4.18-stable review patch. If anyone has any objections, please let me know.
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From: Rafael J. Wysocki rafael.j.wysocki@intel.com
commit da5e79bc70b84971d2b3a55fb252e34e51d81d48 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/cpufreq/cpufreq_conservative.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/cpufreq/cpufreq_conservative.c +++ b/drivers/cpufreq/cpufreq_conservative.c @@ -80,8 +80,10 @@ static unsigned int cs_dbs_update(struct * 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 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;