event interface - hopefully with
some sensible mappings of the axes.
To Alex: Until support is in the kernel, you should be able to use my
program get the screen up'n'running.
The screen supports two fingers touch. I have implemented the following
functionality:
- One finger press: Left click'n'drag.
- Two fingers press:
- Center point of fingers are calculated.
- Distance between fingers is calculated.
- If one finger is released between center or distance has changed
over a certain threshold, a right click'n'drag is initiated.
- If center point is moved beyond a threshold, scrolling mode is
initiated. Vertical and horizontal scroll is affected by the movement of
the center. Relative coordinates.
- If distance is changed beyond a threshold, well mode is initiated.
Wheel is turned to the change of distance. Relative movement.
- If both fingers are released before any mode is initiated, a right
click and release is performed.
The threshold is currently hardcoded into the program. I know this is
ugly - but again (due to my lack of knowledge on kernel programming), I
don't know how to make this a parameter that can be changed. (I expect
one need to make an interface, that HAL can connect to, and in the end,
someone need to make a nice gui program to change the settings... but I
know this is probably further than you want to go right now. I would be
glad, if you in kernel space, would make the necessary preparations for
it to be possible in the future.)
Note, that my sample program opens the file /dev/input/t230h, which I on
my system have set up to be a symlink to /dev/hidraw0. If you do not
want to do this just for testing the driver, just change the input file.
To Alex: I got a udev-rule, which you might find handy too:
SUBSYSTEM=="hidraw", ATTRS{manufacturer}=="Acer",
ATTRS{product}=="T230H", SYMLINK+="input/t230h", GROUP="plugdev"
I have attached the output from lsusb about the device - in case you
think it is useful.
I hope that one of you will take your time to include this into the
kernel driver. A big thanks to him or her :-) I will of course be happy
with what help I can offer - but I have not got much time to do it. The
screen is actually for my parents, and I will set it up for them when I
visit them in the Christmas holidays.
Best regards
Jørn
/**
* Proof-of-concept driver for the Acer T230H touchscreen.
* By JVC, December 2009.
*/
#include <X11/Xlib.h>
#include <X11/extensions/XTest.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <strings.h>
Display *display;
Window winRoot;
#define ACER_T230H_GARB_0 0 /* Was 0 for a long time, but suddenly changed to 247 */
#define ACER_T230H_GARB_1 1 /* Always 1. Sync ? Don't quite trust it - also thought that the above was sync - but proved wrong after a whole day's use... */
#define ACER_T230H_GOT_DATA 2 /* 0 on no data - 7 when finger pressed - 4 when releasing finger (and last data input from that source) */
#define ACER_T230H_IS_POINTER 3 /* 0 if this finger is the (mouse) pointer - see note */
#define ACER_T230H_POS_X_LSB 4
#define ACER_T230H_POS_X_MSB 5
#define ACER_T230H_POS_Y_LSB 6
#define ACER_T230H_POS_Y_MSB 7
#define ACER_T230H_GOT_DATA_2ND 8 /* 0 on no data - 7 when finger pressed - 4 when releasing finger (and last data input from that source) */
#define ACER_T230H_IS_POINTER_2ND 9 /* 0 if this finger is the (mouse) pointer - see note */
#define ACER_T230H_POS_2ND_X_LSB 10
#define ACER_T230H_POS_2ND_X_MSB 11
#define ACER_T230H_POS_2ND_Y_LSB 12
#define ACER_T230H_POS_2ND_Y_MSB 13
#define ACER_T230H_TOUCH_NUM_FINGERS 14 /* 0 (just when putting finger down) - 2 */
/**
* Note: The pointer finger will normaly be the first finger pressed.
* But if the two fingers are pressed, and the first finger is lifted,
* the second finger will receive the pointer flag - AND the data from
* the second finger is automatically copied to the first.
*/
#define BUTTON_LEFT 1
#define BUTTON_MIDDLE 2
#define BUTTON_RIGHT 4
struct ev_data {
int x, y, button, scrollH, scrollV, wheel;
};
#define MOVEMENT_THRESHOLD 40 /* Movement threshold in pixels for mode 2. If finger is released before this threshold has been moved => right finger click. Else wheel or scrool. */
bool decodeData(unsigned char pkt[], struct ev_data *ev) {
static int mode = 0; /* mode/buttons pressed. 0 => no buttons. 1 => left finger. 2 => two fingers => multi functionality */
static unsigned int last_x = 0;
static unsigned int last_y = 0;
static unsigned int last_d = 0;
unsigned int x, y, x2, y2, tmpd, tmpx, tmpy;
int raisingFingerCount = 0;
bool releaseOne; /* True if a finger is released, and the other is still pressed */
bool releaseFull; /* True if a finger is released, and no more fingers are pressed */
static bool pause = false; /* When scrolling or using wheel - one finger can be released to pause action */
/*
static int lastMode = 0;
if(mode != lastMode) {
fprintf(stderr, "Entering mode %d\n", mode);
lastMode = mode;
}
*/
/* packets should start with sync */
/* Apparently the first byte was not sync anyhow... it changed from 0 to 247 for no apparent reason
if (pkt[ACER_T230H_SYNC_0] != 0 || pkt[ACER_T230H_SYNC_1] != 1) {
mode = 0;
return false;
}
*/
/* Zero out buttons and relative axis */
ev->button = 0;
ev->scrollH = 0;
ev->scrollV = 0;
ev->wheel = 0;
/* Calculate position and fingers released - always available */
x = (pkt[ACER_T230H_POS_X_MSB] << 8) | pkt[ACER_T230H_POS_X_LSB]; if(x > 1919) x = 1919;
y = (pkt[ACER_T230H_POS_Y_MSB] << 8) | pkt[ACER_T230H_POS_Y_LSB]; if(y > 1079) y = 1079;
x2 = (pkt[ACER_T230H_POS_2ND_X_MSB] << 8) | pkt[ACER_T230H_POS_2ND_X_LSB]; if(x2 > 1919) x2 = 1919;
y2 = (pkt[ACER_T230H_POS_2ND_Y_MSB] << 8) | pkt[ACER_T230H_POS_2ND_Y_LSB]; if(y2 > 1079) y2 = 1079;
releaseOne = (pkt[ACER_T230H_GOT_DATA] == 4 && pkt[ACER_T230H_GOT_DATA_2ND] == 7) || (pkt[ACER_T230H_GOT_DATA_2ND] == 4 && pkt[ACER_T230H_GOT_DATA] == 7);
releaseFull = (pkt[ACER_T230H_GOT_DATA] == 4 && pkt[ACER_T230H_GOT_DATA_2ND] != 7) || (pkt[ACER_T230H_GOT_DATA_2ND] == 4 && pkt[ACER_T230H_GOT_DATA] != 7);
/* State machine. States:
* 0: No finger pressed. 'Idle'. Next states: 1, 2
* 1: One finger pressed: Left finger. Next states: 0.
* 2: Multi-touch mode. Function not decided. Next states: 3, 4, 5.
* 3: Multi.touch mode. Right click. Next states: 0.
* 4: Multi.touch mode. Scroll. Next states: 0.
* 5: Multi.touch mode. Wheel. Next states: 0.
*
* In addition to next states above, it is also valid to have no state change.
*/
if(pkt[ACER_T230H_TOUCH_NUM_FINGERS] == 0) { /* Reset to mode zero */
mode = 0;
last_x = x;
last_y = y;
ev->x = x;
ev->y = y;
return true;
}
else if(mode == 0) { /* 'Idle' */
if(pkt[ACER_T230H_TOUCH_NUM_FINGERS] == 1) { /* Single finger => left finger */
mode = 1;
ev->x = x;
ev->y = y;
ev->button = BUTTON_LEFT;
return true;
}
if(pkt[ACER_T230H_TOUCH_NUM_FINGERS] == 2) { /* Two fingers => Multi mode */
mode = 2;
last_x = (x + x2) >> 1; /* Becomes center coordinates */
last_y = (y + y2) >> 1; /* Becomes center coordinates */
last_d = (unsigned int) sqrtf((x - x2) * (x - x2) + (y - y2) * (y - y2));
ev->x = x;
ev->y = y;
return true;
}
mode = 0;
return false; /* Unknown value for ACER_T230H_TOUCH_NUM_FINGERS */
}
else if(mode == 1) { /* Left finger */
if(releaseFull) { /* Exit mode */
mode = 0;
return true;
}
if(pkt[ACER_T230H_TOUCH_NUM_FINGERS] == 1) { /* Keep left finger pressed */
ev->x = x;
ev->y = y;
ev->button = BUTTON_LEFT;
return true;
}
if(pkt[ACER_T230H_TOUCH_NUM_FINGERS] == 2) {
ev->x = x;
ev->y = y;
if(releaseOne) /* Had two fingers, but going back to one */
ev->button = BUTTON_LEFT;
else /* Two fingers */
ev->button = BUTTON_LEFT | BUTTON_RIGHT;
return true;
}
/* Error - no fingers pressed ? */
mode = 0;
return false;
}
else if(mode == 2) { /* Multi touch - undecided function */
tmpx = (x + x2) >> 1; /* Center coordinates */
tmpy = (y + y2) >> 1; /* Center coordinates */
tmpd = (unsigned int) sqrtf((x - x2) * (x - x2) + (y - y2) * (y - y2));
/* Releasing two fingers => Make a right click and go back to mode 0 */
if(releaseFull) {
mode = 0;
ev->x = tmpx;
ev->y = tmpy;
ev->button = BUTTON_RIGHT;
return true;
}
/* Wheel moved more than threshold => wheel mode */
if(abs(tmpd - last_d) > MOVEMENT_THRESHOLD) {
mode = 5;
ev->x = tmpx;
ev->y = tmpy;
ev->wheel = tmpd - last_d;
last_d = tmpd;
return true;
}
/* Center moved more than threshold => scroll mode */
if((unsigned int) sqrtf((last_x - tmpx) * (last_x - tmpx) + (last_y - tmpy) * (last_y - tmpy)) > MOVEMENT_THRESHOLD) {
ev->scrollH = tmpx - last_x;
ev->scrollV = tmpy - last_y;
last_x = tmpx;
last_y = tmpy;
mode = 4;
return true;
}
/* No movement exceeded threshold - and release finger => right click */
if(releaseOne) {
mode = 3;
ev->x = tmpx;
ev->y = tmpy;
ev->button = BUTTON_RIGHT;
}
/* No decicion yet */
return true;
}
else if(mode == 3) { /* Multi touch - right button */
if(releaseFull) {
mode = 0;
return true;
}
/* Only accept one finger press */
if(pkt[ACER_T230H_TOUCH_NUM_FINGERS] == 1) {
ev->x = x;
ev->y = y;
ev->button = BUTTON_RIGHT;
return true;
}
/* No movement - but keep button pressed */
ev->button = BUTTON_RIGHT;
return true;
}
else if(mode == 4) { /* Multi touch - scroll */
if(releaseFull) {
mode = 0;
return true;
}
/* Only accept two fingers press */
if(pkt[ACER_T230H_TOUCH_NUM_FINGERS] == 2) {
tmpx = (x + x2) >> 1; /* Center coordinates */
tmpy = (y + y2) >> 1; /* Center coordinates */
if(!pause) {
ev->scrollH = tmpx - last_x;
ev->scrollV = tmpy - last_y;
}
pause = false;
last_x = tmpx;
last_y = tmpy;
return true;
}
/* Silently do nothing */
pause = true;
return true;
}
else if(mode == 5) { /* Multi touch - wheel */
if(releaseFull) {
mode = 0;
return true;
}
/* Only accept two fingers press */
if(pkt[ACER_T230H_TOUCH_NUM_FINGERS] == 2) {
tmpd = (unsigned int) sqrtf((x - x2) * (x - x2) + (y - y2) * (y - y2));
tmpx = (x + x2) >> 1; /* Center coordinates */
tmpy = (y + y2) >> 1; /* Center coordinates */
ev->x = tmpx;
ev->y = tmpy;
if(!pause)
ev->wheel = tmpd - last_d;
last_d = tmpd;
pause = false;
return true;
}
/* Silently do nothing */
pause = true;
return true;
}
/* Should not happen */
mode = 0;
return false;
}
int main(int argc, char *argv[]) {
FILE *hidraw = fopen("/dev/input/t230h", "rb");
if(hidraw == NULL) {
fprintf(stderr, "Could not open /dev/input/t230h. Exiting.\n"); /* /dev/input/t230h is symlink to /dev/hidraw? */
return 1;
}
unsigned char buf[15];
bool left = false, right = false;
struct ev_data ev;
bzero(&ev, sizeof(ev));
int wheelCount = 0;
int scrollHCount = 0;
int scrollVCount = 0;
while(1) {
int s = fread(buf, sizeof(char), 15, hidraw);
if(s == 0) { /* End of stream - perhaps unplugged device */
fprintf(stderr, "End of stream. Perhaps the device is unplugged?\n"); /* /dev/input/t230h is symlink to /dev/hidraw? */
fclose(hidraw);
return 0;
}
if(s != 15) {
fprintf(stderr, "Expected 15 bytes. Got %d instead. Skipping.\n", s);
continue;
}
/*
for(int i=0; i < 15; i++)
printf("%4u ", (unsigned int) buf[i]);
printf("\n");
*/
if(decodeData(buf, &ev)) {
//printf("Mouse pos: %4d x %4d - Scroll: %4d x %4d - Wheel: %4d - Button: %d\n", ev.x, ev.y, ev.scrollH, ev.scrollV, ev.wheel, ev.button);
display = XOpenDisplay(0);
if(display == NULL) {
fprintf(stderr, "Could not open display. Exiting.\n");
return 1;
}
XTestFakeMotionEvent(display, -1, ev.x, ev.y, 0);
if(((ev.button & BUTTON_LEFT)) && !left)
XTestFakeButtonEvent(display, 1, true, 0);
else if(((ev.button & BUTTON_LEFT) == 0) && left)
XTestFakeButtonEvent(display, 1, false, 0);
left = (bool) (ev.button & BUTTON_LEFT);
if(((ev.button & BUTTON_RIGHT)) && !right)
XTestFakeButtonEvent(display, 3, true, 0);
else if(((ev.button & BUTTON_RIGHT) == 0) && right)
XTestFakeButtonEvent(display, 3, false, 0);
right = (bool) (ev.button & BUTTON_RIGHT);
#define MOVE_SPEED 66
wheelCount += ev.wheel;
if(wheelCount > MOVE_SPEED) {
// printf("Wheel up\n");
XTestFakeButtonEvent(display, 4, true, 0);
XTestFakeButtonEvent(display, 4, false, 5);
wheelCount -= MOVE_SPEED;
}
if(wheelCount < -MOVE_SPEED) {
// printf("Wheel down\n");
XTestFakeButtonEvent(display, 5, true, 0);
XTestFakeButtonEvent(display, 5, false, 5);
wheelCount += MOVE_SPEED;
}
scrollHCount += ev.scrollH;
if(scrollHCount > MOVE_SPEED) {
// printf("Scroll H left\n");
XTestFakeButtonEvent(display, 6, true, 0);
XTestFakeButtonEvent(display, 6, false, 5);
scrollHCount -= MOVE_SPEED;
}
if(scrollHCount < -MOVE_SPEED) {
// printf("Scroll H right\n");
XTestFakeButtonEvent(display, 7, true, 0);
XTestFakeButtonEvent(display, 7, false, 5);
scrollHCount += MOVE_SPEED;
}
scrollVCount += ev.scrollV;
if(scrollVCount > MOVE_SPEED) {
// printf("Scroll V up\n");
XTestFakeButtonEvent(display, 4, true, 0);
XTestFakeButtonEvent(display, 4, false, 5);
scrollVCount -= MOVE_SPEED;
}
if(scrollVCount < -MOVE_SPEED) {
// printf("Scroll V down\n");
XTestFakeButtonEvent(display, 5, true, 0);
XTestFakeButtonEvent(display, 5, false, 5);
scrollVCount += MOVE_SPEED;
}
XCloseDisplay(display);
}
else { /* Error - release buttons */
if(left) {
XTestFakeButtonEvent(display, 1, false, 0);
left = false;
}
if(right) {
XTestFakeButtonEvent(display, 3, false, 0);
right = false;
}
}
}
}
Bus 006 Device 007: ID 0408:3000 Quanta Computer, Inc.
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x0408 Quanta Computer, Inc.
idProduct 0x3000
bcdDevice 0.00
iManufacturer 1 Acer
iProduct 2 T230H
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 34
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 0 No Subclass
bInterfaceProtocol 0 None
iInterface 0
** UNRECOGNIZED: 09 21 10 01 00 01 22 d2 00
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 8
Device Status: 0x0000
(Bus Powered)
