linux-kernel - [PATCH v5 19/19] cpufreq/amd-pstate: Drop actions in amd_pstate_epp_cpu

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Message-ID: <20250226074934.1667721-20-superm1@kernel.org>
Date: Wed, 26 Feb 2025 01:49:34 -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>,
	Dhananjay Ugwekar <dhananjay.ugwekar@....com>
Subject: [PATCH v5 19/19] cpufreq/amd-pstate: Drop actions in amd_pstate_epp_cpu_offline()

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

When the CPU goes offline there is no need to change the CPPC request
because the CPU will go into the deepest C-state it supports already.

Actually changing the CPPC request when it goes offline messes up the
cached values and can lead to the wrong values being restored when
it comes back.

Instead drop the actions and if the CPU comes back online let
amd_pstate_epp_set_policy() restore it to expected values.

Reviewed-by: Dhananjay Ugwekar <dhananjay.ugwekar@....com>
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
v5:
 * Reword commit message
 * Add tag
---
 drivers/cpufreq/amd-pstate.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 24a1f9e129b61..4a364ae9b56a1 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1580,14 +1580,7 @@ static int amd_pstate_epp_cpu_online(struct cpufreq_policy *policy)
 
 static int amd_pstate_epp_cpu_offline(struct cpufreq_policy *policy)
 {
-	struct amd_cpudata *cpudata = policy->driver_data;
-	union perf_cached perf = READ_ONCE(cpudata->perf);
-
-	if (cpudata->suspended)
-		return 0;
-
-	return amd_pstate_update_perf(policy, perf.lowest_perf, 0, perf.lowest_perf,
-				      AMD_CPPC_EPP_BALANCE_POWERSAVE, false);
+	return 0;
 }
 
 static int amd_pstate_epp_suspend(struct cpufreq_policy *policy)
-- 
2.43.0