cpufreq: intel_pstate: Also use CPPC nominal_perf for base_frequency

spandruvada · rafaeljw · commit 92a3e426ec06 · 2019-03-25T23:57:21.000+01:00
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: 86d333a ("cpufreq: intel_pstate: Add base_frequency attribute") Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: 4.20+ <stable@vger.kernel.org> # 4.20+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
@@ -385,7 +385,10 @@ static int intel_pstate_get_cppc_guranteed(int cpu)
 	if (ret)
 		return ret;
 
-	return cppc_perf.guaranteed_perf;
+	if (cppc_perf.guaranteed_perf)
+		return cppc_perf.guaranteed_perf;
+
+	return cppc_perf.nominal_perf;
 }
 
 #else /* CONFIG_ACPI_CPPC_LIB */
