Virtual Keyboard (Linux/libevdev) - sending events

[hanusek.w...@gmail.com]

Trying to implement a virtual keyboard. The program sends a keystroke event in the 5 second cycle. Its working on PC (Ubuntu Linux). The problem is that nothing is displayed on BBB.

Plaftorm Beaglebone Black, Debian Jessie:

debian@beaglebone:~$ uname -a
Linux beaglebone 4.9.9-ti-r22 #1 SMP PREEMPT Mon Feb 13 18:39:00 UTC 2017 armv7l GNU/Linux

Code:#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <string.h>
#include <linux/uinput.h>

/* emit function is identical to of the first example */

void emit(int fd, int type, int code, int val)
{
 struct input_event ie;

 ie.type = type;
 ie.code = code;
 ie.value = val;
 /* timestamp values below are ignored */
 ie.time.tv_sec = 0;
 ie.time.tv_usec = 0;

 int res = write(fd, &ie, sizeof(ie));
 printf("emit write bytes=%d fd=%d code=%d val=%d\n",res, fd, code, val);
}

int main(void)
{
 struct uinput_user_dev uud;
 int version, rc, fd;

 fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK);
 printf("fd=%d\n",fd);



 /*
 * The ioctls below will enable the device that is about to be
 * created, to pass key events, in this case the space key.
 */
 int i1 = ioctl(fd, UI_SET_EVBIT, EV_KEY);
 int i2 = ioctl(fd, UI_SET_EVBIT, EV_SYN);
 int i3 = ioctl(fd, UI_SET_KEYBIT, KEY_D);
 int i4 = ioctl(fd, UI_SET_KEYBIT, KEY_U);
 int i5 = ioctl(fd, UI_SET_KEYBIT, KEY_P);
 int i6 = ioctl(fd, UI_SET_KEYBIT, KEY_A);

// printf("ioctl = %d, %d, %d ,%d , %d, %d\n", i1,i2,i3,i4,i5,i6);

 memset(&uud, 0, sizeof(uud));
 snprintf(uud.name, UINPUT_MAX_NAME_SIZE, "uinput-keyboard");
 uud.id.bustype = BUS_HOST;
 uud.id.vendor = 0x1;
 uud.id.product = 0x2;
 uud.id.version = 1;

 write(fd, &uud, sizeof(uud));
 sleep(2);

 int i = ioctl(fd, UI_DEV_CREATE);
 printf("dev create =%d\n", i);

 sleep(2);

 /* Key press, report the event, send key release, and report again */
for(;;)
{
 emit(fd, EV_KEY, KEY_D, 1);
 emit(fd, EV_SYN, SYN_REPORT, 1);
 sleep(1);
 emit(fd, EV_KEY, KEY_D, 0);
 emit(fd, EV_SYN, SYN_REPORT, 0);

 emit(fd, EV_KEY, KEY_U, 1);
 emit(fd, EV_SYN, SYN_REPORT, 0);
 emit(fd, EV_KEY, KEY_U, 0);
 emit(fd, EV_SYN, SYN_REPORT, 0);

 emit(fd, EV_KEY, KEY_P, 1);
 emit(fd, EV_SYN, SYN_REPORT, 0);
 emit(fd, EV_KEY, KEY_P, 0);
 emit(fd, EV_SYN, SYN_REPORT, 0);

 emit(fd, EV_KEY, KEY_A, 1);
 emit(fd, EV_SYN, SYN_REPORT, 0);
 emit(fd, EV_KEY, KEY_A, 0);
 emit(fd, EV_SYN, SYN_REPORT, 0);

 sleep(5);
}
 ioctl(fd, UI_DEV_DESTROY);

 close(fd);
 return 0;
}

/dev/input/event1
   bustype : BUS_HOST
   vendor  : 0x1
   product : 0x2
   version : 1
   name    : "uinput-keyboard"
   bits ev : (null) (null)
root@beaglebone:/home/debian/KeyEvent# evtest
No device specified, trying to scan all of /dev/input/event*
Available devices:
/dev/input/event0:  tps65217_pwr_but
/dev/input/event1:  uinput-keyboard
Select the device event number [0-1]: 1
Input driver version is 1.0.1
Input device ID: bus 0x19 vendor 0x1 product 0x2 version 0x1
Input device name: "uinput-keyboard"
Supported events:
  Event type 0 (EV_SYN)
  Event type 1 (EV_KEY)
    Event code 22 (KEY_U)
    Event code 25 (KEY_P)
    Event code 30 (KEY_A)
    Event code 32 (KEY_D)
Properties:
Testing ... (interrupt to exit)
Event: time 1499869756.493690, type 1 (EV_KEY), code 32 (KEY_D), value 1
Event: time 1499869756.493690, -------------- SYN_REPORT ------------
Event: time 1499869757.494181, type 1 (EV_KEY), code 32 (KEY_D), value 0
Event: time 1499869757.494181, -------------- SYN_REPORT ------------
Event: time 1499869757.494304, type 1 (EV_KEY), code 22 (KEY_U), value 1
Event: time 1499869757.494304, -------------- SYN_REPORT ------------
Event: time 1499869757.494370, type 1 (EV_KEY), code 22 (KEY_U), value 0
Event: time 1499869757.494370, -------------- SYN_REPORT ------------
Event: time 1499869757.494434, type 1 (EV_KEY), code 25 (KEY_P), value 1
Event: time 1499869757.494434, -------------- SYN_REPORT ------------
Event: time 1499869757.494495, type 1 (EV_KEY), code 25 (KEY_P), value 0
Event: time 1499869757.494495, -------------- SYN_REPORT ------------
Event: time 1499869757.494558, type 1 (EV_KEY), code 30 (KEY_A), value 1
Event: time 1499869757.494558, -------------- SYN_REPORT ------------
Event: time 1499869757.499785, type 1 (EV_KEY), code 30 (KEY_A), value 0
Event: time 1499869757.499785, -------------- SYN_REPORT ------------
Event: time 1499869762.502378, type 1 (EV_KEY), code 32 (KEY_D), value 1
Event: time 1499869762.502378, -------------- SYN_REPORT ------------
Event: time 1499869763.225387, type 1 (EV_KEY), code 32 (KEY_D), value 0
Event: time 1499869763.225402, -------------- SYN_REPORT ------------
expected 16 bytes, got -1

[hanusek.w...@gmail.com]

I'm trying to implement a virtual keyboard. 

The program sends a keystroke event in the 5 second cycle. Its working on PC (Ubuntu Linux). The problem is that nothing is displayed on BBB.

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <linux/uinput.h>

void emit(int fd, int type, int code, int val)
{
   struct input_event ie;
   ie.type = type;
   ie.code = code;
   ie.value = val;

   /* timestamp values below are ignored */
   ie.time.tv_sec = 0;
   ie.time.tv_usec = 0;
   int res = write(fd, &ie, sizeof(ie));
   printf("emit write bytes=%d fd=%d code=%d val=%d\n",res, fd, code, val);
}


int main(void)
{

   struct uinput_user_dev uud;

   int fd;

   fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK);
   printf("fd=%d\n",fd);

   int i1 = ioctl(fd, UI_SET_EVBIT, EV_KEY);

   int i2 = ioctl(fd, UI_SET_EVBIT, EV_SYN);
   int i3 = ioctl(fd, UI_SET_KEYBIT, KEY_D);
   int i4 = ioctl(fd, UI_SET_KEYBIT, KEY_U);
   int i5 = ioctl(fd, UI_SET_KEYBIT, KEY_P);
   int i6 = ioctl(fd, UI_SET_KEYBIT, KEY_A);

   memset(&uud, 0, sizeof(uud));

   snprintf(uud.name, UINPUT_MAX_NAME_SIZE, "uinput-keyboard");

   uud.id.bustype = BUS_HOST;
   uud.id.vendor  = 0x1;
   uud.id.product = 0x2;
   uud.id.version = 1;

   write(fd, &uud, sizeof(uud));
   sleep(2);

   int i = ioctl(fd, UI_DEV_CREATE);
   printf("dev create =%d\n", i);

   sleep(2);

for(;;)
{

   emit(fd, EV_KEY, KEY_D, 1);
   emit(fd, EV_SYN, SYN_REPORT, 1);

   emit(fd, EV_KEY, KEY_D, 0);
   emit(fd, EV_SYN, SYN_REPORT, 0);
   emit(fd, EV_KEY, KEY_U, 1);
   emit(fd, EV_SYN, SYN_REPORT, 0);
   emit(fd, EV_KEY, KEY_U, 0);
   emit(fd, EV_SYN, SYN_REPORT, 0);
   emit(fd, EV_KEY, KEY_P, 1);
   emit(fd, EV_SYN, SYN_REPORT, 0);
   emit(fd, EV_KEY, KEY_P, 0);
   emit(fd, EV_SYN, SYN_REPORT, 0);
   emit(fd, EV_KEY, KEY_A, 1);
   emit(fd, EV_SYN, SYN_REPORT, 0);
   emit(fd, EV_KEY, KEY_A, 0);
   emit(fd, EV_SYN, SYN_REPORT, 0);

   sleep(5);

}
   ioctl(fd, UI_DEV_DESTROY);

   close(fd);
   return 0;
}

lsinput - ev bit are correct? :

/dev/input/event1
   bustype : BUS_HOST
   vendor  : 0x1
   product : 0x2
   version : 1
   name    : "uinput-keyboard"
   bits ev : (null) (null)

Evtest - sending event to kernel (its OK):

Plaftorm Beaglebone Black, Debian Jessie: