Hardware bad report only after hibernation

Hi all,

I got the following message if, and only if, after ~2 min resuming from hibernation on my lenovo yoga 520:

  591.578557] Uhhuh. NMI received for unknown reason 21 on CPU 0.
  591.578557] Do you have a strange power saving mode enabled?
  591.578557] Dazed and confused, but trying to continue

From what I have researched, it seems to be a warning on hardware malfunction. However, it only appears after hibernation and only once. And I can work normally.

Suspend and reboot works normally.
It is a message that appears only once, it only occurs after resuming from hibernation, and it doesn’t seem to affect at all my system.

Any ideas on what might be the cause of that? Is it something I should care about (e.g. regarding my hardware)?


The malfunction might be that some hardware does not hibernate properly.


I have found what I think might be a correlation.

I disabled the following option on my tlc configuration and the problem disappeared:

# Set energy performance hints (HWP) for Intel P-state governor:
#   default, performance, balance_performance, balance_power, power
# Values are given in order of increasing power saving.
# Note: Intel Skylake or newer CPU and Kernel >= 4.10 required.

Once I activate it back (uncommenting), the problem returns.

What might be the problem?
Should I report it as a Bug?

Yes be sure to list your hardware ie CPU GPU model etc