cpufreq: intel_pstate: Avoid using DESIRED_PERF when DEC is enabled

In principle, the desired performance level can be set in MSR_HWP_REQUEST
to indicate to the processor what performance level the OS would like
the given CPU to run at, but if the Dynamic Efficiency Control (DEC)
feature is enabled in the processor, doing so may result in confusing
the processor firmware.  It is then better to let the processor firmware
figure out the most suitable performance level by itself.

Accordingly, make intel_pstate always set the desired performance level
to zero (which means "no preference") when running on a platform with
DEC enabled.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/4758098.LvFx2qVVIh@rafael.j.wysocki
This commit is contained in:
Rafael J. Wysocki 2026-08-05 14:18:11 +02:00
commit d657aa1b8e