The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From da5e79bc70b84971d2b3a55fb252e34e51d81d48 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" rafael.j.wysocki@intel.com Date: Mon, 15 Oct 2018 23:21:05 +0200 Subject: [PATCH] cpufreq: conservative: Take limits changes into account properly
If the policy limits change between invocations of cs_dbs_update(), the requested frequency value stored in dbs_info may not be updated and the function may use a stale value of it next time. Moreover, if idle periods are takem into account by cs_dbs_update(), the requested frequency value stored in dbs_info may be below the min policy limit, which is incorrect.
To fix these problems, always update the requested frequency value in dbs_info along with the local copy of it when the previous requested frequency is beyond the policy limits and avoid decreasing the requested frequency below the min policy limit when taking idle periods into account.
Fixes: abb6627910a1 (cpufreq: conservative: Fix next frequency selection) Fixes: 00bfe05889e9 (cpufreq: conservative: Decrease frequency faster for deferred updates) Reported-by: Waldemar Rymarkiewicz waldemarx.rymarkiewicz@intel.com Cc: All applicable stable@vger.kernel.org Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Acked-by: Waldemar Rymarkiewicz waldemarx.rymarkiewicz@intel.com Acked-by: Viresh Kumar viresh.kumar@linaro.org
diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c index f20f20a77d4d..4268f87e99fc 100644 --- a/drivers/cpufreq/cpufreq_conservative.c +++ b/drivers/cpufreq/cpufreq_conservative.c @@ -80,8 +80,10 @@ static unsigned int cs_dbs_update(struct cpufreq_policy *policy) * changed in the meantime, so fall back to current frequency in that * case. */ - if (requested_freq > policy->max || requested_freq < policy->min) + if (requested_freq > policy->max || requested_freq < policy->min) { requested_freq = policy->cur; + dbs_info->requested_freq = requested_freq; + }
freq_step = get_freq_step(cs_tuners, policy);
@@ -92,7 +94,7 @@ static unsigned int cs_dbs_update(struct cpufreq_policy *policy) if (policy_dbs->idle_periods < UINT_MAX) { unsigned int freq_steps = policy_dbs->idle_periods * freq_step;
- if (requested_freq > freq_steps) + if (requested_freq > policy->min + freq_steps) requested_freq -= freq_steps; else requested_freq = policy->min;