6.4-stable review patch. If anyone has any objections, please let me know.
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From: Doug Smythies dsmythies@telus.net
commit d51847acb018d83186e4af67bc93f9a00a8644f7 upstream.
The intel_pstate CPU frequency scaling driver does not use policy->cur and it is 0. When the CPU frequency is outdated arch_freq_get_on_cpu() will default to the nominal clock frequency when its call to cpufreq_quick_getpolicy_cur returns the never updated 0. Thus, the listed frequency might be outside of currently set limits. Some users are complaining about the high reported frequency, albeit stale, when their system is idle and/or it is above the reduced maximum they have set.
This patch will maintain policy_cur for the intel_pstate driver at the current minimum CPU frequency.
Reported-by: Yang Jie yang.jie@linux.intel.com Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217597 Signed-off-by: Doug Smythies dsmythies@telus.net [ rjw: White space damage fixes and comment adjustment ] Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Keyon Jie yang.jie@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/cpufreq/intel_pstate.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -2570,6 +2570,11 @@ static int intel_pstate_set_policy(struc intel_pstate_clear_update_util_hook(policy->cpu); intel_pstate_hwp_set(policy->cpu); } + /* + * policy->cur is never updated with the intel_pstate driver, but it + * is used as a stale frequency value. So, keep it within limits. + */ + policy->cur = policy->min;
mutex_unlock(&intel_pstate_limits_lock);