Error in writemsr

[dgllghr]

Dell XPS 9575 Intel i7-8705G Fedora 30 (installed through https://copr.fedorainfracloud.org/coprs/abn/throttled/ so apologies if this is an issue with the package)

I am hitting the following error when running throttled as a systemd service.

May 13 13:30:20 federation systemd[1]: Started Stop Intel throttling.
May 13 13:30:20 federation throttled[22393]: [I] Detected CPU architecture: Intel Kaby Lake (R)
May 13 13:30:20 federation throttled[22393]: [I] Loading config file.
May 13 13:30:20 federation throttled[22393]: [I] Starting main loop.
May 13 13:30:20 federation throttled[22393]: Exception in thread Thread-1:
May 13 13:30:20 federation throttled[22393]: Traceback (most recent call last):
May 13 13:30:20 federation throttled[22393]:   File "/usr/lib64/python3.7/threading.py", line 917, in _bootstrap_inner
May 13 13:30:20 federation throttled[22393]:     self.run()
May 13 13:30:20 federation throttled[22393]:   File "/usr/lib64/python3.7/threading.py", line 865, in run
May 13 13:30:20 federation throttled[22393]:     self._target(*self._args, **self._kwargs)
May 13 13:30:20 federation throttled[22393]:   File "/usr/bin/throttled", line 554, in power_thread
May 13 13:30:20 federation throttled[22393]:     writemsr(0x64B, write_value)
May 13 13:30:20 federation throttled[22393]:   File "/usr/bin/throttled", line 121, in writemsr
May 13 13:30:20 federation throttled[22393]:     raise e
May 13 13:30:20 federation throttled[22393]:   File "/usr/bin/throttled", line 112, in writemsr
May 13 13:30:20 federation throttled[22393]:     os.write(f, struct.pack('Q', val))
May 13 13:30:20 federation throttled[22393]: OSError: [Errno 5] Input/output error
May 13 13:30:30 federation systemd[1]: Stopping Stop Intel throttling...
May 13 13:30:30 federation systemd[1]: throttled.service: Main process exited, code=killed, status=15/TERM
May 13 13:30:30 federation systemd[1]: throttled.service: Succeeded.

Let me know if I can provide any other information that would be useful for tracking this down

[erpalma]

Do you have secure boot enabled?

[tobimat80]

I have the same issue with my DELL Precision 5530 (i9-8950HK). Secure boot is disabled. Running Ubuntu 18.04.2 LTS

[erpalma]

Hmm strange. Does /dev/cpu/0/msr exist?

[tobimat80]

Yes:

crw------- 1 root root 202, 0 Mai 14 10:32 /dev/cpu/0/msr

[dgllghr]

I can confirm that my secure boot is also disabled and /dev/cpu/0/msr exists for me too

[LoipesMas]

DELL Latitude e6540, same issue. Secure boot disabled, /dev/cpu/0/msr exists, Debian 10

[erpalma]

Does wrmsr works?

[LoipesMas]

wrmsr 0x64b 0x80000000 results in wrmsr: CPU 0 cannot set MSR 0x0000064b to 0x0000000080000000, even after modprobe msr.

[Firenox89]

I also own a Dell XPS 9575 running Arch on it. The thing is not that I can't write to msr at all, but just not to 0x64b. Writing to 0x150 and 0x1a2 works fine.

[Firenox89]

➜  ~ sudo rdmsr 0 0x64b                                                                           
[sudo] password for root: 
0x0000000080000000

If I read the Intel docu correctly, this value means that the TDP config is locked...