multi-touch-dev team mailing list archive

[peng zhang <zhang.austin@xxxxxxxxx>]

Hi, folks,

I have a simple app which emulate multitouch events by send continous MT
event to /dev/input/eventX (that file related with real touch device.), but
after a while, that would lead to the X crash.
Even I already reduce the frequency to 3 times per second, or even one per
second, those events sent to /dev/input/eventX as below (send the whole
sequence 3/s or 1/s and wait for several mins):

/* emulate finger 1*/
event.type = EV_ABS;
event.code = ABS_MT_TRACKING_ID;
event.value = 1;
write(fd, &event, sizeof(struct input_event));

event.type = EV_ABS;
event.code = ABS_MT_POSITION_X;
event.value = 1000;
write(fd, &event, sizeof(struct input_event));

event.type = EV_ABS;
event.code = ABS_MT_POSITION_Y;
event.value = 1000;
write(fd, &event, sizeof(struct input_event));

event.type = EV_SYN;
event.code = SYN_MT_REPORT;
event.value = 0;
write(fd, &event, sizeof(struct input_event));

/* emulate finger 2*/
...

event.type = EV_SYN;
event.code = SYN_REPORT;
event.value = 0;
write(fd, &event, sizeof(struct input_event));

I can read back those events from the /dev/input/eventX by evtest.

After several mins (at most 15 mins), the X crash with many info in log
like:
[  3967.109] (EE) libmtdev sent SYN_MT_REPORT(EE) libmtdev sent
SYN_MT_REPORT(EE)
(many many "(EE) libmtdev sent SYN_MT_REPORT").

Some backtrace like:
Fatal server error:
[  4054.156] Wrong event type 0.
 and
[  4054.194] 0: /usr/bin/Xorg (xorg_backtrace+0x3c) [0x809c4cc]
[  4054.194] 1: /usr/bin/Xorg (0x8047000+0x64396) [0x80ab396]
[  4054.195] 2: (vdso) (__kernel_rt_sigreturn+0x0) [0xb777640c]
[  4054.195] 3: /usr/lib/libmtdev.so.1 (mtdev_empty+0xd) [0xb5cacc0d]
[  4054.195] 4: /usr/lib/libmtdev.so.1 (mtdev_get+0x63) [0xb5cacce3]


But interface with touchpanel with real fingers doesn't lead to this issue.
Anything wrong with above emulation steps?