pigpio: gpioTerminate and interrupt callbacks

If gpioTerminate is called when interrupt callbacks are active the system is left in an inconsistent state. In order to get the system back into a consistent state a reboot is required.

This can be seen with the following program:

#include <unistd.h>
#include <stdio.h>
#include <pigpio.h>

#define GPIO 4

void isr(int gpio, int level, uint32_t tick) {
  printf("isr - gpio: %d, level: %d\n", gpio, level);
}

int main(int argc, char *argv[]) {
  int version;

  if ((version = gpioInitialise()) < 0) {
    return -1;
  }

  printf("version: %d\n", version);

  if (gpioSetISRFunc(GPIO, EITHER_EDGE, 200, isr) != 0) {
    return -1;
  }

  sleep(1);

  gpioTerminate();
}

The first run of this program outputs the following:

version: 39
isr - gpio: 4, level: 2
isr - gpio: 4, level: 2
isr - gpio: 4, level: 2
isr - gpio: 4, level: 2
2015-10-31 07:47:46 sigHandler: Unhandled signal 11, terminating

The second run outputs the following:

2015-10-31 07:47:50 initMboxBlock: init mbox zaps failed

The first run of the program appears to leave the system in an inconsistent state that prevents the program from running successfully a second time.

If the test program is modified to disable the interrupt before calling gpioTerminate everything functions correctly and the program can be run mutiple times successfully.

#include <unistd.h>
#include <stdio.h>
#include <pigpio.h>

#define GPIO 4

void isr(int gpio, int level, uint32_t tick) {
  printf("isr - gpio: %d, level: %d\n", gpio, level);
}

int main(int argc, char *argv[]) {
  int version;

  if ((version = gpioInitialise()) < 0) {
    return -1;
  }

  printf("version: %d\n", version);

  if (gpioSetISRFunc(GPIO, EITHER_EDGE, 200, isr) != 0) {
    return -1;
  }

  sleep(1);

  if (gpioSetISRFunc(GPIO, EITHER_EDGE, 0, NULL) != 0) {
    return -1;
  }

  gpioTerminate();
}

Would it not be better if gpioTerminate disabled interrupts and unexported the appropriate gpios instead of requiring gpioSetISRFunc to be called to perform the task?

About this issue

Original URL
State: closed
Created 9 years ago
Comments: 15 (5 by maintainers)

Most upvoted comments

@Willjobs94 I just tried out the sample code with three LEDs and everything functioned as expected. The following line was removed from the sample code as socket is not defined:

socket.emit('setRGB', parsedRGB);

The output of several test runs can be seen below. During some test runs ctrl-c was hit to see if it had any effect, but it didn’t. Everything still functioned correctly in subsequent test runs.

root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
^C2016-03-30 18:07:09 sigHandler: Unhandled signal 2, terminating

root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
^C2016-03-30 18:07:25 sigHandler: Unhandled signal 2, terminating

root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
^C2016-03-30 18:07:36 sigHandler: Unhandled signal 2, terminating

root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
root@raspberrypi:/home/pi/pigpio# node test.js 
rgb TEst
creating rgb object
setting color
root@raspberrypi:/home/pi/pigpio#

Above you mention the following:

when I stop my scripts and run it again, I loose gpio control until I reboot the system

What exactly does this mean?

Is it the case that the program runs successfully exactly once and then never again?

Additional questions:

What version of the pigpio C library is being used (grep PIGPIO_VERSION /usr/local/include/pigpio.h)?
What version of the pigpio Node.js package is being used?
What version of Node.js is being used?
What version of Rasobian is being used?

fivdi on Mar 30, 2016