linux-kernel - [PATCH 2/2] cpufreq/amd-pstate: Catch failures for amd_pstate_epp_update

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Message-ID: <20240901050035.1739935-3-superm1@kernel.org>
Date: Sun,  1 Sep 2024 00:00:35 -0500
From: Mario Limonciello <superm1@...nel.org>
To: "Gautham R . Shenoy" <gautham.shenoy@....com>,
	Perry Yuan <perry.yuan@....com>
Cc: 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>
Subject: [PATCH 2/2] cpufreq/amd-pstate: Catch failures for amd_pstate_epp_update_limit()

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

amd_pstate_set_epp() calls cppc_set_epp_perf() which can fail for
a variety of reasons but this is ignored.  Change the return flow
to allow failures.

Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 drivers/cpufreq/amd-pstate.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 89438a3654002..b07be4d945e4d 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1556,7 +1556,7 @@ static void amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)
 	pr_debug("CPU %d exiting\n", policy->cpu);
 }
 
-static void amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
+static int amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
 {
 	struct amd_cpudata *cpudata = policy->driver_data;
 	u32 max_perf, min_perf, min_limit_perf, max_limit_perf;
@@ -1606,7 +1606,7 @@ static void amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
 		 * This return value can only be negative for shared_memory
 		 * systems where EPP register read/write not supported.
 		 */
-		return;
+		return epp;
 	}
 
 	if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
@@ -1619,12 +1619,13 @@ static void amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
 	}
 
 	WRITE_ONCE(cpudata->cppc_req_cached, value);
-	amd_pstate_set_epp(cpudata, epp);
+	return amd_pstate_set_epp(cpudata, epp);
 }
 
 static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
 {
 	struct amd_cpudata *cpudata = policy->driver_data;
+	int ret;
 
 	if (!policy->cpuinfo.max_freq)
 		return -ENODEV;
@@ -1634,7 +1635,9 @@ static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
 
 	cpudata->policy = policy->policy;
 
-	amd_pstate_epp_update_limit(policy);
+	ret = amd_pstate_epp_update_limit(policy);
+	if (ret)
+		return ret;
 
 	/*
 	 * policy->cur is never updated with the amd_pstate_epp driver, but it
-- 
2.43.0