# Unknown oid 'hw.acpi.thermal'



## MYXOMOP (Feb 3, 2019)

I was wondering what would be a possible reason to get the message `unknown oid 'hw.acpi.thermal'` as response to
`sysctl hw.acpi.thermal`...

I'm running FreeBSD 12 on a Xeon rig and ACPI running, so I expect to see also the thermals. But this is not the case. The thermals seem to be missing. What might be the reason? Can I control this?

Any help greatly appreciated.


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## ralphbsz (Feb 3, 2019)

Seems that your motherboard, ACPI implementation and FreeBSD don't cooperate to give you temperatures as a sysctl.   If you search this forum, you'll find that this is a common problem. Try two things: "sysctl -a | grep hw.acpi", to see what's there.  And look in all of your dmesg boot output.  This may be hard to debug or fix.


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## rigoletto@ (Feb 4, 2019)

Try `sysctl dev.cpu | grep temperature`. If not `kldload coretemp`.


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## MYXOMOP (Feb 4, 2019)

Hi *ralphbsz*, 

Maybe some more information about my goal: the machine is a HP z820 desktop with 2 Xeon CPUs and the fans (CPU and chassis) are driving me mad. Under Windows/Linux the fans are much quieter. I know, that FreeBSD is inherently an excellent server platform. In addition to that I wanted to test its capabilities as a desktop workstation. So far there are some excellent results as in my Radeon RX 580 is supported and I can run Plasma, but there are also some challenges, such as the fan loudness. Before I throw in the towel, I'd like to try to fix the issue with the tools the OS provides. As such, I think that ACPI is the first pitstop. Since the man of `acpi_thermal` as well as searching for the specific issue (`unknown oid 'hw.acpi.thermal'`) got me nowhere, I decided to ask around.

There is a lot coming from the `sysctl -a | grep hw.acpi` command, but none of it contains "thermal". 


```
hw.acpi.cpu.cx_lowest: C1
hw.acpi.reset_video: 0
hw.acpi.handle_reboot: 1
hw.acpi.disable_on_reboot: 0
hw.acpi.verbose: 0
hw.acpi.s4bios: 0
hw.acpi.sleep_delay: 1
hw.acpi.suspend_state: S3
hw.acpi.standby_state: NONE
hw.acpi.lid_switch_state: NONE
hw.acpi.sleep_button_state: S3
hw.acpi.power_button_state: S5
hw.acpi.supported_sleep_state: S3 S4 S5
```


*rigoletto@*, coretemp is loaded and I can use it to read the temperature of all cores. They are quite low actually (32-39°C). It is interesting to know about the temps. However my main challenge remains.

I'd be very interested in why acpi doesn't contain any thermal values and how I can debug it. Also, I'd be completely open to any other suggestions on how to reduce fan noise level while idle.

Cheers,
*MYXOMOP*


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