cpufreq: intel_pstate: Get per-CPU max freq via MSR_HWP_CAPABILITIES if available

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Currently, when turbo is disabled (either by BIOS or by the user),
the intel_pstate driver reads the max non-turbo frequency from the
package-wide MSR_PLATFORM_INFO(0xce) register.

However, on asymmetric platforms it is possible in theory that small
and big core with HWP enabled might have different max non-turbo CPU
frequency, because MSR_HWP_CAPABILITIES is per-CPU scope according
to Intel Software Developer Manual.

The turbo max freq is already per-CPU in current code, so make
similar change to the max non-turbo frequency as well.

Reported-by: Wendy Wang <wendy.wang@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
[ rjw: Subject and changelog edits ]
Cc: 4.18+ <stable@vger.kernel.org> # 4.18+: a45ee4d4e1: cpufreq: intel_pstate: Change intel_pstate_get_hwp_max() argument
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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Chen Yu 2021-01-12 13:21:27 +08:00 • committed by Rafael J. Wysocki

parent 597ffbc8d0

commit 6f67e06008

1 changed files with 3 additions and 2 deletions

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drivers/cpufreq/intel_pstate.c

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