Commit 92a3e426 authored by Srinivas Pandruvada's avatar Srinivas Pandruvada Committed by Rafael J. Wysocki

cpufreq: intel_pstate: Also use CPPC nominal_perf for base_frequency

The ACPI specification states that if the "Guaranteed Performance
Register" is not implemented, the OSPM assumes guaranteed performance
to always be equal to nominal performance.

So for invalid or unimplemented guaranteed performance register, use
nominal performance as guaranteed performance.

This change will fall back to nominal_perf when guranteed_perf is
invalid.  If nominal_perf is also invalid or not present, fall back
to the existing implementation, which is to read from HWP Capabilities
MSR.

Fixes: 86d333a8 ("cpufreq: intel_pstate: Add base_frequency attribute")
Suggested-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 4.20+ <stable@vger.kernel.org> # 4.20+
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent edef1ef1
......@@ -385,7 +385,10 @@ static int intel_pstate_get_cppc_guranteed(int cpu)
if (ret)
return ret;
if (cppc_perf.guaranteed_perf)
return cppc_perf.guaranteed_perf;
return cppc_perf.nominal_perf;
}
#else /* CONFIG_ACPI_CPPC_LIB */
......
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