With Intel's recently-launched [1]Bartlett Lake P-core-only processors intended for the embedded market, there is a rather surprising oversight under Linux: the Intel P-State driver reporting a 7.0+ GHz clock speed. While many would yearn for a 7GHz CPU, the Core 9 273PE where this issue was discovered in reality can only boost up to 5.7GHz for its maximum turbo frequency.

A QNAP engineer has been posting patches this week for the Intel P-State driver to correct the scaling factor for the Bartlett Lake P-core processors. QNAP engineer Henry Tseng sums up simply:

"On Bartlett Lake P-core only SKUs (e.g. Intel Core 9 273PE), cpuinfo_max_freq is reported as 7.0/7.3 GHz, exceeding the datasheet Max Turbo Frequency of 5.7 GHz."

This comes down to the wrong CPU scaling factor being propagated for Bartlett Lake processors. A six line patch to the Intel P-State CPU frequency scaling driver is then able to report the correct scaling factor and in turn the correct maximum frequencies for these P-core-only processors.

[2]

With Intel Bartlett Lake catering to the embedded market and edge computing where Linux is heavily used, it's surprising this issue was only uncovered and being patched now after these P-core CPUs are already shipping to customers. More so, surprising it's a QNAP engineer taking to getting this Linux kernel driver issue fixed rather than Intel engineers.

[3]

In any event, if you happen to have your hands on Intel Bartlett Lake, [4]this patch series is what's being worked on for reporting the correct maximum frequency.



[1] https://www.phoronix.com/search/Bartlett+Lake

[2] https://www.phoronix.com/image-viewer.php?id=2026&image=intel_bartlett_lake_1_lrg

[3] https://www.phoronix.com/image-viewer.php?id=2026&image=intel_bartlett_lake_2_lrg

[4] https://lore.kernel.org/linux-pm/20260508063032.3248602-1-henrytseng@qnap.com/