Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | [PATCH v2 3/3] cpufreq: intel_pstate: Fix intel_pstate_verify_policy() | Date | Wed, 01 Mar 2017 00:11:05 +0100 |
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The code added to intel_pstate_verify_policy() by commit 1443ebbacfd7 (cpufreq: intel_pstate: Fix sysfs limits enforcement for performance policy) should use perf_limits instead of limits, because otherwise setting global limits via sysfs may affect policies inconsistently.
For example, in the sequence of shell commands below, the scaling_min_freq attribute for policy1 and policy2 should be affected in the same way, because scaling_governor is set in the same way for both of them:
# cat cpufreq/policy1/scaling_governor powersave # cat cpufreq/policy2/scaling_governor powersave # echo performance > cpufreq/policy0/scaling_governor # echo 94 > intel_pstate/min_perf_pct # cat cpufreq/policy0/scaling_min_freq 2914000 # cat cpufreq/policy1/scaling_min_freq 2914000 # cat cpufreq/policy2/scaling_min_freq 800000
The are affected differently, because intel_pstate_verify_policy() is invoked with limits set to &performance_limits (left behind by policy0) for policy1 and with limits set to &powersave_limits (left behind by policy1) for policy2. Since perf_limits is set to the set of limits matching the policy being updated, using it instead of limits fixes the inconsistency.
Fixes: 1443ebbacfd7 (cpufreq: intel_pstate: Fix sysfs limits enforcement for performance policy) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> --- drivers/cpufreq/intel_pstate.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
Index: linux-pm/drivers/cpufreq/intel_pstate.c =================================================================== --- linux-pm.orig/drivers/cpufreq/intel_pstate.c +++ linux-pm/drivers/cpufreq/intel_pstate.c @@ -2208,9 +2208,9 @@ static int intel_pstate_verify_policy(st unsigned int max_freq, min_freq; max_freq = policy->cpuinfo.max_freq * - limits->max_sysfs_pct / 100; + perf_limits->max_sysfs_pct / 100; min_freq = policy->cpuinfo.max_freq * - limits->min_sysfs_pct / 100; + perf_limits->min_sysfs_pct / 100; cpufreq_verify_within_limits(policy, min_freq, max_freq); }
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