RPi3 /sys/class/thermal/thermal_zone0/temp not working for armv7

[Bob-le-pirate]

Dear all,

I find this bug on kernel linux-raspberrypi4 for armv7 that seems to be solved for arm64 (look at #4077).

It seems to be related only to linux-raspberrypi4 (works well with linux-raspberrypi)

# uname -a Linux raspberrypi3 5.10.79-2-raspberrypi4-ARCH #1 SMP Tue Nov 16 20:28:12 UTC 2021 armv7l GNU/Linux

# cat /sys/class/thermal/thermal_zone0/temp cat: /sys/class/thermal/thermal_zone0/temp: Argument invalide

Best regards

[pelwell]

You talk of linux-raspberrypi4 in your text but the command log shows linux-raspberrypi3 - what are these devices and what software are they running?

[Bob-le-pirate]

I use archlinux arm and the kernel is linux-raspberrypi4 for the PI 3 as it was indicated here : https://archlinuxarm.org/packages/armv7h/linux-raspberrypi4.

cat /proc/cpuinfo | grep Model Model : Raspberry Pi 3 Model B Rev 1.2

[pelwell]

This is working for me on a rev 1.2 3B using our kernel build (from bcm2709_defconfig):

pi@raspberrypi:/sys/class/thermal/thermal_zone0$ cd
pi@raspberrypi:~$ cat /sys/class/thermal/thermal_zone0/temp
46698
pi@raspberrypi:~$ uname -a
Linux raspberrypi 5.10.79-v7+ #1487 SMP Tue Nov 16 12:24:24 GMT 2021 armv7l GNU/Linux

@Dark-Sky May have some insight into the difference with the Arch kernel.

[Dark-Sky]

Although most of our programs are from arch-arm I build my kernels always starting with RPi's _defconfig's as a base and add what people want for extra modules. Looking at arch-arms's config/config8 with meld it looks like they need to enable CONFIG_BCM2835_THERMAL=y in their config.

[pelwell]

Thanks!

[Bob-le-pirate]

After updating to last kernel 5.10.81-1-raspberrypi4-ARCH no evolution : /sys/class/thermal/thermal_zone0/temp still not working. Looking in linux-raspberrypi4/config8, CONFIG_BCM2835_THERMAL=y seems to be enabled but it doesn't work.

[Dark-Sky]

Your OP infers you are using 32bit kernel not 64bit. If that is true you need to be looking in this config: https://archlinuxarm.org/packages/armv7h/linux-raspberrypi4/files/config

You need to inform them to enable this if you are using linux-raspberrypi4 for 32bit for your RPi3:

CONFIG_BCM2835_THERMAL=y

[Bob-le-pirate]

Thank you Dark-Sky, you're right I'm using 32 bits kernel on my RPI3. @graysky2, can you update linux-raspberrypi4/config to modify

- # CONFIG_BCM2835_THERMAL is not set 
+ CONFIG_BCM2835_THERMAL=y

If necessary I can write a pull request.

[pelwell]

It sounds like this problem is understood so I'm ducking out. Please close the issue when you are ready.

[graysky2]

@Bob-le-pirate - Please try 5.10.81-2 and report back. Might be faster if you build it yourself, the builders are working on a queue.

[Bob-le-pirate]

Thank you @graysky2, I try to build (first time for me), but I have an error with file 0001-Make-proc-cpuinfo-consistent-on-arm64-and-arm.patch I write the content of the file. May be I made a mistake ?

[graysky2]

Just clone the repo or download the zip snapshot. The build of the kernel was successful. Is your mirror up to date?

[Bob-le-pirate]

Mirror is not up to date, please can you give me the address where I can download the snapshot ?

[Bob-le-pirate]

Thank you @graysky2, last kernel core/linux-rpi 5.10.81-3 solve the problem