linux-kernel - [PATCH 2/2] cpufreq: arm_scmi: Set fast_switch

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200617094332.8391-2-nicola.mazzucato@arm.com>
Date:   Wed, 17 Jun 2020 10:43:32 +0100
From:   Nicola Mazzucato <nicola.mazzucato@....com>
To:     linux-kernel@...r.kernel.org, sudeep.holla@....com,
        rjw@...ysocki.net, viresh.kumar@...aro.org,
        linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org
Cc:     lukasz.luba@....com
Subject: [PATCH 2/2] cpufreq: arm_scmi: Set fast_switch_possible conditionally

Currently the fast_switch_possible flag is set unconditionally
to true. Based on this, schedutil does not create a
thread for frequency switching and would always use the
fast switch path.
However, if the platform does not support frequency
fast switch, this may cause the governor to attempt an
operation that is not supported by the platform.

Fix this by correctly retrieve the fast_switch capability
from the driver which knows if the platform can support
this feature.

Suggested-by: Lukasz Luba <lukasz.luba@....com>
Signed-off-by: Nicola Mazzucato <nicola.mazzucato@....com>
---
 drivers/cpufreq/scmi-cpufreq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/scmi-cpufreq.c b/drivers/cpufreq/scmi-cpufreq.c
index 61623e2ff149..1cf688fcb56b 100644
--- a/drivers/cpufreq/scmi-cpufreq.c
+++ b/drivers/cpufreq/scmi-cpufreq.c
@@ -198,7 +198,8 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy)
 
 	policy->cpuinfo.transition_latency = latency;
 
-	policy->fast_switch_possible = true;
+	policy->fast_switch_possible =
+		handle->perf_ops->fast_switch_possible(handle, cpu_dev);
 
 	em_register_perf_domain(policy->cpus, nr_opp, &em_cb);
 
-- 
2.27.0