From 2368dd5e22684616c60628378a27ff58db0fc922 Mon Sep 17 00:00:00 2001
From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Date: Wed, 26 May 2021 10:10:50 +0800
Subject: [PATCH] cpufreq: intel_pstate: Also use CPPC nominal_perf for
base_frequency
mainline inclusion
from mainline-v5.1-rc3
commit 92a3e426ec06e72b1c363179c79d30712447ff76
category: feature
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=44
CVE: NA
-----------------------------------------------
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: 86d333a8cc7f ("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>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
drivers/cpufreq/intel_pstate.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index e4125f404d86..96e2a0875798 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -383,7 +383,10 @@ 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 */
--
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