linux-kernel - [PATCH v2] cpufreq/amd-pstate: Fix the return value of amd_pstate_fast

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Date:   Mon, 27 Nov 2023 16:41:21 +0530
From:   "Gautham R. Shenoy" <gautham.shenoy@....com>
To:     Wyes Karny <wyes.karny@....com>, Huang Rui <ray.huang@....com>,
        "Mario Limonciello" <mario.limonciello@....com>,
        Perry Yuan <Perry.Yuan@....com>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>
CC:     <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Gautham R. Shenoy" <gautham.shenoy@....com>,
        Perry Yuan <perry.yuan@....com>, <stable@...r.kernel.org>
Subject: [PATCH v2] cpufreq/amd-pstate: Fix the return value of amd_pstate_fast_switch()

cpufreq_driver->fast_switch() callback expects a frequency as a return
value. amd_pstate_fast_switch() was returning the return value of
amd_pstate_update_freq(), which only indicates a success or failure.

Fix this by making amd_pstate_fast_switch() return the target_freq
when the call to amd_pstate_update_freq() is successful, and return
the current frequency from policy->cur when the call to
amd_pstate_update_freq() is unsuccessful.

Fixes: 4badf2eb1e98 ("cpufreq: amd-pstate: Add ->fast_switch() callback")
Acked-by: Huang Rui <ray.huang@....com>
Reviewed-by: Wyes Karny <wyes.karny@....com>
Reviewed-by: Perry Yuan <perry.yuan@....com>
Cc: stable@...r.kernel.org # v6.4+
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@....com>
---
 drivers/cpufreq/amd-pstate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 9a1e194d5cf8..300f81d36291 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -518,7 +518,9 @@ static int amd_pstate_target(struct cpufreq_policy *policy,
 static unsigned int amd_pstate_fast_switch(struct cpufreq_policy *policy,
 				  unsigned int target_freq)
 {
-	return amd_pstate_update_freq(policy, target_freq, true);
+	if (!amd_pstate_update_freq(policy, target_freq, true))
+		return target_freq;
+	return policy->cur;
 }
 
 static void amd_pstate_adjust_perf(unsigned int cpu,
-- 
2.25.1