Why can't I stop this timer

[duxinglang]

I defined a timer and start the timer when application open gps, it can prevent the timeout of star search failure;  When the gps search star successful, I will turn off the timer.  However, when the program was running, I found that after the GPS positioning was successful, I called the function to stop the timer in advance, but the timer did not actually stop running. After the time was up, it still triggered the overdue function. Could you tell me what caused this?  

static void APP_Ask_GPS_Data_timerout(struct k_timer *timer_id);
K_TIMER_DEFINE(app_wait_gps_timer, APP_Ask_GPS_Data_timerout, NULL);

void APP_Ask_GPS_Data_timerout(struct k_timer *timer)
{
	u8_t str_gps[20] = {0};
	u32_t tmp1;
	double tmp2;

	LOG_INF("[%s] begin\n", __func__);
	
	app_gps_off = true;

	APP_GPS_data_send(false);
}

void APP_Ask_GPS_Data(void)
{
	static u8_t time_init = false;

	if(!app_gps_on)
	{
		LOG_INF("[%s] begin\n", __func__);
		
		app_gps_on = true;
		k_timer_start(&app_wait_gps_timer, K_MSEC(3*60*1000), NULL);
	}
}

..
	case GPS_EVT_PVT_FIX:
		LOG_INF("GPS_EVT_PVT_FIX");
		sprintf(tmpbuf, "Longitude:%f, Latitude:%f\n", evt->pvt.longitude, evt->pvt.latitude);
		LOG_INF("%s",tmpbuf);
		
		memcpy(&gps_pvt_data, &(evt->pvt), sizeof(evt->pvt));
		if(k_timer_remaining_get(&app_wait_gps_timer) > 0)
		{
			LOG_INF("[%s] stop gps wait timer\n", __func__);
			k_timer_stop(&app_wait_gps_timer);
		}

		break;
..

[Didrik Rokhaug]

Hi,

This code works for me, using NCS v1.5.0:

#include <zephyr.h>
#include <kernel.h>

void timer_handler(struct k_timer *timer) {
	printk("Timer handler\n");
}

K_TIMER_DEFINE(my_timer, timer_handler, NULL);

void main(void)
{
	printk("Timer stop test\n");
	printk("Starting timer\n");
	k_timer_start(&my_timer, K_MSEC(300), K_NO_WAIT);
	printk("Stopping timer\n");
	k_timer_stop(&my_timer);
	printk("Timer stopped\n");
}

Are you sure k_timer_stop() is called, or that the timer hasn't been restarted?

Best regards,

Didrik

[duxinglang]

Thanks for your help, I found that it seems to be the problem caused by multiple threads, actually in a single thread, the timer works correctly.  So, this raises the question of how do I pass messages between different threads?  I have three work queues started in my current application, and I find that in addition to interruptions, I often have problems transferring messages between them.  

[Didrik Rokhaug]

Hi, and sorry for the late answer.

Why do you need three workqueues? In most cases, one should be enough (just make sure you avoid deadlocks by having one task wait for another).

As for how to send messages between threads, I recommend you read through Zephyr's documentation about the different kernel services: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/reference/kernel/index.html#

There you will find different solutions ranging from simple semaphores, to more complex solutions such as message queues, mailboxess and pipes.

[duxinglang]

Hi,thanks for you reply! I will look at the documents.

I have tried to perform these tasks in a workqueue, but the fact is that must be finished before a task processing will be the next mission, in many cases, our application needs to start at the same time, for example when connected to the network to send data, also will be required to open the GPS, in order to avoid this kind of waiting, so I didn't set up three job queue.