linux-kernel - [PATCH v3 3/6] cpufreq: amd-pstate: Move cpufreq driver check later

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Date:   Thu, 14 Apr 2022 11:47:58 -0500
From:   Mario Limonciello <mario.limonciello@....com>
To:     Rui Huang <ray.huang@....com>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>
CC:     "open list:AMD PSTATE DRIVER" <linux-pm@...r.kernel.org>,
        Perry Yuan <Perry.Yuan@....com>,
        open list <linux-kernel@...r.kernel.org>,
        "Mario Limonciello" <mario.limonciello@....com>
Subject: [PATCH v3 3/6] cpufreq: amd-pstate: Move cpufreq driver check later

The cpufreq driver check occurs before we verify if the CPU is supported.

Depending upon module load order, this may mean that users are never
notified they can enable the shared memory solution.

Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
v2->v3:
 * New patch

 drivers/cpufreq/amd-pstate.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index ecd1fd5e5b5a..d323f3e3888c 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -653,10 +653,6 @@ static int __init amd_pstate_init(void)
 		return -ENODEV;
 	}
 
-	/* don't keep reloading if cpufreq_driver exists */
-	if (cpufreq_get_current_driver())
-		return -EEXIST;
-
 	/* capability check */
 	if (boot_cpu_has(X86_FEATURE_CPPC)) {
 		pr_debug("AMD CPPC MSR based functionality is supported\n");
@@ -670,6 +666,10 @@ static int __init amd_pstate_init(void)
 		return -ENODEV;
 	}
 
+	/* don't keep reloading if cpufreq_driver exists */
+	if (cpufreq_get_current_driver())
+		return -EEXIST;
+
 	/* enable amd pstate feature */
 	ret = amd_pstate_enable(true);
 	if (ret) {
-- 
2.34.1