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AAEONAEU-SW edited this page Nov 26, 2020 · 1 revision

WARNING: On UP Squared and UP Core Plus MWAIT is disabled by default (and so Intel_Idle driver) by the OS configuration "Intel Linux" due to a Intel SoC SKU bug where MWAIT is unreliable and it can cause long boot time and other issues.

If you want to use MWAIT anyway, at your own risk, you can switch the OS configuration under the Boot Menu to "Windows" and then follow the next steps.

On a system with Ubuntu distribution installed, the default configuration should show the following when running the command:

 cat /sys/devices/system/cpu/cpuidle/current_driver

If the driver in use is "acpi_idle", the following steps are necessary to enable the intel_idle driver.

BIOS settings update

We need to enable MWAIT in the BIOS With admin password:upassw0rd

CRB Setup -> CRB Advanced -> CPU Configuration -> Enable Monitor Mwait, as shown below

Then boot into Ubuntu and with sudo edit (or vim) /etc/default/grub, and edit the GRUB_CMDLINE_LINUX_DEFAULT line adding

Verify MWAIT enabled

With the command:

 cat /sys/devices/system/cpu/cpuidle/current_driver

The output now should be "intel_idle"

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