Verdin imx8mm does not reboot after thermal trip

Hi all,

We have spotted a problem with our devices during the very hot weather where a thermal trip causes a permanent shutdown. I was expecting a reboot once the temperature cooled but that does not seem to happen. What is the expected behaviour here?

Also, is it possible to trigger the trip point in software so I don’t have to use my ‘practical setup’ :slight_smile:

Screenshot 2022-06-23 141044

Cheers

Ed

After fully cooled I checked the board and can see that the 3.3 V supply is up but the 1.8 V from the SOM is not present.
@RoccoBr @drew.tx @jaski.tx

Dear @edwaugh, how are you?

Could you please share more information about the exact version of your module?

Also, what were the test conditions that you performed? At which temperature did you set the heater? Was it inside a closed environment with a more distributed temperature or a single-point heat source as it appears to be on your picture?

Best regards,

Hi @gclaudino.tx,
The module is a Verdin imx8mm v1.1a serial 06827566. I just warm the SOM until the CPU hits its temperature trip. We have also seen the same behaviour in a temperature chamber but I don’t have one in my office to use. The heat is quite evenly distributed and builds quite slowly.

I think the main question for me is; what is the expected behaviour? I saw some documentation that said it might just be shutdown in which case behaviour is as expected and we just need to avoid that case. Do customers need to implment their own handling of over temperature conditions?

Thanks

Ed

Hello Edwaugh,

I need a bit more information on this. In fact the SOC temperature has to go below 85 c to reboot again. So that means your ambiance temp in your test might already be below 85 c but the SOC is not.
So until then the SOM should stuck in uboot. Can you check the console logs during that time for me?

Best Regards,

Matthias

Hi @matthias.tx

I can confirm cpu temperature definitely goes under 85 C without rebooting. Can you give the commands you would like for the logs, I couldn’t see anything using dmesg. Any chance you can have a try on a board you have?

Thanks

Ed

Hi @matthias.tx,
I made a log of the serial port. As you can see it trips and then I wait 10 minutes+ and CPU is cool then power cycle. It boots ok reporting a cpu temperature of 38 C but did not reboot itself.

Ed
thermal trip log.txt (6.7 KB)