linux-kernel - [PATCH AUTOSEL 4.19 21/26] cpufreq: intel_pstate: Fix intel_pstate_get_hwp

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Message-Id: <20200907163426.1281284-21-sashal@kernel.org>
Date:   Mon,  7 Sep 2020 12:34:21 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Francisco Jerez <currojerez@...eup.net>,
        Caleb Callaway <caleb.callaway@...el.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Sasha Levin <sashal@...nel.org>, linux-pm@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 21/26] cpufreq: intel_pstate: Fix intel_pstate_get_hwp_max() for turbo disabled

From: Francisco Jerez <currojerez@...eup.net>

[ Upstream commit eacc9c5a927e474c173a5d53dd7fb8e306511768 ]

This fixes the behavior of the scaling_max_freq and scaling_min_freq
sysfs files in systems which had turbo disabled by the BIOS.

Caleb noticed that the HWP is programmed to operate in the wrong
P-state range on his system when the CPUFREQ policy min/max frequency
is set via sysfs.  This seems to be because in his system
intel_pstate_get_hwp_max() is returning the maximum turbo P-state even
though turbo was disabled by the BIOS, which causes intel_pstate to
scale kHz frequencies incorrectly e.g. setting the maximum turbo
frequency whenever the maximum guaranteed frequency is requested via
sysfs.

Tested-by: Caleb Callaway <caleb.callaway@...el.com>
Signed-off-by: Francisco Jerez <currojerez@...eup.net>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
[ rjw: Minor subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/cpufreq/intel_pstate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 8fa22aa2ac65b..864a7e8ebdfc3 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -712,7 +712,7 @@ static void intel_pstate_get_hwp_max(unsigned int cpu, int *phy_max,
 
 	rdmsrl_on_cpu(cpu, MSR_HWP_CAPABILITIES, &cap);
 	WRITE_ONCE(all_cpu_data[cpu]->hwp_cap_cached, cap);
-	if (global.no_turbo)
+	if (global.no_turbo || global.turbo_disabled)
 		*current_max = HWP_GUARANTEED_PERF(cap);
 	else
 		*current_max = HWP_HIGHEST_PERF(cap);
-- 
2.25.1