Zephyr Power Management PM_STATE_SOFT_OFF

RE: Zephyr Power Management PM_STATE_SOFT_OFF

Michal — Mon, 08 Aug 2022 12:32:25 GMT

I understand. Running everything in a lower priority thread than the workqueue is probably the easiest solution.

Best regards,
Michal

RE: Zephyr Power Management PM_STATE_SOFT_OFF

akaun — Thu, 04 Aug 2022 04:55:30 GMT

I am using driver for max17262 as a base from zephyr drivers. The only thing I did was added a timer for a trigger, so it reads values every 5 minutes by using a workqueue.

I will just make sure everything is running in a thread and that powerdown will have highest priority. Thank you.

RE: Zephyr Power Management PM_STATE_SOFT_OFF

Michal — Mon, 01 Aug 2022 07:20:36 GMT

Hello,
Could you tell me the names of (or send me the links to) the driver and example that you have used? I could take a look at those.
There should be nothing wrong with doing it via a workqueue, but you have to be wary of the thread priorities, especially with the main() thread if you're using that.

Best regards,
Michal

RE: Zephyr Power Management PM_STATE_SOFT_OFF

akaun — Fri, 29 Jul 2022 22:16:03 GMT

OK, I understand that, I have a battery gauge thats periodically checking battery level and if battery is low I need to shut down the system. Per driver documentation its best to have any trigger return through a workqueue. But it will never shut down. Should I just avoid using workqueue in driver trigger implementation then?

As far as k_sleep in power_down, I am not sure why its there, thats how it is written in the SDK example so I figured it needs to be there.

RE: Zephyr Power Management PM_STATE_SOFT_OFF

Michal — Fri, 29 Jul 2022 14:14:13 GMT

Hello,

Running a workqueue thread is not like just calling a function. It is spawning a separate thread. I would recommend reading the documentation about Workqueque Threads (and maybe threads in zephyr in general).

The main() thread by default has the highest priority. More about that HERE
Your workqueue thread will have lower priority and that's why it will not work.

If you suspend the main thread, for example by running k_sleep(K_FOREVER); then your workqueue thread will run properly.
You could also let the main() return.

Also, the k_sleep in power_down will not work when run properly, since it happens after switching the state to PM_STATE_SOFT_OFF which equals to the SYSTEM OFF mode.

Best regards,

Michal