linux-kernel - [PATCH v3 01/18] cpufreq/amd-pstate: Invalidate cppc_req

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Message-ID: <20250217220707.1468365-2-superm1@kernel.org>
Date: Mon, 17 Feb 2025 16:06:50 -0600
From: Mario Limonciello <superm1@...nel.org>
To: "Gautham R . Shenoy" <gautham.shenoy@....com>,
	Perry Yuan <perry.yuan@....com>
Cc: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>,
	linux-kernel@...r.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	linux-pm@...r.kernel.org (open list:CPU FREQUENCY SCALING FRAMEWORK),
	Mario Limonciello <mario.limonciello@....com>,
	Miroslav Pavleski <miroslav@...leski.net>
Subject: [PATCH v3 01/18] cpufreq/amd-pstate: Invalidate cppc_req_cached during suspend

From: Mario Limonciello <mario.limonciello@....com>

During resume it's possible the firmware didn't restore the CPPC request MSR
but the kernel thinks the values line up. This leads to incorrect performance
after resume from suspend.

To fix the issue invalidate the cached value at suspend. During resume use
the saved values programmed as cached limits.

Reported-by: Miroslav Pavleski <miroslav@...leski.net>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217931
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 drivers/cpufreq/amd-pstate.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index f425fb7ec77d7..12fb63169a24c 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1611,7 +1611,7 @@ static int amd_pstate_epp_reenable(struct cpufreq_policy *policy)
 					  max_perf, policy->boost_enabled);
 	}
 
-	return amd_pstate_update_perf(cpudata, 0, 0, max_perf, cpudata->epp_cached, false);
+	return amd_pstate_epp_update_limit(policy);
 }
 
 static int amd_pstate_epp_cpu_online(struct cpufreq_policy *policy)
@@ -1660,6 +1660,9 @@ static int amd_pstate_epp_suspend(struct cpufreq_policy *policy)
 	if (cppc_state != AMD_PSTATE_ACTIVE)
 		return 0;
 
+	/* invalidate to ensure it's rewritten during resume */
+	cpudata->cppc_req_cached = 0;
+
 	/* set this flag to avoid setting core offline*/
 	cpudata->suspended = true;
 
-- 
2.43.0