T95 mini CPU temperature issues causing shutdowns

I have a T95 mini TV box (Tanix tx6) where I am having a issue of it reporting CPU temperatures going up to 95C + and then LibreElec shutting down the box because of this. Even when I leave the box idle and the CPU is never going over 30% utilization, eventually the temperatures creep up into the 90s. Yet if I boot the box of the Android image from the internal flash storage I do not have this problem with CPU temperatures, I even ran an Android app called CPU stress and cooler which ran all cores up to 100% for over 20 minutes and reported the temperatures and the box didn't crash or shutdown and never got to 95C +.

So I definitely think this is a software issue rather than hardware, and that either one of the OS is misreading the temperatures or Android is throttling the CPU differently to stop it overheating.

I have also tried a few Armbian builds for this box and experienced the same problem of it overheating there as well so it appears to be an issue not just with LibreElec but Linux in general.

I took the box apart and put a stack of coins on top of the cpu cooler to give it a bigger thermal mass to see if that would help keep the temperatures down but it didn't seem to make any difference it still shutdown after a while.

The image is for Tanix tx6 TV boxes and info from the build is

Ver 19.4.0 complied 2922-03-05

Additional info: I managed to find an Armbian build from 2020 (Armbian_20.07_Aw-h6-tv_focal_current_5.7.7_desktop) which didn't appear to have any CPU throttling enabled, as when I ran stress on the CPU the temperatures climbed well above 100C without the TV box crashing and seemed still stable at was reported as 125C. And it wasn't until the CPU got to 160C that it eventually caused the box to crash and reboot.

Quote from JoeAverage

it could be that the global warming took place ...

serious:

- thermal paste "worn" out ?

- cooler fans full of dust

The T95 was new in box only got it this week. And is clean inside as I have opened it up and checked the cooler and its stuck on with a thermal pad and is on there pretty tight. And even if it was dust on the cooler causing the issue it wouldn't explain why it doesn't overheat and shutdown when I run Android only on LibreElec and Armbian.

Quote from jernej

mod81 can you post clear photo of T95 PCB? One developer noticed that some boards need to have AVCC power enabled for thermal sensor to work correctly.

As requested here are photos of both sides of the PCB from my T95.

FYI I know there is no heat sink fitted on the H6 CPU on the picture, but that isn't the cause of the overheating. As it was overheating in LibreElec and Armbian before I removed the stock heat sink to fit a bigger one from a SSD cooler to see if that would make any difference to the CPU temps. But I had to take the SSD cooler off to take the pics of the PCB. (The SSD cooler did not resolve the overheating issues on LibreElec but did make it take a few minutes longer before it shutdown)

Quote from JoeAverage

is this box in general able to run LE ?

if so:

a link to an uploaded output of the logs would be good

see:

https://wiki.libreelec.tv/support/log-files

Log files as requested http://ix.io/3VHM

After some further research I found a similar problem experienced by forum member genidy.m on another Allwinner H6 box which was overheating in LibreElec but temperatures reported OK in Android.

Quote

Allwinner H6 chipset overheated, so back to android they disabled multi core and and reduced frequency to 1.4GHz, after applied this in Libreelec, temperature idle average about 60C same as android,....

Does anyone know how I can try this solution myself on LibreElec? As unfortunately genidy.m didn't elaborate on how he made those changed to LibreElec and doesn't appear to have been active on the forums since June 2021.

After some Googling I figured out how to limit my box to only 2 CPU cores on LibreElec by adding maxcpus=2 into the boot settings config file.

I have been running the box for with just the 2 cores enabled. This seems to keep the temperatures under control even when running stress-ng and maxing out the 2 cores the temps never went over 85C. There was no apparent need to clock the CPU down to 1.4ghz.

Obviously I have lost half of the CPU cores but not noticed any slowness yet because of this. I have streamed a HD video for over an hour and all seems stable with Htop reporting 25% usage on the 2 cores, and cputemps of about 68C

OP linked to below

How helpful will this be to getting LibreELEC on allwinner android boxes?

Quote from jernej

I think we should determine first if it's really thermal driver issue or is just aggressive throttling on Android that helps

I am happy to try any other settings if someone were to suggest something to try to see if it is a thermal driver issue or not. Certainly Android reports that is running on all 4 cores and ive only seen it throttle down to about 1Ghz even after a stress test running over 20 mins. Something i could never achieve on LibreElec with all 4 cores enabled it would report overheating after a few mins and shutdown.