imx8mq TMU(thermal monitor unit) temperature value not updating issue

[wenyong]

Dear NXP engineers, 

We have seen issues with the thermal monitor unit, where the value read from the following node would not change after Linux runs for a while:

cat /sys/class/thermal/thermal_zone0/temp

The TMU driver registers this node. When this issue occurs, the raw value from the TMU's 0x100/0x110/0x120 registers also doesn't update. 

So it doesn't look like a software logic issue. 

I also dump the TMU registers when TMU is still updating and when TMU is not updating temperature values. 

Could you give us any guidance?

Thanks,

Wenyong

[Zhiming_Liu]

Hi,

Please refer answer in this thread.

Solved: Re: imx8mq kernel ignoring devicetree settings for thermal trips - NXP Community

Best Regards,
Zhiming

[wenyong]

Hi ZhiMing, 

The issue described in the link is not the same as the issue I have. 

The issue I have is that the "temperature value" read from TMU is not updated any more. It's different from alert/critical temperature settings in the device tree. 

Thanks,

Wenyong

[Zhiming_Liu]

Hi,

I did test on EVK while running the GPU rendering program. From the test results, it is not an internal problem with the i.mx8mq. The heatsink reaches some kind of equilibrium, so the temperature is constant, and when I stop the test program, the temperature is updated immediately. The attachment is test log.

Best Regards,
Zhiming