x86/intel_pstate: Handle runtime turbo disablement/enablement in frequency invariance

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On some platforms such as the Dell XPS 13 laptop the firmware disables turbo
when the machine is disconnected from AC, and viceversa it enables it again
when it's reconnected. In these cases a _PPC ACPI notification is issued.

The scheduler needs to know freq_max for frequency-invariant calculations.
To account for turbo availability to come and go, record freq_max at boot as
if turbo was available and store it in a helper variable. Use a setter
function to swap between freq_base and freq_max every time turbo goes off or on.

Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lkml.kernel.org/r/20200122151617.531-7-ggherdovich@suse.cz

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Giovanni Gherdovich 2020-01-22 16:16:17 +01:00 • committed by Ingo Molnar

parent 298c6f99bf

commit 918229cdd5

3 changed files with 16 additions and 5 deletions

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5

arch/x86/include/asm/topology.h

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15

arch/x86/kernel/smpboot.c

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1

drivers/cpufreq/intel_pstate.c

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